Django接收自定义http header

原文:http://callmepeanut.blog.51cto.com/7756998/1390769

用Django做后台,客户端向Django请求数据,为了区分不同的请求,想把每个请求类别加在HTTP头部(headers)里面。

先做实验,就用Python的httplib库来做模拟客户端,参考网上写出模拟代码如下:

#coding=utf8
import httplib
httpClient = None
try:
    myheaders = { "category": "Books",
                  "id": "21",
                  My-Agent: "Super brower"
              }
    httpClient = httplib.HTTPConnection(10.14.1XX.XXX,8086,timeout=30)
    httpClient.request(GET,/headinfo/,headers=myheaders)
    response = httpClient.getresponse()
    print response.status
    print response.reason
    print response.read()
except Exception, e:
    print e
finally:
    if httpClient:
        httpClient.close()
 

其中‘/headinfo/‘为服务器的响应目录。

然后是服务端的响应代码,《The Django Book》第七章有个获取META的例子:

# GOOD (VERSION 2)
def ua_display_good2(request):
    ua = request.META.get(HTTP_USER_AGENT, unknown)
    return HttpResponse("Your browser is %s" % ua)
 

正好看过这个例子,就模拟上面的这个写了一个能够返回客户端自定义头部的模块:

from django.http import HttpResponse
def headinfo(request):
    category = request.META.get(CATEGORY, unkown)
    id = request.META.get(ID,unkown)
    agent = request.META.get(MY-AGENT,unkown)
    html = "<html><body>Category is %s, id is %s, agent is %s</body></html>" % (category, id, agent)
    return HttpResponse(html)
 

运行结果如下:

$python get.py
#输出:
#200
#OK
#<html><body>Category is unkown, id is unkown, agent is unkown</body></html>
 

可以看到服务器成功响应了,但是却没有返回自定义的内容。

我以为是客户端模拟headers出问题了,查找和试验了许多次都没有返回正确的结果。后来去查Django的文档,发现了相关的描述:

HttpRequest.META

A standard Python dictionary containing all available HTTP headers. Available headers depend on the client and server, but here are some examples:

  • CONTENT_LENGTH – the length of the request body (as a string).

  • CONTENT_TYPE – the MIME type of the request body.

  • HTTP_ACCEPT_ENCODING – Acceptable encodings for the response.

  • HTTP_ACCEPT_LANGUAGE – Acceptable languages for the response.

  • HTTP_HOST – The HTTP Host header sent by the client.

  • HTTP_REFERER – The referring page, if any.

  • HTTP_USER_AGENT – The client’s user-agent string.

  • QUERY_STRING – The query string, as a single (unparsed) string.

  • REMOTE_ADDR – The IP address of the client.

  • REMOTE_HOST – The hostname of the client.

  • REMOTE_USER – The user authenticated by the Web server, if any.

  • REQUEST_METHOD – A string such as "GET" or "POST".

  • SERVER_NAME – The hostname of the server.

  • SERVER_PORT – The port of the server (as a string).

With the exception of CONTENT_LENGTH and CONTENT_TYPE, as given above, any HTTP headers in the request are converted toMETA keys by converting all characters to uppercase, replacing any hyphens with underscores and adding an HTTP_ prefix to the name. So, for example, a header called X-Bender would be mapped to the META key HTTP_X_BENDER.

其中红色的部分说明是说除了两个特例之外,其他的头部在META字典中的key值都会被加上“HTTP_”的前缀,终于找到问题所在了,赶紧修改服务端代码:

category = request.META.get(HTTP_CATEGORY, unkown)
id = request.META.get(HTTP_ID,unkown)
 

果然,执行后返回了想要的结果:

$python get.py
#正确的输出:
#200
#OK
#<html><body>Category is Books, id is 21, agent is Super brower</body></html>

得到的经验就是遇到问题要多查文档,搜索引擎并不一定比文档更高效。

 

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