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| author | EuAndreh <eu@euandre.org> | 2024-11-18 08:21:58 -0300 |
|---|---|---|
| committer | EuAndreh <eu@euandre.org> | 2024-11-18 08:44:57 -0300 |
| commit | 960e4410f76801356ebd42801c914b2910a302a7 (patch) | |
| tree | 615d379416f72956d0c1666c63ce062859041fbe /_tils | |
| parent | Remove jekyll infrastructure setup (diff) | |
| download | euandre.org-960e4410f76801356ebd42801c914b2910a302a7.tar.gz euandre.org-960e4410f76801356ebd42801c914b2910a302a7.tar.xz | |
v0 migration to mkwb
Diffstat (limited to '_tils')
24 files changed, 0 insertions, 2132 deletions
diff --git a/_tils/2020-08-12-nome-de-arquivo-com-timestamp-simplificado.md b/_tils/2020-08-12-nome-de-arquivo-com-timestamp-simplificado.md deleted file mode 100644 index 2e7fc32..0000000 --- a/_tils/2020-08-12-nome-de-arquivo-com-timestamp-simplificado.md +++ /dev/null @@ -1,45 +0,0 @@ ---- - -title: Nome de arquivo com timestamp simplificado - -date: 2020-08-12 - -updated_at: 2020-11-04 - -layout: post - -lang: pt - -ref: simple-filename-timestamp - -eu_categories: shell - ---- - -Quando vou escrever um post no Jekyll ou criar um arquivo de log com a data no -nome, eu normalmente engasgo para achar um jeito direto de fazer isso. Há uma -solução simples: `date -I`. - -```shell -./meu-programa.sh > meu-programa.$(date -I).log -cp template-de-post.md _posts/$(date -I)-slug-do-post.md -``` - -Usar essa ferramenta padrão do GNU/Linux permite que você simplesmente escreva -`touch $(date -I).md` para criar um arquivo `2020-08-12.md`. - -Eu sempre tinha que parar para reler o `man date` ou buscar na internet de novo -e de novo como fazer isso, e depois de sempre chegar no mesmo resultado ficou -claro para mim que `date -I` quanto `date -Is` (`s` de segundos) são as -respostas que eu estou procurando 95% do tempo: - -```shell -# dentro do meu-programa.sh -echo "Programa começou em $(date -Is)" -# saída é: -# Programa começou em 2020-08-12T09:15:16-03:00 -``` - -Ambos os formatos de data são hierárquicos, com intervalos de tempo maior à -esquerda. Isso significa que você pode facilmente ordená-los (e até usar TAB -para completar) sem esforço ou ferramenta extra. diff --git a/_tils/2020-08-12-simple-filename-timestamp.md b/_tils/2020-08-12-simple-filename-timestamp.md deleted file mode 100644 index 7495fc9..0000000 --- a/_tils/2020-08-12-simple-filename-timestamp.md +++ /dev/null @@ -1,44 +0,0 @@ ---- - -title: Simple filename timestamp - -date: 2020-08-12 - -updated_at: - -layout: post - -lang: en - -ref: simple-filename-timestamp - -eu_categories: shell - ---- - -When writing Jekyll posts or creating log files with dates on them, I usually -struggle with finding a direct way of accomplishing that. There's a simple -solution: `date -I`. - -```shell -./my-program.sh > my-program.$(date -I).log -cp post-template.md _posts/$(date -I)-post-slug.md -``` - -Using this built-in GNU/Linux tool allows you to `touch $(date -I).md` to readily -create a `2020-08-12.md` file. - -I always had to read `man date` or search the web over and over, and after doing -this repeatedly it became clear that both `date -I` and `date -Is` (`s` here -stands for seconds) are the thing that I'm looking for 95% of the time: - -```shell -# inside my-program.sh -echo "Program started at $(date -Is)" -# output is: -# Program started at 2020-08-12T09:04:58-03:00 -``` - -Both date formats are hierarchical, having the bigger time intervals to the -left. This means that you can easily sort them (and even tab-complete them) with -no extra effort or tool required. diff --git a/_tils/2020-08-13-anchor-headers-and-code-lines-in-jekyll.md b/_tils/2020-08-13-anchor-headers-and-code-lines-in-jekyll.md deleted file mode 100644 index 6566928..0000000 --- a/_tils/2020-08-13-anchor-headers-and-code-lines-in-jekyll.md +++ /dev/null @@ -1,155 +0,0 @@ ---- -title: Anchor headers and code lines in Jekyll -date: 2020-08-13 -layout: post -lang: en -ref: anchor-headers-and-code-lines-in-jekyll ---- -The default Jekyll toolbox ([Jekyll][0], [kramdown][1] and [rouge][2]) doesn't -provide with a configuration option to add anchors to headers and code blocks. - -[0]: https://jekyllrb.com/ -[1]: https://kramdown.gettalong.org/ -[2]: http://rouge.jneen.net/ - -The best way I found of doing this is by creating a simple Jekyll plugin, more -specifically, a [Jekyll hook][3]. These allow you to jump in to the Jekyll build -and add a processing stage before of after Jekyll performs something. - -[3]: https://jekyllrb.com/docs/plugins/hooks/ - -All you have to do is add the code to `_plugins/my-jekyll-plugin-code.rb`, and -Jekyll knows to pick it up and call your code on the appropriate time. - -## Anchor on headers - -Since I wanted to add anchors to headers in all documents, this Jekyll hook -works on `:documents` after they have been transformed into HTML, the -`:post_render` phase: - -```ruby -Jekyll::Hooks.register :documents, :post_render do |doc| - if doc.output_ext == ".html" - doc.output = - doc.output.gsub( - /<h([1-6])(.*?)id="([\w-]+)"(.*?)>(.*?)<\/h[1-6]>/, - '<a href="#\3"><h\1\2id="\3"\4>\5</h\1></a>' - ) - end -end -``` - -I've derived my implementations from two "official"[^official] hooks, -[jemoji][4] and [jekyll-mentions][5]. - -[4]: https://github.com/jekyll/jemoji -[5]: https://github.com/jekyll/jekyll-mentions -[^official]: I don't know how official they are, I just assumed it because they - live in the same organization inside GitHub that Jekyll does. - -All I did was to wrap the header tag inside an `<a>`, and set the `href` of that -`<a>` to the existing id of the header. Before the hook the HTML looks like: - -```html -...some unmodified text... -<h2 id="my-header"> - My header -</h2> -...more unmodified text... -``` - -And after the hook should turn that into: - -```html -...some unmodified text... -<a href="#my-header"> - <h2 id="my-header"> - My header - </h2> -</a> -...more unmodified text... -``` - -The used regexp tries to match only h1-h6 tags, and keep the rest of the HTML -attributes untouched, since this isn't a general HTML parser, but the generated HTML -is somewhat under your control. Use at your own risk because -[you shouldn't parse HTML with regexps][6]. Also I used this strategy in my -environment, where no other plugins are installed. I haven't considered how this -approach may conflict with other Jekyll plugins. - -[6]: https://stackoverflow.com/questions/1732348/regex-match-open-tags-except-xhtml-self-contained-tags/1732454#1732454 - -In the new anchor tag you can add your custom CSS class to style it as you wish. - -## Anchor on code blocks - -Adding anchors to code blocks needs a little bit of extra work, because line -numbers themselves don't have preexisting ids, so we need to generate them -without duplications between multiple code blocks in the same page. - -Similarly, this Jekyll hook also works on `:documents` in the `:post_render` -phase: - -```ruby -PREFIX = '<pre class="lineno">' -POSTFIX = '</pre>' -Jekyll::Hooks.register :documents, :post_render do |doc| - if doc.output_ext == ".html" - code_block_counter = 1 - doc.output = doc.output.gsub(/<pre class="lineno">[\n0-9]+<\/pre>/) do |match| - line_numbers = match - .gsub(/<pre class="lineno">([\n0-9]+)<\/pre>/, '\1') - .split("\n") - - anchored_line_numbers_array = line_numbers.map do |n| - id = "B#{code_block_counter}-L#{n}" - "<a id=\"#{id}\" href=\"##{id}\">#{n}</a>" - end - code_block_counter += 1 - - PREFIX + anchored_line_numbers_array.join("\n") + POSTFIX - end - end -end -``` - -This solution assumes the default Jekyll toolbox with code line numbers turned -on in `_config.yml`: - -```yaml -kramdown: - syntax_highlighter_opts: - span: - line_numbers: false - block: - line_numbers: true -``` - -The anchors go from B1-L1 to BN-LN, using the `code_block_counter` to track -which code block we're in and don't duplicate anchor ids. Before the hook the -HTML looks like: - -```html -...some unmodified text... -<pre class="lineno">1 -2 -3 -4 -5 -</pre> -...more unmodified text... -``` - -And after the hook should turn that into: - -```html -...some unmodified text... -<pre class="lineno"><a id="B1-L1" href="#B1-L1">1</a> -<a id="B1-L2" href="#B1-L2">2</a> -<a id="B1-L3" href="#B1-L3">3</a> -<a id="B1-L4" href="#B1-L4">4</a> -<a id="B1-L5" href="#B1-L5">5</a></pre> -...more unmodified text... -``` - -Happy writing :) diff --git a/_tils/2020-08-14-browse-a-git-repository-at-a-specific-commit.md b/_tils/2020-08-14-browse-a-git-repository-at-a-specific-commit.md deleted file mode 100644 index d06f0c1..0000000 --- a/_tils/2020-08-14-browse-a-git-repository-at-a-specific-commit.md +++ /dev/null @@ -1,84 +0,0 @@ ---- - -title: Browse a git repository at a specific commit - -date: 2020-08-14 - -layout: post - -lang: en - -ref: browse-a-git-repository-at-a-specific-commit - -eu_categories: git - ---- - -I commonly use tools like `git log` together with `git show` when