HTTPClient_ReadHeader

Read a header from a buffer containing a complete HTTP response. This will return the location of the response header value in the HTTPResponse_t.pBuffer buffer.

HTTPStatus_t HTTPClient_ReadHeader( const HTTPResponse_t * pResponse,
                                    const char * pField,
                                    size_t fieldLen,
                                    const char ** pValueLoc,
                                    size_t * pValueLen );

The location, within HTTPResponse_t.pBuffer, of the value found, will be returned in pValue. If the header value is empty for the found pField, then this function will return HTTPSuccess, and set the values for pValueLoc and pValueLen as NULL and zero respectively. According to RFC 2616, it is not invalid to have an empty value for some header fields.

Note

This function should only be called on a complete HTTP response. If the request is sent through the HTTPClient_Send function, the HTTPResponse_t is incomplete until HTTPClient_Send returns.

Parameters

[in]	pResponse	The buffer containing the completed HTTP response.
[in]	pField	The header field name to read.
[in]	fieldLen	The length of the header field name in bytes.
[out]	pValueLoc	This will be populated with the location of the header value in the response buffer, HTTPResponse_t.pBuffer.
[out]	pValueLen	This will be populated with the length of the header value in bytes.

Returns

One of the following:

• HTTPSuccess (If successful.)
• HTTPInvalidParameter (If any provided parameters or their members are invalid.)
• HTTPHeaderNotFound (Header is not found in the passed response buffer.)
• HTTPInvalidResponse (Provided response is not a valid HTTP response for parsing.)
• HTTPParserInternalError(If an error in the response parser.)

Example

HTTPStatus_t httpLibraryStatus = HTTPSuccess;
// Assume that response is returned from a successful invocation of
// HTTPClient_Send().
HTTPResponse_t response;
 
char * pDateLoc = NULL;
size_t dateLen = 0;
// Search for a "Date" header field. pDateLoc will be the location of the
// Date header value in response.pBuffer.
httpLibraryStatus = HTTPClient_ReadHeader( &response,
                                           "Date",
                                           sizeof("Date") - 1,
                                           &pDateLoc,
                                           &dateLen );