Python connecting to an HTTP server

问题

In my program, I am trying to access https://api.dropbox.com/1/oauth2/token. In order to do that, I was trying to use http.client.HTTPSConnection(). However, I am receiving a 400 statement from the server, even though when I send the same request through my browser, I get an actual response:

{"error": "Call requires one of the following methods: POST, OPTIONS. Got GET."}

I believe that this happens for subdomains, since I also tested the function for https://docs.python.org/3/, and the result is very similar.

Here is my code (Python3):

conn = http.client.HTTPSConnection('docs.python.org')
conn.request('get', '/3/')
response = conn.getresponse().read()
print(response)

How should I use the http.client library to send the proper request?

回答1:

TL;DR: Change the lowercase 'get' to uppercase 'GET' should resolve the problem.

The reason: according to section 5.1.1, RFC2616:

The Method token indicates the method to be performed on the resource identified by the Request-URI. The method is case-sensitive.

RFC2616 also defined 8 methods which are "OPTIONS", "GET", "HEAD", "POST", "PUT", "DELETE", "TRACE", and "CONNECT". All of them are uppercase.

We do know some HTTP clients like python-requests and jQuery.ajax also support lowercase methods but they are just not the standard way defined by the RFC for using those methods. To prevent issues, use uppercase ones first.

来源：https://stackoverflow.com/questions/40035567/python-connecting-to-an-http-server