inspecting -past changes in a repository: - -```shell -git log -# search for a the commit I'm looking for -git show <my-commit> -# see the diff for the commit -``` - -But I also wanted to not only be able to look at the diff of a specific commit, -but to browse the whole repository at that specific commit. - -I used to accomplish it the "brute force" way: clone the whole repository in -another folder and checkout the commit there: - -```shell -git clone <original-repo> /tmp/tmp-repo-clone -cd /tmp-repo-clone -git checkout <my-commit> -``` - -But git itself allows we to specific the directory of the checkout by using the -`--work-tree` global git flag. This is what `man git` says about it: - -```txt ---work-tree=<path> - Set the path to the working tree. It can be an absolute path or a path relative to the current working - directory. This can also be controlled by setting the GIT_WORK_TREE environment variable and the - core.worktree configuration variable (see core.worktree in git-config(1) for a more detailed - discussion). -``` - -So it allows us to set the desired path of the working tree. So if we want to -copy the contents of the current working tree into `copy/`: - -```shell -mkdir copy -git --work-tree=copy/ checkout . -``` - -After that `copy/` will contain a replica of the code in HEAD. But to checkout a -specific, we need some extra parameters: - -```shell -git --work-tree=<dir> checkout <my-commit> -- . -``` - -There's an extra `-- .` at the end, which initially looks like we're sending -Morse signals to git, but we're actually saying to `git-checkout` which -sub directory of `<my-commit>` we want to look at. Which means we can do -something like: - -```shell -git --work-tree=<dir> checkout <my-commit> -- src/ -``` - -And with that `<dir>` will only contain what was inside `src/` at `<commit>`. - -After any of those checkouts, you have to `git reset .` to reset your current -staging area back to what it was before the checkout. - - -## References - -1. [GIT: Checkout to a specific folder][0] (StackOverflow) - -[0]: https://stackoverflow.com/a/16493707 diff --git a/_tils/2020-08-16-search-in-git.md b/_tils/2020-08-16-search-in-git.md deleted file mode 100644 index f3ae6f0..0000000 --- a/_tils/2020-08-16-search-in-git.md +++ /dev/null @@ -1,59 +0,0 @@ ---- - -title: Search in git - -date: 2020-08-16 - -layout: post - -lang: en - -ref: search-in-git - -eu_categories: git - ---- - -Here's a useful trio to know about to help you search things in git: - -1. `git show <commit>` -2. `git log --grep='<regexp>'` -3. `git grep '<regexp>' [commit]` - -## 1. `git show <commit>` - -Show a specific commit and it's diff: - -```shell -git show -# shows the latest commit -git show <commit> -# shows an specific <commit> -git show v1.2 -# shows commit tagged with v1.2 -``` - -## 2. `git log --grep='<regexp>'` - -Search through the commit messages: - -```shell -git log --grep='refactor' -``` - -## 3. `git grep '<regexp>' [commit]` - -Search content in git history: - -```shell -git grep 'TODO' -# search the repository for the "TODO" string -git grep 'TODO' $(git rev-list --all) -# search the whole history for "TODO" string -``` - -And if you find an occurrence of the regexp in a specific commit and you want to -browse the repository in that point in time, you can -[use git checkout for that][0]. - -[0]: {% link _tils/2020-08-14-browse-a-git-repository-at-a-specific-commit.md %} diff --git a/_tils/2020-08-28-grep-online-repositories.md b/_tils/2020-08-28-grep-online-repositories.md deleted file mode 100644 index 8b3b63f..0000000 --- a/_tils/2020-08-28-grep-online-repositories.md +++ /dev/null @@ -1,139 +0,0 @@ ---- - -title: Grep online repositories - -date: 2020-08-28 - -layout: post - -lang: en - -ref: grep-online-repositories - -eu_categories: git - ---- - -I often find interesting source code repositories online that I want to grep for -some pattern but I can't, because either: - -- the repository is on [cgit][cgit] or a similar code repository that doesn't - allow search in files, or; -- the search function is really bad, and doesn't allow me to use regular expressions for searching patterns in the code. - -[cgit]: https://git.zx2c4.com/cgit/ - -Here's a simple script that allows you to overcome that problem easily: - -```shell -#!/usr/bin/env bash -set -eu - -end="\033[0m" -red="\033[0;31m" -red() { echo -e "${red}${1}${end}"; } - -usage() { - red "Missing argument $1.\n" - cat <<EOF -Usage: - $0 <REGEX_PATTERN> <REPOSITORY_URL> - - Arguments: - REGEX_PATTERN Regular expression that "git grep" can search - REPOSITORY_URL URL address that "git clone" can download the repository from - -Examples: - Searching "make get-git" in cgit repository: - git search 'make get-git' https://git.zx2c4.com/cgit/ - git search 'make get-git' https://git.zx2c4.com/cgit/ -- \$(git rev-list --all) -EOF - exit 2 -} - - -REGEX_PATTERN="${1:-}" -REPOSITORY_URL="${2:-}" -[[ -z "${REGEX_PATTERN}" ]] && usage 'REGEX_PATTERN' -[[ -z "${REPOSITORY_URL}" ]] && usage 'REPOSITORY_URL' - -mkdir -p /tmp/git-search -DIRNAME="$(echo "${REPOSITORY_URL%/}" | rev | cut -d/ -f1 | rev)" -if [[ ! -d "/tmp/git-search/${DIRNAME}" ]]; then - git clone "${REPOSITORY_URL}" "/tmp/git-search/${DIRNAME}" -fi -pushd "/tmp/git-search/${DIRNAME}" - -shift 3 || shift 2 # when "--" is missing -git grep "${REGEX_PATTERN}" "${@}" -``` - -It is a wrapper around `git grep` that downloads the repository when missing. -Save in a file called `git-search`, make the file executable and add it to your -path. - -Overview: - -- *lines 1~2*: - - Bash shebang and the `set -eu` options to exit on error or undefined - variables. - -- *lines 4~30*: - - Usage text to be printed when providing less arguments than expected. - -- *line 33*: - - Extract the repository name from the URL, removing trailing slashes. - -- *lines 34~37*: - - Download the repository when missing and go to the folder. - -- *line 39*: - - Make the variable `$@` contain the rest of the unused arguments. - -- *line 40*: - - Perform `git grep`, forwarding the remaining arguments from `$@`. - -Example output: -```shell -$ git search 'make get-git' https://git.zx2c4.com/cgit/ -Clonage dans '/tmp/git-search/cgit'... -remote: Enumerating objects: 542, done. -remote: Counting objects: 100% (542/542), done. -remote: Compressing objects: 100% (101/101), done. -warning: object 51dd1eff1edc663674df9ab85d2786a40f7ae3a5: gitmodulesParse: could not parse gitmodules blob -remote: Total 7063 (delta 496), reused 446 (delta 441), pack-reused 6521 -Réception d'objets: 100% (7063/7063), 8.69 Mio | 5.39 Mio/s, fait. -Résolution des deltas: 100% (5047/5047), fait. -/tmp/git-search/cgit ~/dev/libre/songbooks/docs -README: $ make get-git - -$ git search 'make get-git' https://git.zx2c4.com/cgit/ -/tmp/git-search/cgit ~/dev/libre/songbooks/docs -README: $ make get-git -``` - -Subsequent greps on the same repository are faster because no download is needed. - -When no argument is provided, it prints the usage text: -```shell -$ git search -Missing argument REGEX_PATTERN. - -Usage: - /home/andreh/dev/libre/dotfiles/scripts/ad-hoc/git-search <REGEX_PATTERN> <REPOSITORY_URL> - - Arguments: - REGEX_PATTERN Regular expression that "git grep" can search - REPOSITORY_URL URL address that "git clone" can download the repository from - -Examples: - Searching "make get-git" in cgit repository: - git search 'make get-git' https://git.zx2c4.com/cgit/ - git search 'make get-git' https://git.zx2c4.com/cgit/ -- $(git rev-list --all) -``` diff --git a/_tils/2020-09-04-send-emails-using-the-command-line-for-fun-and-profit.md b/_tils/2020-09-04-send-emails-using-the-command-line-for-fun-and-profit.md deleted file mode 100644 index 320f3ab..0000000 --- a/_tils/2020-09-04-send-emails-using-the-command-line-for-fun-and-profit.md +++ /dev/null @@ -1,80 +0,0 @@ ---- -title: Send emails using the command line for fun and profit! -date: 2020-09-04 -layout: post -lang: en -ref: send-emails-using-the-command-line-for-fun-and-profit ---- -Here are a few reasons why: - -1. send yourself and other people notification of cronjobs, scripts runs, CI - jobs, *etc.