Re: question on sub-requests

gAzZaLi <[email protected]> Mon, 12 Nov 2012 22:03:50 -0800
Newsgroups	gmane.comp.apache.mod-perl
Message-ID	<[email protected]>
Hi, you're welcome, glad to be of any help.
Sounds like you're close to getting it done or done
with it already.

If you're interested, here's the redirect idea in a little
more detail and doesn't involve edits or renaming.

All requests to html files in /abc/def/ could be handled with, say,

RedirectMatch ^/abc/def/(.*)\.html$ /common/global.html?$1

which loads the frameset file global.html (in the 'common' dir.) with a 
param in the URL that denotes the actual file that was requested.

Since the static file at /abc/def/ghi.html will be served up in the 
bottom frame, and should not be intercepted by the RedirectMatch above, 
/abc/def could use an alias, say

Alias /bottomframecontent /var/www/htdocs/abc/def

Here's global.html with a little Javascript to load the frames.

global.html
-----------
<html><head>

<script>
var loadFrames = function(){
      var viewFile = location.search.replace('?', '');
	
     document.getElementById('topframe').src = 
"/perlResponseHandler?arg=" + viewFile;	

      document.getElementById('bottomframe').src = 
"/bottomframecontent/" + viewFile + ".html";
};

window.onload = loadFrames;
</script>

</head>

<frameset rows="100, *">
     <frame name="topframe" src="">
     <frame id="bottomframe" src="">
</frameset>

</html>
------------




On 11/12/2012 3:42 PM, André Warnier wrote:
> Hi.
> Thank you for your response.
> You are not missing the point of my questions.
>
> But I do not really have control over the requests.  Or rather, I do,
> but there are hundreds of pages containing hundreds of similar (but not
> equal) links, and it is in the practice not doable to edit them all..
> And my "mangle.pl" URI was an oversimplification for the sake of this
> post.  The real URI for that first frame is more complicated to
> generate, and beyond what I can do with mod_rewrite et al.
>
> But second, I just realised that I cannot do things the way I explain
> below anyway, because inside a <frame> tag, you cannot put content. You
> can only use <frame src="..URI..">.
> So basically, my skeleton ResponseHandler works as I expected and does
> create the <frameset> document that I wanted and returns it, but that
> document is invalid html.
> Shucks. Back to the drawing board.
>
> Which now creates another issue :
> I could create instead a document like :
> <html>
> <head></head>
> <frameset rows="100,*">
>    <frame name="topframe" src="/cgi-bin/mangle.pl?arg=ghi" />
>    <frame name="bottomframe" src=/abc/def/ghi.html">
> </frameset>
> </html>
>
> but.. the URI of the request for the second frame would trigger my
> ResponseHandler again, and I'd be stuck in a forever-loop of embedded
> frames, fractal-like.
>
> So now I am going to re-read your suggestions below, and see if I can
> figure out something along those lines which does not force me to edit
> and/or rename all the pages.
>
> Maybe instead of generating the second frame as
>    <frame name="bottomframe" src=/abc/def/ghi.html">
> I can instead generate it as
>    <frame name="bottomframe" src=/abc/def/ghi.html.perl">
> and then detect this in the Handler, change the $r->uri back to the
> correct one, and let Apache's default handler serve it by returning
> DECLINED.  I'll try that.
>
> Thanks for helping me think.
>
>
> gAzZaLi wrote:
>>
>> Q1: At first glance, using a mod_perl handler to serve an existing
>> static html file seems like overkill.
>>
>> Couldn't Apache respond (RedirectMatch?) with a common frameset html
>> file with some Javascript, which then fills the first frame with the
>> response to mangle.pl and the second frame with the static html file?
>>
>> If you have control over the creation of the request URLs, you could
>> also have them come in as say, "show.html?ghi", which will be a
>> frameset html file which works as above and not have Apache do any
>> extra work.
>>
>> In each case, your mod_perl handler would be simpler and deal only
>> with responding to the value of arg.
>>
>> Of course you may have already considered and rejected these ideas and
>> I'm missing the point entirely.
>>
>>
>> On 11/12/2012 9:19 AM, André Warnier wrote:
>>> Hi.
>>>
>>> context: Apache2.x, mod_perl 2.x
>>>
>>> In response to some request URLs, I have to compose a response
>>> structured as follows :
>>>
>>> - a html frameset document with two frames
>>> - in the 1st frame, the result of another HTTP request to the same
>>> Apache server.
>>>    This URI of this HTTP request is created by "mangling" the original
>>> request URL somewhat.
>>> - in the 2d frame, the content of the HTML file corresponding to the
>>> original request URI.
>>>
>>> For example, if the original request URI was something like :
>>> "/abc/def/ghi.html", then
>>>    - the top frame should contain the (html) output of a request to
>>> "/cgi-bin/mangle.pl?arg=ghi"
>>>    - the bottom frame should contain the content of the
>>> originally-requested "/abc/def/ghi.html" URI (which is a static file).
>>>
>>> I am thinking of doing this by :
>>> - creating a mod_perl ResponseHandler
>>> - having this response handler make a first sub-request to the
>>> "/cgi-bin/mangle.pl?arg=ghi" URI, grabbing the content of the response
>>> to that sub-request, and insert it into the first <frame> of the output
>>> <frameset> document.
>>> - having the response handler do a lookup_uri of the original URI, get
>>> the resulting filename, reading the file and insert its content into the
>>> second <frame> of the output <frameset> document.
>>>
>>> My 1st question is : is the above a valid plan, or is there something
>>> fundamentally wrong with this approach ?
>>>
>>> My 2d question is : looking at the Apache2::SubRequest documentation, I
>>> do not see a clear way of getting the response content of a subrequest.
>>> For example, the run() method explanation seems to indicate that the
>>> response content is sent directly to the client.
>>> Am I missing something ?
>>>
>>> TIA
>>>
>>>
>>>
>>
>>
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>
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