Merge pull request #1034 from electron/language-query-fix

add lang query param and document it in contributing

CONTRIBUTING.md

@@ -144,6 +144,15 @@ See
 on how to get started, or jump right into translating at 
 [crowdin.com/project/electron](https://crowdin.com/project/electron).
 
+#### Sharing Localized URLs
+
+If you wish to share a URL linking to a translated page of the Electron website,
+add a `lang` param to the URL. This will override the visitor's existing 
+language preferences and display the given page in the specified language:
+
+Example: 
+[/docs/api/browser-window?lang=fr-FR](https://electronjs.org/docs/api/browser-window?lang=fr-FR)
+
 ## Routes
 
 Website routes are defined in [server.js](server.js).

middleware/context-builder.js

@@ -9,19 +9,21 @@ module.exports = function contextBuilder (req, res, next) {
   req.i18n = i18n
 
   // This allows the language to be set per-request using a query param, so
-  // folks can share a link like /docs/api/app?language=fr-FR and know that
+  // folks can share a link like /docs/api/app?lang=fr-FR and know that
   // the recipient will see the doc in that language, regardless of their
   // language settings. If no query param is set, fall back to the default
   // language (or the one set in the cookie)
-  const targetLanguage = req.query.language || req.language
+  if (req.query.lang) {
+    req.language = req.query.lang
+  }
 
-  const localized = i18n.website[targetLanguage]
+  const localized = i18n.website[req.language]
 
   // Page titles, descriptions, etc
   let page = Object.assign({
     title: 'Electron',
     path: req.path
-  }, i18n.website[targetLanguage].pages[req.path])
+  }, i18n.website[req.language].pages[req.path])
 
   if (req.path !== '/') {
     page.title = `${page.title} | Electron`
@@ -41,7 +43,7 @@ module.exports = function contextBuilder (req, res, next) {
   }
 
   if (req.path.startsWith('/docs')) {
-    req.context.docs = i18n.docs[targetLanguage]
+    req.context.docs = i18n.docs[req.language]
   }
 
   return next()