Putting posts content on the index page

Posted on July 6, 2015

Once you have created a Hakyll based site the first page contains only the titles of your posts. It can be acceptable if your first page contains another content, but if there are only the latest posts it looks weird. Let’s check how does it works.

Default index page template includes post-list.html template which contains following code:

<ul>
  $for(posts)$
    <li>
      <a href="$url$">$title$</a> - $date$
    </li>
  $endfor$
</ul>

You could change this code, but you should remember that archives page uses same template for rendering. So, it would be better to create separate snippet for the complete post list. This template will be really simple:

<ul>
  $for(posts)$
    <li class="post-preview">
      <a href="$url$">$title$</a> - $date$
      $body$
    </li>
  $endfor$
</ul>

But where the posts came from? Definitely from the Haskell code. The initial site.hs has following code to fill the index page:

match "pages/index.html" $ do
    route idRoute
    compile $ do
        posts <- recentFirst =<< loadAll "posts/*"
        let indexCtx =
                listField "posts" postCtx (return posts) `mappend`
                defaultContext

        getResourceBody
            >>= applyAsTemplate indexCtx
            >>= loadAndApplyTemplate "templates/default.html" indexCtx
            >>= relativizeUrls

Actually we don’t want to have complete post here, but only the post content. We can achieve it using snapshots. So, instead of using loadAll we can get it from snapshot prepared on rendering posts:

        posts <- recentFirst =<< loadAllSnapshots "posts/*" "content"

So, you need to save snapshot when you processing your posts:

match "posts/*" $ do
    route $ setExtension "html"
    compile $ pandocCompiler
        >>= saveSnapshot "content"
        >>= loadAndApplyTemplate "templates/post.html"    postCtx
        >>= loadAndApplyTemplate "templates/post-with-comment.html" postCtx
        >>= loadAndApplyTemplate "templates/default.html" postCtx
        >>= relativizeUrls

Finally, it would be nice to have a post preview. Fortunately, this functionality is already implemented in Hakyll. In your blog post you need to put <!--more--> marker in the place you’d like to stop preview. When you need to use teaserField function which takes name of teaser variable and name of the snapshot to use and creates Context String. Since Context is a Monoid you can combine it with default post context using mappend.

    match "pages/index.html" $ do
        route idRoute
        compile $ do
            posts <- recentFirst =<< loadAll "posts/*"
            let indexCtx =
                    listField "posts" previewCtx (return posts) `mappend`
                    defaultContext

        getResourceBody
            >>= applyAsTemplate indexCtx
            >>= loadAndApplyTemplate "templates/default.html" indexCtx
            >>= relativizeUrls

previewCtx :: Context String
previewCtx = teaserField "preview" "content" `mappend` postCtx

And you also need to update the template to make it preview aware:

<ul>
  $for(posts)$
    <li class="post-preview">
      <a href="$url$">$title$</a> - $date$
      $if(preview)$
        $preview$
      $else$
        $body$
      $endif$
    </li>
  $endfor$
</ul>

And that’s it. Of course there a lot of things are still missed, like tags and pagination. I’m going to cover it in the next posts as soon as I’ll add them to this blog.

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