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Re: Getting both a chunk and HText callbacks

From: Joel Young <jdy@godel.cs.brown.edu>
Date: Fri, 25 May 2001 17:14:36 -0400
Message-Id: <200105252114.RAA05065@godel.cs.brown.edu>
To: www-lib@w3.org
cc: jdy@cs.brown.edu

I figured out a hack using a hint from the archive:

http://lists.w3.org/Archives/Public/www-lib/msg00377.html

By adding a pointer to "chunk" as an element of the request context, 
the following "converter tee" (Maciej Puzio) does the trick.

//////
static HTStream* HTMLPresentAndChunk ( 
        HTRequest*      request, 
        void*           param, 
        HTFormat        input_format, 
        HTFormat        output_format, 
        HTStream*       output_stream) 
{ 
  requestcontext_t* context = 
    reinterpret_cast<requestcontext_t*>(HTRequest_context(request));
  return HTTee(
      HTMLPresent(request,param,input_format,output_format,output_stream), 
      HTStreamToChunk(request,&context->chunk,-1),0);
}
//////

When combined with

//////
HTRequest* request = HTRequest_new();
requestcontext_t* context = new requestcontext_t(this);
HTRequest_setContext(request,context);

HTNet_addAfter(&term_handler, 0, 0, HT_ALL, HT_FILTER_LAST);
HText_registerCDCallback(&RHText_new,&RHText_delete);
HText_registerTextCallback(&add_text);
HText_registerLinkCallback(&found_link);

HTAlert_setInteractive(NO);
HTHost_setEventTimeout(15000); // if can't load 15 secs, abort

HTAnchor* anchor = HTAnchor_findAddress(url);

HTConversion_add( 
    HTFormat_conversion(),
    "text/html", 
    "www/present", 
    (HTConverter*)&HTMLPresentAndChunk, 
    1.0, 0.0, 0.0);

HTLoadAnchor(anchor, request);

HTEventList_newLoop();
//////

and now context->chunk contains the page.

Does this make sense?  

Why doesn't HTRequest_conversion(request) work instead of the
HTFormat_conversion()?  

Why doesn't RHText_delete ever get called?  Since the "system" doesn't
call it, where should I call it from?

How does one know that that is the correct place to do the
HTConversion_add?  Is there a better place?

I am still missing the "big picture" with this library.

Thanks,

Joel
jdy@cs.brown.edu
--------
From: Joel Young <jdy@godel.cs.brown.edu>
Date: Fri, 25 May 2001 15:30:24 -0400
  To: www-lib@w3.org
  Cc: jdy@cs.brown.edu
Subj: Getting both a chunk and HText callbacks

I am trying to use HTTee to get libwww to simultaneously from one
HTLoad to load the webpage into a chunk and also to call my HText
callbacks.  Here is the code I am using:

HTRequest* request = HTRequest_new();
HTNet_addAfter(&term_handler, 0, 0, HT_ALL, HT_FILTER_LAST);
HTAlert_setInteractive(NO);
HTHost_setEventTimeout(15000); // if can't load 15 secs, abort

HTAnchor* anchor = HTAnchor_findAddress(url);
HTRequest_setAnchor(request, anchor);

HTChunk* chunkchunk = 0; 
//  HTRequest_setOutputFormat(request,WWW_SOURCE);
HTStream* chunkstream = HTStreamToChunk(request,&chunkchunk,-1);

HText_registerCDCallback(&RHText_new,&RHText_delete);
HText_registerTextCallback(&add_text);
HText_registerLinkCallback(&found_link);

HTStream* target = HTTee(chunkstream, HTRequest_outputStream(request),0);

HTRequest_setOutputStream(request, target);

HTLoad(request, NO);

HTEventList_newLoop();

std::cerr << HTChunk_size(chunkchunk) << std::endl;
char* strchunk = HTChunk_toCString(chunkchunk);
std::cerr << strchunk << std::endl;


Depending on if the HTRequest_setOutputFormat line is commented or not I
either get the HText callbacks or I get the chunk, but I can't seem to
get both.

Any suggestions?

Joel
jdy@cs.brown.edu
Received on Friday, 25 May 2001 17:14:41 GMT

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