Re: Return a 200 0K status and send the content of the request later

On Tue, 13 May 2025 14:57:15 -0500
Mithun Bhattacharya <[email protected]> wrote:

Hi Mithun,

> Hence if you are writing a mod_perl handler for such an endpoint you retu=
rn
> success immediately and then start processing the request. In most cases
> this is simply a matter of doing $r->print on the headers followed by pri=
nt
> of two new lines.
>=20

Nice!

Your comment made me revisit mod_perl's documentation, and I found this :

https://perl.apache.org/docs/2.0/user/coding/coding.html#Forcing_HTTP_Respo=
nse_Headers_Out

The following works, where exportation($r) is the long running sub that bui=
lds a tar file and returns a page with a link to the file, for the user to =
click. '<h3>Building tar file</h3>' does get sent first, then the rest of t=
he response after completion of the sub.


	$r->content_type('text/html; charset=3Dutf-8') ;

	$r->print('<h3>Building tar file</h3>') ;

	$r->rflush; # send the headers out

	$r->print( exportation($r) ) ;

	return Apache2::Const::OK ;


This is great, I can thus send a message to the user, maybe with an estimat=
ed time of arrival. Thanks for the help.

I have an another question, if I may.

Is there a way I could do :

	$r->print('<h3>Building tar file</h3>') ;

every second or other until the tar file is built? I can't seem to think of=
 one.

My handler calls an sql script that dumps the database with system() :

    @args =3D ('psql', '-f', '/path/to/script/to/export_raw_data.sql', '-v'=
, 'id_client=3D' . $r->pnotes('session')->{id_client}, '-v',  'database=3D'=
 . $database, 'postgres') ;

    system(@args) =3D=3D 0 or warn "system @args failed: $!" ;

then waits for the resulting file before proceeding to compress and tar it,=
 also with a system() call.=20

How can I wrap this in a loop that re-sends the 'Building tar file' message=
 until the file exists?



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					Bien =E0 vous, Vincent Veyron=20

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