Re: LYNX-DEV External filters

[root]

Klaus Weide wrote:
> 
> On Sun, 23 Feb 1997, Tom Zerucha wrote:
> > An earlier suggestion would be to define a filter lynx could use between
> > the HTTP receive and the rendering (so I could put my table renderer or
> > whatever there).
> 
> [ I am commenting mostly on the last sentence, I haven't tried to
> understand exactly the exact use of this w.r.t. bookmarks, pine, etc. ]
> 
> Implementing a HTStream which pipes bytes through an external filter 
> program would in itself not be difficult (on Unix and "similar enough")
> systems.  In fact, it has already been done:  See WebFilter at
> 
>    Linkname: Filtering the Web using WebFilter
>         URL: http://math-www.uni-paderborn.de/~axel/NoShit/
> 
> The file HTPipe.c from the sources of WebFilter could be used within
> Lynx with little adaptation.  (It is meant to be included in the CERN
> *server*, but the server code is based on the same Reference Library
> as Lynx, so it used the same data structures - HTStream * etc.)
> Tom, are you up to putting it in the Lynx code?
> 
> The problems:
> 
> 1/ It will not work on all (non-Unix) systems.
> 
> 2/ The main problem is when and how to decide and control *when* to
> call this.  It probably doesn't make sence to pipe every piece of
> text/html through such an external program - much too much overhead.  
> But there is no external indication when a document needs to be piped
> through this for e.g. table rendering.  So it must be under user 
> control.  Which means adding new command line flags, Options, keystroke
> etc.
> 
> (WebFilter uses an extended rule file syntax for deciding when to include
> the external filter program in a pipe, based on regex matching on the URL.
> But (1) I don't think that is good enough for a clinet like Lynx, and
> (2) rule files are already used in the CERN server, but not in Lynx -
> although there is a hook for it in HTAccess.c's get_phusical().)
> 
>   Klaus

Couldn't the filter simply say: "I want to be called if you get a text/html
with <table> in it." (I would sugest some oddity in the mailcap).  Then,
when lynx gets a text/html it can scan it for the regx "<table[> ]" (you
could possibly have this in an attribitue value, but if you do, you deserve
what you get.) And, if it finds it, convert to a lynxcgi: link.  Better yet,
define a lynxpipe:program?URLtopipe class URL.

  --- James Mastros
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