Deprecate old static badge

Now that the static badge has been moved in #2284, next in line for cleaning out `server.js` is this “static badge, old format.” I imagine this route is _very, very old_. (Actually I wouldn’t be surprised if it’s not used at all. I’d be cuious to see some stats on that endpoint.)

In the case of URLs which have permanently changed, an approach I’d like to try is issuing a 301 Redirect.

The benefit is that if a user pastes the URL into the address bar while they are previewing or editing it, the browser will replace the address with the corrected URL when it loads. I figure this will cause some people to update their URLs with no effort, simply because they previewed the badge in their browser, and others to change over, if they notice it.

We incur a slight cost, which is a second request. However many browsers cache the 301’s indefinitely, and we can set an effectively infinite cache duration so the CDN and most other downstream caches will keep them a long time. And handling the redirect is extremely cheap.

This is a nice way to preserve backward compatibility of old routes without having to complicate the new route, such as in the case of vso -> azure-devops. For maintenance purposes, the route that redirects can effectively be treated separately.

It’s also a nice, gentle, and confidence-inspiring way to signal that users should update their URLs.

server.js

@@ -19,6 +19,7 @@ const GithubConstellation = require('./services/github/github-constellation')
 const PrometheusMetrics = require('./lib/sys/prometheus-metrics')
 const sysMonitor = require('./lib/sys/monitor')
 const log = require('./lib/log')
+const { staticBadgeUrl } = require('./lib/make-badge-url')
 const makeBadge = require('./gh-badges/lib/make-badge')
 const suggest = require('./lib/suggest')
 const {
@@ -243,32 +244,26 @@ camp.route(/^\/flip\.svg$/, (data, match, end, ask) => {
   makeSend('svg', ask.res, end)(svg)
 })
 
-// Any badge, old version.
-camp.route(/^\/([^/]+)\/(.+).png$/, (data, match, end, ask) => {
-  const subject = match[1]
-  const status = match[2]
-  const color = data.color
+// Any badge, old version. This route must be registered last.
+camp.route(/^\/([^/]+)\/(.+).png$/, (queryParams, match, end, ask) => {
+  const [, label, message] = match
+  const { color } = queryParams
 
-  // Cache management - the badge is constant.
-  const cacheDuration = (3600 * 24 * 1) | 0 // 1 day.
+  const redirectUrl = staticBadgeUrl({
+    label,
+    message,
+    color,
+    format: 'png',
+  })
+
+  ask.res.statusCode = 301
+  ask.res.setHeader('Location', redirectUrl)
+
+  // The redirect is permanent.
+  const cacheDuration = (365 * 24 * 3600) | 0 // 1 year
   ask.res.setHeader('Cache-Control', `max-age=${cacheDuration}`)
-  if (+new Date(ask.req.headers['if-modified-since']) >= +serverStartTime) {
-    ask.res.statusCode = 304
-    ask.res.end() // not modified.
-    return
-  }
-  ask.res.setHeader('Last-Modified', serverStartTime.toGMTString())
-
-  // Badge creation.
-  try {
-    const badgeData = { text: [subject, status] }
-    badgeData.colorscheme = color
-    const svg = makeBadge(badgeData)
-    makeSend('png', ask.res, end)(svg)
-  } catch (e) {
-    const svg = makeBadge({ text: ['error', 'bad badge'], colorscheme: 'red' })
-    makeSend('png', ask.res, end)(svg)
-  }
+
+  ask.res.end()
 })
 
 if (config.redirectUri) {

services/service-tester.js

@@ -64,13 +64,14 @@ class ServiceTester {
       })
       // eslint-disable-next-line mocha/prefer-arrow-callback
       .finally(function() {
+        let responseBody
+        try {
+          responseBody = JSON.parse(this._response.body)
+        } catch (e) {
+          responseBody = this._response.body
+        }
         // `this` is the IcedFrisby instance.
-        trace.logTrace(
-          'outbound',
-          emojic.shield,
-          'Response',
-          JSON.parse(this._response.body)
-        )
+        trace.logTrace('outbound', emojic.shield, 'Response', responseBody)
       })
 
     this.specs.push(spec)

services/static-badge/static-badge.tester.js

@@ -38,3 +38,8 @@ t.create('Override colorB')
 t.create('Override label')
   .get('/badge/label-message-blue.json?style=_shields_test&label=mylabel')
   .expectJSON({ name: 'mylabel', value: 'message', colorB: '#007ec6' })
+
+t.create('Old static badge')
+  .get('/foo/bar.png?color=blue', { followRedirect: false })
+  .expectStatus(301)
+  .expectHeader('Location', '/badge/foo-bar-blue.png')