[PATCH] 1.3.X mod_headers: New Directive "ErrorHeader"

[Sander van Zoest <sa...@yahoo-inc.com>]

It is common practice to set Cookie's to pass along on HTTP
redirects for "login" authentication. 

When implementing P3P <http://www.w3.org/P3P/> using 
mod_headers.c the Header directive only sets r->headers_out 
and does not pass the headers along for non-2XX responses 
such as error pages and redirects.

To provide this functionality we added the ErrorHeader 
directive which populates r->err_headers_out instead.

Below follows a patch for 1.3.X by Michael Radwin.

I have some code that attempts to add Directive to 2.0.X, but
it seems that output_filters are shortcuted on 3XX responses.
While now by setting the Header directive it also passes the headers
along at for all non-2XX responses except 3XX responses.

Cheers,

-- 
Sander van Zoest                                          +1 (619) 881-3000
Yahoo!, Inc.                                           sander@yahoo-inc.com
<http://www.yahoo.com/>                       <http://sander.vanzoest.com/>

Index: apache-1.3/src/modules/standard/mod_headers.c
===================================================================
RCS file: /work/cvs/root/asf/httpd/apache-1.3/src/modules/standard/mod_headers.c,v
retrieving revision 1.27
diff -u -p -r1.27 mod_headers.c
--- apache-1.3/src/modules/standard/mod_headers.c	13 Mar 2002 21:05:33 -0000	1.27
+++ apache-1.3/src/modules/standard/mod_headers.c	16 May 2002 04:41:08 -0000
@@ -116,6 +116,7 @@ typedef struct {
     hdr_actions action;
     char *header;
     char *value;
+    int do_err;
 } header_entry;
 
 /*
@@ -128,6 +129,9 @@ typedef struct {
 
 module MODULE_VAR_EXPORT headers_module;
 
+static char c_err;
+#define HDR_ERR &c_err
+
 static void *create_headers_config(pool *p, server_rec *s)
 {
     headers_conf *a =
@@ -169,6 +173,12 @@ static const char *header_cmd(cmd_parms 
         new = (header_entry *) ap_push_array(serverconf->headers);
     }
 
+    if (cmd->info == HDR_ERR) {
+	new->do_err = 1;
+    } else {
+	new->do_err = 0;
+    }
+
     if (!strcasecmp(action, "set"))
         new->action = hdr_set;
     else if (!strcasecmp(action, "add"))
@@ -200,6 +210,8 @@ static const command_rec headers_cmds[] 
 {
     {"Header", header_cmd, NULL, OR_FILEINFO, TAKE23,
      "an action, header and value"},
+    {"ErrorHeader", header_cmd, HDR_ERR, OR_FILEINFO, TAKE23,
+     "an action, header and value"},
     {NULL}
 };
 
@@ -209,18 +221,19 @@ static void do_headers_fixup(request_rec
 
     for (i = 0; i < headers->nelts; ++i) {
         header_entry *hdr = &((header_entry *) (headers->elts))[i];
+	table *tbl = (hdr->do_err ? r->err_headers_out : r->headers_out);
         switch (hdr->action) {
         case hdr_add:
-            ap_table_addn(r->headers_out, hdr->header, hdr->value);
+            ap_table_addn(tbl, hdr->header, hdr->value);
             break;
         case hdr_append:
-            ap_table_mergen(r->headers_out, hdr->header, hdr->value);
+            ap_table_mergen(tbl, hdr->header, hdr->value);
             break;
         case hdr_set:
-            ap_table_setn(r->headers_out, hdr->header, hdr->value);
+            ap_table_setn(tbl, hdr->header, hdr->value);
             break;
         case hdr_unset:
-            ap_table_unset(r->headers_out, hdr->header);
+            ap_table_unset(tbl, hdr->header);
             break;
         }
     }
@@ -264,5 +277,7 @@ module MODULE_VAR_EXPORT headers_module 
     NULL,                       /* child_exit */
     NULL                        /* post read-request */
 };
+
+