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Subject: About mod_setenvif in general, application to mod_deflate in
	particular.
From: Francois PESCE <fp-axiliance@wanadoo.fr>
Reply-To: fp-axiliance@wanadoo.fr
To: dev@httpd.apache.org
Content-Type: multipart/mixed; boundary="=-xPs1CBrZR6Eeg6kN7/sU"
Organization: Axiliance
Message-Id: <1096035331.12535.75.camel@gotham-laptop>
Mime-Version: 1.0
Date: 24 Sep 2004 16:15:31 +0200


--=-xPs1CBrZR6Eeg6kN7/sU
Content-Type: text/plain
Content-Transfer-Encoding: 7bit

	Hi,

    Today, mod_setenvif does not provide a way to "set environment
variable if" something is interesting in response headers.

For example, in a reverse proxy architecture, this feature may allow to
gzip/deflate documents according to their Content-Type, and not only to
the request-uri or other client-side provided information that may hide
the real content of what is requested (documents requested via a web
applications are good examples too).

I find that the obvious location to put this feature is mod_setenvif
because of its name, and of the way it is used now worldwide to set the
"no-gzip" env.

As I developed this feature (because my company need it anyway) I
provide it to you the patch to have some feed-back about it and if your
community may want to incorporate it in the httpd source tree.

The patch is attached, as well as a commented version to explain what
and why I did this or that.

- Francois PESCE


--=-xPs1CBrZR6Eeg6kN7/sU
Content-Disposition: attachment; filename=setenvif_output_header.patch
Content-Type: text/plain; name=setenvif_output_header.patch; charset=UTF-8
Content-Transfer-Encoding: quoted-printable