* - -2. leverage the POSIX pipe `|`, and pipe emails away! - -3. because you can. - -Reason 3 is the fun part, reasons 1 and 2 are the profit part. - -First [install and configure SSMTP][ssmtp] for using, say, Gmail as the email -server: - -```shell -# file /etc/ssmtp/ssmtp.conf -FromLineOverride=YES -MailHub=smtp.gmail.com:587 -UseSTARTTLS=YES -UseTLS=YES -rewriteDomain=gmail.com -root=username@gmail.com -AuthUser=username -AuthPass=password -``` - -Now install [GNU Mailutils][gnu-mailutils] (`sudo apt-get install mailutils` or the -equivalent on your OS), and send yourself your first email: - -```shell -echo body | mail -aFrom:email@example.com email@example.com -s subject -``` - -And that's about it, you've got mail. Here are some more places where it might -be applicable: - -```shell -# report a backup cronjob, attaching logs -set -e - -finish() { - status=$? - if [[ $status = 0 ]]; then - STATUS="SUCCESS (status $status)" - else - STATUS="FAILURE (status $status)" - fi - - mail user@example.com \ - -s "Backup job report on $(hostname): ${STATUS}" \ - --content-type 'text/plain; charset=utf-8' \ - -A"$LOG_FILE" <<< 'The log report is in the attachment.' -} -trap finish EXIT - -do-long-backup-cmd-here -``` - -``` -# share the output of a cmd with someone -some-program | mail someone@example.com -s "The weird logs that I was talking about" -``` - -...and so on. - -You may consider adding a `alias mail='mail -aFrom:email@example.com'` so you -don't keep re-entering the "From: " part. - -Send yourself some emails to see it working! - -[ssmtp]: https://wiki.archlinux.org/index.php/SSMTP -[gnu-mailutils]: https://mailutils.org/ -[forwarding-wiki-section]: https://wiki.archlinux.org/index.php/SSMTP#Forward_to_a_Gmail_mail_server diff --git a/_tils/2020-09-05-pull-requests-with-git-the-old-school-way.md b/_tils/2020-09-05-pull-requests-with-git-the-old-school-way.md deleted file mode 100644 index 5b4e445..0000000 --- a/_tils/2020-09-05-pull-requests-with-git-the-old-school-way.md +++ /dev/null @@ -1,118 +0,0 @@ ---- - -title: Pull requests with Git, the old school way - -date: 2020-09-05 - -layout: post - -lang: en - -ref: pull-requests-with-git-the-old-school-way - -eu_categories: git - ---- -It might be news to you, as it was to me, that "pull requests" that you can -create on a Git hosting provider's web UI[^pr-webui] like -GitLab/Bitbucket/GitHub actually comes from Git itself: `git request-pull`. - -[^pr-webui]: And maybe even using the Git hosting provider's API from the - command line! - -At the very core, they accomplish the same thing: both the original and the web -UI ones are ways for you to request the project maintainers to pull in your -changes from your fork. It's like saying: "hi there, I did some changes on my -clone of the repository, what do you think about bringing those in?". - -The only difference is that you're working with only Git itself, so you're not -tied to any Git hosting provider: you can send pull requests across them -transparently! You could even use your own [cgit][cgit] installation. No need to -be locked in by any of them, putting the "D" back in "DVCS": it's a -**distributed** version control system. - -[cgit]: https://git.zx2c4.com/cgit/ - -## `git request-pull` introduction - -Here's the raw output of a `git request-pull`: - -```shell -$ git request-pull HEAD public-origin -The following changes since commit 302c9f2f035c0360acd4e13142428c100a10d43f: - - db post: Add link to email exchange (2020-09-03 21:23:55 -0300) - -are available in the Git repository at: - - https://euandre.org/git/euandre.org/ - -for you to fetch changes up to 524c646cdac4153e54f2163e280176adbc4873fa: - - db post: better pinpoint sqlite unsuitability (2020-09-03 22:08:56 -0300) - ----------------------------------------------------------------- -EuAndreh (1): - db post: better pinpoint sqlite unsuitability - - _posts/2020-08-31-the-database-i-wish-i-had.md | 12 ++++++------ - 1 file changed, 6 insertions(+), 6 deletions(-) -``` - -That very first line is saying: "create me a pull request with only a single -commit, defined by `HEAD`, and use the URL defined by `public-origin`". - -Here's a pitfall: you may try using your `origin` remote at first where I put -`public-origin`, but that is many times pointing to something like -`git@example.com`, or `git.example.com:repo.git` (check that with -`git remote -v | grep origin`). On both cases those are addresses available for -interaction via SSH, and it would be better if your pull requests used an -address ready for public consumption. - -A simple solution for that is for you to add the `public-origin` alias as the -HTTPS alternative to the SSH version: - -```shell -$ git remote add public-origin https://example.com/user/repo -``` - -Every Git hosting provider exposes repositories via HTTPS. - -Experiment it yourself, and get acquainted with the CLI. - -## Delivering decentralized pull requests - -Now that you can create the content of a pull request, you can just -[deliver it][cli-email] to the interested parties email: - -```shell -# send a PR with your last commit to the author's email -git request-pull HEAD public-origin | mail author@example.com -s "PR: Add thing to repo" - -# send a PR with your last 5 commits to the project's mailing -# list, including the patch -git request-pull -p HEAD~5 public-origin | \ - mail list@example.com -s "PR: Add another thing to repo" - -# send every commit that is new in "other-branch" -git request-pull master public-origin other-branch | \ - mail list@example.com -s 'PR: All commits from my "other-brach"' -``` - -[cli-email]: {% link _tils/2020-09-04-send-emails-using-the-command-line-for-fun-and-profit.md %} - -## Conclusion - -In practice, I've never used or seen anyone use pull requests this way: -everybody is just [sending patches via email][decentralized-git]. - -If you stop to think about this model, the problem of "Git hosting providers -becoming too centralized" is a non-issue, and "Git federation" proposals are a -less attractive as they may sound initially. - -Using Git this way is not scary or so weird as the first impression may suggest. -It is actually how Git was designed to be used. - -Check `git help request-pull` for more info. - -[decentralized-git]: https://drewdevault.com/2018/07/23/Git-is-already-distributed.html diff --git a/_tils/2020-10-11-search-changes-to-a-filename-pattern-in-git-history.md b/_tils/2020-10-11-search-changes-to-a-filename-pattern-in-git-history.md deleted file mode 100644 index 251abe9..0000000 --- a/_tils/2020-10-11-search-changes-to-a-filename-pattern-in-git-history.md +++ /dev/null @@ -1,41 +0,0 @@ ---- - -title: Search changes to a filename pattern in Git history - -date: 2020-10-11 - -layout: post - -lang: en - -ref: search-changes-to-a-filename-pattern-in-git-history - -eu_categories: git - ---- - -This is [yet][git-til-1] [another][git-til-2] ["search in Git"][git-til-3] TIL -entry. You could say that Git has a unintuitive CLI, or that is it very -powerful. - -I wanted to search for an old file that I new that was in the -history of the repository, but was deleted some time ago. So I didn't really -remember the name, only bits of it. - -I immediately went to the list of TILs I had written on searching in Git, but -it wasn't readily obvious how to do it, so here it goes: - -```shell -git log -- *pattern* -``` - -You could add globs before the pattern to match things on any directory, and add -our `-p` friend to promptly see the diffs: - -```shell -git log -p -- **/*pattern* -``` - -[git-til-1]: {% link _tils/2020-08-14-browse-a-git-repository-at-a-specific-commit.md %} -[git-til-2]: {% link _tils/2020-08-16-search-in-git.md %} -[git-til-3]: {% link _tils/2020-08-28-grep-online-repositories.md %} diff --git a/_tils/2020-11-08-find-broken-symlinks-with-find.md b/_tils/2020-11-08-find-broken-symlinks-with-find.md deleted file mode 100644 index bc97fc6..0000000 --- a/_tils/2020-11-08-find-broken-symlinks-with-find.md +++ /dev/null @@ -1,36 +0,0 @@ ---- - -title: Find broken symlinks with "find" - -date: 2020-11-08 - -layout: post - -lang: en - -ref: find-broken-symlinks-with-find - -eu_categories: shell - ---- - -The `find` command knows how to show broken symlinks: - -```shell -find . -xtype l -``` - -This was useful to me when combined with [Git Annex][git-annex]. Its -[`wanted`][git-annex-wanted] option allows you to have a "sparse" checkout of -the content, and save space by not having to copy every annexed file locally: - -```shell -git annex wanted . 'exclude=Music/* and exclude=Videos/*' -``` - -You can `find` any broken symlinks outside those directories by querying with -Git Annex itself, but `find . -xtype l` works on other places too, where broken -symlinks might be a problem. - -[git-annex]: https://git-annex.branchable.com/ -[git-annex-wanted]: https://git-annex.branchable.com/git-annex-wanted/ diff --git a/_tils/2020-11-12-diy-bare-bones-ci-server-with-bash-and-nix.md b/_tils/2020-11-12-diy-bare-bones-ci-server-with-bash-and-nix.md deleted file mode 100644 index 3336482..0000000 --- a/_tils/2020-11-12-diy-bare-bones-ci-server-with-bash-and-nix.md +++ /dev/null @@ -1,74 +0,0 @@ ---- - -title: DIY bare bones CI server with Bash and Nix - -date: 2020-11-12 3 - -layout: post - -lang: en - -ref: diy-bare-bones-ci-server-with-bash-and-nix - -eu_categories: ci - ---- - -With a server with Nix installed (no need for NixOS), you can leverage its build -isolation for running CI jobs by adding a [post-receive][post-receive] Git hook -to the server. - -In most of my project I like to keep a `test` attribute which runs the test with -`nix-build -A test`. This way, a post-receive hook could look like: - -```shell -#!