为什么我不能使用 pyCurl 发布到 Django？

Question

我在 pyCurl 脚本访问本地 Django-Tastypie REST 网络服务器时遇到了一些真正奇怪的事情。

当我使用除 pycurl（包括 curl）之外的所有内容时，向服务器发出 HTTP PUT 请求成功，并且在 pycurl 中失败并出现错误 400。

经过大量的谷歌搜索和实验，我很难过。 这里出了什么问题？

有效的卷曲调用：

curl --verbose -X PUT -H 'Content-Type: application/json' -d '{"first_name": "Gaius","id": 1,"last_name": "Balthazar","login": "gbalthazar"}' http://localhost:8000/api/person/1/

PyCurl 调用不起作用（错误 400）：

import pycurl
import StringIO
curl = pycurl.Curl()
url = 'http://localhost:8000/api/person/1/'
curl.setopt(pycurl.URL,url)
curl.setopt(pycurl.VERBOSE, 1)
body = '{"first_name": "Gaius","id": 1,"last_name": "Baltar","login": "gbaltar"}'
curl.setopt(pycurl.READFUNCTION, StringIO.StringIO(body).read)
curl.setopt(pycurl.UPLOAD, 1)
curl.setopt(pycurl.HTTPHEADER,['Content-Type: application/json','Expect:'])
curl.setopt(curl.TIMEOUT, 5)
curl.perform()

（我也尝试删除 Expects 标头，我看到标头在 pycurl 调用中设置为 100-Continue，但结果相同。）

不幸的是，这个项目确实确实需要 pycurl 对 HTTP 计时统计信息的低级访问来衡量性能，所以我无法使用另一个 HTTP/REST 库来做到这一点。

卷曲调用的输出：

* About to connect() to localhost port 8000 (#0)
*   Trying 127.0.0.1...
* connected
* Connected to localhost (127.0.0.1) port 8000 (#0)
> PUT /api/person/1/ HTTP/1.1
> User-Agent: curl/7.27.0
> Host: localhost:8000
> Accept: */*
> Content-Type: application/json
> Content-Length: 78
> 
* upload completely sent off: 78 out of 78 bytes
* HTTP 1.0, assume close after body
< HTTP/1.0 200 OK
< Date: Thu, 05 Jun 2014 23:45:26 GMT
< Server: WSGIServer/0.1 Python/2.7.3
< Vary: Accept
< X-Frame-Options: SAMEORIGIN
< Content-Type: application/json
< 
* Closing connection #0
{"first_name": "Gaius", "id": 1, "last_name": "Balthazar", "login": "gbalthazar", "pk": "1", "resource_uri": "/api/person/1/"}

PyCurl 详细调用的输出：

* About to connect() to localhost port 8000 (#0)
*   Trying 127.0.0.1...
* connected
* Connected to localhost (127.0.0.1) port 8000 (#0)
> PUT /api/person/1/ HTTP/1.1
User-Agent: PycURL/7.27.0
Host: localhost:8000
Accept: */*
Transfer-Encoding: chunked
Content-Type: application/json

* HTTP 1.0, assume close after body
< HTTP/1.0 400 BAD REQUEST
< Date: Thu, 05 Jun 2014 23:44:25 GMT
< Server: WSGIServer/0.1 Python/2.7.3
< X-Frame-Options: SAMEORIGIN
< Content-Type: application/json
< 
* Closing connection #0
{"error": ""}

我错过了什么？

Answer 1

找到答案： 它需要请求正文的长度才能正确处理

对于 POST：

curl.setopt(pycurl.POSTFIELDSIZE, len(body))  

对于 PUT：

curl.setopt(pycurl.INFILESIZE, len(body))

（是的，对于不同的 HTTP 调用，这是一个不同的选项……这就是你的 libcurl）

不完全确定是什么触发了这种行为，但上面修复了它，测试现在可以工作了。

编辑：从这里添加详细的 pycurl 输出：

* About to connect() to localhost port 8000 (#0)
*   Trying 127.0.0.1...
* connected
* Connected to localhost (127.0.0.1) port 8000 (#0)
> PUT /api/person/1/ HTTP/1.1
User-Agent: PycURL/7.27.0
Host: localhost:8000
Accept: */*
Content-Type: application/json
Content-Length: 72

* We are completely uploaded and fine
* HTTP 1.0, assume close after body
< HTTP/1.0 200 OK
< Date: Fri, 06 Jun 2014 17:41:38 GMT
< Server: WSGIServer/0.1 Python/2.7.3
< Vary: Accept
< X-Frame-Options: SAMEORIGIN
< Content-Type: application/json
< 
* Closing connection #0
{"first_name": "Gaius", "id": 1, "last_name": "Baltar", "login": "gbaltar", "pk": "1", "resource_uri": "/api/person/1/"}