--- mod_setenvif.c.orig	2004-09-24 15:20:57.000000000 +0200
+++ mod_setenvif.c	2004-09-24 15:40:59.000000000 +0200
@@ -101,7 +101,8 @@
     SPECIAL_REQUEST_URI,
     SPECIAL_REQUEST_METHOD,
     SPECIAL_REQUEST_PROTOCOL,
-    SPECIAL_SERVER_ADDR
+    SPECIAL_SERVER_ADDR,
+    SPECIAL_OUTPUT_HEADER
 };
 typedef struct {
     char *name;                 /* header name */
@@ -116,6 +117,7 @@
=20
 typedef struct {
     apr_array_header_t *conditionals;
+    int output_filter_on;        /* act as output_filter for headers_out ?=
 */
 } sei_cfg_rec;
=20
 module AP_MODULE_DECLARE_DATA setenvif_module;
@@ -134,6 +136,7 @@
     sei_cfg_rec *new =3D (sei_cfg_rec *) apr_palloc(p, sizeof(sei_cfg_rec)=
);
=20
     new->conditionals =3D apr_array_make(p, 20, sizeof(sei_entry));
+    new->output_filter_on =3D 0;
     return (void *) new;
 }
=20
@@ -154,6 +157,8 @@
=20
     a->conditionals =3D apr_array_append(p, base->conditionals,
                                        overrides->conditionals);
+    if(base->output_filter_on || overrides->output_filter_on)
+        a->output_filter_on =3D 1;
     return a;
 }
=20
@@ -163,6 +168,7 @@
  */
 #define ICASE_MAGIC	((void *)(&setenvif_module))
 #define SEI_MAGIC_HEIRLOOM "setenvif-phase-flag"
+#define SEI_OUTPUT_FILTER_NAME  "setenvif-output-filter"
=20
 static int is_header_regex(apr_pool_t *p, const char* name)=20
 {
@@ -306,26 +312,6 @@
         new->name =3D fname;
         new->regex =3D regex;
         new->icase =3D icase;
-        if ((simple_pattern =3D non_regex_pattern(cmd->pool, regex))) {
-            new->pattern =3D apr_strmatch_precompile(cmd->pool,
-                                                   simple_pattern, !icase)=
;
-            if (new->pattern =3D=3D NULL) {
-                return apr_pstrcat(cmd->pool, cmd->cmd->name,
-                                   " pattern could not be compiled.", NULL=
);
-            }
-            new->preg =3D NULL;
-        }
-        else {
-            new->preg =3D ap_pregcomp(cmd->pool, regex,
-                                    (REG_EXTENDED | (icase ? REG_ICASE : 0=
)));
-            if (new->preg =3D=3D NULL) {
-                return apr_pstrcat(cmd->pool, cmd->cmd->name,
-                                   " regex could not be compiled.", NULL);
-            }
-            new->pattern =3D NULL;
-        }
-        new->features =3D apr_table_make(cmd->pool, 2);
-
         if (!strcasecmp(fname, "remote_addr")) {
             new->special_type =3D SPECIAL_REMOTE_ADDR;
         }
@@ -344,7 +330,36 @@
         else if (!strcasecmp(fname, "server_addr")) {
             new->special_type =3D SPECIAL_SERVER_ADDR;
         }
-        else {
+        else if (!strcasecmp(fname, "output_header")) {
+            new->special_type =3D SPECIAL_OUTPUT_HEADER;
+            sconf->output_filter_on =3D 1;
+            /*
+             * The regex is the 3rd word here, because we keep the same sy=
ntax
+             * as for header string, but we added the output_header key wo=
rd to
+             * keep backward compatibility.  (to avoid the matching of bot=
h
+             * request and response header on a regex).
+             * In this case the 2nd param of the directive is the header
+             * regex/name.
+             */
+            new->name =3D regex;
+            if (is_header_regex(cmd->pool, new->name)) {
+                new->pnamereg =3D ap_pregcomp(cmd->pool, new->name, (REG_E=
XTENDED |
+                REG_NOSUB | (icase ? REG_ICASE : 0)));
+                if (new->pnamereg =3D=3D NULL)
+                    return apr_pstrcat(cmd->pool, cmd->cmd->name, "Header =
name
+                                        regex could not be compiled.", NUL=
L);
+            }
+            else {
+                new->pnamereg =3D NULL;
+            }
+            regex =3D ap_getword_conf(cmd->pool, &args);
+            if (!*regex) {
+                return apr_pstrcat(cmd->pool, "Missing regular expression =
for ",
+                cmd->cmd->name, NULL);
+            }
+            new->regex =3D regex;
+        }
+         else {
             new->special_type =3D SPECIAL_NOT;
             /* Handle fname as a regular expression.
              * If fname a simple header string, identify as such
@@ -364,6 +379,30 @@
                 new->pnamereg =3D NULL;
             }
         }
+        /*
+         * This block must be after the identification of the parameters, =
as
+         * the regex may be in an other position than the second one depen=
ds
+         * of the special type.
+         */
+        if ((simple_pattern =3D non_regex_pattern(cmd->pool, regex))) {
+            new->pattern =3D apr_strmatch_precompile(cmd->pool,
+                                                   simple_pattern, !icase)=
;
+            if (new->pattern =3D=3D NULL) {
+                return apr_pstrcat(cmd->pool, cmd->cmd->name,
+                                   " pattern could not be compiled.", NULL=
);
+            }
