[mp2] The right way to use CGI parameters in a handler

[Colin Wetherbee <cw...@denterprises.org>]

Hello!

It's been about four years since I've used mod_perl to any great extent, 
and I'm afraid I'm somewhat rusty.  I'm trying to create a handler that 
can parse CGI parameters, but I'm unsure of the most modern way of doing 
that.

I know Apache2::Request is supposed to be able to grab CGI parameters; 
is that "better" than using CGI.pm?  How about these APR modules that 
seem to wind their way into the framework?

When I tried creating an Apache2::Request->new($r) object to use to get 
CGI parameters, I found that everything I tried to print after the 
object's instantiation wouldn't show up anywhere.  All the pages served 
were zero bytes, and I couldn't even print to STDERR.

Here's a simple handler I wrote.  It works, but I'm afraid I might be 
doing something incorrectly by mixing Apache2 and CGI.  I'm wondering 
how it would look if someone who was more up-to-date on mod_perl wrote 
it? :)

# BEGIN CODE BLOCK
use Apache2::Const -compile => qw(OK);
use CGI;

sub handler
{
   my ($r) = @_;

   my $cgi = CGI->new($r);

   $r->content_type('text/html');

   if (defined $cgi->param('foo'))
   {
     print 'foo: ' . $cgi->param('foo') . "<br />\n";
   }

   return Apache2::Const::OK;
}
# END CODE BLOCK

Thanks. :)

Colin

Re: [mp2] The right way to use CGI parameters in a handler

[Jeff Pang <pa...@earthlink.net>]

Foo JH 写道:

> You'd see that Apache2::Request exposes more stuff, which you can 
> (lazily) use. Unless you are looking for some backward compatibility to 
> tradditional CGI programming, why not embrace the entire modperl library?
> 

I second it.Using Apache2::Request is not harder than CGI,but much faster.

Re: [mp2] The right way to use CGI parameters in a handler

[Colin Wetherbee <cw...@denterprises.org>]

Colin Wetherbee wrote:
> # BEGIN CODE BLOCK
>   my $req = Apache2::Request->new($r);
> 
>   $r->content_type('text/html');
>   $r->print("test<br />\n");
> # END CODE BLOCK

OK, problem solved.

I didn't have mod_apreq enabled.  For what it's worth, I don't recall 
seeing anything about enabling mod_apreq in the documentation; it just 
said enable mod_perl, and showers of gold will fall from the sky or 
something. :P

Thanks for your help, everyone.

Colin

Re: [mp2] The right way to use CGI parameters in a handler

[Colin Wetherbee <cw...@denterprises.org>]

Jonathan Vanasco wrote:
>> As I said in my original post, I tried to use Apache2::Request, but 
>> after creating that object, I couldn't print anything anymore.  
>> Perhaps someone could give me a hint on how to implement it?
> 
> could you print beforehand?
> 
> 'print' might not be tied to the same output.

Printing beforehand wouldn't allow me to use the CGI parameters to 
determine the output. :)

> this might not be right based on your compile.
>>>>     print 'foo: ' . $cgi->param('foo') . "<br />\n";
> 
> try:
>     $r->print( 'foo: ' . $cgi->param('foo') . "<br />\n" );

No dice.

# BEGIN CODE BLOCK
   my $req = Apache2::Request->new($r);

   $r->content_type('text/html');
   $r->print("test<br />\n");
# END CODE BLOCK

The content-type doesn't even show up in this case.

If I put the $r->content_type() and $r->print() before the $req object 
is created, *still* nothing shows up.

Colin

Re: [mp2] The right way to use CGI parameters in a handler

[Jonathan Vanasco <jv...@2xlp.com>]

On Jun 11, 2007, at 4:29 PM, Colin Wetherbee wrote:

> That sounds good to me.  I'm not looking for any particular  
> backward compatibility, and speed is an issue.

last i checked the speed difference is negligible.  its 'more proper'  
to use libapreq, and if you're doing things in term of mod_perl  
handlers (ie, not anything that would run as a std cgi ), then  
there's little reason to use  otherwise.



> As I said in my original post, I tried to use Apache2::Request, but  
> after creating that object, I couldn't print anything anymore.   
> Perhaps someone could give me a hint on how to implement it?

could you print beforehand?

