2009/9/15 Rich Bowen <[email protected]>:
> FallbackHandler and FrontController both make a lot of sense to me.
> FrontController seems like it might be more "correct", in terms of accepted
> usage in the larger world out there, but either one makes me happy.
Looks like a name was found (or not). :-)
Besides the name I'd like to propose two features to that directive
- the possibility to override a previous setting back to default (e.g.
for subdirectories, Fallback disabled). I don't know if this is useful
but it was implemented into DirectoryIndex as well
- the possibility to disable the setting for subrequest lookups to
address Rüdiger's comment
http://www.mail-archive.com/[email protected]/msg44257.html
(Fallback fooressource nosub)
(- some debug logging+docs)
Bob
Index: modules/mappers/mod_dir.c
===================================================================
--- modules/mappers/mod_dir.c (revision 815380)
+++ modules/mappers/mod_dir.c (working copy)
@@ -41,6 +41,7 @@
apr_array_header_t *index_names;
slash_cfg do_slash;
const char *dflt;
+ const char *nosub;
} dir_config_rec;
#define DIR_CMD_PERMS OR_INDEXES
@@ -73,6 +74,28 @@
return NULL;
}
+static const char *config_fallback(cmd_parms *cmd, void *dummy, const char *uri,
+ char *nosub)
+{
+ dir_config_rec *d = dummy;
+ const char *t, *w;
+
+ t = uri;
+ if (!strcasecmp(t, "disabled")) {
+ d->dflt = "\0";
+ }
+ else {
+ d->dflt = t;
+ }
+
+ w = nosub;
+ if (w != NULL) {
+ d->nosub = "true";
+ }
+
+ return NULL;
+}
+
static const char *configure_slash(cmd_parms *cmd, void *d_, int arg)
{
dir_config_rec *d = d_;
@@ -83,9 +106,8 @@
static const command_rec dir_cmds[] =
{
- AP_INIT_TAKE1("Fallback", ap_set_string_slot,
- (void*)APR_OFFSETOF(dir_config_rec, dflt),
- DIR_CMD_PERMS, "Set a default handler"),
+ AP_INIT_TAKE12("Fallback", config_fallback, NULL, DIR_CMD_PERMS,
+ "Set a fallback ressource"),
AP_INIT_RAW_ARGS("DirectoryIndex", add_index, NULL, DIR_CMD_PERMS,
"a list of file names"),
AP_INIT_FLAG("DirectorySlash", configure_slash, NULL, DIR_CMD_PERMS,
@@ -99,6 +121,8 @@
new->index_names = NULL;
new->do_slash = SLASH_UNSET;
+ new->dflt = NULL;
+ new->nosub = NULL;
return (void *) new;
}
@@ -112,6 +136,8 @@
new->do_slash =
(add->do_slash == SLASH_UNSET) ? base->do_slash : add->do_slash;
new->dflt = add->dflt ? add->dflt : base->dflt;
+ /* override nosub if Fallback was present */
+ new->nosub = add->dflt ? add->nosub : base->nosub;
return new;
}
@@ -125,12 +151,13 @@
return DECLINED;
}
name_ptr = d->dflt;
- if (name_ptr == NULL) {
+ if (name_ptr == NULL || name_ptr[0] == '\0'
+ || (r->main != NULL && d->nosub != NULL)) {
return DECLINED;
}
/* XXX: if Fallback points to something that doesn't exist,
* this may recurse until it hits the limit for internal redirects
- * before returning an Internal Server Error.
+ * before returning an Internal Server Error if nosub was not set.
*/
/* The logic of this function is basically cloned and simplified
@@ -143,6 +170,9 @@
if (rr->status == HTTP_OK
&& ( (rr->handler && !strcmp(rr->handler, "proxy-server"))
|| rr->finfo.filetype == APR_REG)) {
+ ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r,
+ "Fallback: Fallback to filename %s (%s) for %s",
+ rr->filename, rr->uri, r->filename);
ap_internal_fast_redirect(rr, r);
return OK;
}
@@ -154,11 +184,17 @@
rr->headers_out);
r->err_headers_out = apr_table_overlay(r->pool, r->err_headers_out,
rr->err_headers_out);
+ ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r,
+ "Fallback: Fallback of URI-path %s resolved to "
+ "an external redirect to URI %s.", r->uri, rr->filename);
error_notfound = rr->status;
}
else if (rr->status && rr->status != HTTP_NOT_FOUND
&& rr->status != HTTP_OK) {
error_notfound = rr->status;
+ ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r,
+ "Fallback: Ressource %s returned %s for "
+ "fallback of URI-path %s.", rr->filename, rr->status, r->uri);
}
ap_destroy_sub_req(rr);
Index: docs/manual/mod/mod_dir.xml
===================================================================
--- docs/manual/mod/mod_dir.xml (revision 815380)
+++ docs/manual/mod/mod_dir.xml (working copy)
@@ -166,8 +166,8 @@
<directivesynopsis>
<name>Fallback</name>
<description>Define a default URL for requests that don't map to a file</description>
-<syntax>Fallback <var>local-url</var></syntax>
-<default>None - httpd will return 404 (Not Found)</default>
+<syntax>Fallback <var>local-url [nosub]</var></syntax>
+<default>disabled - httpd will return 404 (Not Found)</default>
<contextlist><context>server config</context><context>virtual host</context>
<context>directory</context><context>.htaccess</context></contextlist>
@@ -175,13 +175,40 @@
<usage>
<p>Use this to set a handler for any URL that doesn't map to anything
in your filesystem, and would otherwise return HTTP 404 (Not Found).
+
+ The <var>local-url</var> can be either a filename which will be treated relative
+ to the directory of the current request or an <var>URL-path</var>.
For example</p>
<example>
<code>Fallback not-404.php</code>
</example>
<p>will cause requests for non-existent files to be handled by
- <code>not-404.php</code>, while requests for files that exist
- are unaffected.</p>
+ <code>not-404.php</code>, while requests for files that exist or resources
+ with other handlers assigned are unaffected. If the directive was inserted
+ under <code>/var/www</code> and the request resolved to
+ <code>/var/www/foo/nonexistent</code> while the folder <code>foo</code>
+ exists, httpd will try to fall back to <code>/foo/not-404.php</code>.
+ In order to avoid such a relative fall back, an <var>URL-path</var> can be used:</p>
+ <example>
+ <code>Fallback /not-404.php</code>
+ </example>
+ <p>will cause requests for non-existent files to be handled by
+ <code>/not-404.php</code>, regardless of the current directory of the request.</p>
+
+ <p>A previous setting can be disabled by associating the value <var>disabled</var>:</p>
+ <example>
+ <code>Fallback disabled</code>
+ </example>
+ <p>This will override a previously given local-url and httpd will return to
+ its default 404 error handling.</p>
+
+ <p>To avoid interaction with subrequests (e.g. lookups for index files defined by
+ <directive>DirectoryIndex</directive> or includes by <module>mod_include</module>)
+ an optional argument <var>nosub</var> can be used to disable the fall back
+ for subrequests:</p>
+ <example>
+ <code>Fallback /not-404.php nosub</code>
+ </example>
</usage>
</directivesynopsis>
