python-requests making a GET instead of POST reque

I have a daily cron which handles some of the recurring events at my app, and from time to time I notice one weird error that pops up in logs. The cron, among other things, does a validation of some codes, and it uses the webapp running on the same server, so the validation request is made via POST request with some data.

url = 'https://example.com/validate/'
payload = {'pin': pin, 'sku': sku, 'phone': phone, 'AR': True}
validation_post = requests.post(url, data=payload)

So, this makes the actual request and I log the response. From time to time, and recently up to 50% of the request, the response contains the following message from nginx:

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN">
<title>405 Method Not Allowed</title>
<h1>Method Not Allowed</h1>
<p>The method GET is not allowed for the requested URL.</p>

So, the actual request was made using the GET method, not the POST as it was instructed in the code. In the nginx access.log I can see that entry:

123.123.123.123 - - [18/Feb/2015:12:26:50 -0500] "GET /validate/ HTTP/1.1" 405 182 "-" "python-requests/2.2.1 CPython/2.7.6 Linux/3.13.0-37-generic"

And the uwsgi log for the app shows the similar thing:

[pid: 6888|app: 0|req: 1589/58763] 123.123.123.123 () {40 vars in 613 bytes} [Mon Apr  6 11:42:41 2015] GET /validate/ => generated 182 bytes in 1 msecs (HTTP/1.1 405) 4 headers in 234 bytes (1 switches on core 0)

So, everything points out that the actual request was not made using the POST. The app route that handles this code is simple, and this is an excerpt: @app.route('/validate/', methods=['POST']) @login_required

def validate():
    if isinstance(current_user.user, Sales):
        try:
            #do the stuff here
        except Exception, e:
            app.logger.exception(str(e))
            return 0
    abort(403)

The app route can fail, and there are some returns inside the try block, but even if those fails or there is an expcetion, there is nothing that could raise the 405 error code in this block, only 403 which rarely happens since I construct and login the user manually from the cron.

I have found similar thing here but the soultion there was that there was a redirect from HTTP to HTTPS version, and I also have that redirect present in the server, but the URL the request is being made has the HTTPS in it, so I doubt this is the cause.

The stack I am running this on is uwsgi+nginx+flask. Can anyone see what might be causing this? To repeat, its not happening always, so sometimes its working as expected, sometimes not. I recently migrated from apache and mod_wsgi to this new stack and from that point I have started encontering this error; can't recally ever seeing it on apache environment.

Thanks!

The only time we ever change a POST request to a GET is when we're handling a redirect. Depending on the redirect code, we will change the request method. If you want to be sure that we don't follow redirects, you need to pass allow_redirects=False. That said, you need to figure out why your application is generating redirects (including if it's redirecting to HTTP or to a different domain, or using a specific status code).