mod_negotiation: Do not send the qs parameter in the Content-Type.

A MultiViews response took the media type of the selected file as it was,
so the qs source quality set with AddType was sent to the client. Drop it
after the variant has been selected. Other parameters are kept. PR 53595.

Author: arturobernalg

changes-entries/negotiation-qs-content-type.txt

@@ -0,0 +1,2 @@
+  *) mod_negotiation: Do not send the "qs" source quality parameter of the selected
+     variant in the Content-Type of a response negotiated by MultiViews. PR 53595

modules/mappers/mod_negotiation.c

@@ -3068,6 +3068,41 @@ static int handle_map_file(request_rec *r)
     return OK;
 }
 
+/* The "qs" parameter of a variant's media type is only its source quality
+ * for the selection, see get_entry(), and does not belong in the
+ * Content-Type of the response.  Return content_type without it, all
+ * other parameters are kept as they are.
+ */
+static const char *strip_source_quality(apr_pool_t *p,
+                                        const char *content_type)
+{
+    const char *line = content_type;
+    char *stripped;
+    int found = 0;
+
+    if (!ap_strcasestr(content_type, "qs")) {
+        return content_type;
+    }
+
+    stripped = ap_get_token(p, &line, 0);
+    while (*line == ';') {
+        const char *param = line++;
+        const char *name = ap_get_token(p, &line, 1);
+        apr_size_t len = strcspn(name, "= \t");
+
+        if (len == 2 && name[len] && !ap_cstr_casecmpn(name, "qs", 2)) {
+            found = 1;
+        }
+        else {
+            stripped = apr_pstrcat(p, stripped,
+                                   apr_pstrmemdup(p, param, line - param),
+                                   NULL);
+        }
+    }
+
+    return found ? apr_pstrcat(p, stripped, line, NULL) : content_type;
+}
+
 static int handle_multi(request_rec *r)
 {
     negotiation_state *neg;
@@ -3124,6 +3159,14 @@ static int handle_multi(request_rec *r)
     /* now do a "fast redirect" ... promotes the sub_req into the main req */
     ap_internal_fast_redirect(sub_req, r);
 
+    if (r->content_type) {
+        const char *type = strip_source_quality(r->pool, r->content_type);
+
+        if (type != r->content_type) {
+            ap_set_content_type_ex(r, type, AP_REQUEST_IS_TRUSTED_CT(r));
+        }
+    }
+
     /* give no advise for time on this subrequest.  Perhaps we
      * should tally the last mtime among all variants, and date
      * the most recent, but that could confuse the proxies.

test/pytest_suite/t/conf/extra.conf.in

@@ -135,6 +135,15 @@
         LanguagePriority zh-TW fr fu en de 
     </Directory>
 
+    <Directory @SERVERROOT@/htdocs/modules/negotiation/qs>
+        Options +MultiViews
+        AddType text/html;qs=0.9 .html
+        AddType application/xhtml+xml;qs=1.0 .xhtml
+        AddType "text/html;charset=utf-8;qs=0.8" .qsafter
+        AddType "text/html;QS=0.8;charset=utf-8" .qsbefore
+        AddType "application/example;foo=\"a;b\";q=0.7;qs=0.5;bar=\"c, d\"" .quoted
+    </Directory>
+
    <IfDefine APACHE2>
        <IfModule @CGI_MODULE@>
             <Directory @SERVERROOT@/htdocs/modules/negotiation/query>

test/pytest_suite/t/htdocs/modules/negotiation/qs/after.qsafter

@@ -0,0 +1 @@
+after

test/pytest_suite/t/htdocs/modules/negotiation/qs/before.qsbefore

@@ -0,0 +1 @@
+before

test/pytest_suite/t/htdocs/modules/negotiation/qs/doc.html

@@ -0,0 +1 @@
+html

test/pytest_suite/t/htdocs/modules/negotiation/qs/doc.xhtml

@@ -0,0 +1 @@
+xhtml

test/pytest_suite/t/htdocs/modules/negotiation/qs/quoted.quoted

@@ -0,0 +1 @@
+quoted

test/pytest_suite/t/htdocs/modules/negotiation/qs/tm1.htm

@@ -0,0 +1 @@
+html

test/pytest_suite/t/htdocs/modules/negotiation/qs/tm2.xht

@@ -0,0 +1 @@
+xht