Python POST二进制数据

Question

我正在编写一些代码与redmine接口，我需要上传一些文件作为过程的一部分，但我不确定如何从包含二进制文件的python做POST请求。

我试着模仿这里的命令:

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

在python中(见下)，但它似乎不起作用。我不确定这个问题是否与编码文件有关，或者头是否有问题。

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，它看起来像一个编码错误:

...
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)

Answer 1

基本上你做的是正确的。看看你链接到的redmine文档，似乎url中点后面的后缀表示发布数据的类型。json表示json， . XML表示XML)，这与您得到的响应一致——Processing by AttachmentsController#upload as XML。我猜也许有一个bug在文档和发布二进制数据，你应该尝试使用http://redmine/uploads url而不是http://redmine/uploads.xml。

顺便说一句，我强烈推荐Python中非常好的非常流行的http请求库。它比标准库(urllib2)中的要好得多。它也支持身份验证，但为了简单起见，我在这里省略了它。

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，我们必须检查发送的内容的差异。为了看到这一点，我将流量发送到运行在端口8888上的http代理(Fiddler):

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

和使用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

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

我看不出有什么差异可以证明你所观察到的不同行为。已经说过，http服务器检查User-Agent头并根据其值改变行为并不罕见。尝试逐个更改请求发送的标头，使它们与urllib2发送的标头相同，并查看何时停止工作

Answer 2

这与格式错误的上传无关。HTTP错误明确指定401未授权，并告诉您CSRF令牌无效。尝试在上传时发送一个有效的CSRF令牌。

关于csrf令牌的更多信息:

什么是CSRF令牌?它的重要性是什么?它是如何工作的?

Answer 3

您需要添加Content-Disposition头文件，就像这样(虽然我在这里使用了mod-python，但原理应该是一样的):

request.headers_out['Content-Disposition'] = 'attachment; filename=%s' % myfname

Answer 4

您可以使用unirest，它提供了简单的方法来发布请求。'

import unirest
 
def callback(response):
 print "code:"+ str(response.code)
 print "******************"
 print "headers:"+ str(response.headers)
 print "******************"
 print "body:"+ str(response.body)
 print "******************"
 print "raw_body:"+ str(response.raw_body)
 
# consume async post request
def consumePOSTRequestASync():
 params = {'test1':'param1','test2':'param2'}
 
 # we need to pass a dummy variable which is open method
 # actually unirest does not provide variable to shift between
 # application-x-www-form-urlencoded and
 # multipart/form-data
  
 params['dummy'] = open('dummy.txt', 'r')
 url = 'http://httpbin.org/post'
 headers = {"Accept": "application/json"}
 # call get service with headers and params
 unirest.post(url, headers = headers,params = params, callback = callback)
 
 
# post async request multipart/form-data
consumePOSTRequestASync()