it may because you use multipart/form to upload file.try use data like code below

data = open(localFilePath, 'rb').read()
headers = {
    "Content-Type":"application/binary",
}
upload = requests.put(uploadUrl,data=data,headers=headers)

Basically what you do is correct. Looking at redmine docs you linked to, it seems that suffix after the dot in the url denotes type of posted data (.json for JSON, .xml for XML), which agrees with the response you get - Processing by AttachmentsController#upload as XML. I guess maybe there's a bug in docs and to post binary data you should try using http://redmine/uploads url instead of http://redmine/uploads.xml.

Btw, I highly recommend very good and very popular Requests library for http in Python. It's much better than what's in the standard lib (urllib2). It supports authentication as well but I skipped it for brevity here.

import requests
with open('./x.png', 'rb') as f:
    data = f.read()
res = requests.post(url='http://httpbin.org/post',
                    data=data,
                    headers={'Content-Type': 'application/octet-stream'})

# let's check if what we sent is what we intended to send...
import json
import base64

assert base64.b64decode(res.json()['data'][len('data:application/octet-stream;base64,'):]) == data

UPDATE

To find out why this works with Requests but not with urllib2 we have to examine the difference in what's being sent. To see this I'm sending traffic to http proxy (Fiddler) running on port 8888:

Using Requests

import requests

data = 'test data'
res = requests.post(url='http://localhost:8888',
                    data=data,
                    headers={'Content-Type': 'application/octet-stream'})

we see

POST http://localhost:8888/ HTTP/1.1
Host: localhost:8888
Content-Length: 9
Content-Type: application/octet-stream
Accept-Encoding: gzip, deflate, compress
Accept: */*
User-Agent: python-requests/1.0.4 CPython/2.7.3 Windows/Vista

test data

and using urllib2

import urllib2

data = 'test data'    
req = urllib2.Request('http://localhost:8888', data)
req.add_header('Content-Length', '%d' % len(data))
req.add_header('Content-Type', 'application/octet-stream')
res = urllib2.urlopen(req)

we get

POST http://localhost:8888/ HTTP/1.1
Accept-Encoding: identity
Content-Length: 9
Host: localhost:8888
Content-Type: application/octet-stream
Connection: close
User-Agent: Python-urllib/2.7

test data

I don't see any differences which would warrant different behavior you observe. Having said that it's not uncommon for http servers to inspect User-Agent header and vary behavior based on its value. Try to change headers sent by Requests one by one making them the same as those being sent by urllib2 and see when it stops working.

There are two large differences:

1. The PHP code posts a field named file, your Python code posts a field named bulk_test2.mov.

2. Your Python code posts an empty file. There Content-Length header is 160 bytes, exactly the amount of space the multipart boundaries and Content-Disposition part header take up. Either the bulk_test2.mov file is indeed empty, or you tried to post the file multiple times without rewinding or reopening the file object.

To fix the first problem, use 'file' as the key in your files dictionary:

files = {'file': open('bulk_test2.mov', 'rb')}
response = requests.post(url, files=files)

I used just the open file object as the value; requests will get the filename directly from the file object in that case.

The second issue is something only you can fix. Make sure you don't reuse files when repeatedly posting. Reopen, or use files['file'].seek(0) to rewind the read position back to the start.

The Expect: 100-continue header is an optional client feature that asks the server to confirm that the body upload can go ahead; it is not a required header and any failure to post your file object is not going to be due to requests using this feature or not. If an HTTP server were to misbehave if you don't use this feature, it is in violation of the HTTP RFCs and you'll have bigger problems on your hands. It certainly won't be something requests can fix for you.

If you do manage to post actual file data, any small variations in Content-Length are due to the (random) boundary being a different length between Python and PHP. This is normal, and not the cause of upload problems, unless your target server is extremely broken. Again, don't try to fix such brokenness with Python.

However, I'd assume you overlooked something much simpler. Perhaps the server blacklists certain User-Agent headers, for example. You could clear some of the default headers requests sets by using a Session object:

files = {'file': open('bulk_test2.mov', 'rb')}
session = requests.Session()
del session.headers['User-Agent']
del session.headers['Accept-Encoding']
response = session.post(url, files=files)

and see if that makes a difference.

If the server fails to handle your request because it fails to handle HTTP persistent connections, you could try to use the session as a context manager to ensure that all session connections are closed:

files = {'file': open('bulk_test2.mov', 'rb')}
with requests.Session() as session:
    response = session.post(url, files=files, stream=True)

and you could add:

response.raw.close()

for good measure.