+            new->preg =3D NULL;
+        }
+        else {
+            new->preg =3D ap_pregcomp(cmd->pool, regex,
+                                    (REG_EXTENDED | (icase ? REG_ICASE : 0=
)));
+            if (new->preg =3D=3D NULL) {
+                return apr_pstrcat(cmd->pool, cmd->cmd->name,
+                                   " regex could not be compiled.", NULL);
+            }
+            new->pattern =3D NULL;
+        }
+        new->features =3D apr_table_make(cmd->pool, 2);
     }
     else {
         new =3D &entries[i];
@@ -435,6 +474,95 @@
 };
=20
 /*
+ * This routine get from a header (or subprocess_env if no match in header=
),
+ * the value that correspond to a header name or a header matching regexp.
+ * (according to a sei_entry).
+ */
+static void get_header_val(sei_entry *b, apr_table_t *headers, apr_table_t=
 *subprocess_env, char const **val, request_rec *r) {
+    const apr_table_entry_t *elts;
+    /* Matching headers_in against a regex. Iterate through
+     * the headers until we find a match or run out of
+     * headers.
+     */
+    const apr_array_header_t *arr =3D apr_table_elts(headers);
+    int j;
+
+
+    if (b->pnamereg) {
+        elts =3D (const apr_table_entry_t *) arr->elts;
+        *val =3D NULL;
+        for (j =3D 0; j < arr->nelts; ++j) {
+            if (!ap_regexec(b->pnamereg, elts[j].key, 0, NULL, 0)) {=20
+                *val =3D elts[j].val;
+                /*
+                 * Jok: either we may break or add a condition NULL
+                 * !=3D val in the for loop cond ?
+                 * or maybe concatene ?!?
+                 */
+            }
+        }
+    }
+    else {
+        /* Not matching against a regex */
+        *val =3D apr_table_get(headers, b->name);
+        if (*val =3D=3D NULL) {
+            *val =3D apr_table_get(subprocess_env, b->name);
+        }
+    }
+}
+
+
+/*
+ * This routine set environment variable according to val.
+ * Question : why sei_entry's not const ? because ap_regexec is not define=
d as
+ * well... pcreposix does not define the use of the regex as not modifying=
 it?
+ */
+static void setenvif_val_match(request_rec *r, const char *val, apr_size_t
+        val_len, sei_entry *b) {
+    regmatch_t regm[AP_MAX_REG_MATCH];
+    const apr_table_entry_t *elts;
+    int j;
+
+    /*
+     * A NULL value indicates that the header field or special entity
+     * wasn't present or is undefined.  Represent that as an empty string
+     * so that REs like "^$" will work and allow envariable setting
+     * based on missing or empty field.
+     */
+    if (val =3D=3D NULL) {
+        val =3D "";
+        val_len =3D 0;
+    }
+
+    if ((b->pattern && apr_strmatch(b->pattern, val, val_len)) ||
+            (!b->pattern && !ap_regexec(b->preg, val, AP_MAX_REG_MATCH, re=
gm,
+                                        0))) {
+        const apr_array_header_t *arr =3D apr_table_elts(b->features);
+        elts =3D (const apr_table_entry_t *) arr->elts;
+
+        for (j =3D 0; j < arr->nelts; ++j) {
+            if (*(elts[j].val) =3D=3D '!') {
+                apr_table_unset(r->subprocess_env, elts[j].key);
+            }
+            else {
+                if (!b->pattern) {
+                    char *replaced =3D ap_pregsub(r->pool, elts[j].val, va=
l,
+                            AP_MAX_REG_MATCH, regm);
+                    if (replaced) {
+                        apr_table_setn(r->subprocess_env, elts[j].key,
+                                replaced);
+                    }
+                }
+                else {
+                    apr_table_setn(r->subprocess_env, elts[j].key,
+                            elts[j].val);
+                }
+            }
+        }
+    }
+}
+
+/*
  * This routine gets called at two different points in request processing:
  * once before the URI has been translated (during the post-read-request
  * phase) and once after (during the header-parse phase).  We use differen=
t
@@ -447,12 +575,10 @@
 {
     sei_cfg_rec *sconf;
     sei_entry *entries;
-    const apr_table_entry_t *elts;
     const char *val;
     apr_size_t val_len =3D 0;
-    int i, j;
+    int i;
     char *last_name;
-    regmatch_t regm[AP_MAX_REG_MATCH];
=20
     if (!ap_get_module_config(r->request_config, &setenvif_module)) {
         ap_set_module_config(r->request_config, &setenvif_module,
@@ -466,10 +592,11 @@
     }
     entries =3D (sei_entry *) sconf->conditionals->elts;
     last_name =3D NULL;
-    val =3D NULL;
+
     for (i =3D 0; i < sconf->conditionals->nelts; ++i) {
         sei_entry *b =3D &entries[i];
=20
+        val =3D NULL;
         /* Optimize the case where a bunch of directives in a row use the
          * same header.  Remember we don't need to strcmp the two header
          * names because we made sure the pointers were equal during
@@ -498,79 +625,73 @@
                 val =3D r->protocol;
                 break;
             case SPECIAL_NOT:
