Porting Guide

Guide for porting the HTTP client library to a new platform.

To use the HTTP client library, a platform must implement the following components:

1. Configuration Macros
2. Transport Interface

Configuration Macros

Settings that can be set as macros in the config header core_http_config.h, or passed in as compiler options.

Note

If the custom configuration header core_http_config.h is not provided, then the HTTP_DO_NOT_USE_CUSTOM_CONFIG macro must be defined.

See also

Configurations

The following macros can be configured for this library:

• HTTP_MAX_RESPONSE_HEADERS_SIZE_BYTES
• HTTP_USER_AGENT_VALUE

In addition, the following logging macros are used throughout this library:

• LogError
• LogWarn
• LogInfo
• LogDebug

Transport Interface

The HTTP client library relies on transport interface callbacks that must be implemented in order to send and receive packets on a network.

See also

The Transport Interface documentation for more information.

The transport interface API used by the HTTP client is defined in transport_interface.h. A port must implement functions corresponding to the following functions pointers:

• Transport Receive: A function to receive bytes from a network.

  int32_t (* TransportRecv_t )(
      NetworkContext_t * pNetworkContext, void * pBuffer, size_t bytesToRecv
  );

• Transport Send: A function to send bytes over a network.

  int32_t (* TransportSend_t )(
      NetworkContext_t * pNetworkContext, const void * pBuffer, size_t bytesToSend
  );

The above two functions take in a pointer to a NetworkContext_t, the type name of a struct NetworkContext. The NetworkContext struct must also be defined by the user's implementation, and ought to contain any information necessary to send and receive data with the TransportSend_t and TransportRecv_t implementations, respectively:

struct NetworkContext {
    // Fields necessary for the transport implementations, e.g. a TCP socket descriptor.
};