This guide is for those who want to implement an HTTP client as part of HCC Embedded’s MISRA-compliant TCP/IP stack.  This HTTP client provides an Application Programming Interface (API) for retrieving content from a web server. It supports the GET, HEAD, POST, PUT, and DELETE methods.

The HTTP client module works with both IPv4 and IPv6 networks. Its place in the HCC TCP/IP stack is shown below. (In this diagram green lines show interfaces available to users of the stack, red lines show interfaces internal to the TCP/IP system.)

The Hypertext Transfer Protocol (HTTP) and its secure equivalent (HTTPS) provide communication over computer networks. HTTP resources are identified and located on the network using Uniform Resource Identifiers (URIs). 

HTTP operates as a request-response protocol in the client/server model. The HTTP client provides an API for retrieving content from a web server.

The client sends an HTTP request message to the server. The server, which may provide resources such as HTML files to the client, or perform other functions for it, sends a response message back to the client. This contains completion status information about the request. It may also contain requested content within its message body.