HTTP requests

Here is an example request:

GET /path/to/file/index.html HTTP/1.1
Host: www.educative.io
Connection: close
User-agent: Mozilla/5.0
Accept-language: fr
Accept: text/html

• HTTP messages are in ASCII text
• Each line ends in a carriage return and a newline: \r\n
• The first line is a request line, and the rest of the lines are header lines.

The request line anatomy

HTTP methods

• GET requests data
• POST posts data to the server
• The server responds with the location of the object - usually used when the client doesn't know where to put the data.
• HEAD is similar to get, but only requests the header of the data.
• Used to check whether some object still exists
• PUT uploads data to a specific spot defined by a URI.
• Often used after a POST request.
• DELETE deletes data at a given URL

URI

A Universal Resource Identifier is like a URL, but it can also target fragments of a resource. This is encoded as a # in text, for example (https://en.wikipedia.org/wikiTransmission_Control_Protocol#Network_function) is a URI.

HTTP Header Lines Anatomy

Here is a list of all HTTP header fields. Below are some explanations of commonly used and non-obvious ones

• Connection defines whether the connection is persistent or not. In the case of the example above, it is a non-persistent connection.
• User-agent defines the client, and is useful when the server has different versions of an object for different browsers.
• Accept defines the sort of response to accept.