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，我需要上传一些文件作为该过程的一部分，但我不确定如何从包含二进制文件的 python 执行 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.

我试图在这里模仿命令:

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

在python(如下)中，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:somefoldersomefile.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

我可以访问服务器，但看起来像是编码错误:

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

基本上你所做的都是正确的.查看您链接到的 redmine 文档，url 中点之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#上传为 XML.我想文档中可能存在错误，要发布二进制数据，您应该尝试使用 http://redmine/uploads url 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，我强烈推荐非常好的和非常受欢迎的 Requests 库，用于 http inPython.它比标准库 (urllib2) 中的要好得多.它也支持身份验证，但为了简洁起见我在这里跳过了.

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

更新

要找出为什么这适用于请求而不适用于 urllib2，我们必须检查发送内容的差异.为了看到这一点，我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

我没有看到任何可以保证您观察到不同行为的差异.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.尝试一一更改请求发送的标头，使它们与 urllib2 发送的标头相同，并查看它何时停止工作.

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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