How are parameters sent in an HTTP POST request?

The values are sent in the request body, in the format that the content type specifies.

Usually the content type is application/x-www-form-urlencoded, so the request body uses the same format as the query string:

parameter=value&also=another
When you use a file upload in the form, you use the multipart/form-data encoding instead, which has a different format. It's more complicated, but you usually don't need to care what it looks like, so I won't show an example, but it can be good to know that it exists.

3 years ago

The content is put after the HTTP headers. The format of an HTTP POST is to have the HTTP headers, followed by a blank line, followed by the request body. The POST variables are stored as key-value pairs in the body.

You can see this in the raw content of an HTTP Post, shown below:

POST /path/script.cgi HTTP/1.0

From: xyz@abc.com

User-Agent: HTTPTool/1.0

Content-Type: application/x-www-form-urlencoded

Content-Length: 32



home=Cosby&favorite+flavor=flies

3 years ago

The default media type in a POST request is application/x-www-form-urlencoded. This is a format for encoding key-value pairs. The keys can be duplicate. Each key-value pair is separated by an & character, and each key is separated from its value by an = character.
For example:

Name: John Smith

Grade: 19

Is encoded as:

Name=John+Smith&Grade=19

This is placed in the request body after the HTTP headers.

3 years ago