/usr/bin/env bash -set -Eeuo pipefail -set -x - -LOGS_DIR="/data/static/ci-logs/libedn" -mkdir -p "$LOGS_DIR" -LOGFILE="${LOGS_DIR}/$(date -Is)-$(git rev-parse master).log" -exec &> >(tee -a "${LOGFILE}") - -unset GIT_DIR -CLONE="$(mktemp -d)" -git clone . "$CLONE" -pushd "$CLONE" - -finish() { - printf "\n\n>>> exit status was %s\n" "$?" -} -trap finish EXIT - -nix-build -A test -``` - -We initially (lines #5 to #8) create a log file, named after *when* the run is -running and for *which* commit it is running for. The `exec` and `tee` combo -allows the output of the script to go both to `stdout` *and* the log file. This -makes the logs output show up when you do a `git push`. - -Lines #10 to #13 create a fresh clone of the repository and line #20 runs the -test command. - -After using a similar post-receive hook for a while, I now even generate a -simple HTML file to make the logs available ([example project][ci-logs]) -through the browser. - -[post-receive]: https://git-scm.com/book/en/v2/Customizing-Git-Git-Hooks -[ci-logs]: https://euandreh.xyz/remembering/ci.html - -## Upsides - -No vendor lock-in, as all you need is a server with Nix installed. - -And if you pin the Nixpkgs version you're using, this very simple setup yields -extremely sandboxed runs on a very hermetic environment. - -## Downsides - -Besides the many missing shiny features of this very simplistic CI, `nix-build` -can be very resource intensive. Specifically, it consumes too much memory. So if -it has to download too many things, or the build closure gets too big, the -server might very well run out of memory. diff --git a/_tils/2020-11-12-git-bisect-automation.md b/_tils/2020-11-12-git-bisect-automation.md deleted file mode 100644 index 9c34b2a..0000000 --- a/_tils/2020-11-12-git-bisect-automation.md +++ /dev/null @@ -1,35 +0,0 @@ ---- - -title: Git bisect automation - -date: 2020-11-12 2 - -layout: post - -lang: en - -ref: git-bisect-automation - -eu_categories: git - ---- - -It is good to have an standardized way to run builds and tests on the repository -of a project, so that you can find when a bug was introduced by using -`git bisect run`. - -I've already been in the situation when a bug was introduced and I didn't know -how it even was occurring, and running Git bisect over hundreds of commits to -pinpoint the failing commit was very empowering: - -``` -$ GOOD_COMMIT_SHA=e1fd0a817d192c5a5df72dd7422e36558fa78e46 -$ git bisect start HEAD $GOOD_COMMIT_SHA -$ git bisect run sn -c './build.sh && ./run-failing-case.sh' -``` - -Git will than do a binary search between the commits, and run the commands you -provide it with to find the failing commit. - -Instead of being afraid of doing a bisect, you should instead leverage it, and -make Git help you dig through the history of the repository to find the bad code. diff --git a/_tils/2020-11-12-useful-bash-variables.md b/_tils/2020-11-12-useful-bash-variables.md deleted file mode 100644 index 33a072e..0000000 --- a/_tils/2020-11-12-useful-bash-variables.md +++ /dev/null @@ -1,72 +0,0 @@ ---- - -title: Useful Bash variables - -date: 2020-11-12 1 - -layout: post - -lang: en - -ref: useful-bash-variables - -eu_categories: shell - ---- - -[GNU Bash][gnu-bash] has a few two letter variables that may be useful when -typing on the terminal. - -[gnu-bash]: https://www.gnu.org/software/bash/ - -## `!!`: the text of the last command - -The [`!!` variable][previous-command] refers to the previous command, and I find -useful when following chains for symlinks: - -[previous-command]: https://www.gnu.org/software/bash/manual/bash.html#Event-Designators - -```shell -$ which git -/run/current-system/sw/bin/git -$ readlink $(!!) -readlink $(which git) -/nix/store/5bgr1xpm4m0r72h9049jbbhagxdyrnyb-git-2.28.0/bin/git -``` - -It is also useful when you forget to prefix `sudo` to a command that requires -it: - -```shell -$ requires-sudo.sh -requires-sudo.sh: Permission denied -$ sudo !! -sudo ./requires-sudo.sh -# all good -``` - -Bash prints the command expansion before executing it, so it is better for you -to follow along what it is doing. - -## `$_`: most recent parameter - -The [`$_` variable][recent-parameter] will give you the most recent parameter -you provided to a previous argument, which can save you typing sometimes: - -```shell -# instead of... -$ mkdir -p a/b/c/d/ -$ cd a/b/c/d/ - -# ...you can: -$ mkdir -p a/b/c/d/ -$ cd $_ -``` - -[recent-parameter]: https://www.gnu.org/software/bash/manual/bash.html#Special-Parameters - -## Conclusion - -I wouldn't use those in a script, as it would make the script terser to read, I -find those useful shortcut that are handy when writing at the interactive -terminal. diff --git a/_tils/2020-11-14-gpodder-as-a-media-subscription-manager.md b/_tils/2020-11-14-gpodder-as-a-media-subscription-manager.md deleted file mode 100644 index a74b225..0000000 --- a/_tils/2020-11-14-gpodder-as-a-media-subscription-manager.md +++ /dev/null @@ -1,33 +0,0 @@ ---- - -title: gPodder as a media subscription manager - -date: 2020-11-14 - -layout: post - -lang: en - -ref: gpodder-as-a-media-subscription-manager - ---- - -As we [re-discover][rss] the value of Atom/RSS feeds, most useful feed clients I -know of don't support media, specifically audio and video. - -[gPodder][gpodder] does. - -It is mostly know as a desktop podcatcher. But the thing about podcasts is that -the feed is provided through an RSS/Atom feed. So you can just use gPodder as -your media feed client, where you have control of what you look at. - -I audio and video providers I know of offer an RSS/Atom view of their content, -so you can, say, treat any YouTube channel like a feed on its own. - -gPodder will then managed your feeds, watched/unwatched, queue downloads, etc. - -Being obvious now, it was a big finding for me. If it got you interested, I -recommend you giving gPodder a try. - -[rss]: https://www.charlieharrington.com/unexpected-useless-and-urgent -[gpodder]: https://gpodder.github.io/ diff --git a/_tils/2020-11-30-storing-ci-data-on-git-notes.md b/_tils/2020-11-30-storing-ci-data-on-git-notes.md deleted file mode 100644 index f8dd063..0000000 --- a/_tils/2020-11-30-storing-ci-data-on-git-notes.md +++ /dev/null @@ -1,122 +0,0 @@ ---- - -title: Storing CI data on Git notes - -date: 2020-11-30 - -layout: post - -lang: en - -ref: storing-ci-data-on-git-notes - -eu_categories: git,ci - ---- - -Extending the bare bones CI server I've [talked about before][previous-article], -divoplade on Freenode suggested storing CI artifacts on [Git notes][git-notes], -such as tarballs, binaries, logs, *etc*. - -I've written a small script that will put log files and CI job data on Git notes, -and make it visible on the porcelain log. It is a simple extension of the -previous article: - -```shell -#!/usr/bin/env bash -set -Eeuo pipefail -set -x - -PREFIX='/srv/ci/vps' -mkdir -p "$PREFIX" -read -r _ SHA _ # oldrev newrev refname -FILENAME="$(date -Is)-$SHA.log" -LOGFILE="$PREFIX/$FILENAME" -exec &> >(tee -a "$LOGFILE") - -echo "Starting CI job at: $(date -Is)" - -finish() { - STATUS="$?" - printf "\n\n>>> exit status was %s\n" "$STATUS" - echo "Finishing CI job at: $(date -Is)" - popd - NOTE=$(cat <<EOF -See CI logs with: - git notes --ref=refs/notes/ci-logs show $SHA - git notes --ref=refs/notes/ci-data show $SHA -EOF -) - git notes --ref=refs/notes/ci-data add -f -m "$STATUS $FILENAME" - git notes --ref=refs/notes/ci-logs add -f -F "$LOGFILE" - git notes add -f -m "$NOTE" - printf "\n\n>>> CI logs added as Git note." -} -trap finish EXIT - -unset GIT_DIR -CLONE="$(mktemp -d)" -git clone . "$CLONE" -pushd "$CLONE" -git config --global user.email git@euandre.org -git config --global user.name 'EuAndreh CI' - -./container make check site -./container make publish -``` - -The important part is in the `finish()` function: -- #25 stores the exit status and the generated filename separated by spaces; -- #26 adds the log file in a note using the `refs/notes/ci-logs` ref; -- #27 it adds a note to the commit saying how to see the logs. - -A commit now has an attached note, and shows it whenever you look at it: - -```diff -$ git show 87c57133abd8be5d7cc46afbf107f59b26066575 -commit 87c57133abd8be5d7cc46afbf107f59b26066575 -Author: EuAndreh <eu@euandre.org> -Date: Wed Feb 24 21:58:28 2021 -0300 - - vps/machines.scm: Change path to cronjob files - -Notes: - See CI logs with: - git notes --ref=refs/notes/ci-logs show 87c57133abd8be5d7cc46afbf107f59b26066575 - git notes --ref=refs/notes/ci-data show 87c57133abd8be5d7cc46afbf107f59b26066575 - -diff --git a/servers/vps/machines.scm b/servers/vps/machines.scm -index d1830ca..a4ccde7 100644 ---- a/servers/vps/machines.scm -+++ b/servers/vps/machines.scm -@@ -262,8 +262,8 @@ pki " mail-domain " key \"" (tls-priv-for mail-domain) "\"")) - (service mcron-service-type - (mcron-configuration - (jobs -- (list #~(job "30 1 * * 1" "guix gc -d") -- #~(job "30 0 * * *" "/var/lib/euandreh/backup.sh"))))) -+ (list #~(job "30 1 * * 1" "/opt/bin/gc.sh") -+ #~(job "30 0 * * *" "/opt/bin/backup.sh"))))) - (service dhcp-client-service-type) - #; - (service opensmtpd-service-type -``` - -Other tools such as [cgit][cgit] will also show notes on the web interface: -<https://euandre.org/git/servers/commit?id=87c57133abd8be5d7cc46afbf107f59b26066575>. - -You can go even further: since cgit can serve raw blob directly, you can even -serve such artifacts (log files, release artifacts, binaries) from cgit itself: - -```shell -$ SHA="$(git notes --ref=refs/notes/ci-logs list 87c57133abd8be5d7cc46afbf107f59b26066575)" -$ echo "https://euandre.org/git/servers/blob?id=$SHA" -https://euandre.org/git/servers/blob?id=1707a97bae24e3864fe7943f8dda6d01c294fb5c -``` - -And like that you'll have cgit serving the artifacts for you: -<https://euandre.org/git/servers/blob?id=1707a97bae24e3864fe7943f8dda6d01c294fb5c>. - -[previous-article]: {% link _tils/2020-11-12-diy-bare-bones-ci-server-with-bash-and-nix.md %} -[git-notes]: https://git-scm.com/docs/git-notes -[cgit]: https://git.zx2c4.com/cgit/ diff --git a/_tils/2020-12-15-awk-snippet-shellcheck-all-scripts-in-a-repository.md b/_tils/2020-12-15-awk-snippet-shellcheck-all-scripts-in-a-repository.md deleted file mode 100644 index 71d10a3..0000000 --- a/_tils/2020-12-15-awk-snippet-shellcheck-all-scripts-in-a-repository.md +++ /dev/null @@ -1,171 +0,0 @@ ---- - -title: 'Awk snippet: ShellCheck all scripts in a repository' - -date: 2020-12-15 - -updated_at: 2020-12-16 - -layout: post - -lang: en - -ref: awk-snippet-shellcheck-all-scripts-in-a-repository - -eu_categories: shell - ---- - -Inspired by Fred Herbert's "[Awk in 20 Minutes][awk-20min]", here's a problem I -just solved with a line of Awk: run ShellCheck in all scripts of a repository. - -In my repositories I usually have Bash and POSIX scripts, which I want to keep -tidy with [ShellCheck][shellcheck]. Here's the first version of -`assert-shellcheck.sh`: - -```shell -#!/bin/sh -eux - -find . -type f -name '*.sh' -print0 | xargs -0 shellcheck -``` - -This is the type of script that I copy around to all repositories, and I want it -to be capable of working on any repository, without requiring a list of files to -run ShellCheck on. - -This first version worked fine, as all my scripts had the '.sh' ending. But I -recently added some scripts without any extension, so `assert-shellcheck.sh` -called for a second version. The first attempt was to try grepping the shebang -line: - -```shell -$ grep '^#!/' assert-shellcheck.sh -#!/usr/sh -``` - -Good, we have a grep pattern on the first try. Let's try to find all the -matching files: - -```shell -$ find . -type f | xargs grep -l '^#!/' -./TODOs.org -./.git/hooks/pre-commit.sample -./.git/hooks/pre-push.sample -./.git/hooks/pre-merge-commit.sample -./.git/hooks/fsmonitor-watchman.sample -./.git/hooks/pre-applypatch.sample -./.git/hooks/pre-push -./.git/hooks/prepare-commit-msg.sample -./.git/hooks/commit-msg.sample -./.git/hooks/post-update.sample -./.git/hooks/pre-receive.sample -./.git/hooks/applypatch-msg.sample -./.git/hooks/pre-rebase.sample -./.git/hooks/update.sample -./build-aux/with-guile-env.in -./build-aux/test-driver -./build-aux/missing -./build-aux/install-sh -./build-aux/install-sh~ -./bootstrap -./scripts/assert-todos.sh -./scripts/songbooks -./scripts/compile-readme.sh -./scripts/ci-build.sh -./scripts/generate-tasks-and-bugs.sh -./scripts/songbooks.in -./scripts/with-container.sh -./scripts/assert-shellcheck.sh -``` - -This approach has a problem, though: it includes files ignored by Git, such as -`builld-aux/install-sh~`, and even goes into the `.git/` directory and finds -sample hooks in `.git/hooks/*`. - -To list the files that Git is tracking we'll try `git ls-files`: - -```shell -$ git ls-files | xargs grep -l '^#!/' -TODOs.org -bootstrap -build-aux/with-guile-env.in -old/scripts/assert-docs-spelling.sh -old/scripts/build-site.sh -old/scripts/builder.bats.sh -scripts/assert-shellcheck.sh -scripts/assert-todos.sh -scripts/ci-build.sh -scripts/compile-readme.sh -scripts/generate-tasks-and-bugs.sh -scripts/songbooks.in -scripts/with-container.sh -``` - -It looks to be almost there, but the `TODOs.org` entry shows a flaw in it: grep -is looking for a `'^#!/'` pattern on any part of the file. In my case, -`TODOs.org` had a snippet in the middle of the file where a line started with -`#!/bin/sh`. - -So what we actually want is to match the **first** line against the pattern. We -could loop through each file, get the first line with `head -n 1` and grep -against that, but this is starting to look messy. I bet there is another way of -doing it concisely... - -Let's try Awk. I need a way to select the line numbers to replace `head -n 1`, -and to stop processing the file if the pattern matches. A quick search points me -to using `FNR` for the former, and `{ nextline }` for the latter. Let's try it: - -```shell -$ git ls-files | xargs awk 'FNR>1 { nextfile } /^#!\// { print FILENAME; nextfile }' -bootstrap -build-aux/with-guile-env.in -old/scripts/assert-docs-spelling.sh -old/scripts/build-site.sh -old/scripts/builder.bats.sh -scripts/assert-shellcheck.sh -scripts/assert-todos.sh -scripts/ci-build.sh -scripts/compile-readme.sh -scripts/generate-tasks-and-bugs.sh -scripts/songbooks.in -scripts/with-container.sh -``` - -Great! Only `TODOs.org` is missing, but the script is much better: instead of -matching against any part of the file that may have a shebang-like line, we only -look for the first. Let's put it back into the `assert-shellcheck.sh` file and -use `NULL` for separators to accommodate files with spaces in the name: - -``` -#!/usr/sh -eux - -git ls-files -z | \ - xargs -0 awk 'FNR>1 { nextfile } /^#!\// { print FILENAME; nextfile }' | \ - xargs shellcheck -``` - -This is where I've stopped, but I imagine a likely improvement: match against -only `#!/bin/sh` and `#!/usr/bin/env bash` shebangs (the ones I use most), to -avoid running ShellCheck on Perl files, or other shebangs. - -Also when reviewing the text of this article, I found that `{ nextfile }` is a -GNU Awk extension. It would be an improvement if `assert-shellcheck.sh` relied -on the POSIX subset of Awk for working correctly. - -## *Update* - -After publishing, I could remove `{ nextfile }` and even make the script -simpler: - -```shell -#!/usr/sh -eux - -git ls-files -z | \ - xargs -0 awk 'FNR==1 && /^#!\// { print FILENAME }' | \ - xargs shellcheck -``` - -Now both the shell and Awk usage are POSIX compatible. - -[awk-20min]: https://ferd.ca/awk-in-20-minutes.html -[shellcheck]: https://www.shellcheck.net/ diff --git a/_tils/2020-12-29-svg-favicon.md b/_tils/2020-12-29-svg-favicon.md deleted file mode 100644 index 54cca9a..0000000 --- a/_tils/2020-12-29-svg-favicon.md +++ /dev/null @@ -1,134 +0,0 @@ ---- - -title: SVG favicon - -date: 2020-12-29 - -updated_at: 2021-01-12 - -layout: post - -lang: en - -ref: svg-favicon - ---- - -I've wanted to change this website's favicon from a plain `.ico` file to a -proper SVG. The problem I was trying to solve was to reuse the same image on -other places, such as avatars. - -Generating a PNG from the existing 16x16 icon was possible but bad: the final -image was blurry. Converting the `.ico` to an SVG was possible, but sub-optimal: -tools try to guess some vector paths, and the final SVG didn't match the -original. - -Instead I used a tool to draw the "vector pixels" as black squares, and after -getting the final result I manually cleaned-up the generated XML: - -```xml -<?xml version="1.0" encoding="UTF-8" standalone="no"?> -<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 16 16" width="16" height="16"> - <path d="M 0 8 L 1 8 L 1 9 L 0 9 L 0 8 Z" /> - <path d="M 0 13 L 1 13 L 1 14 L 0 14 L 0 13 Z" /> - <path d="M 1 8 L 2 8 L 2 9 L 1 9 L 1 8 Z" /> - <path d="M 1 13 L 2 13 L 2 14 L 1 14 L 1 13 Z" /> - <path d="M 2 8 L 3 8 L 3 9 L 2 9 L 2 8 Z" /> - <path d="M 2 13 L 3 13 L 3 14 L 2 14 L 2 13 Z" /> - <path d="M 3 8 L 4 8 L 4 9 L 3 9 L 3 8 Z" /> - <path d="M 3 13 L 4 13 L 4 14 L 3 14 L 3 13 Z" /> - <path d="M 4 7 L 5 7 L 5 8 L 4 8 L 4 7 Z" /> - <path d="M 4 8 L 5 8 L 5 9 L 4 9 L 4 8 Z" /> - <path d="M 4 13 L 5 13 L 5 14 L 4 14 L 4 13 Z" /> - <path d="M 5 6 L 6 6 L 6 7 L 5 7 L 5 6 Z" /> - <path d="M 5 7 L 6 7 L 6 8 L 5 8 L 5 7 Z" /> - <path d="M 5 13 L 6 13 L 6 14 L 5 14 L 5 13 Z" /> - <path d="M 6 5 L 7 5 L 7 6 L 6 6 L 6 5 Z" /> - <path d="M 6 6 L 7 6 L 7 7 L 6 7 L 6 6 Z" /> - <path d="M 6 14 L 7 14 L 7 15 L 6 15 L 6 14 Z" /> - <path d="M 7 1 L 8 1 L 8 2 L 7 2 L 7 1 Z" /> - <path d="M 7 14 L 8 14 L 8 15 L 7 15 L 7 14 Z" /> - <path d="M 7 15 L 8 15 L 8 16 L 7 16 L 7 15 Z" /> - <path d="M 7 2 L 8 2 L 8 3 L 7 3 L 7 2 Z" /> - <path d="M 7 3 L 8 3 L 8 4 L 7 4 L 7 3 Z" /> - <path d="M 7 4 L 8 4 L 8 5 L 7 5 L 7 4 Z" /> - <path d="M 7 5 L 8 5 L 8 6 L 7 6 L 7 5 Z" /> - <path d="M 8 1 L 9 1 L 9 2 L 8 2 L 8 1 Z" /> - <path d="M 8 15 L 9 15 L 9 16 L 8 16 L 8 15 Z" /> - <path d="M 9 1 L 10 1 L 10 2 L 9 2 L 9 1 Z" /> - <path