Add DAVBasePath directive to allow users to configure the real repos

root path if the DAV repos is configured using a regex match.

* modules/dav/main/mod_dav.c
  (dav_get_resource): If available, pass the configured base path
  as the repos root to repos provider.
  On the error path for fetching a resource, detect and warn
  specifically when the location is configured via a regex.
  (dav_cmd_davbasepath): New function.

PR: 35077

modules/dav/main/mod_dav.c

@@ -85,6 +85,7 @@ typedef struct {
     const char *provider_name;
     const dav_provider *provider;
     const char *dir;
+    const char *base;
     int locktimeout;
     int allow_depthinfinity;
     int allow_lockdiscovery;
@@ -207,6 +208,7 @@ static void *dav_merge_dir_config(apr_pool_t *p, void *base, void *overrides)
 
     newconf->locktimeout = DAV_INHERIT_VALUE(parent, child, locktimeout);
     newconf->dir = DAV_INHERIT_VALUE(parent, child, dir);
+    newconf->base = DAV_INHERIT_VALUE(parent, child, base);
     newconf->allow_depthinfinity = DAV_INHERIT_VALUE(parent, child,
                                                      allow_depthinfinity);
     newconf->allow_lockdiscovery = DAV_INHERIT_VALUE(parent, child,
@@ -295,6 +297,18 @@ static const char *dav_cmd_dav(cmd_parms *cmd, void *config, const char *arg1)
     return NULL;
 }
 
+/*
+ * Command handler for the DAVBasePath directive, which is TAKE1
+ */
+static const char *dav_cmd_davbasepath(cmd_parms *cmd, void *config, const char *arg1)
+{
+    dav_dir_conf *conf = config;
+
+    conf->base = arg1;
+
+    return NULL;
+}
+
 /*
  * Command handler for the DAVDepthInfinity directive, which is FLAG.
  */
@@ -788,7 +802,7 @@ DAV_DECLARE(dav_error *) dav_get_resource(request_rec *r, int label_allowed,
                                    int use_checked_in, dav_resource **res_p)
 {
     dav_dir_conf *conf;
-    const char *label = NULL;
+    const char *label = NULL, *base;
     dav_error *err;
 
     /* if the request target can be overridden, get any target selector */
@@ -805,11 +819,27 @@ DAV_DECLARE(dav_error *) dav_get_resource(request_rec *r, int label_allowed,
                              ap_escape_html(r->pool, r->uri)));
     }
 
+    /* Take the repos root from DAVBasePath if configured, else the
+     * path of the enclosing section. */
+    base = conf->base ? conf->base : conf->dir;
+
     /* resolve the resource */
-    err = (*conf->provider->repos->get_resource)(r, conf->dir,
+    err = (*conf->provider->repos->get_resource)(r, base,
                                                  label, use_checked_in,
                                                  res_p);
     if (err != NULL) {
+        /* In the error path, give a hint that DavBasePath needs to be
+         * used if the location was configured via a regex match. */
+        if (!conf->base) {
+            core_dir_config *conf = ap_get_core_module_config(r->per_dir_config);
+
+            if (conf->r) {
+                ap_log_error(APLOG_MARK, APLOG_ERR, 0, NULL, APLOGNO(10484)
+                             "failed to find repository for location configured "
+                             "via regex match - missing DAVBasePath?");
+            }
+        }
+
         err = dav_push_error(r->pool, err->status, 0,
                              "Could not fetch resource information.", err);
         return err;
@@ -5289,6 +5319,10 @@ static const command_rec dav_cmds[] =
     AP_INIT_TAKE1("DAV", dav_cmd_dav, NULL, ACCESS_CONF,
                   "specify the DAV provider for a directory or location"),
 
+    /* per directory/location */
+    AP_INIT_TAKE1("DAVBasePath", dav_cmd_davbasepath, NULL, ACCESS_CONF,
+                  "specify the DAV repository base URL"),
+
     /* per directory/location, or per server */
     AP_INIT_TAKE1("DAVMinTimeout", dav_cmd_davmintimeout, NULL,
                   ACCESS_CONF|RSRC_CONF,