I. Introduction
HTTP protocol specified in the data message to be submitted post body (entity-body) but the data protocol does not specify what must encoding used. HTTP protocol is ASCII-code transmission, the establishment of standardized application layer on top of another TCP / IP protocol. HTTP request is divided into three parts: the status line, request headers and a message body. Looks like this:
<method> <request-URL> <version> <headers> <entity-body>
Server typically acquired message body of the request is encoded according to the manner in which the request header (header) field in Content_Type, and then parses the message body.
Second, the browser form submission form
1.form form common properties as follows:
action: url address, the server receives the form data address method: Submit http server method, typically post and GET name: the enctype: encoding type used when submitting the form data, default "application / x-www-form -urlencoded" If using a POST request, the value of the specified content-type header is the value requested. If you have a file upload form, encoding type requires the use of "multipart / form-data", type to complete the transfer file data.
PS: encoding format to form enctype form data, Content-type of encoding format of the HTTP data transmission, to distinguish the two! ! !
2. When the browser submits the form, it will perform the following steps:
① identify valid entry form elements form, as submissions
② build a form data set
③ encoding data as a content-type content-type attribute value based on the value of the form attribute enctype form
④ transmits data to the specified address according to url form action attribute in a form and method attributes
3. Submit in different ways
① get: After the form data will be encodeURIComponent as arguments: name1 = value1 & name2 = value2 url comes back in, and then sent to the server, and displayed in the url?.
② post: enctype Default "application / x-www-form-urlencoded" encoded form data, key data is transmitted in the http request to the server; if enctype attribute is "multipart / form-data", places the message the form is sent to the server.
Three, four common coding
1.application/x-www-form-urlencoded
The most common post submitted by encoding data. Native form form browser, if enctype attribute settings, default submission data application / x-www-form-urlencoded encoding. for example:
POST http://www.example.com HTTP/1.1
Content-Type:application/x-www-form-urlencoded;charset=utf-8 title=test&sub%5B%5D=1&sub%5B%5D=2&sub%5B%5D=3
2.multipart/form-data
In addition to traditional application / x-www-form-urlencoded form, the other is used to upload files form, which form the type multipart / form-data for example.:
<form action="/upload" enctype="multipart/form-data" method="post"> Username: <input type="text" name="username"> Password: <input type="password" name="password"> File: <input type="file" name="file"> <input type="submit"> </form>
3.application/json
4.text/xml
Four, post body transmission request four kinds of ways
1. The body of the request is application / x-www-form-urlencoded
Form: requests.post (URL = '', Data = { 'key1': 'VALUE1', 'key2': 'value2'}, = {headers 'the Type-the Content': 'multipart / form-Data'})
Requests sending a request to support post form form form, just to the parameters configured to request a dictionary, and then passed requests.post () of the dataparameters can be
import requests url = "http://httpbin.org/post" data = {"key1":"value1","key2":"value2"} headers = {"Content-type":"application/x-www-form-urlencoded"} r = requests.post(url=url,data=data,headers=headers) print(r.text)
由上图可以看到，请求头中的Content-Type字段已设置为application/x-www-form-urlencoded，且data = {'key1': 'value1', 'key2': 'value2'}以form表单的形式提交到服务端，服务端返回的form字段即是提交的数据。
2.请求正文是multipart/form-data
形式：
requests.post(url='',data={'key1':'value1','key2':'value2'},headers={'Content-Type':'multipart/form-data'})
from requests_toolbelt import MultipartEncoder import requests url="http://httpbin.org/post" m = MultipartEncoder(fields={"field0":"value","field1":"value"}) # 删掉fields效果一样 headers = {"Content-Type":m.content_type} r = requests.post(url=url,data = m,headers=headers) print(r.text)
3.请求正文是raw
形式：
① 传入xml格式文本（可扩展性语言：Extensible markup language）
requests.post(url='',data='<?xml ?>',headers={'Content-Type':'text/xml'})
② 传入json格式文本
requests.post(url='',data=json.dumps({'key1':'value1','key2':'value2'}),headers={'Content-Type':'application/json'})
或：requests.post(url='',json={{'key1':'value1','key2':'value2'}},headers={'Content-Type':'application/json'})
for example：
import requests import json url = "http://httpbin.org/post" j = {"key1":"value1","key2":"value2"} data = json.dumps(j) # json模块下的dumps函数将dict转换为str headers = {"Content-type":"application/json"} r = requests.post(url=url,data=data,json=j,headers=headers) print(r.text)
PS:脚本中dumps不要写成dump，否则会报缺失fp(类文件指针)的错误
python中json.dumps()和json.dump()的区别： https://www.cnblogs.com/fengff/p/11008353.html
4.请求正文是binary
形式：
requests.post(url='',files={'file':open('test.xls','rb')},headers={'Content-Type':'binary'})
import requests url = "http://httpbin.org/post" files = {"file":open("test.xlsx","rb")} headers = {"Content-type":"binary"} r = requests.post(url=url,files=files,headers=headers) print(r.text)
另外，requests也支持multipart方式发送post请求，只需将一文件传给requests.post()的参数files即可。
import requests url = "http://httpbin.org/post" files = {"file":open("report.txt","rb")} r = requests.post(url=url,files=files) print(r.text)
PS：为了避免文件路径的问题，建议文件直接放在当前py文件的同一级目录下。