-                if (b->pnamereg) {
-                    /* Matching headers_in against a regex. Iterate throug=
h
-                     * the headers_in until we find a match or run out of
-                     * headers.
-                     */
-                    const apr_array_header_t
-                        *arr =3D apr_table_elts(r->headers_in);
-
-                    elts =3D (const apr_table_entry_t *) arr->elts;
-                    val =3D NULL;
-                    for (j =3D 0; j < arr->nelts; ++j) {
-                        if (!ap_regexec(b->pnamereg, elts[j].key, 0, NULL,=
 0)) {=20
-                            val =3D elts[j].val;
-                        }
-                    }
-                }
-                else {
-                    /* Not matching against a regex */
-                    val =3D apr_table_get(r->headers_in, b->name);
-                    if (val =3D=3D NULL) {
-                        val =3D apr_table_get(r->subprocess_env, b->name);
-                    }
-                }
+                get_header_val(b, r->headers_in, r->subprocess_env, &val, =
r);
             }
             val_len =3D val ? strlen(val) : 0;
         }
=20
-        /*
-         * A NULL value indicates that the header field or special entity
-         * wasn't present or is undefined.  Represent that as an empty str=
ing
-         * so that REs like "^$" will work and allow envariable setting
-         * based on missing or empty field.
-         */
-        if (val =3D=3D NULL) {
-            val =3D "";
-            val_len =3D 0;
-        }
+        setenvif_val_match(r, val, val_len, b);
=20
-        if ((b->pattern && apr_strmatch(b->pattern, val, val_len)) ||
-            (!b->pattern && !ap_regexec(b->preg, val, AP_MAX_REG_MATCH, re=
gm,
-                                        0))) {
-            const apr_array_header_t *arr =3D apr_table_elts(b->features);
-            elts =3D (const apr_table_entry_t *) arr->elts;
+    }
=20
-            for (j =3D 0; j < arr->nelts; ++j) {
-                if (*(elts[j].val) =3D=3D '!') {
-                    apr_table_unset(r->subprocess_env, elts[j].key);
-                }
-                else {
-                    if (!b->pattern) {
-                        char *replaced =3D ap_pregsub(r->pool, elts[j].val=
, val,
-                                                    AP_MAX_REG_MATCH, regm=
);
-                        if (replaced) {
-                            apr_table_setn(r->subprocess_env, elts[j].key,
-                                           replaced);
-                        }
-                    }
-                    else {
-                        apr_table_setn(r->subprocess_env, elts[j].key,
-                                       elts[j].val);
-                    }
-                }
+    if (sconf->output_filter_on =3D=3D 1)
+        ap_add_output_filter(SEI_OUTPUT_FILTER_NAME, sconf, r, r->connecti=
on);
+   =20
+    return DECLINED;
+}
+
+/*
+ * This (output) filter process headers_out to find condition to set env.
+ */
+static apr_status_t setenvif_out_filter(ap_filter_t * f, apr_bucket_brigad=
e * bb)
+{
+    sei_cfg_rec *sconf;
+    sei_entry *entries;
+    const char *val;
+    apr_size_t val_len =3D 0;
+    int i;
+    char *last_name;
+
+    sconf  =3D (sei_cfg_rec *) f->ctx;
+    entries =3D (sei_entry *) sconf->conditionals->elts;
+    last_name =3D NULL;
+    for (i =3D 0; i < sconf->conditionals->nelts; ++i) {
+        sei_entry *b =3D &entries[i];
+
+        val =3D NULL;
+        /*
+         * Optimize the case where a bunch of directives in a row use the
+         * same header.  Remember we don't need to strcmp the two header
+         * names because we made sure the pointers were equal during
+         * configuration.
+         */
+        if (b->name !=3D last_name) {
+            last_name =3D b->name;
+            if (b->special_type =3D=3D SPECIAL_OUTPUT_HEADER) {
+                /*
+                 * As output filter, only headers_out are interresting for=
 us
+                 * so we just process this type of conditions.
+                 */
+                get_header_val(b, f->r->headers_out, f->r->subprocess_env,=
 &val, f->r);
+                val_len =3D val ? strlen(val) : 0;
+                setenvif_val_match(f->r, val, val_len, b);
             }
         }
     }
=20
-    return DECLINED;
+    ap_remove_output_filter(f);
+    return ap_pass_brigade(f->next, bb);
 }
=20
 static void register_hooks(apr_pool_t *p)
 {
     ap_hook_header_parser(match_headers, NULL, NULL, APR_HOOK_MIDDLE);
     ap_hook_post_read_request(match_headers, NULL, NULL, APR_HOOK_MIDDLE);
+    /*
+     * ftype is set to AP_FTYPE_CONTENT_SET + 1 to make this filter hooked
+     * before deflate (it's specific for the moment).
+     */
+    ap_register_output_filter(SEI_OUTPUT_FILTER_NAME, setenvif_out_filter,=
 NULL, AP_FTYPE_CONTENT_SET);
 }
=20
 module AP_MODULE_DECLARE_DATA setenvif_module =3D

