provide a simple (no <If>) way to set a header only if it's not already there.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1496338 13f79535-47bb-0310-9956-ffa450edef68

diff --git a/CHANGES b/CHANGES
index bff69119d1630837f38e7c1b8dbc8b26ecdefdf9..6016a7bb14c715973c52f134e9d549c096f922c1 100644 (file)
--- a/CHANGES
+++ b/CHANGES
@@ -1,6 +1,9 @@
                                                          -*- coding: utf-8 -*-
 Changes with Apache 2.5.0
 
+  *) mod_headers: Add 'setifempty' command to Header and RequestHeader.
+     [Eric Covener]
+
   *) AIX: Install DSO's with "cp" instead of "install" in instdso.sh
      [Eric Covener]
 

diff --git a/docs/manual/mod/mod_headers.xml b/docs/manual/mod/mod_headers.xml
index 528e7f2d0d876e1b45e659240a460a320b74bed4..774cadc4f62c1ad1057d3889a0877d5c0c2e89e7 100644 (file)
--- a/docs/manual/mod/mod_headers.xml
+++ b/docs/manual/mod/mod_headers.xml
@@ -248,6 +248,10 @@ Header merge Cache-Control no-store env=NO_STORE
     <dt><code>set</code></dt>
     <dd>The request header is set, replacing any previous header
     with this name</dd>
+  
+    <dt><code>setifempty</code></dt>
+    <dd>The request header is set, but only if there is no previous header
+    with this name</dd>
 
     <dt><code>unset</code></dt>
     <dd>The request header of this name is removed, if it exists. If
@@ -388,6 +392,10 @@ Header merge Cache-Control no-store env=NO_STORE
     <dd>The response header is set, replacing any previous header
     with this name. The <var>value</var> may be a format string.</dd>
 
+    <dt><code>setifempty</code></dt>
+    <dd>The request header is set, but only if there is no previous header
+    with this name</dd>
+
     <dt><code>unset</code></dt>
     <dd>The response header of this name is removed, if it exists.
     If there are multiple headers of the same name, all will be

diff --git a/modules/metadata/mod_headers.c b/modules/metadata/mod_headers.c
index 9ce2fdec67f2f5da81390869371d3478e5194c18..6c03e71839da9d9d413bb8d9f9b115da9a7afb9e 100644 (file)
--- a/modules/metadata/mod_headers.c
+++ b/modules/metadata/mod_headers.c
@@ -96,7 +96,8 @@ typedef enum {
     hdr_unset = 'u',            /* unset header */
     hdr_echo = 'e',             /* echo headers from request to response */
     hdr_edit = 'r',             /* change value by regexp, match once */
-    hdr_edit_r = 'R'            /* change value by regexp, everymatch */
+    hdr_edit_r = 'R',            /* change value by regexp, everymatch */
+    hdr_setifempty = 'i'        /* set value if header not already present*/
 } hdr_actions;
 
 /*
@@ -431,6 +432,8 @@ static APR_INLINE const char *header_inout_cmd(cmd_parms *cmd,
 
     if (!strcasecmp(action, "set"))
         new->action = hdr_set;
+    else if (!strcasecmp(action, "setifempty"))
+        new->action = hdr_setifempty;
     else if (!strcasecmp(action, "add"))
         new->action = hdr_add;
     else if (!strcasecmp(action, "append"))
@@ -446,7 +449,7 @@ static APR_INLINE const char *header_inout_cmd(cmd_parms *cmd,
     else if (!strcasecmp(action, "edit*"))
         new->action = hdr_edit_r;
     else
-        return "first argument must be 'add', 'set', 'append', 'merge', "
+        return "first argument must be 'add', 'set', 'setifempty', 'append', 'merge', "
                "'unset', 'echo', 'edit', or 'edit*'.";
 
     if (new->action == hdr_edit || new->action == hdr_edit_r) {
@@ -755,6 +758,14 @@ static int do_headers_fixup(request_rec *r, apr_table_t *headers,
             }
             apr_table_setn(headers, hdr->header, process_tags(hdr, r));
             break;
+        case hdr_setifempty:
+            if (NULL == apr_table_get(headers, hdr->header)) {
+                if (!strcasecmp(hdr->header, "Content-Type")) {
+                    ap_set_content_type(r, process_tags(hdr, r));
+                }
+                apr_table_setn(headers, hdr->header, process_tags(hdr, r));
+            }
+            break;
         case hdr_unset:
             apr_table_unset(headers, hdr->header);
             break;