'print' might not be tied to the same output.

this might not be right based on your compile.
>>>     print 'foo: ' . $cgi->param('foo') . "<br />\n";

try:
	$r->print( 'foo: ' . $cgi->param('foo') . "<br />\n" );




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Re: [mp2] The right way to use CGI parameters in a handler

[Colin Wetherbee <cw...@denterprises.org>]

Foo JH wrote:
> You'd see that Apache2::Request exposes more stuff, which you can 
> (lazily) use. Unless you are looking for some backward compatibility to 
> tradditional CGI programming, why not embrace the entire modperl library?

That sounds good to me.  I'm not looking for any particular backward 
compatibility, and speed is an issue.

As I said in my original post, I tried to use Apache2::Request, but 
after creating that object, I couldn't print anything anymore.  Perhaps 
someone could give me a hint on how to implement it?

Here's the original code again.

>> # BEGIN CODE BLOCK
>> use Apache2::Const -compile => qw(OK);
>> use CGI;
>>
>> sub handler
>> {
>>   my ($r) = @_;
>>
>>   my $cgi = CGI->new($r);
>>
>>   $r->content_type('text/html');
>>
>>   if (defined $cgi->param('foo'))
>>   {
>>     print 'foo: ' . $cgi->param('foo') . "<br />\n";
>>   }
>>
>>   return Apache2::Const::OK;
>> }
>> # END CODE BLOCK

Thank you very much.

Colin

Re: [mp2] The right way to use CGI parameters in a handler

[Foo JH <jh...@extracktor.com>]

I've kinda moved out of CGI since I started using modperl for primarily 
2 reasons: speed and functionality.

You'd see that Apache2::Request exposes more stuff, which you can 
(lazily) use. Unless you are looking for some backward compatibility to 
tradditional CGI programming, why not embrace the entire modperl library?

Colin Wetherbee wrote:
> Hello!
>
> It's been about four years since I've used mod_perl to any great 
> extent, and I'm afraid I'm somewhat rusty.  I'm trying to create a 
> handler that can parse CGI parameters, but I'm unsure of the most 
> modern way of doing that.
>
> I know Apache2::Request is supposed to be able to grab CGI parameters; 
> is that "better" than using CGI.pm?  How about these APR modules that 
> seem to wind their way into the framework?
>
> When I tried creating an Apache2::Request->new($r) object to use to 
> get CGI parameters, I found that everything I tried to print after the 
> object's instantiation wouldn't show up anywhere.  All the pages 
> served were zero bytes, and I couldn't even print to STDERR.
>
> Here's a simple handler I wrote.  It works, but I'm afraid I might be 
> doing something incorrectly by mixing Apache2 and CGI.  I'm wondering 
> how it would look if someone who was more up-to-date on mod_perl wrote 
> it? :)
>
> # BEGIN CODE BLOCK
> use Apache2::Const -compile => qw(OK);
> use CGI;
>
> sub handler
> {
>   my ($r) = @_;
>
>   my $cgi = CGI->new($r);
>
>   $r->content_type('text/html');
>
>   if (defined $cgi->param('foo'))
>   {
>     print 'foo: ' . $cgi->param('foo') . "<br />\n";
>   }
>
>   return Apache2::Const::OK;
> }
> # END CODE BLOCK
>
> Thanks. :)
>
> Colin

Re: [mp2] The right way to use CGI parameters in a handler

[Joe Schaefer <jo...@sunstarsys.com>]

"Perrin Harkins" <pe...@elem.com> writes:

> On 6/10/07, Colin Wetherbee <cw...@denterprises.org> wrote:
>> I know Apache2::Request is supposed to be able to grab CGI parameters;
>> is that "better" than using CGI.pm?
>
> It's faster, but CGI.pm fully supports Apache 2 and works fine.  If
> speed is not an issue for you, it's fine to stick with your CGI.pm
> code.

For a typical mod_perl application, I tend to agree.  However there
is a significant difference in how apreq handles the raw post data
versus CGI.  Because apreq is implemented as a transparent input
filter, it does not remove the post data from the input filter chain.
The upshot of that design is that it allows you to use apreq in
situations where CGI.pm's behavior of removing the post data is 
undesirable, for instance when implementing an output filter or 
an auth handler where the content handler itself isn't even mod-perl
based.


-- 
Joe Schaefer

Re: [mp2] The right way to use CGI parameters in a handler

[Perrin Harkins <pe...@elem.com>]

On 6/10/07, Colin Wetherbee <cw...@denterprises.org> wrote:
> I know Apache2::Request is supposed to be able to grab CGI parameters;
> is that "better" than using CGI.pm?

It's faster, but CGI.pm fully supports Apache 2 and works fine.  If
speed is not an issue for you, it's fine to stick with your CGI.pm
code.

- Perrin