--=-xPs1CBrZR6Eeg6kN7/sU
Content-Disposition: attachment;
 filename=setenvif_output_header_commented_patch.txt
Content-Type: text/plain; name=setenvif_output_header_commented_patch.txt;
 charset=UTF-8
Content-Transfer-Encoding: quoted-printable

--- mod_setenvif.c.orig	2004-09-24 15:20:57.000000000 +0200
+++ mod_setenvif.c	2004-09-24 15:40:59.000000000 +0200

# I've added a new type of condition to clearly avoid mistake between input
# headers (SPECIAL_NOT) and output headers (SPECIAL_OUTPUT_HEADER).
@@ -101,7 +101,8 @@
     SPECIAL_REQUEST_URI,
     SPECIAL_REQUEST_METHOD,
     SPECIAL_REQUEST_PROTOCOL,
-    SPECIAL_SERVER_ADDR
+    SPECIAL_SERVER_ADDR,
+    SPECIAL_OUTPUT_HEADER
 };
 typedef struct {
     char *name;                 /* header name */

# Here, is added a boolean/int that indicate if this module may act as an
# output filter or not (will be useful to add the filter when processing
# request).
@@ -116,6 +117,7 @@
=20
 typedef struct {
     apr_array_header_t *conditionals;
+    int output_filter_on;        /* act as output_filter for headers_out ?=
 */
 } sei_cfg_rec;
=20
 module AP_MODULE_DECLARE_DATA setenvif_module;

# Set by default the server configuration to not make it act as a filter.
@@ -134,6 +136,7 @@
     sei_cfg_rec *new =3D (sei_cfg_rec *) apr_palloc(p, sizeof(sei_cfg_rec)=
);
=20
     new->conditionals =3D apr_array_make(p, 20, sizeof(sei_entry));
+    new->output_filter_on =3D 0;
     return (void *) new;
 }
=20
# Include the process of the boolean output_filter_on in the merging functi=
on.
@@ -154,6 +157,8 @@
=20
     a->conditionals =3D apr_array_append(p, base->conditionals,
                                        overrides->conditionals);
+    if(base->output_filter_on || overrides->output_filter_on)
+        a->output_filter_on =3D 1;
     return a;
 }
=20
# Add a macro to define the name of the new output filter.
@@ -163,6 +168,7 @@
  */
 #define ICASE_MAGIC	((void *)(&setenvif_module))
 #define SEI_MAGIC_HEIRLOOM "setenvif-phase-flag"
+#define SEI_OUTPUT_FILTER_NAME  "setenvif-output-filter"
=20
 static int is_header_regex(apr_pool_t *p, const char* name)=20
 {

# Move this code below the parsing of the key word as explained in the comm=
ent
# The regex is the 3rd word when we use the keyword "output_header".
# because we keep the same syntax for output headers as for input header
# string ie:=20
# SetEnvIf output_header Content-Type .*gif.* no-gzip
# must be parsed the same way as :
# SetEnvIf Accept-Type .*no-gzip.* no-gzip
# Then we redefine new->name and new->regex when we encounter output_header
# key word.
@@ -306,26 +312,6 @@
         new->name =3D fname;
         new->regex =3D regex;
         new->icase =3D icase;
-        if ((simple_pattern =3D non_regex_pattern(cmd->pool, regex))) {
-            new->pattern =3D apr_strmatch_precompile(cmd->pool,
-                                                   simple_pattern, !icase)=
;
-            if (new->pattern =3D=3D NULL) {
-                return apr_pstrcat(cmd->pool, cmd->cmd->name,
-                                   " pattern could not be compiled.", NULL=
);
-            }
-            new->preg =3D NULL;
-        }
-        else {
-            new->preg =3D ap_pregcomp(cmd->pool, regex,
-                                    (REG_EXTENDED | (icase ? REG_ICASE : 0=
)));
-            if (new->preg =3D=3D NULL) {
-                return apr_pstrcat(cmd->pool, cmd->cmd->name,
-                                   " regex could not be compiled.", NULL);
-            }
-            new->pattern =3D NULL;
-        }
-        new->features =3D apr_table_make(cmd->pool, 2);
-
         if (!strcasecmp(fname, "remote_addr")) {
             new->special_type =3D SPECIAL_REMOTE_ADDR;
         }

