x/land@v0.9.2/cache.ts

Run Deno X module without installation.
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import { ensureDir } from "https://deno.land/std@0.136.0/fs/ensure_dir.ts";import { join } from "https://deno.land/std@0.136.0/path/mod.ts";
/** download and cache remote contents */export async function cache( url: string,): Promise<{ content: Uint8Array; contentType: string | null }> { const { protocol, hostname, port, pathname, search } = new URL(url); const isLocalhost = ["0.0.0.0", "127.0.0.1", "localhost"].includes(hostname); const cacheDir = join( await getDenoDir(), "deps", protocol.replace(":", ""), hostname + (port ? "_PORT" + port : ""), ); const hashname = toHex( await crypto.subtle.digest( "sha-256", new TextEncoder().encode(pathname + search), ), ); const contentFilepath = join(cacheDir, hashname); const metaFilepath = join(cacheDir, hashname + ".metadata.json");
if ( !isLocalhost && await existsFile(contentFilepath) && await existsFile(metaFilepath) ) { const [content, meta] = await Promise.all([ Deno.readFile(contentFilepath), Deno.readTextFile(metaFilepath), ]); try { const { headers = {} } = JSON.parse(meta); return { content, contentType: headers["content-type"] || null, }; } catch (_e) { // ignore } }
const retryTimes = 3; let err = new Error("Unknown"); for (let i = 0; i < retryTimes; i++) { try { const resp = await fetch(url); if (resp.status >= 400) { err = new Error(resp.statusText); continue; } const buffer = await resp.arrayBuffer(); const content = new Uint8Array(buffer); if (!isLocalhost) { const headers: Record<string, string> = {}; resp.headers.forEach((val, key) => { headers[key] = val; }); await ensureDir(cacheDir); await Promise.all([ Deno.writeFile(contentFilepath, content), Deno.writeTextFile( metaFilepath, JSON.stringify( { headers, url, createdAt: Date.now() }, undefined, 2, ), ), ]); } return { content, contentType: resp.headers.get("content-type"), }; } catch (e) { err = e; } }
return Promise.reject(err);}
function toHex(buffer: ArrayBuffer) { const bytes = new Uint8Array(buffer); return [...bytes].map((b) => b.toString(16).padStart(2, "0")).join("");}
/** get the deno cache dir. */async function getDenoDir() { const p = Deno.run({ cmd: [Deno.execPath(), "info", "--json"], stdout: "piped", stderr: "null", }); const output = new TextDecoder().decode(await p.output()); const { denoDir } = JSON.parse(output); p.close(); if (denoDir === undefined || !await existsDir(denoDir)) { throw new Error(`can"t find the deno dir`); } return denoDir;}
/* check whether or not the given path exists as a directory. */async function existsDir(path: string): Promise<boolean> { try { const fi = await Deno.lstat(path); if (fi.isDirectory) { return true; } return false; } catch (err) { if (err instanceof Deno.errors.NotFound) { return false; } throw err; }}
/* check whether or not the given path exists as regular file. */async function existsFile(path: string): Promise<boolean> { try { const fi = await Deno.lstat(path); if (fi.isFile) { return true; } return false; } catch (err) { if (err instanceof Deno.errors.NotFound) { return false; } throw err; }}