`pre_write` extension callbacks cannot modify the rendered HTML

[halostatue]

I'm working on an extension that parses links like [foo]($ref:foo.md) and turns it into a proper link so that I don't have to know the full rendered path to the post. I'm doing this as part of a pre_write extension with Floki to parse the the <a href= (or <img src=) value and convert $ref:foo.md to the appropriate full path for the post named foo.md.

It doesn't work. I think that the fix is relatively small in lib/mix/tasks/tableau.build.ex:

     token = put_in(token.site[:pages], pages)
     token = mods |> extensions_for(:pre_write) |> run_extensions(:pre_write, token)

-    for %{body: body, permalink: permalink} <- pages do
+    for %{body: body, permalink: permalink} <- token.site[:pages] do
       file_path = build_file_path(out, permalink)
       dir = Path.dirname(file_path)

       File.mkdir_p!(dir)

       File.write!(file_path, body)
    end

As long as the pre_write/1 callback updates token.site[:pages] as part of its flow, it should be able to work.

[mhanberg]

I believe you're correct.

I think this was missed because my use use (Tableau.OGExtension) didn't need to modify the HTML, just needed to see all rendered pages.

Technically I think I built that extension "incorrectly", as it should probably add the pages to the site token and let the framework write the files for it.

PR is welcome!

[halostatue]

I implemented my own build as a copy with the proposed fix and it does work correctly when that's done. I'm in the process of reviewing a few things but can submit a PR for this maybe later today. I have several extensions that I've built for my site that I'll be extracting after I review them and make sure that they're well tested.

I have one other issue open (this will require more thinking because I think that Tableau would benefit from a "slugify" strategy that all extensions could take advantage of) but will probably have a few more proposals (I've also overridden to use MDEx 0.10 which uses plugins, and I have a possible change to the mdex converter, but it needs better configurability than I currently have before I propose it).

[halostatue]

Technically I think I built that extension "incorrectly", as it should probably add the pages to the site token and let the framework write the files for it.

I know what you mean. One of the internal items that I have built is a HumansTxt extension (post_write/1) which should probably just be a TextConverter with a layout that generates plaintext (which could technically be markdown). It doesn't add the generated humans.txt page to the site token, but writes it to the root of the out_dir. It needs thinking.