# It is a basic rip of the last else {} block to set correctly the regexps =
to
# match header name and content.
@@ -344,7 +330,36 @@
         else if (!strcasecmp(fname, "server_addr")) {
             new->special_type =3D SPECIAL_SERVER_ADDR;
         }
-        else {
+        else if (!strcasecmp(fname, "output_header")) {
+            new->special_type =3D SPECIAL_OUTPUT_HEADER;
+            sconf->output_filter_on =3D 1;
+            /*
+             * The regex is the 3rd word here, because we keep the same sy=
ntax
+             * as for header string, but we added the output_header key wo=
rd to
+             * keep backward compatibility.  (to avoid the matching of bot=
h
+             * request and response header on a regex).
+             * In this case the 2nd param of the directive is the header
+             * regex/name.
+             */
+            new->name =3D regex;
+            if (is_header_regex(cmd->pool, new->name)) {
+                new->pnamereg =3D ap_pregcomp(cmd->pool, new->name, (REG_E=
XTENDED |
+                REG_NOSUB | (icase ? REG_ICASE : 0)));
+                if (new->pnamereg =3D=3D NULL)
+                    return apr_pstrcat(cmd->pool, cmd->cmd->name, "Header =
name
+                                        regex could not be compiled.", NUL=
L);
+            }
+            else {
+                new->pnamereg =3D NULL;
+            }
+            regex =3D ap_getword_conf(cmd->pool, &args);
+            if (!*regex) {
+                return apr_pstrcat(cmd->pool, "Missing regular expression =
for ",
+                cmd->cmd->name, NULL);
+            }
+            new->regex =3D regex;
+        }
+         else {
             new->special_type =3D SPECIAL_NOT;
             /* Handle fname as a regular expression.
              * If fname a simple header string, identify as such

# This is the block of code we move from the top of this block.
@@ -364,6 +379,30 @@
                 new->pnamereg =3D NULL;
             }
         }
+        /*
+         * This block must be after the identification of the parameters, =
as
+         * the regex may be in an other position than the second one depen=
ds
+         * of the special type.
+         */
+        if ((simple_pattern =3D non_regex_pattern(cmd->pool, regex))) {
+            new->pattern =3D apr_strmatch_precompile(cmd->pool,
+                                                   simple_pattern, !icase)=
;
+            if (new->pattern =3D=3D NULL) {
+                return apr_pstrcat(cmd->pool, cmd->cmd->name,
+                                   " pattern could not be compiled.", NULL=
);
+            }
+            new->preg =3D NULL;
+        }
+        else {
+            new->preg =3D ap_pregcomp(cmd->pool, regex,
+                                    (REG_EXTENDED | (icase ? REG_ICASE : 0=
)));
+            if (new->preg =3D=3D NULL) {
+                return apr_pstrcat(cmd->pool, cmd->cmd->name,
+                                   " regex could not be compiled.", NULL);
+            }
+            new->pattern =3D NULL;
+        }
+        new->features =3D apr_table_make(cmd->pool, 2);
     }
     else {
         new =3D &entries[i];

