Add Response Header Field

This hook function, if defined, is called by μC/HTTP-server before starting to transmit the response message as shown on Hook Functions. It allows the upper application to add header field to the response by calling a specific API function with header field type and value.

Prototype

CPU_BOOLEAN  HTTPs_RespHdrTxHook (const  HTTPs_INSTANCE  *p_instance,
                                         HTTPs_CONN      *p_conn,
                                  const  void            *p_hook_cfg);

Arguments

p_instance

Pointer to the instance structure (read only).

p_conn

Pointer to the connection structure (read only).

p_hook_cfg

Pointer to hook application data.

Return Value

DEF_YES

If all header fields are added without error.

DEF_NO

otherwise.

Required Configuration

HTTPs_CFG_HDR_EN must be enabled in the http-s_cfg.h file (see section Module Configuration).

The header feature must also be enabled in the Instance configuration (see section Instance Parameters Configuration).

See section Hook Configuration.

Notes / Warnings

The instance structure is for read-only. It must not be modified.
Connection structure must not be modified by this function since the response is mostly ready to be transmitted.

Example Template

The listing below is shown to demonstrate the µC/HTTP-server module capabilities. It adds two header fields to a response message for an HTML document.

Listing - Add Header Field Hook Function Example Code

static  CPU_BOOLEAN  HTTPs_RespHdrTxHook (const  HTTPs_INSTANCE  *p_instance,
                                                 HTTPs_CONN      *p_conn,
                                          const  void            *p_hook_cfg)
{
#if (HTTPs_CFG_HDR_EN == DEF_ENABLED)
           HTTPs_HDR_BLK  *p_resp_hdr_blk;
	const  HTTPs_CFG      *p_cfg;
           CPU_CHAR       *str_data;
           CPU_SIZE_T      str_len;
           HTTPs_ERR       http_err;
    
      
	p_cfg = p_instance->CfgPtr;

    switch (p_conn->StatusCode) {
	    case HTTPs_STATUS_OK:                                                              (1)
             if (p_conn->FileContentType == HTTPs_CONTENT_TYPE_HTML) {                     (2)
                 p_resp_hdr_blk = HTTPs_RespHdrGet(p_instance,                             (3)
                                                   p_conn,
                                                   HTTPs_HDR_FIELD_SET_COOKIE,
                                                   HTTPs_HDR_VAL_TYPE_STR_DYN,
                                                  &http_err);
                 if (p_resp_hdr_blk == DEF_NULL) {
                     return(DEF_FAIL);
                 }

				 str_data = "user=micrium";
                 str_len = Str_Len_N(str_data, p_cfg->RespHdrStrLenMax);
                 Str_Copy_N(p_resp_hdr_blk->ValPtr,                                        (4)
                            str_data,
                            str_len);

                 p_resp_hdr_blk->ValLen = str_len;                    
          
                 p_resp_hdr_blk = HTTPs_RespHdrGet(p_instance,                             (5)
                                                   p_conn,
                                                   HTTPs_HDR_FIELD_SERVER,
                                                   HTTPs_HDR_VAL_TYPE_STR_DYN,
                                                  &http_err);
                 if (p_resp_hdr_blk == DEF_NULL) {
                     return(DEF_FAIL);
                 }
          
                 str_data = "uC-HTTPs V2.00.00";
                 str_len = Str_Len_N(str_data, p_cfg->RespHdrStrLenMax);                   (6)
                 Str_Copy_N(p_resp_hdr_blk->ValPtr,
                            str_data,
                            str_len);

                 p_resp_hdr_blk->ValLen = str_len;
             }
             break;
          
         default:
             break;
	}
#endif

	return (DEF_YES);
}

Ensure that we don’t add header field to a response with an error
Make sure to add header field only on HTML document.
Acquire and add a first header field block of type ‘Cookie’ and with a string value type to the connection
Set the value string value (cookie content) and the string length.
Acquire and add a second header field block of type ‘Server’ and with a string value type to the connection
Set the value string value (server name) and the string length.