Python httplib and POST
Solution 1
try adding:
conn.set_debuglevel(1)
to your code so you can see what is actually happening.
Solution 2
The putrequest
method does not automatically add the Content Length header, you need to do it yourself or use the request
method.
Add this to your code above the for
loop:
headers['Content-Length'] = "%d"%(len('[{"id":"route"}]'))
julx
Updated on July 09, 2022Comments
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julx almost 2 years
I am currently working with a piece of code that has been written by somebody else. It uses
httplib
to make requests to server. It has all the data supplied in a correct format - for example message body, header values, etc.The problem is that each time it attempts to send a POST requests, the data is there - I can see it on the client side, however nothing arrives to the server. I've read through the library specification and the usage seems to be correct.
The extracted library calls go as follows:
import httplib conn = httplib.HTTPConnection('monkeylabs.pl', 80) conn.connect() request = conn.putrequest('POST', '/api/snippet/') headers = {} headers['Content-Type'] = 'application/json' headers['User-Agent'] = 'Envjs/1.618 (SpyderMonkey; U; Linux x86_64 2.6.38-10-generic; pl_PL.utf8; rv:2.7.1) Resig/20070309 PilotFish/1.3.pre03' headers['Accept'] = '*/*' for k in headers: conn.putheader(k, headers[k]) conn.endheaders() conn.send('[{"id":"route"}]') resp = conn.getresponse() print resp.status print resp.reason print resp.read() conn.close()
Is this some known issue, or what? I'm using Python 2.7. Not sure how to check the version of httplib.
Please don't suggest to exchange httplib for something else unless it's something really similar (httplib2 perhaps). As I said, the code isn't mine and it comes in much greater amounts than what I've just posted above. Refactoring it would cause a major problem. I'm interested in any reliable workarounds.
EDIT
The debug output:
send: 'POST /api/snippet/ HTTP/1.1\r\nHost: monkeylabs.pl\r\nAccept-Encoding: identity\r\nContent-Type: application/json\r\nAccept: */*\r\nUser-Agent: Envjs/1.618 (SpyderMonkey; U; Linux x86_64 2.6.38-10-generic; pl_PL.utf8; rv:2.7.1) Resig/20070309 PilotFish/1.3.pre03\r\n\r\n[{"id":"route"}]' reply: 'HTTP/1.0 201 CREATED\r\n' header: Date: Fri, 10 Jun 2011 23:54:00 GMT header: Server: WSGIServer/0.1 Python/2.7.1+ header: Vary: Cookie header: Content-Type: application/json header: Content-Length: 0 201 CREATED
Note that the information after reply actually talks about the server reply, not the request itself, which in this case is empty. The primary cause is that the request body itself is empty which I can observe by getting a log:
[11/Jun/2011 01:54:00] "POST /api/snippet/ HTTP/1.1" 201 0
And those three lines:
`` <QueryDict: {}> <QueryDict: {}>
out of:
print '`%s`' % request.raw_post_data print request.GET print request.POST
on the Django server. So it seems it attempts to send the body but doesn't send it in the end.
EDIT(2)
Ok, I took a dump and it indeed told me that in the message sent from the browser there is an additional parameter called 'Content-Length' which has been omitted in the regular usage of the library. Silly me.
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Darien almost 13 yearsBTW, if you think you'll be debugging this thing a lot, install Wireshark and use it to spy on what's actually going over the wire.
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julx almost 13 yearsThanks, I was a non-believer at the beginning but it actually led me to the solution. Thanks again
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Admin over 11 yearsThe server has: response.set_header('Access-Control-Allow-Origin', '*') ????
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julx almost 13 yearsYes, I did read the API documentation and everything seems fine. The problem is that it isn't fine. The same request made by various other means - say a browser or another library works well. Removing 'Accept' header doesn't change anything. The example that you copy pasted from the API is just doing something totally different. It's not a POST and it doesn't attempt to upload the message body.