# This block of code are two functions out-sourced from match_headers
# function. I basically out-sourced them to avoid code duplication from the
# request hook in the filter.
@@ -435,6 +474,95 @@
 };
=20
 /*
+ * This routine get from a header (or subprocess_env if no match in header=
),
+ * the value that correspond to a header name or a header matching regexp.
+ * (according to a sei_entry).
+ */
+static void get_header_val(sei_entry *b, apr_table_t *headers, apr_table_t=
 *subprocess_env, char const **val, request_rec *r) {
+    const apr_table_entry_t *elts;
+    /* Matching headers_in against a regex. Iterate through
+     * the headers until we find a match or run out of
+     * headers.
+     */
+    const apr_array_header_t *arr =3D apr_table_elts(headers);
+    int j;
+
+
+    if (b->pnamereg) {
+        elts =3D (const apr_table_entry_t *) arr->elts;
+        *val =3D NULL;
+        for (j =3D 0; j < arr->nelts; ++j) {
+            if (!ap_regexec(b->pnamereg, elts[j].key, 0, NULL, 0)) {=20
+                *val =3D elts[j].val;
+                /*
+                 * Jok: either we may break or add a condition NULL
+                 * !=3D val in the for loop cond ?
+                 * or maybe concatene ?!?
+                 */
+            }
+        }
+    }
+    else {
+        /* Not matching against a regex */
+        *val =3D apr_table_get(headers, b->name);
+        if (*val =3D=3D NULL) {
+            *val =3D apr_table_get(subprocess_env, b->name);
+        }
+    }
+}
+
+
+/*
+ * This routine set environment variable according to val.
+ * Question : why sei_entry's not const ? because ap_regexec is not define=
d as
+ * well... pcreposix does not define the use of the regex as not modifying=
 it?
+ */
+static void setenvif_val_match(request_rec *r, const char *val, apr_size_t
+        val_len, sei_entry *b) {
+    regmatch_t regm[AP_MAX_REG_MATCH];
+    const apr_table_entry_t *elts;
+    int j;
+
+    /*
+     * A NULL value indicates that the header field or special entity
+     * wasn't present or is undefined.  Represent that as an empty string
+     * so that REs like "^$" will work and allow envariable setting
+     * based on missing or empty field.
+     */
+    if (val =3D=3D NULL) {
+        val =3D "";
+        val_len =3D 0;
+    }
+
+    if ((b->pattern && apr_strmatch(b->pattern, val, val_len)) ||
+            (!b->pattern && !ap_regexec(b->preg, val, AP_MAX_REG_MATCH, re=
gm,
+                                        0))) {
+        const apr_array_header_t *arr =3D apr_table_elts(b->features);
+        elts =3D (const apr_table_entry_t *) arr->elts;
+
+        for (j =3D 0; j < arr->nelts; ++j) {
+            if (*(elts[j].val) =3D=3D '!') {
+                apr_table_unset(r->subprocess_env, elts[j].key);
+            }
+            else {
+                if (!b->pattern) {
+                    char *replaced =3D ap_pregsub(r->pool, elts[j].val, va=
l,
+                            AP_MAX_REG_MATCH, regm);
+                    if (replaced) {
+                        apr_table_setn(r->subprocess_env, elts[j].key,
+                                replaced);
+                    }
+                }
+                else {
+                    apr_table_setn(r->subprocess_env, elts[j].key,
+                            elts[j].val);
+                }
+            }
+        }
+    }
+}
+
+/*
  * This routine gets called at two different points in request processing:
  * once before the URI has been translated (during the post-read-request
  * phase) and once after (during the header-parse phase).  We use differen=
t

# Removal of variable that were exclusivly in the functions out-sourced.
@@ -447,12 +575,10 @@
 {
     sei_cfg_rec *sconf;
     sei_entry *entries;
-    const apr_table_entry_t *elts;
     const char *val;
     apr_size_t val_len =3D 0;
-    int i, j;
+    int i;
     char *last_name;
-    regmatch_t regm[AP_MAX_REG_MATCH];
=20
     if (!ap_get_module_config(r->request_config, &setenvif_module)) {
         ap_set_module_config(r->request_config, &setenvif_module,

# The reset of val variable was in a function out-sourced so now it is set =
in
# the for loop.
@@ -466,10 +592,11 @@
     }
     entries =3D (sei_entry *) sconf->conditionals->elts;
     last_name =3D NULL;
-    val =3D NULL;
+
     for (i =3D 0; i < sconf->conditionals->nelts; ++i) {
         sei_entry *b =3D &entries[i];
=20
+        val =3D NULL;
         /* Optimize the case where a bunch of directives in a row use the
          * same header.  Remember we don't need to strcmp the two header
          * names because we made sure the pointers were equal during

