Generate Atom feed for the React Native blog.

Summary:
An Atom feed is now generated as part of the build script. This is done statically and not as a React view because React is not the right tool for generating XML documents.

Some additional metadata is stored in `metadata-blog.js` and duplicated to `metadata-blog.json` in the `server/` directory to aid in the generation of the feed. Let me know if there's a better way to import this data using the existing Haste module that wouldn't require writing an additional JSON file.

The feed will be available at https://facebook.github.io/react-native/blog.xml

A sample output of the Atom feed is included at the bottom. It is a [valid Atom 1.0 feed](https://validator.w3.org/feed/check.cgi), with some additional recommendations that can be ignored for now.

> Congratulations!
>
> [Valid Atom 1.0] This is a valid Atom 1.0 feed.
> Recommendations
>
> This feed is valid, but interoperability with the widest range of feed readers could be improved by implementing the following recommendations.
> line 2, col
Closes https://github.com/facebook/react-native/pull/10611

Differential Revision: D4097381

Pulled By: mkonicek

fbshipit-source-id: 8d2e18923358d1903b2715b00c48680b0c4dff68

website/.gitignore

@@ -1,5 +1,6 @@
 src/react-native/docs/**
 src/react-native/blog/**
 core/metadata*
+server/metadata*
 *.log
 /build/

website/core/BlogPost.js

@@ -22,7 +22,7 @@ var BlogPost = React.createClass({
     var post = this.props.post;
     var content = this.props.content;
 
-    var match = post.path.match(/([0-9]+)\/([0-9]+)\/([0-9]+)/);
+    var match = post.publishedAt.match(/([0-9]+)-([0-9]+)-([0-9]+)/);
     // Because JavaScript sucks at date handling :(
     var year = match[1];
     var month = [

website/package.json

@@ -14,6 +14,7 @@
     "bluebird": "^2.9.21",
     "connect": "2.8.3",
     "deep-assign": "^2.0.0",
+    "feed": "^0.3.0",
     "flow-parser": "^0.32.0",
     "fs.extra": "1.3.2",
     "glob": "6.0.4",

website/server/convert.js

@@ -191,9 +191,16 @@ function execute() {
       .replace(/\./g, '-')
       .replace(/\-md$/, '.html');
 
+    // Extract 2015-08-13 from 2015/08/13/blog-post-name-0-5.html
+    var match = filePath.match(/([0-9]+)\/([0-9]+)\/([0-9]+)/);
+    var year = match[1];
+    var month = match[2];
+    var day = match[3];
+    var publishedAt = year + '-' + month + '-' + day;
+
     var res = extractMetadata(fs.readFileSync(file, {encoding: 'utf8'}));
     var rawContent = res.rawContent;
-    var metadata = Object.assign({path: filePath, content: rawContent}, res.metadata);
+    var metadata = Object.assign({path: filePath, content: rawContent, publishedAt: publishedAt}, res.metadata);
 
     metadatasBlog.files.push(metadata);
 
@@ -210,7 +217,6 @@ function execute() {
       buildFile('BlogPageLayout', { page: page, perPage: perPage })
     );
   }
-
   fs.writeFileSync(
     'core/metadata-blog.js',
     '/**\n' +
@@ -219,6 +225,11 @@ function execute() {
     ' */\n' +
     'module.exports = ' + JSON.stringify(metadatasBlog, null, 2) + ';'
   );
+  fs.writeFileSync(
+    'server/metadata-blog.json',
+    JSON.stringify(metadatasBlog, null, 2)
+  );
+
 }
 
 if (argv.convert) {

website/server/generate.js

@@ -14,6 +14,7 @@ var glob = require('glob');
 var fs = require('fs.extra');
 var mkdirp = require('mkdirp');
 var server = require('./server.js');
+var Feed = require('feed');
 
 require('./convert.js')();
 server.noconvert = true;
@@ -23,6 +24,49 @@ server.noconvert = true;
 // requests.
 var queue = Promise.resolve();
 
+// Generate RSS Feeds
+queue = queue.then(function() {
+  return new Promise(function(resolve, reject) {
+    var targetFile = 'build/react-native/blog/feed.xml';
+
+    var basePath = 'https://facebook.github.io/react-native/';
+    var blogPath = basePath + 'blog/';
+
+    var metadataBlog = JSON.parse(fs.readFileSync('server/metadata-blog.json'));
+    var latestPost = metadataBlog.files[0];
+    var feed = new Feed({
+      title: 'React Native Blog',
+      description: 'The best place to stay up-to-date with the latest React Native news and events.',
+      id: blogPath,
+      link: blogPath,
+      image: basePath + 'img/header_logo.png',
+      copyright: 'Copyright © ' + new Date().getFullYear() + ' Facebook Inc.',
+      updated: new Date(latestPost.publishedAt),
+    });
+
+    metadataBlog.files.forEach(function(post) {
+      var url = blogPath + post.path;
+      feed.addItem({
+        title: post.title,
+        id: url,
+        link: url,
+        date: new Date(post.publishedAt),
+        author: [{
+          name: post.author,
+          link: post.authorURL
+        }],
+        description: post.content.trim().split('\n')[0],
+      });
+    });
+
+    mkdirp.sync(targetFile.replace(new RegExp('/[^/]*$'), ''));
+    fs.writeFileSync(targetFile, feed.render('atom-1.0'));
+    console.log('Generated RSS feed')
+    resolve();
+  });
+});
+
+// Generate HTML for each non-source code JS file
 glob('src/**/*.*', function(er, files) {
   files.forEach(function(file) {
     var targetFile = file.replace(/^src/, 'build');