python3.5 aiohttp, request post, json format and 405 errors

Question

I finally sign up because I have no more idea for my problem. I use asyncio and aiohttp for my back-end part and javascript for the front-end part. But I stuck with a 405 error. (I precise I am a beginner with theses libraries)

I wish retrieve a json from a post request. Here the javascript function:

function postJson (data){

    $.ajax({

           url : 'http://localhost:8080/postJson',
           type : 'POST',
           dataType : 'json',
           contentType : 'application/json',
           data  : data, //data are ready at json format, I do not think I need to use JSON.stringify ? I does not change anything to the error anywhere
           success : function(code_html, statut){ 
             console.log("success POST");
           },

           error : function(resultat, statut, erreur){
             console.log("error POST");
           }

        });
  }

and the python code:

async def postJson(request): 
   data = await request.post()
   #some code
   return Response()


@asyncio.coroutine
def init(loop):
    app = Application(loop=loop)
    app.router.add_route('POST', '/postJson', postJson)

    handler = app.make_handler()
    srv = yield from loop.create_server(handler, '127.0.0.1', 8080)
    print("Server started at http://127.0.0.1:8080")
    return srv, handler

loop = asyncio.get_event_loop()
srv, handler = loop.run_until_complete(init(loop))

try:
    loop.run_forever()
except KeyboardInterrupt:
    loop.run_until_complete(handler.finish_connections())

With this code I get a 405 error. Here a bite of what says firebug about the request:

Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8 // so json is not in the list.

however, if I take back the line contentType : 'application/json' in my javascript file, it works (but the request send a object called MultiDictProxy and I don't understand how to use the function json() from aiohttp.web package ( here ).

I really need to get a json object. Someone could help me?

Answer 1

I find the solution. I post the conclusion here for people who could be interested:

python side:

replace the line app.router.add_route('POST', '/postJson', postConf) by

app.router.add_route('POST', '/postJson', postConf, expect_handler = aiohttp.web.Request.json)

in the postJson method:

replace data = await request.post() by data = await request.json()

and on javascript side:

data  : JSON.stringify(data)

with this, my method works.

Answer 2

Your example works fine except two things:

1. @asyncio.coroutine and async with are mutually exclusive
2. postJson() must return response instance, not None