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const CACHE_NAME = "static-shared-assets";
const FALLBACK_PATHS = {
img: "/fallback-image-FIXME.svg",
data: {
static: "/fallback-data-FIXME.json",
},
};
const leafValues = tree =>
Object.values(tree).map(x =>
typeof x !== "object"
? x
: leafValues(x)
);
const collectLeaves = tree =>
leafValues(tree).flat(Infinity);
const DEFAULT_INSTALL_PATHS = [
"/",
"index.html",
"style.css",
"img/favicon.svg",
// "papo.js",
// ].concat(collectLeaves(FALLBACK_PATHS));
];
const mkInstallHandler = ({ self, caches }) => event => {
self.skipWaiting();
event.waitUntil(
caches.open(CACHE_NAME).then(
cache => cache.addAll(DEFAULT_INSTALL_PATHS),
),
);
};
const store = async (caches, request, response) => {
const cache = await caches.open(CACHE_NAME);
await cache.put(request, response);
};
const getPrefixIn = (paths, segments) => {
if (paths === undefined) {
return null;
}
if (segments.length === 0) {
return null;
}
if (typeof paths === "string") {
return paths;
}
return getPrefixIn(paths[segments[0]], segments.slice(1));
};
const fromCache = async (caches, fetch, { request, preloadResponse }) => {
const cachedResponse = await caches.match(request);
if (cachedResponse) {
fetch(request).then(async freshResponse =>
store(caches, request, freshResponse));
return cachedResponse;
}
const preloadedResponse = await preloadResponse;
if (preloadedResponse) {
store(caches, request, preloadeResponse.clone());
return preloadedResponse;
}
try {
const fetchedResponse = await fetch(request);
store(caches, request, fetchedResponse.clone());
return fetchedResponse;
} catch (e) {
const fallbackResponse = await maybeFallback(caches, request);
if (fallbackResponse) {
return fallbackResponse;
}
throw e;
}
};
const maybeFallback = async (caches, request, paths = FALLBACK_PATHS) => {
const url = new URL(request.url)
const segments = url.pathname.split("/").filter(s => !!s)
const fallbackPath = getPrefixIn(paths, segments);
if (fallbackPath) {
return await caches.match(fallbackPath);
}
return null;
}
const CONFIG_PATHS = {
immutable: {
"some": {
"path": true,
},
},
staleOK: {
},
};
const PRIORITY_ORDERING = [
"immutable",
"staleFallback",
"stale",
];
const pullThroughCache = (env, ctx) => {
};
/*
// FIXME: handle base paths
const STRATEGIES = [
{
name: "immutable",
routes: new Set([
"/cas",
]),
fn: immutable,
},
{
name: "staleFallback",
routes: {
"/img/icon/": "",
},
fn: staleFallback,
},
{
name: "staleOnly",
routes: new Set([
// FIXME: add "/"
"/index.html": true,
"/style.css": true,
"/papo.js": true,
]),
img: "/fallback-image-FIXME.svg",
data: {
static: "/fallback-data-FIXME.json",
},
fn: staleOnly,
},
};
*/
const asSegments = pathname =>
pathname.split("/").filter(s => !!s);
const requestSegments = ({ url }) =>
asSegments(new URL(url).pathname);
/*
const strategyFor = (segments, paths = CONFIG_PATHS) => {
for (const strategy of PRIORITY_ORDERING) {
if (getPrefixIn(paths[strategy.name], segments)) {
return strategy;
}
}
};
*/
const networkOnly = async (_env, { fetch, event }) => {
const preloaded = await event.preloadResponse;
if (preloaded) {
return preloaded;
}
return await fetch(event.request);
};
const strategyFor = (segments, paths = CONFIG_PATHS) => {
return networkOnly;
};
// FIXME: noop if "Connection": "Upgrade" is in header
// if (event.request.headers.get("Connection").toLowerCase() == "upgrade");
// out([...event.request.headers.entries()]);
const mkFetchHandler = env => (event, mkfetch = () => fetch) => {
if (event.request.method !== "GET") {
return;
}
const segments = requestSegments(event.request);
const strategyFn = strategyFor(segments);
event.respondWith(strategyFn(env, {
event,
segments,
fetch: mkfetch(),
}));
};
const mkActivateHandler = ({ self, clients }) => event =>
event.waitUntil(Promise.all([
clients.claim(),
self.registration.navigationPreload?.enable(),
]));
const registerListeners = env => {
env.self.addEventListener("install", mkInstallHandler(env));
env.self.addEventListener("activate", mkActivateHandler(env));
env.self.addEventListener("fetch", mkFetchHandler(env));
};
const main = ({
self,
caches,
clients,
out = console.log,
err = console.warn,
} = {}) =>
registerListeners({
self,
caches,
clients,
baseSegments: asSegments(self.location.pathname),
out,
err,
});
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