d="M 9 2 L 10 2 L 10 3 L 9 3 L 9 2 Z" /> - <path d="M 9 6 L 10 6 L 10 7 L 9 7 L 9 6 Z" /> - <path d="M 9 15 L 10 15 L 10 16 L 9 16 L 9 15 Z" /> - <path d="M 10 2 L 11 2 L 11 3 L 10 3 L 10 2 Z" /> - <path d="M 10 3 L 11 3 L 11 4 L 10 4 L 10 3 Z" /> - <path d="M 10 4 L 11 4 L 11 5 L 10 5 L 10 4 Z" /> - <path d="M 10 5 L 11 5 L 11 6 L 10 6 L 10 5 Z" /> - <path d="M 10 6 L 11 6 L 11 7 L 10 7 L 10 6 Z" /> - <path d="M 11 6 L 12 6 L 12 7 L 11 7 L 11 6 Z" /> - <path d="M 11 8 L 12 8 L 12 9 L 11 9 L 11 8 Z" /> - <path d="M 10 15 L 11 15 L 11 16 L 10 16 L 10 15 Z" /> - <path d="M 11 10 L 12 10 L 12 11 L 11 11 L 11 10 Z" /> - <path d="M 11 12 L 12 12 L 12 13 L 11 13 L 11 12 Z" /> - <path d="M 11 14 L 12 14 L 12 15 L 11 15 L 11 14 Z" /> - <path d="M 11 15 L 12 15 L 12 16 L 11 16 L 11 15 Z" /> - <path d="M 12 6 L 13 6 L 13 7 L 12 7 L 12 6 Z" /> - <path d="M 12 8 L 13 8 L 13 9 L 12 9 L 12 8 Z" /> - <path d="M 12 10 L 13 10 L 13 11 L 12 11 L 12 10 Z" /> - <path d="M 12 12 L 13 12 L 13 13 L 12 13 L 12 12 Z" /> - <path d="M 12 14 L 13 14 L 13 15 L 12 15 L 12 14 Z" /> - <path d="M 13 6 L 14 6 L 14 7 L 13 7 L 13 6 Z" /> - <path d="M 13 8 L 14 8 L 14 9 L 13 9 L 13 8 Z" /> - <path d="M 13 10 L 14 10 L 14 11 L 13 11 L 13 10 Z" /> - <path d="M 13 12 L 14 12 L 14 13 L 13 13 L 13 12 Z" /> - <path d="M 13 13 L 14 13 L 14 14 L 13 14 L 13 13 Z" /> - <path d="M 13 14 L 14 14 L 14 15 L 13 15 L 13 14 Z" /> - <path d="M 14 7 L 15 7 L 15 8 L 14 8 L 14 7 Z" /> - <path d="M 14 8 L 15 8 L 15 9 L 14 9 L 14 8 Z" /> - <path d="M 14 9 L 15 9 L 15 10 L 14 10 L 14 9 Z" /> - <path d="M 14 10 L 15 10 L 15 11 L 14 11 L 14 10 Z" /> - <path d="M 14 11 L 15 11 L 15 12 L 14 12 L 14 11 Z" /> - <path d="M 14 12 L 15 12 L 15 13 L 14 13 L 14 12 Z" /> -</svg> -``` - -The good thing about this new favicon -(at [`/static/lord-favicon.svg`](/static/lord-favicon.svg)) is that -a) it is simple enough that I feel -comfortable editing it manually and b) it is an SVG, which means I can generate -any desired size. - -With the new favicon file, I now had to add to the templates' `<head>` a -`<link>` to this icon: -```html -<head> - <meta charset="UTF-8" /> - <link rel="icon" type="image/svg+xml" href="/static/favicon.svg"> - ... -``` - -Still missing is a bitmap image for places that can't handle vector images. I -used Jekyll generator to create an PNG from the existing SVG: - -```ruby -module Jekyll - class FaviconGenerator < Generator - safe true - priority :high - - SIZE = 420 - - def generate(site) - svg = 'static/favicon.svg' - png = 'static/favicon.png' - unless File.exist? png then - puts "Missing '#{png}', generating..." - puts `inkscape -o #{png} -w #{SIZE} -h #{SIZE} #{svg}` - end - end - end -end -``` - -I had to increase the priority of the generator so that it would run before -other places that would use a `{% link /static/lord-favicon.png %}`, otherwise -the file would be considered missing. diff --git a/_tils/2021-01-12-awk-snippet-send-email-to-multiple-recipients-with-curl.md b/_tils/2021-01-12-awk-snippet-send-email-to-multiple-recipients-with-curl.md deleted file mode 100644 index 880ddf1..0000000 --- a/_tils/2021-01-12-awk-snippet-send-email-to-multiple-recipients-with-curl.md +++ /dev/null @@ -1,142 +0,0 @@ ---- - -title: 'Awk snippet: send email to multiple recipients with cURL' - -date: 2021-01-12 - -layout: post - -lang: en - -ref: awk-snippet-send-email-to-multiple-recipients-with-curl - ---- - -As I experiment with [Neomutt][neomutt], I wanted to keep being able to enqueue emails for sending later like my previous setup, so that I didn't rely on having an internet connection. - -My requirements for the `sendmail` command were: -1. store the email in a file, and send it later. -1. send from different addresses, using different SMTP servers; - -I couldn't find an MTA that could accomplish that, but I was able to quickly write a solution. - -The first part was the easiest: store the email in a file: - -```shell -# ~/.config/mutt/muttrc: -set sendmail=~/bin/enqueue-email.sh - -# ~/bin/enqueue-email.sh: -#!/bin/sh -eu - -cat - > "$HOME/mbsync/my-queued-emails/$(date -Is)" -``` - -Now that I had the email file store locally, I needed a program to send the email from the file, so that I could create a cronjob like: - -```shell -for f in ~/mbsync/my-queued-emails/*; do - ~/bin/dispatch-email.sh "$f" && rm "$f" -done -``` - -The `dispatch-email.sh` would have to look at the `From: ` header and decide which SMTP server to use. -As I [found out][curl-email] that [curl][curl] supports SMTP and is able to send emails, this is what I ended up with: - -```shell -#!/bin/sh -eu - -F="$1" - -rcpt="$(awk ' - match($0, /^(To|Cc|Bcc): (.*)$/, m) { - split(m[2], tos, ",") - for (i in tos) { - print "--mail-rcpt " tos[i] - } - } -' "$F")" - -if grep -qE '^From: .*<addr@server1\.org>$' "$F"; then - curl \ - -s \ - --url smtp://smtp.server1.org:587 \ - --ssl-reqd \ - --mail-from addr@server1.org \ - $rcpt \ - --user 'addr@server1.org:my-long-and-secure-passphrase' \ - --upload-file "$F" -elif grep -qE '^From: .*<addr@server2\.org>$' "$F"; then - curl \ - -s \ - --url smtp://smtp.server2.org:587 \ - --ssl-reqd \ - --mail-from addr@server2.org \ - $rcpt \ - --user 'addr@server2.org:my-long-and-secure-passphrase' \ - --upload-file "$F" -else - echo 'Bad "From: " address' - exit 1 -fi -``` - -Most of curl flags used are self-explanatory, except for `$rcpt`. - -curl connects to the SMTP server, but doesn't set the recipient address by looking at the message. -My solution was to generate the curl flags, store them in `$rcpt` and use it unquoted to leverage shell word splitting. - -To me, the most interesting part was building the `$rcpt` flags. -My first instinct was to try grep, but it couldn't print only matches in a regex. -As I started to turn towards sed, I envisioned needing something else to loop over the sed output, and I then moved to Awk. - -In the short Awk snippet, 3 things were new to me: the `match(...)`, `split(...)` and `for () {}`. -The only other function I have ever used was `gsub(...)`, but these new ones felt similar enough that I could almost guess their behaviour and arguments. -`match(...)` stores the matches of a regex on the given array positionally, and `split(...)` stores the chunks in the given array. - -I even did it incrementally: - -```shell -$ H='To: to@example.com, to2@example.com\nCc: cc@example.com, cc2@example.com\nBcc: bcc@example.com,bcc2@example.com\n' -$ printf "$H" | awk '/^To: .*$/ { print $0 }' -To: to@example.com, to2@example.com -$ printf "$H" | awk 'match($0, /^To: (.*)$/, m) { print m }' -awk: ligne de commande:1: (FILENAME=- FNR=1) fatal : tentative d'utilisation du tableau « m » dans un contexte scalaire -$ printf "$H" | awk 'match($0, /^To: (.*)$/, m) { print m[0] }' -To: to@example.com, to2@example.com -$ printf "$H" | awk 'match($0, /^To: (.*)$/, m) { print m[1] }' -to@example.com, to2@example.com -$ printf "$H" | awk 'match($0, /^To: (.*)$/, m) { split(m[1], tos, " "); print tos }' -awk: ligne de commande:1: (FILENAME=- FNR=1) fatal : tentative d'utilisation du tableau « tos » dans un contexte scalaire -$ printf "$H" | awk 'match($0, /^To: (.*)$/, m) { split(m[1], tos, " "); print tos[0] }' - -$ printf "$H" | awk 'match($0, /^To: (.*)$/, m) { split(m[1], tos, " "); print tos[1] }' -to@example.com, -$ printf "$H" | awk 'match($0, /^To: (.*)$/, m) { split(m[1], tos, " "); print tos[2] }' -to2@example.com -$ printf "$H" | awk 'match($0, /^To: (.*)$/, m) { split(m[1], tos, " "); print tos[3] }' - -``` - -(This isn't the verbatim interactive session, but a cleaned version to make it more readable.) - -At this point, I realized I needed a for loop over the `tos` array, and I moved the Awk snippet into the `~/bin/dispatch-email.sh`. -I liked the final thing: - -```awk -match($0, /^(To|Cc|Bcc): (.*)$/, m) { - split(m[2], tos, ",") - for (i in tos) { - print "--mail-rcpt " tos[i] - } -} -``` - -As I learn more about Awk, I feel that it is too undervalued, as many people turn to Perl or other programming languages when Awk suffices. -The advantage is pretty clear: writing programs that run on any POSIX system, without extra dependencies required. - -Coding to the standards is underrated. - -[neomutt]: https://neomutt.org/ -[curl-email]: https://blog.edmdesigner.com/send-email-from-linux-command-line/ -[curl]: https://curl.se/ diff --git a/_tils/2021-01-17-posix-sh-and-shebangs.md b/_tils/2021-01-17-posix-sh-and-shebangs.md deleted file mode 100644 index 938d1bd..0000000 --- a/_tils/2021-01-17-posix-sh-and-shebangs.md +++ /dev/null @@ -1,57 +0,0 @@ ---- - -title: POSIX sh and shebangs - -date: 2021-01-17 - -layout: post - -lang: en - -ref: posix-sh-and-shebangs - ---- - -As I [keep moving][posix-awk-0] [towards POSIX][posix-awk-1], I'm on the process of migrating all my Bash scripts to POSIX sh. - -As I dropped `[[`, arrays and other Bashisms, I was left staring at the first line of every script, wondering what to do: what is the POSIX sh equivalent of `#!