Initial commit

src/app.mjs

@@ -0,0 +1,99 @@
+//Imports
+  import express from "express"
+  import fs from "fs"
+  import path from "path"
+  import octokit from "@octokit/graphql"
+  import cache from "memory-cache"
+  import ratelimit from "express-rate-limit"
+  import metrics from "./metrics.mjs"
+
+//Load svg template, style and query
+  async function load() {
+    return await Promise.all(["template.svg", "style.css", "query.graphql"].map(async file => `${await fs.promises.readFile(path.join("src", file))}`))
+  }
+
+//Setup
+  export default async function setup() {
+
+    //Load settings
+      const settings = JSON.parse((await fs.promises.readFile(path.join("settings.json"))).toString())
+      console.log(settings)
+      const {token, maxusers = 0, restricted = [], debug = false, cached = 30*60*1000, port = 3000, ratelimiter = null} = settings
+    //Load svg template, style and query
+      let [template, style, query] = await load()
+      const graphql = octokit.graphql.defaults({headers:{authorization: `token ${token}`}})
+
+    //Setup server
+      const app = express()
+      const middlewares = []
+    //Rate limiter middleware
+      if (ratelimiter) {
+        app.set("trust proxy", 1)
+        middlewares.push(ratelimit({
+          skip(req, res) { return !!cache.get(req.params.login) },
+          message:"Too many requests",
+          ...ratelimiter
+        }))
+      }
+    //Cache headers middleware
+      middlewares.push((req, res, next) => {
+        res.header("Cache-Control", cached ? `public, max-age=${cached}` : "no-store, no-cache")
+        next()
+      })
+
+    //Base routes
+      app.get("/", (req, res) => res.redirect("https://github.com/lowlighter/metrics"))
+      app.get("/favicon.ico", (req, res) => res.sendStatus(204))
+
+    //Metrics
+      app.get("/:login", ...middlewares, async (req, res) => {
+
+        //Request params
+          const {login} = req.params
+          if ((restricted.length)&&(!restricted.includes(login)))
+            return res.sendStatus(403)
+
+        //Read cached data if possible
+          if ((!debug)&&(cached)&&(cache.get(login))) {
+            res.header("Content-Type", "image/svg+xml")
+            res.send(cache.get(login))
+            return
+          }
+        //Maximum simultaneous users
+          if ((maxusers)&&(cache.size()+1 > maxusers))
+            return res.sendStatus(503)
+
+        //Compute rendering
+          try {
+            //Render
+              if (debug)
+                [template, style, query] = await load()
+              const rendered = await metrics({login}, {template, style, query, graphql})
+            //Cache
+              if ((!debug)&&(cached))
+                cache.put(login, rendered, cached)
+            //Send response
+              res.header("Content-Type", "image/svg+xml")
+              res.send(rendered)
+          }
+        //Internal error
+          catch (error) {
+            //Not found user
+              if ((error instanceof Error)&&(/^user not found$/.test(error.message)))
+                return res.sendStatus(404)
+            //General error
+              console.error(error)
+              res.sendStatus(500)
+          }
+      })
+
+    //Listen
+      app.listen(port, () => console.log([
+        `Listening on port      | ${port}`,
+        `Debug mode             | ${debug}`,
+        `Restricted to users    | ${restricted.size ? [...restricted].join(", ") : "(unrestricted)"}`,
+        `Cached time            | ${cached} seconds`,
+        `Rate limiter           | ${ratelimiter ? JSON.stringify(ratelimiter) : "(enabled)"}`,
+        `Max simultaneous users | ${maxusers ? `${maxusers} users` : "(unrestricted)"}`
+      ].join("\n")))
+  }