python 3 tornados file body with headers

Question

I'm tying to write some simple app on python3 and tornado for server, and requests for client, and I'm getting some headers in 'self.request.body', which I can't dispose of. For instance, for file 'blahblahblah', I get:

--cb5f6ba84bdf42d382dfd3204f6307c7\r\nContent-Disposition: form-data; name="file"; filename="1.bin"\r\n\r\nblahblahblah\n\r\n--cb5f6ba84bdf42d382dfd3204f6307c7--\r\n

Files are sent by

f = {'file': open(FILE, 'rb')}
requests.post(URL_UPLOAD, files=f)

and received by

class UploadHandler(tornado.web.RequestHandler):
    def post(self, filename):
        with open(Dir + filename, 'wb') as f:
            f.write(self.request.body)

My full code can be seen here

When I send the file by curl with curl -X POST -d $(cat ./1.bin) http://localhost:8080/upload/1.bin I get the correct file, but without \n.

There must be something I missed. Please can someone help me with that? Thank You.

score 0 · Accepted Answer · edited May 23 '17 at 12:20

There are two ways to upload files: simply using the file as the request body (usually, but not necessarily, with the HTTP PUT method), or using a multipart wrapper (usually with the HTTP POST method). If you upload the file from an HTML form, it will usually use the multipart wrapper. Your requests example is using a multipart wrapper and the curl one is not; your server is not expecting the wrapper.

To use a multipart wrapper: in requests, pass files= as you've done here. With curl, see this answer: Using curl to upload POST data with files. On the server, use self.request.files instead of self.request.body: http://www.tornadoweb.org/en/stable/httpserver.html#tornado.httpserver.HTTPRequest.files

To not use the multipart wrapper, use data=open(FILE, 'rb').read() from requests, and keep the other two components the same.

It is possible to support both styles simultaneously on the server: use self.requests.files when self.request.headers['Content-Type'] == 'multipart/form-data' and self.request.body otherwise.

python 3 tornados file body with headers

1 Answers1