sitelinks: allow to set lang=auto

addressing #21 (comment)
maxlath · Jan 13, 2022 · 232dcde · 232dcde
1 parent 912c240
commit 232dcde
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Showing 3 changed files with 24 additions and 6 deletions.
diff --git a/docs/readme/user_guide.md b/docs/readme/user_guide.md
@@ -56,12 +56,12 @@ By default, the destination is Wikipedia in the user language, which is guessed
 #### Wikimedia Projects
 ###### lang
 
-Pass a `lang` parameter (or just `l`) to override the `accept-language` header. Pass several values to set the fallback chain.
+Pass a `lang` parameter (or just `l`) to override the `accept-language` header. Pass several values to set the fallback chain. The value `auto` can be used to represent the value of the `accept-language` header.
 
-|  request                                    | redirection                                          |
-|:--------------------------------------------|:-----------------------------------------------------|
-| `/Q184226?lang=fr`                          | https://fr.wikipedia.org/wiki/Gilles_Deleuze         |
-| `/Q184226?lang=als,oc,fr,en&site=wikiquote` | https://oc.wikipedia.org/wiki/Gilles_Deleuze         |
+|  request                                         | redirection                                          |
+|:-------------------------------------------------|:-----------------------------------------------------|
+| `/Q184226?lang=fr`                               | https://fr.wikipedia.org/wiki/Gilles_Deleuze         |
+| `/Q184226?lang=als,oc,auto,fr,en&site=wikiquote` | https://oc.wikipedia.org/wiki/Gilles_Deleuze         |
 
 ###### site
 

diff --git a/lib/get_request_data.js b/lib/get_request_data.js
@@ -13,7 +13,19 @@ module.exports = (query, headers, context) => {
   }
 
   const site = query.site || 'wiki'
-  const lang = query.lang || parseLangHeader(headers) || 'en'
+
+  const langHeader = parseLangHeader(headers)
+
+  let lang
+  if (query.lang) {
+    lang = query.lang
+      .split(',')
+      .map(l => l === 'auto' ? langHeader : l)
+      .join(',')
+  } else {
+    lang = langHeader || 'en'
+  }
+
   logger.info('site', site)
   logger.info('lang', lang)
 

diff --git a/test/sitelinks.js b/test/sitelinks.js
@@ -22,6 +22,12 @@ describe('sitelinks', function () {
     res.headers.get('location').should.equal('https://de.wikipedia.org/wiki/Gilles_Deleuze')
   })
 
+  it('should use the header in auto mode', async () => {
+    const res = await get('/Q184226?lang=auto,de,fr', 'es')
+    res.statusCode.should.equal(302)
+    res.headers.get('location').should.equal('https://es.wikipedia.org/wiki/Gilles_Deleuze')
+  })
+
   it('should take the site from the query', async () => {
     const res = await get('/Q184226?site=wikiquote')
     res.statusCode.should.equal(302)