# Out-sourced above.
# at the end of this diff block are :=20
# 1/ the ap_add_output_filter if needed.
# 2/ the filter function.
# 3/ the ap_register_output_filter.
@@ -498,79 +625,73 @@
                 val =3D r->protocol;
                 break;
             case SPECIAL_NOT:
-                if (b->pnamereg) {
-                    /* Matching headers_in against a regex. Iterate throug=
h
-                     * the headers_in until we find a match or run out of
-                     * headers.
-                     */
-                    const apr_array_header_t
-                        *arr =3D apr_table_elts(r->headers_in);
-
-                    elts =3D (const apr_table_entry_t *) arr->elts;
-                    val =3D NULL;
-                    for (j =3D 0; j < arr->nelts; ++j) {
-                        if (!ap_regexec(b->pnamereg, elts[j].key, 0, NULL,=
 0)) {=20
-                            val =3D elts[j].val;
-                        }
-                    }
-                }
-                else {
-                    /* Not matching against a regex */
-                    val =3D apr_table_get(r->headers_in, b->name);
-                    if (val =3D=3D NULL) {
-                        val =3D apr_table_get(r->subprocess_env, b->name);
-                    }
-                }
+                get_header_val(b, r->headers_in, r->subprocess_env, &val, =
r);
             }
             val_len =3D val ? strlen(val) : 0;
         }
=20
-        /*
-         * A NULL value indicates that the header field or special entity
-         * wasn't present or is undefined.  Represent that as an empty str=
ing
-         * so that REs like "^$" will work and allow envariable setting
-         * based on missing or empty field.
-         */
-        if (val =3D=3D NULL) {
-            val =3D "";
-            val_len =3D 0;
-        }
+        setenvif_val_match(r, val, val_len, b);
=20
-        if ((b->pattern && apr_strmatch(b->pattern, val, val_len)) ||
-            (!b->pattern && !ap_regexec(b->preg, val, AP_MAX_REG_MATCH, re=
gm,
-                                        0))) {
-            const apr_array_header_t *arr =3D apr_table_elts(b->features);
-            elts =3D (const apr_table_entry_t *) arr->elts;
+    }
=20
-            for (j =3D 0; j < arr->nelts; ++j) {
-                if (*(elts[j].val) =3D=3D '!') {
-                    apr_table_unset(r->subprocess_env, elts[j].key);
-                }
-                else {
-                    if (!b->pattern) {
-                        char *replaced =3D ap_pregsub(r->pool, elts[j].val=
, val,
-                                                    AP_MAX_REG_MATCH, regm=
);
-                        if (replaced) {
-                            apr_table_setn(r->subprocess_env, elts[j].key,
-                                           replaced);
-                        }
-                    }
-                    else {
-                        apr_table_setn(r->subprocess_env, elts[j].key,
-                                       elts[j].val);
-                    }
-                }
+    if (sconf->output_filter_on =3D=3D 1)
+        ap_add_output_filter(SEI_OUTPUT_FILTER_NAME, sconf, r, r->connecti=
on);
+   =20
+    return DECLINED;
+}
+
+/*
+ * This (output) filter process headers_out to find condition to set env.
+ */
+static apr_status_t setenvif_out_filter(ap_filter_t * f, apr_bucket_brigad=
e * bb)
+{
+    sei_cfg_rec *sconf;
+    sei_entry *entries;
+    const char *val;
+    apr_size_t val_len =3D 0;
+    int i;
+    char *last_name;
+
+    sconf  =3D (sei_cfg_rec *) f->ctx;
+    entries =3D (sei_entry *) sconf->conditionals->elts;
+    last_name =3D NULL;
+    for (i =3D 0; i < sconf->conditionals->nelts; ++i) {
+        sei_entry *b =3D &entries[i];
+
+        val =3D NULL;
+        /*
+         * Optimize the case where a bunch of directives in a row use the
+         * same header.  Remember we don't need to strcmp the two header
+         * names because we made sure the pointers were equal during
+         * configuration.
+         */
+        if (b->name !=3D last_name) {
+            last_name =3D b->name;
+            if (b->special_type =3D=3D SPECIAL_OUTPUT_HEADER) {
+                /*
+                 * As output filter, only headers_out are interresting for=
 us
+                 * so we just process this type of conditions.
+                 */
+                get_header_val(b, f->r->headers_out, f->r->subprocess_env,=
 &val, f->r);
+                val_len =3D val ? strlen(val) : 0;
+                setenvif_val_match(f->r, val, val_len, b);
             }
         }
     }
=20
-    return DECLINED;
+    ap_remove_output_filter(f);
+    return ap_pass_brigade(f->next, bb);
 }
=20
 static void register_hooks(apr_pool_t *p)
 {
     ap_hook_header_parser(match_headers, NULL, NULL, APR_HOOK_MIDDLE);
     ap_hook_post_read_request(match_headers, NULL, NULL, APR_HOOK_MIDDLE);
+    /*
+     * ftype is set to AP_FTYPE_CONTENT_SET + 1 to make this filter hooked
+     * before deflate (it's specific for the moment).
+     */
+    ap_register_output_filter(SEI_OUTPUT_FILTER_NAME, setenvif_out_filter,=
 NULL, AP_FTYPE_CONTENT_SET);
 }
=20
 module AP_MODULE_DECLARE_DATA setenvif_module =3D

--=-xPs1CBrZR6Eeg6kN7/sU--