通过POST请求发送数据

Question

I had been using sockets, with Python, for some time ago and I'm trying to understand why this POST which should send some data on fields data1 and data2 do not work.

POST /method.php HTTP/1.1\\r\\nHost: localhost\\r\\nContent-Type: multipart/form-data\\r\\n\\r\\ndata1=something&data2= otherthing\\r\\n\\r\\n

What is the problem with this request?

Answer 1

Have you tried using the Requests library instead, example of a post request below

import requests
header = {"Content-Type": "multipart/form-data"}
data1="something"
data2= "otherthing"

session_requests = requests.session()
result = session_requests.post("http://localhost/", data=dict(data1, data2), headers=header)

Answer 2

It might be easier to use the requests library so your code would look something like this:

import requests

# Data
data = {
    'data1':'something', 
    'data2':'otherthing'
}

# Custom headers
headers = {
    'content-type': 'multipart/form-data'
}

# Get response from server
response = requests.post('http://localhost/', data=data, headers=headers)

# If you care about the response
print(response.json())

You can also send files and a whole lot of other stuff

Answer 3

There are several things wrong with your request:

 POST /method.php HTTP/1.1
 Host: localhost
 Content-Type: multipart/form-data

 data1=something&data2= otherthing

First, whenever a body is used within a HTTP request the length of the body must be known. This is typically done by given the length up-front with Content-length in the HTTP header although also chunked encoding might be used if the full length is not known up front. Your request does not do any of these which means the request is an invalid HTTP request.

Additionally you claim a Content-Type of multipart/form-data although your body is not of this type. With multipart/form-data your body would consist of several MIME parts separated by a text boundary and this boundary would need to have been declared in your Content-type header. The correct type for the body you show would be instead application/x-www-form-urlencoded .

Even with application/x-www-form-urlencoded the body is partly wrong. This type of body should be only pairs of key=value concatenated by & , ie there should be neither as space after a key as you have after data2= nor there should be new lines added after the end of the data as you have.

When removing all these problems you should probably send the following request:

body = "data1=something&data2=otherthing"
request = ("POST /method.php HTTP/1.1\r\n" + \
    "Host: localhost\r\n" + \
    "Content-Type: application/x-www-form-urlencoded\r\n" + \
    "Content-Length: %d\r\n" + \
    "\r\n%s") % (len(body),body)

But once you have send this request the trouble continues since getting the response correctly is complex too. Generally I recommend to not code your own HTTP handling unless you really know what you do but instead use existing libraries. While HTTP might look simple when just looking at a few example requests it is way more complex than it initially looks. And while your code might seem to work against specific servers it might fail with other servers.