Reading raw body for specific route

sysashi · February 8, 2018, 12:51pm

Hello, I have a phoenix project that talks to some external api and registers some web hooks handlers there (e.g. my app generates some url to be used as a callback).
I have to verify that webhooks requests come from legitimate party, to do so I need to read raw body of the request and calculate hmac.
I was looking at Plug docs and found out that you can skip parsing for some content type with pass option, which in my case would be application/json however I don’t want to turn off json parsing for my other routes.
What are my options?

idi527 · February 8, 2018, 12:53pm

You can have a separate endpoint for that. Or you can read the raw body from the conn somehow.

sysashi · February 8, 2018, 12:55pm

Thanks, separate endpoint makes sense! And reading body after it’s being parsed it’s not possible… Thanks for the idea tho

idi527 · February 8, 2018, 12:56pm

You can have a plug which would save the body into :private or :assigns before the parser plug for your callback route.

sysashi · February 8, 2018, 12:58pm

I would still need to check the current path of the connection/request so I don’t carry raw body for other routes.

idi527 · February 8, 2018, 1:02pm

It would still be simpler than adding an extra endpoint, I think.

idi527 · February 8, 2018, 1:07pm

github.com/phoenixframework/phoenix

Way to Read Request Body As String

opened 11:27AM - 05 Nov 14 UTC

closed 02:25PM - 05 Nov 14 UTC

rylev

I need to a way to access the body of a request as a raw string. Plug supports t…his functionality (https://github.com/elixir-lang/plug/blob/master/lib/plug/conn.ex#L418-L448) but as the docs say this can only be done once. Once the body is consumed, trying to read the body will result in an empty string. I believe that if you use a Phoenix controller, reading the body as string is impossible. If a client sends a request with the content-type set to application/json Phoenix will automatically parse the body as params meaning any future attempts by client code to access the body will result in an empty string. Is there any way for client code inside of a controller to access the body as a raw string?

sysashi · February 8, 2018, 1:49pm

Thanks a lot! I was thinking about same approach, although i generate webhooks handler for each entity (e.g. //webhook). Probably i should move them under specific path (webhook/) and apply that plug.