Re: [libmicrohttpd] POST processing "any" mime type

[Andreas Wehrmann]

On 05/22/2014 07:49 PM, Shantanu Tushar Jha wrote:
> [Please CC me in replies, I'm not subscribed to the list]
>
> Hi,
>
> I was searching about how to process application/json in POST data in a
> server written using MHD. I came across this thread
> http://lists.gnu.org/archive/html/libmicrohttpd/2011-11/msg00013.html where
> Andreas says that he implemented a generic processor to handle
> application/JSON.
>
> I want to do the same, but MHD_AccessHandlerCallback::upload_data is always
> NULL, and I can't use MHD_create_post_processor because
> MHD_PostDataIterator works on a key/data basis. How do I register a generic
> POST processor? (My existing code is at
> https://github.com/shaan7/fibrous/blob/master/cpp/httpserver.cpp#L42 )
>
> Thanks,

The following are incomplete snippets from my code.
Note: "request" is a private handle.

When I get a new connection, I do:

else if( request_method == MHD_HTTP_METHOD_POST )
{
    request->request_type = POST;
    request->postProcessor = MHD_create_post_processor( connection, 1024,
Server_impl::post_iterator,
reinterpret_cast< void* >( request ) );

    if( request->postProcessor == NULL )
    {
        if( content_type == NULL )
        {
            PlogNotice( "[HTTPD] unable to create POST processor: 
unknown content type!" );
            return MHD_NO;
        }

        /* check for other MIME types supported by us */
        if( isJsonType( content_type ) && jsonCallback )
        {
            return MHD_YES;
        }
        else if( isXmlType( content_type ) && xmlCallback )
        {
            return MHD_YES;
        }
        else
        {
            /* NOTE: is it better here to return "501 - not 
implemented"? */
            PlogWarn( "[HTTPD] unable to handle POST request with 
content of type %s",
                        content_type );
            return MHD_NO;
        }
    }
}

****************************************************
When I get more data I do:

else if( request->request_type == POST )
{
    if( 0 != *upload_data_size )
    {
        if( MHD_post_process( request->postProcessor, upload_data, 
*upload_data_size ) == MHD_NO )
        {
            if( isJsonType( content_type ) || isXmlType( content_type ) )
            {
                request->postRawData.append( upload_data, 
*upload_data_size );
            }
            else
            {
                PlogError( "[HTTPD] don't know how to handle content of 
type: %s",
                            content_type );
                return MHD_NO;
            }
        }
        *upload_data_size = 0;

        return MHD_YES;
    }
    else    /* received data completely, now inform user and build 
answer page */
    {
        std::string rsp;    /* response to send in case of user handled 
mime types */
        bool handleJsonRequest  = isJsonType( content_type ) && 
jsonCallback;
        bool handleXmlRequest   = isXmlType( content_type ) && xmlCallback;

        if( handleJsonRequest )
        {
            jsonCallback( requested_url, request->postRawData, rsp );
        }
        else if( handleXmlRequest )
        {
            xmlCallback( requested_url, request->postRawData, rsp );
        }
        else if( setClearSilverDataCB )
        {
            std::string fileName( getFilename( requested_url ) );
            setClearSilverDataCB( fileName, request->postFormData );
        }

        /* --- cut here --- */
    }
}

Regards,
Andreas