https://guide.aelve.com/haskell/feed/category/gr6kte152016-03-18T19:29:37Zl8p4vyrc2016-03-18T19:29:37Z<h1> <span class="item-name">atom-basic</span> (<a href="https://hackage.haskell.org/package/atom-basic">Hackage</a>) </h1><h2>Pros</h2><ul></ul><h2>Cons</h2><ul></ul>x7ekxq7y2016-03-18T19:29:28Z<h1> <span class="item-name">yesod-newsfeed</span> (<a href="https://hackage.haskell.org/package/yesod-newsfeed">Hackage</a>) </h1><h2>Pros</h2><ul></ul><h2>Cons</h2><ul><p><li>Not a standalone library – can only be used with Yesod.</li></p></ul>dnt8urny2016-03-18T19:28:47Z<h1> <span class="item-name">rss</span> (<a href="https://hackage.haskell.org/package/rss">Hackage</a>) </h1><h2>Pros</h2><ul></ul><h2>Cons</h2><ul><p><li>Can't generate Atom feeds.</li></p><p><li>Uses <code>String</code> instead of <code>Text</code>.</li></p></ul>m9jtvxuv2016-03-18T19:28:35Z<h1> <span class="item-name">feed</span> (<a href="https://hackage.haskell.org/package/feed">Hackage</a>) </h1><p>A big and fairly complete (but messy) library for generating, parsing, and validating Atom/RSS feeds.</p> <h2>Pros</h2><ul><p><li>The only library here that can parse feeds in addition to generating them.</li></p><p><li>Supports the most number of formats (Atom, RSS 2.x, and even old RSS 1.0).</li></p></ul><h2>Cons</h2><ul><p><li>Uses <code>String</code> instead of <code>Text</code>.</li></p><p><li>Kinda complicated (and you would have to take several looks at others' feeds and at the documentation for Atom/RSS formats, since the library itself doesn't have much documentation).</li></p></ul><h2>Notes</h2><h1><span id="item-notes-m9jtvxuv-links"></span>Links</h1><ul> <li><a href="https://github.com/bergmark/feed/blob/master/tests/Example/CreateAtom.hs">An example of creating an Atom feed</a></li> </ul> <h1><span id="item-notes-m9jtvxuv-imports"></span>Imports</h1><p>For Atom feeds:</p> <div class="sourceCode"><pre class="sourceCode"><code class="sourceCode"><span class="kw">import qualified</span> <span class="dt">Text.Feed.Types</span> <span class="kw">as</span> <span class="dt">Feed</span> <span class="kw">import qualified</span> <span class="dt">Text.Feed.Util</span> <span class="kw">as</span> <span class="dt">Feed</span> <span class="kw">import qualified</span> <span class="dt">Text.Atom.Feed</span> <span class="kw">as</span> <span class="dt">Atom</span> <span class="kw">import qualified</span> <span class="dt">Text.Atom.Feed.Export</span> <span class="kw">as</span> <span class="dt">Atom</span> <span class="co">-- from the “xml” package</span> <span class="kw">import qualified</span> <span class="dt">Text.XML.Light.Output</span> <span class="kw">as</span> <span class="dt">XML</span></code></pre></div> <h1><span id="item-notes-m9jtvxuv-creating-an-atom-feed"></span>Creating an Atom feed</h1><p>There are several types that you would need:</p> <ul> <li><a href="https://hackage.haskell.org/package/feed/docs/Text-Atom-Feed.html#t:Feed"><code>Feed</code></a></li> <li><a href="https://hackage.haskell.org/package/feed/docs/Text-Atom-Feed.html#t:Entry"><code>Entry</code></a> (feed entry)</li> <li><a href="https://hackage.haskell.org/package/feed/docs/Text-Atom-Feed.html#t:EntryContent"><code>EntryContent</code></a> (can be e.g. <code>TextContent</code>, <code>HTMLContent</code>, or a few others)</li> <li><a href="https://hackage.haskell.org/package/feed/docs/Text-Atom-Feed.html#t:TextContent"><code>TextContent</code></a> is unrelated to <code>EntryContent</code>, and can be a <code>TextString</code> or a <code>HTMLString</code></li> <li><a href="https://hackage.haskell.org/package/feed/docs/Text-Atom-Feed.html#t:Person"><code>Person</code></a> (author of an entry)</li> <li><a href="https://hackage.haskell.org/package/feed/docs/Text-Atom-Feed.html#t:Link"><code>Link</code></a></li> </ul> <p>Each of these (apart from <code>EntryContent</code> and <code>TextContent</code>) is a record with lots of fields. You would almost never need all of those fields, so there are some helper functions available that make initialising them easier. For instance, to create a <code>Link</code>, use <code>nullLink</code>:</p> <div class="sourceCode"><pre class="sourceCode"><code class="sourceCode"><span class="co">-- URI = String</span> <span class="ot">nullLink ::</span> <span class="dt">URI</span> <span class="ot">-&gt;</span> <span class="dt">Link</span></code></pre></div> <p>And then you can customise some of the fields:</p> <div class="sourceCode"><pre class="sourceCode"><code class="sourceCode">nullLink <span class="st">&quot;http://foo.bar&quot;</span> { linkTitle <span class="fu">=</span> <span class="dt">Just</span> <span class="st">&quot;Foo Bar&quot;</span> }</code></pre></div> <p>Same with <code>nullEntry</code> and <code>nullFeed</code>; a complete example can be found <a href="https://github.com/bergmark/feed/blob/master/tests/Example/CreateAtom.hs">here</a>. Note that:</p> <ul> <li> <p>The example uses <code>String</code>s as dates. If you want to convert <code>UTCTime</code> to the string format expected by the library, use <code>toFeedDateStringUTC AtomKind</code> (from <code>Text.Feed.Util</code> and <code>Text.Feed.Types</code> respectively).</p> </li> <li> <p>The newest entry should be the 1st in the list.</p> </li> <li> <p>The feed ID (i.e. the 1st parameter to <code>nullFeed</code>) doesn't have to be a link – for instance, for <a href="https://github.com/bergmark/feed/commits/master.atom">Github feeds</a> it's something like</p> <div class="sourceCode"><pre class="sourceCode"><code class="sourceCode">tag:github.com,2008:/bergmark/feed/commits/master</code></pre></div> <p>Entry IDs, contrary to what the example says, don't have to be links either.</p> </li> </ul>