Python POST二进制数据 [英] Python POST binary data

问题描述

我正在编写一些代码来与Redmine交互，并且作为过程的一部分，我需要上传一些文件，但是我不确定如何从包含二进制文件的python发出POST请求.

I am writing some code to interface with redmine and I need to upload some files as part of the process, but I am not sure how to do a POST request from python containing a binary file.

我正在尝试模仿此处的命令:

I am trying to mimic the commands here:

curl --data-binary "@image.png" -H "Content-Type: application/octet-stream" -X POST -u login:password http://redmine/uploads.xml

在python中(如下)，但它似乎不起作用.我不确定问题是否与文件编码有关，或者标题是否有问题.

In python (below), but it does not seem to work. I am not sure if the problem is somehow related to encoding the file or if something is wrong with the headers.

import urllib2, os

FilePath = "C:\somefolder\somefile.7z"
FileData = open(FilePath, "rb")
length = os.path.getsize(FilePath)

password_manager = urllib2.HTTPPasswordMgrWithDefaultRealm()
password_manager.add_password(None, 'http://redmine/', 'admin', 'admin')
auth_handler = urllib2.HTTPBasicAuthHandler(password_manager)
opener = urllib2.build_opener(auth_handler)
urllib2.install_opener(opener)
request = urllib2.Request( r'http://redmine/uploads.xml', FileData)
request.add_header('Content-Length', '%d' % length)
request.add_header('Content-Type', 'application/octet-stream')
try:
    response = urllib2.urlopen( request)
    print response.read()
except urllib2.HTTPError as e:
    error_message = e.read()
    print error_message

我有权访问服务器，它看起来像是一个编码错误:

I have access to the server and it looks like a encoding error:

...
invalid byte sequence in UTF-8
Line: 1
Position: 624
Last 80 unconsumed characters:
7z¼¯'ÅÐз2^Ôøë4g¸R<süðí6kĤª¶!»=}jcdjSPúá-º#»ÄAtD»H7Ê!æ½]j):

(further down)

Started POST "/uploads.xml" for 192.168.0.117 at 2013-01-16 09:57:49 -0800
Processing by AttachmentsController#upload as XML
WARNING: Can't verify CSRF token authenticity
  Current user: anonymous
Filter chain halted as :authorize_global rendered or redirected
Completed 401 Unauthorized in 13ms (ActiveRecord: 3.1ms)

推荐答案

基本上您所做的是正确的.查看链接到的Redmine文档，URL中点后的后缀似乎表示发布数据的类型(JSON为.json，XML为.xml)，这与您得到的响应一致-Processing by AttachmentsController#upload as XML.我想可能是文档中存在一个错误，要发布二进制数据，您应该尝试使用http://redmine/uploads网址而不是http://redmine/uploads.xml.

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.

顺便说一句，我强烈建议在Python中使用非常好的和非常受欢迎的 Requests 库.它比标准库(urllib2)中的库要好得多.它也支持身份验证，但是为了简洁起见，我跳过了它.

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

data = open('./x.png', 'rb').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

更新

要弄清为什么它适用于Requests而不适用于urllib2，我们必须检查发送的内容之间的差异.要查看此信息，我正在将流量发送到在端口8888上运行的http代理(Fiddler):

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:

使用请求

import requests

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

我们看到

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

并使用urllib2

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)

我们得到

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

我看不到有任何差异可以保证您观察到不同的行为.话虽如此，http服务器检查User-Agent标头并根据其值改变行为的情况并不少见.尝试一个接一个地更改请求发送的标头，使其与urllib2发送的标头相同，然后查看何时停止工作.

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.

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