tmbb

Syntax Highlighting for code in the Phoenix (= Plug) debugger

Just created a very simple library that allows you to have syntax highlighting in the Phoenix debugger. Code here: GitHub - tmbb/phoenix_with_pretty_debugger: Add syntax highlighting to the Plug debugger used by Phoenix · GitHub

PhoenixWithPrettyDebugger

Adds support for syntax highlighting in the Phoenix debugger.

To use, replace the following line in your application’s endpoint:


use Phoenix.Endpoint, otp_app: :your_app

by the this line:


use PhoenixWithPrettyDebugger.Endpoint, otp_app: :your_app

No other changes are needed.

Happy hacking with a prettier debugging experience!

The highlighter supports elixir and erlang by default (so it can even highlight code in the cowboy modules). Internaly this project uses the makeup syntax highlighting library and you can add support for other languages by importing the appropriate lexers.

Example output:

Highlighting Elixir:

Highlighting Erlang:

Is this safe?!

This library simply defines an alternative to the default Phoenix.Endpoint module which is actually API compatible. We reuse as much functionality from that module as possible and only redefine the parts we need to add our new debugger. Becuase the debugger is only used in :dev and never in :prod

5 comments

/phoenix #library #plug #debug

0 1502 5

2020-10-04 23:47:23 UTC

First Post!

Eiji

@tmbb Hmm … honestly I do not see why it’s a standalone library … If I remember correctly makeup is used even in ex_doc, so I do not see why it could not be a part of phoenix … Did you proposed this enhancement before? If so can you please link to such discussion for a reference, please?

Post #1

Most Liked

tmbb

The debugger is part of Plug and not Phoenix. I’ve proposed to add syntax highlighting to Plug here: Syntax highlihting for the Debugger: minimum viable PR; needs cleaning by tmbb · Pull Request #763 · elixir-plug/plug · GitHub

I think that instead of adding syntax highlighting to plug debugger is rather have a way of of setting a custom debugger in the Phoenix.Endpoint module (as my last message from that PR explains).

Post #2

tmbb

Can you please describe if and how it’s possible to write said debuggers and have your syntax highlighting at the same time?

You just have to duplicate the functionality in your own debugger module, of course. I’m not interested at all in exposing any part of this as public API. Just copy and paste the relevant files into your own project.

Post #4

Last Post!

tmbb

I’ve added some new capabilities to my debugger. You can now (using the debugger page) add breakpoints to a function in on any of the frames and replay the request handling with that breakpoint (and pry that breakpoint in IEx). You have to start your phoenix app

It’s not as useful as I though it would be (beam stack frames aren’t that awesome and they lose a lot of information), but its pretty cool. It can also serve as an example for other who might want to extend Phoenix’s debugger.

You can get it from github master.

Post #5