stas 02/04/27 11:32:39
Modified: src/docs/1.0/guide Changes.pod porting.pod
Log:
new section "Preventing Apache::Constants Stringification"
Submitted by: Per Einar Ellefsen <[EMAIL PROTECTED]>
Revision Changes Path
1.15 +3 -0 modperl-docs/src/docs/1.0/guide/Changes.pod
Index: Changes.pod
===================================================================
RCS file: /home/cvs/modperl-docs/src/docs/1.0/guide/Changes.pod,v
retrieving revision 1.14
retrieving revision 1.15
diff -u -r1.14 -r1.15
--- Changes.pod 21 Apr 2002 05:00:09 -0000 1.14
+++ Changes.pod 27 Apr 2002 18:32:39 -0000 1.15
@@ -17,6 +17,9 @@
* guide::porting
+ o add a new section "Preventing Apache::Constants Stringification"
+ [Per Einar]
+
o add a new section presenting a hackish solution for libraries
collision, via do() or %INC mangling.
1.9 +51 -0 modperl-docs/src/docs/1.0/guide/porting.pod
Index: porting.pod
===================================================================
RCS file: /home/cvs/modperl-docs/src/docs/1.0/guide/porting.pod,v
retrieving revision 1.8
retrieving revision 1.9
diff -u -r1.8 -r1.9
--- porting.pod 17 Apr 2002 04:38:52 -0000 1.8
+++ porting.pod 27 Apr 2002 18:32:39 -0000 1.9
@@ -3157,6 +3157,57 @@
=back
+=head1 Preventing Apache::Constants Stringification
+
+In mod_perl, you are going to use a certain number of constants in
+your code, mainly exported from C<Apache::Constants>. However, in some
+cases, Perl will not understand that the constant you're trying to
+call is really a constant, but interprets it as a string. This is the
+case with the hash notation C<=E<gt>>, which automatically stringifies
+the key.
+
+For example:
+
+ $r->custom_response(FORBIDDEN => "File size exceeds quota.");
+
+This will not set a custom response for C<FORBIDDEN>, but for the
+string C<"FORBIDDEN">, which clearly isn't what is expected. You'll
+get an error like this:
+
+ [Tue Apr 23 19:46:14 2002] null: Argument "FORBIDDEN" isn't numeric
+ in subroutine entry at ...
+
+Therefore, you can avoid this by not using the hash notation for
+things that don't require it.
+
+ $r->custom_response(FORBIDDEN, "File size exceeds quota.");
+
+There are other workarounds, which you should avoid using unless you
+really have to use hash notation:
+
+ my %hash = (
+ FORBIDDEN() => 'this is forbidden',
+ +AUTH_REQUIRED => "You aren't authorized to enter!",
+ );
+
+Another important note is that you should be using the correct
+constants defined here, and not direct HTTP codes. For example:
+
+ sub handler {
+ return 200;
+ }
+
+Is not correct. The correct use is:
+
+ use Apache::Constants qw(OK);
+
+ sub handler {
+ return OK;
+ }
+
+Also remember that C<OK != HTTP_OK>.
+
+
=head1 Transitioning from Apache::Registry to Apache handlers
Even if you are a CGI script die-hard at some point you might want to
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