The HTTP Protocol

HTTP communicates over TCP/IP. An HTTP client connects to an HTTP server using TCP. After establishing a connection, the client can send an HTTP request message to the server:

POST /item HTTP/1.1
Host: 189.123.345.239
Content-Type: text/plain
Content-Length: 200

The server then processes the request and sends an HTTP response back to the client. The response contains a status code that indicates the status of the request:

200 OK
Content-Type: text/plain
Content-Length: 200

In the example above, the server returned a status code of 200. This is the standard success code for HTTP.

If the server could not decode the request, it could have returned something like this:

400 Bad Request
Content-Length: 0


SOAP HTTP Binding

A SOAP method is an HTTP request/response that complies with the SOAP encoding rules.
HTTP + XML = SOAP

A SOAP request could be an HTTP POST or an HTTP GET request.

The HTTP POST request specifies at least two HTTP headers: Content-Type and Content-Length.
Content-Type
The Content-Type header for a SOAP request and response defines the MIME type for the message and the character encoding (optional) used for the XML body of the request or response.
Syntax

Content-Type: MIMEType; charset=character-encoding

Example

POST /item HTTP/1.1
Content-Type: application/soap+xml; charset=utf-8


Content-Length
The Content-Length header for a SOAP request and response specifies the number of bytes in the body of the request or response.
Syntax

Content-Length: bytes

Example

POST /item HTTP/1.1
Content-Type: application/soap+xml; charset=utf-8
Content-Length: 250