lyo5ha
GET request with JSON body - is it possible to handle?
Hi! I want to receive GET request with JSON body.
#router
...
pipeline :api do
plug :accepts, ["json"]
end
scope "/", PsRbkWeb do
pipe_through :api
get "/order", PaymentController, :index
end
...
# controller
...
def index(conn, _some_params) do
IO.inspect(conn) # empty body_params: %{} in conn
end
...
After I made GET request to “/order” with some json in body (with header Content-Type=application/json). - have empty body_params: %{} in conn in my controller.
Here is resulting conn, sorry for length:
%Plug.Conn{
adapter: {Plug.Cowboy.Conn, :...},
assigns: %{},
before_send: [#Function<1.112466771/1 in Plug.Logger.call/2>,
#Function<0.66982185/1 in Phoenix.LiveReloader.before_send_inject_reloader/2>],
body_params: %{},
cookies: %Plug.Conn.Unfetched{aspect: :cookies},
halted: false,
host: "localhost",
method: "GET",
owner: #PID<0.596.0>,
params: %{},
path_info: ["order"],
path_params: %{},
port: 4000,
private: %{
PsRbkWeb.Router => {[], %{}},
:phoenix_action => :index,
:phoenix_controller => PsRbkWeb.PaymentController,
:phoenix_endpoint => PsRbkWeb.Endpoint,
:phoenix_format => "json",
:phoenix_layout => {PsRbkWeb.LayoutView, :app},
:phoenix_pipelines => [:api],
:phoenix_router => PsRbkWeb.Router,
:phoenix_view => PsRbkWeb.PaymentView,
:plug_session_fetch => #Function<1.58261320/1 in Plug.Session.fetch_session/1>
},
query_params: %{},
query_string: "",
remote_ip: {127, 0, 0, 1},
req_cookies: %Plug.Conn.Unfetched{aspect: :cookies},
req_headers: [
{"accept", "*/*"},
{"accept-charset", "UTF-8"},
{"accept-encoding", "gzip, deflate"},
{"cache-control", "no-cache"},
{"connection", "keep-alive"},
{"content-length", "353"},
{"content-type", "application/json"},
{"host", "localhost:4000"},
{"postman-token", "70bc9e11-1ef4-493d-a556-cf4876d28bc2"},
{"user-agent", "PostmanRuntime/7.4.0"}
],
request_path: "/order",
resp_body: nil,
resp_cookies: %{},
resp_headers: [
{"cache-control", "max-age=0, private, must-revalidate"},
{"x-request-id", "2lonnum7h1c48rmudk000gu1"}
],
scheme: :http,
script_name: [],
secret_key_base: :...,
state: :unset,
status: nil
}
So, the question is: Is it possible to receive any json data in GET request body and access it form controller? (Or I have to give up and use POST with JSON body). Please, guide me to the right direction.
Marked As Solved
lyo5ha
Not supposed to, but I like to have such option. ![]()
I found quite hacky solution:
# controller
...
def index(conn, _some_params) do
{:ok, body, _conn} = Plug.Conn.read_body(conn)
IO.inspect(body) # got string with escape characters, but better than nothing
end
I think to write custom plug and put this body to some custom field in conn. By the way, Plug.Parsers don’t parse GET requests, so no point to add custom handler for GET requests into parsers. I hope, this will help somebody.
…
Also Liked
NobbZ
HTTP GET does not have a body as far as I remember…
NobbZ
Ohyeah, you are right, according to RFC 7231:
A payload within a GET request message has no defined semantics;
sending a payload body on a GET request might cause some existing
implementations to reject the request.
So, according to the RFC, you either should be able to access the body or never see the request.
Perhaps the pipeline doesn’t parse the body as it does not expect it? How is your plug parser configured?








