Erlang Cowboy Rest Handler for POST request

Question

The response is 415 (Unsupported Media Type) .

Client Side Code:

$.ajax({
      url: "/book",
      //contentType: 'application/json',
      data: {action: "hello", method: "json"},
      dataType: "json",
      type: "POST",
      complete: function(a, b) {
        console.log(a);
        console.log(b);
      }
    });

Server Side Code:

content_types_provided(Req, State) ->
    {[
        {<<"application/json">>, handle_to_all}
    ], Req, State}.

handle_to_all(Req, State) ->
    Body = <<"{\"rest\": \"Hello World!\"}">>,
    {Body, Req, State}.

If I update the type from "POST" to "GET" from client side, everything is okay.

Anything I missed?

Answer 1

content_types_provided method of cowboy accepts only GET and HEAD

Go through the following link and change the code accordingly

https://ninenines.eu/docs/en/cowboy/1.0/manual/cowboy_rest/

Answer 2

You can use cowboy_rest, implement the content_types_accepted/2 callback method like so:

 content_types_accepted(Req, State) ->
   case cowboy_req:method(Req) of
     {<<"POST">>, _ } ->
       Accepted = {[{<<"application/json">>, put_json}], Req, State};
     {<<"PUT">>, _ } ->
       Accepted = {[{<<"application/json">>, post_json}], Req, State}
   end,
 Accepted.

I think this way you can have separate handlers for different HTTP Verbs/Methods. This gives you cleaner code too :)

And the various handlers:

 %% handle http put requests
 put_file(Req, State) ->

   {true, Req, State}.
 %% handle http post requests
 post_json(Req, State) ->

   {true, Req, State}.