/usr/bin/env bash`? -I already knew that POSIX says nothing about shebangs, and that the portable way to call a POSIX sh script is `sh script.sh`, but I didn't know what to do with that first line. - -What I had previously was: -```shell -#!/usr/bin/env bash -set -Eeuo pipefail -cd "$(dirname "${BASH_SOURCE[0]}")" -``` - -Obviously, the `$BASH_SOURCE` would be gone, and I would have to adapt some of my scripts to not rely on the script location. -The `-E` and `-o pipefail` options were also gone, and would be replaced by nothing. - -I converted all of them to: -```shell -#!/bin/sh -eu -``` - -I moved the `-eu` options to the shebang line itself, striving for conciseness. -But as I changed callers from `./script.sh` to `sh script.sh`, things started to fail. -Some tests that should fail reported errors, but didn't return 1. - -My first reaction was to revert back to `./script.sh`, but the POSIX bug I caught is a strong strain, and when I went back to it, I figured that the callers were missing some flags. -Specifically, `sh -eu script.sh`. - -Then it clicked: when running with `sh script.sh`, the shebang line with the sh options is ignored, as it is a comment! - -Which means that the shebang most friendly with POSIX is: - -```shell -#!/bin/sh -set -eu -``` - -1. when running via `./script.sh`, if the system has an executable at `/bin/sh`, it will be used to run the script; -1. when running via `sh script.sh`, the sh options aren't ignored as previously. - -TIL. - -[posix-awk-0]: {% link _tils/2020-12-15-awk-snippet-shellcheck-all-scripts-in-a-repository.md %} -[posix-awk-1]: {% link _tils/2021-01-12-awk-snippet-send-email-to-multiple-recipients-with-curl.md %} diff --git a/_tils/2021-04-24-clojure-auto-curry.md b/_tils/2021-04-24-clojure-auto-curry.md deleted file mode 100644 index c1e277f..0000000 --- a/_tils/2021-04-24-clojure-auto-curry.md +++ /dev/null @@ -1,135 +0,0 @@ ---- - -title: Clojure auto curry - -date: 2021-04-24 1 - -updated_at: 2021-04-27 - -layout: post - -lang: en - -ref: clojure-auto-curry - ---- - -Here's a simple macro defined by [Loretta He][lorettahe] to create Clojure functions that are curried on all arguments, relying on Clojure's multi-arity support: - -```clojure -(defmacro defcurry - [name args & body] - (let [partials (map (fn [n] - `(~(subvec args 0 n) (partial ~name ~@(take n args)))) - (range 1 (count args)))] - `(defn ~name - (~args ~@body) - ~@partials))) -``` - -A naive `add` definition, alongside its usage and macroexpansion: - -```clojure -user=> (defcurry add - [a b c d e] - (+ 1 2 3 4 5)) -#'user/add - -user=> (add 1) -#object[clojure.core$partial$fn__5857 0x2c708440 "clojure.core$partial$fn__5857@2c708440"] - -user=> (add 1 2 3 4) -#object[clojure.core$partial$fn__5863 0xf4c0e4e "clojure.core$partial$fn__5863@f4c0e4e"] - -user=> ((add 1) 2 3 4 5) -15 - -user=> (((add 1) 2 3) 4 5) -15 - -user=> (use 'clojure.pprint) -nil - -user=> (pprint - (macroexpand - '(defcurry add - [a b c d e] - (+ 1 2 3 4 5)))) -(def - add - (clojure.core/fn - ([a b c d e] (+ 1 2 3 4 5)) - ([a] (clojure.core/partial add a)) - ([a b] (clojure.core/partial add a b)) - ([a b c] (clojure.core/partial add a b c)) - ([a b c d] (clojure.core/partial add a b c d)))) -nil -``` - -This simplistic `defcurry` definition doesn't support optional parameters, multi-arity, `&` rest arguments, docstrings, etc., but it could certainly evolve to do so. - -I like how `defcurry` is so short, and abdicates the responsability of doing the multi-arity logic to Clojure's built-in multi-arity support. -Simple and elegant. - -Same Clojure as before, now with auto-currying via macros. - -[lorettahe]: http://lorettahe.github.io/clojure/2016/09/22/clojure-auto-curry - -## Comparison with Common Lisp - -My attempt at writing an equivalent for Common Lisp gives me: - -```lisp -(defun partial (fn &rest args) - (lambda (&rest args2) - (apply fn (append args args2)))) - -(defun curry-n (n func) - (cond ((< n 0) (error "Too many arguments")) - ((zerop n) (funcall func)) - (t (lambda (&rest rest) - (curry-n (- n (length rest)) - (apply #'partial func rest)))))) - -(defmacro defcurry (name args &body body) - `(defun ,name (&rest rest) - (let ((func (lambda ,args ,@body))) - (curry-n (- ,(length args) (length rest)) - (apply #'partial func rest))))) -``` - -Without built-in multi-arity support, we have to do more work, like tracking the number of arguments consumed so far. -We also have to write `#'partial` ourselves. -That is, without dependending on any library, sticking to ANSI Common Lisp. - -The usage is pretty similar: - -```lisp -* (defcurry add (a b c d e) - (+ a b c d e)) -ADD - -* (add 1) -#<FUNCTION (LAMBDA (&REST REST) :IN CURRY-N) {100216419B}> - -* (funcall (add 1) 2 3 4) -#<FUNCTION (LAMBDA (&REST REST) :IN CURRY-N) {100216537B}> - -* (funcall (add 1) 2 3 4 5) -15 - -* (funcall (funcall (add 1) 2 3) 4 5) -15 - -* (macroexpand-1 - '(defcurry add (a b c d e) - (+ a b c d e))) -(DEFUN ADD (&REST REST) - (LET ((FUNC (LAMBDA (A B C D E) (+ A B C D E)))) - (CURRY-N (- 5 (LENGTH REST)) (APPLY #'PARTIAL FUNC REST)))) -T -``` - -This also require `funcall`s, since we return a `lambda` that doesn't live in the function namespace. - -Like the Clojure one, it doesn't support optional parameters, `&rest` rest arguments, docstrings, etc., but it also could evolve to do so. diff --git a/_tils/2021-04-24-common-lisp-argument-precedence-order-parameterization-of-a-generic-function.md b/_tils/2021-04-24-common-lisp-argument-precedence-order-parameterization-of-a-generic-function.md deleted file mode 100644 index 8051232..0000000 --- a/_tils/2021-04-24-common-lisp-argument-precedence-order-parameterization-of-a-generic-function.md +++ /dev/null @@ -1,137 +0,0 @@ ---- - -title: Common Lisp argument precedence order parameterization of a generic function - -date: 2021-04-24 2 - -layout: post - -lang: en - -ref: common-lisp-argument-precedence-order-parameterization-of-a-generic-function - ---- - -When CLOS dispatches a method, it picks the most specific method definition to the argument list: - -```lisp - -* (defgeneric a-fn (x)) -#<STANDARD-GENERIC-FUNCTION A-FN (0) {5815ACB9}> - -* (defmethod a-fn (x) :default-method) -#<STANDARD-METHOD A-FN (T) {581DB535}> - -* (defmethod a-fn ((x number)) :a-number) -#<STANDARD-METHOD A-FN (NUMBER) {58241645}> - -* (defmethod a-fn ((x (eql 1))) :number-1) -#<STANDARD-METHOD A-FN ((EQL 1)) {582A7D75}> - -* (a-fn nil) -:DEFAULT-METHOD - -* (a-fn "1") -:DEFAULT-METHOD - -* (a-fn 0) -:A-NUMBER - -* (a-fn 1) -:NUMBER-1 -``` - -CLOS uses a similar logic when choosing the method from parent classes, when multiple ones are available: - -```lisp -* (defclass class-a () ()) - -#<STANDARD-CLASS CLASS-A {583E0B25}> -* (defclass class-b () ()) - -#<STANDARD-CLASS CLASS-B {583E7F6D}> -* (defgeneric another-fn (obj)) - -#<STANDARD-GENERIC-FUNCTION ANOTHER-FN (0) {583DA749}> -* (defmethod another-fn ((obj class-a)) :class-a) -; Compiling LAMBDA (.PV-CELL. .NEXT-METHOD-CALL. OBJ): -; Compiling Top-Level Form: - -#<STANDARD-METHOD ANOTHER-FN (CLASS-A) {584523C5}> -* (defmethod another-fn ((obj class-b)) :class-b) -; Compiling LAMBDA (.PV-CELL. .NEXT-METHOD-CALL. OBJ): -; Compiling Top-Level Form: - -#<STANDARD-METHOD ANOTHER-FN (CLASS-B) {584B8895}> -``` - -Given the above definitions, when inheriting from `class-a` and `class-b`, the order of inheritance matters: - -```lisp -* (defclass class-a-coming-first (class-a class-b) ()) -#<STANDARD-CLASS CLASS-A-COMING-FIRST {584BE6AD}> - -* (defclass class-b-coming-first (class-b class-a) ()) -#<STANDARD-CLASS CLASS-B-COMING-FIRST {584C744D}> - -* (another-fn (make-instance 'class-a-coming-first)) -:CLASS-A - -* (another-fn (make-instance 'class-b-coming-first)) -:CLASS-B -``` - -Combining the order of inheritance with generic functions with multiple arguments, CLOS has to make a choice of how to pick a method given two competing definitions, and its default strategy is prioritizing from left to right: - -```lisp -* (defgeneric yet-another-fn (obj1 obj2)) -#<STANDARD-GENERIC-FUNCTION YET-ANOTHER-FN (0) {584D9EC9}> - -* (defmethod yet-another-fn ((obj1 class-a) obj2) :first-arg-specialized) -#<STANDARD-METHOD YET-ANOTHER-FN (CLASS-A T) {5854269D}> - -* (defmethod yet-another-fn (obj1 (obj2 class-b)) :second-arg-specialized) -#<STANDARD-METHOD YET-ANOTHER-FN (T CLASS-B) {585AAAAD}> - -* (yet-another-fn (make-instance 'class-a) (make-instance 'class-b)) -:FIRST-ARG-SPECIALIZED -``` - -CLOS has to make a choice between the first and the second definition of `yet-another-fn`, but its choice is just a heuristic. -What if we want the choice to be based on the second argument, instead of the first? - -For that, we use the `:argument-precedence-order` option when declaring a generic function: - -```lisp -* (defgeneric yet-another-fn (obj1 obj2) (:argument-precedence-order obj2 obj1)) -#<STANDARD-GENERIC-FUNCTION YET-ANOTHER-FN (2) {584D9EC9}> - -* (yet-another-fn (make-instance 'class-a) (make-instance 'class-b)) -:SECOND-ARG-SPECIALIZED -``` - -I liked that the `:argument-precedence-order` option exists. -We shouldn't have to change the arguments from `(obj1 obj2)` to `(obj2 obj1)` just to make CLOS pick the method that we want. -We can configure its default behaviour if desired, and keep the order of arguments however it best fits the generic function. - -## Comparison with Clojure - -Clojure has an equivalent, when using `defmulti`. - -Since when declaring a multi-method with `defmulti` we must define the dispatch function, Clojure uses it to pick the method definition. -Since the dispatch function is required, there is no need for a default behaviour, such as left-to-right. - -## Conclusion - -Making the argument precedence order configurable for generic functions but not for class definitions makes a lot of sense. - -When declaring a class, we can choose the precedence order, and that is about it. -But when defining a generic function, the order of arguments is more important to the function semantics, and the argument precedence being left-to-right is just the default behaviour. - -One shouldn't change the order of arguments of a generic function for the sake of tailoring it to the CLOS priority ranking algorithm, but doing it for a class definition is just fine. - -TIL. - -## References - -1. [Object-Oriented Programming in Common Lisp: A Programmer's Guide to CLOS](https://en.wikipedia.org/wiki/Object-Oriented_Programming_in_Common_Lisp), by Sonja E. Keene diff --git a/_tils/2021-04-24-three-way-conditional-for-number-signs-on-lisp.md b/_tils/2021-04-24-three-way-conditional-for-number-signs-on-lisp.md deleted file mode 100644 index f53451b..0000000 --- a/_tils/2021-04-24-three-way-conditional-for-number-signs-on-lisp.md +++ /dev/null @@ -1,63 +0,0 @@ ---- - -title: Three-way conditional for number signs on Lisp - -date: 2021-04-24 3 - -updated_at: 2021-08-14 - -layout: post - -lang: en - -ref: three-way-conditional-for-number-signs-on-lisp - ---- - -A useful macro from Paul Graham's [On Lisp][on-lisp] book: - -```lisp -(defmacro nif (expr pos zero neg) - (let ((g (gensym))) - `(let ((,g ,expr)) - (cond ((plusp ,g) ,pos) - ((zerop ,g) ,zero) - (t ,neg))))) -``` - -After I looked at this macro, I started seeing opportunities to using it in many places, and yet I didn't see anyone else using it. - -The latest example I can think of is section 1.3.3 of [Structure and Interpretation of Computer Programs][sicp], which I was reading recently: - -```scheme -(define (search f neg-point pos-point) - (let ((midpoint (average neg-point pos-point))) - (if (close-enough? neg-point post-point) - midpoint - (let ((test-value (f midpoint))) - (cond ((positive? test-value) - (search f neg-point midpoint)) - ((negative? test-value) - (search f midpoint pos-point)) - (else midpoint)))))) -``` - -Not that the book should introduce such macro this early, but I couldn't avoid feeling bothered by not using the `nif` macro, which could even remove the need for the intermediate `test-value` variable: - -```scheme -(define (search f neg-point pos-point) - (let ((midpoint (average neg-point pos-point))) - (if (close-enough? neg-point post-point) - midpoint - (nif (f midpoint) - (search f neg-point midpoint) - (midpoint) - (search f midpoint pos-point))))) -``` - -It also avoids `cond`'s extra clunky parentheses for grouping, which is unnecessary but built-in. - -As a macro, I personally feel it tilts the balance towards expressivenes despite its extra cognitive load toll. - -[on-lisp]: http://www.paulgraham.com/onlisptext.html -[sicp]: https://mitpress.mit.edu/sites/default/files/sicp/index.html diff --git a/_tils/2021-07-23-gpg-verification-of-git-repositories-without-tls.md b/_tils/2021-07-23-gpg-verification-of-git-repositories-without-tls.md deleted file mode 100644 index fd42c1c..0000000 --- a/_tils/2021-07-23-gpg-verification-of-git-repositories-without-tls.md +++ /dev/null @@ -1,56 +0,0 @@ ---- - -title: GPG verification of Git repositories without TLS - -date: 2021-07-23 - -layout: post - -lang: en - -ref: gpg-verification-of-git-repositories-without-tls - ---- - -For online Git repositories that use the [Git Protocol] for serving code, you -can can use GPG to handle authentication, if you have the committer's public -key. - -Here's how I'd verify that I've cloned an authentic version of -[remembering][remembering][^not-available]: - -[^not-available]: Funnily enough, not available anymore via the Git Protocol, now only with HTTPS. - -```shell -$ wget -qO- https://euandre.org/public.asc | gpg --import - -gpg: clef 81F90EC3CD356060 : « EuAndreh <eu@euandre.org> » n'est pas modifiée -gpg: Quantité totale traitée : 1 -gpg: non modifiées : 1 -$ pushd `mktemp -d` -$ git clone git://euandreh.xyz/remembering . -$ git verify-commit HEAD -gpg: Signature faite le dim. 27 juin 2021 16:50:21 -03 -gpg: avec la clef RSA 5BDAE9B8B2F6C6BCBB0D6CE581F90EC3CD356060 -gpg: Bonne signature de « EuAndreh <eu@euandre.org> » [ultime] -``` - -On the first line we import the public key (funnily enough, available via -HTTPS), and after cloning the code via the insecure `git://` protocol, we use -`git verify-commit` to check the signature. - -The verification is successful, and we can see that the public key from the -signature matches the fingerprint of the imported one. However -`git verify-commit` doesn't have an option to check which public key you want -to verify the commit against. Which means that if a MITM attack happens, the -attacker could very easily serve a malicious repository with signed commits, -and you'd have to verify the public key by yourself. That would need to happen -for subsequent fetches, too. - -Even though this is possible, it is not very convenient, and certainly very -brittle. Despite the fact that the Git Protocol is much faster, it being harder -to make secure is a big downside. - - - -[Git Protocol]: https://git-scm.com/book/en/v2/Git-on-the-Server-The-Protocols#_the_git_protocol -[remembering]: https://euandreh.xyz/remembering/ diff --git a/_tils/2021-08-11-encoding-and-decoding-javascript-bigint-values-with-reviver.md b/_tils/2021-08-11-encoding-and-decoding-javascript-bigint-values-with-reviver.md deleted file mode 100644 index d71174d..0000000 --- a/_tils/2021-08-11-encoding-and-decoding-javascript-bigint-values-with-reviver.md +++ /dev/null @@ -1,100 +0,0 @@ ---- - -title: Encoding and decoding JavaScript BigInt values with reviver - -date: 2021-08-11 - -updated_at: 2021-08-13 - -layout: post - -lang: en - -ref: encoding-and-decoding-javascript-bigint-values-with-reviver - ---- - -`JSON.parse()` accepts a second parameter: a [`reviver()` function][reviver]. -It is a function that can be used to transform the `JSON` values as they're -being parsed. - -[reviver]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/parse#using_the_reviver_parameter - -As it turns out, when combined with JavaScript's [`BigInt`] type, you can parse -and encode JavaScript `BigInt` numbers via JSON: - -[`BigInt`]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/BigInt - -```javascript -const bigIntReviver = (_, value) => - typeof value === "string" && value.match(/^-?[0-9]+n$/) - ? BigInt(value.slice(0, value.length - 1)) - : value; -``` - -I chose to interpret strings that contains only numbers and an ending `n` suffix -as `BigInt` values, similar to how JavaScript interprets `123` (a number) -differently from `123n` (a `bigint`); - -We do those checks before constructing the `BigInt` to avoid throwing needless -exceptions and catching them on the parsing function, as this could easily -become a bottleneck when parsing large JSON values. - -In order to do the full roundtrip, we now only need the `toJSON()` counterpart: - -```javascript -BigInt.prototype.toJSON = function() { - return this.toString() + "n"; -}; -``` - -With both `bigIntReviver` and `toJSON` defined, we can now successfully parse -and encode JavaScript objects with `BigInt` values transparently: - -```javascript -const s = `[ - null, - true, - false, - -1, - 3.14, - "a string", - { "a-number": "-123" }, - { "a-bigint": "-123n" } -]`; - -const parsed = JSON.parse(s, bigIntReviver); -const s2 = JSON.stringify(parsed); - -console.log(parsed); -console.log(s2); - -console.log(typeof parsed[6]["a-number"]) -console.log(typeof parsed[7]["a-bigint"]) -``` - -The output of the above is: - -``` -[ - null, - true, - false, - -1, - 3.14, - 'a string', - { 'a-number': '-123' }, - { 'a-bigint': -123n } -] -[null,true,false,-1,3.14,"a string",{"a-number":"-123"},{"a-bigint":"-123n"}] -string -bigint -``` - -If you're on a web browser, you can probably try copying and pasting the above -code on the console right now, as is. - -Even though [`JSON`] doesn't include `BigInt` number, encoding and decoding them -as strings is quite trivial on JavaScript. - -[`JSON`]: https://datatracker.ietf.org/doc/html/rfc8259 |