Move legacy services from server.js into services/ (#1958)

This builds on the work of #1931 by moving the legacy services into `services/`.

services/pub/pub.service.js

@@ -0,0 +1,42 @@
+'use strict'
+
+const LegacyService = require('../legacy-service')
+const { makeBadgeData: getBadgeData } = require('../../lib/badge-data')
+const { addv: versionText } = require('../../lib/text-formatters')
+const { version: versionColor } = require('../../lib/color-formatters')
+const { latest: latestVersion } = require('../../lib/version')
+
+// For Dart's pub.
+module.exports = class Pub extends LegacyService {
+  static registerLegacyRouteHandler({ camp, cache }) {
+    camp.route(
+      /^\/pub\/v(pre)?\/(.*)\.(svg|png|gif|jpg|json)$/,
+      cache((data, match, sendBadge, request) => {
+        const includePre = Boolean(match[1])
+        const userRepo = match[2] // eg, "box2d"
+        const format = match[3]
+        const apiUrl = 'https://pub.dartlang.org/packages/' + userRepo + '.json'
+        const badgeData = getBadgeData('pub', data)
+        request(apiUrl, (err, res, buffer) => {
+          if (err != null) {
+            badgeData.text[1] = 'inaccessible'
+            sendBadge(format, badgeData)
+            return
+          }
+          try {
+            const data = JSON.parse(buffer)
+            // Grab the latest stable version, or an unstable
+            const versions = data.versions
+            const version = latestVersion(versions, { pre: includePre })
+            badgeData.text[1] = versionText(version)
+            badgeData.colorscheme = versionColor(version)
+            sendBadge(format, badgeData)
+          } catch (e) {
+            badgeData.text[1] = 'invalid'
+            sendBadge(format, badgeData)
+          }
+        })
+      })
+    )
+  }
+}