have webfinger output a JSON file in STORAGE_ROOT/webfinger/(acct/..)

setup/web.sh

@@ -34,6 +34,8 @@ update-rc.d php-fastcgi defaults
 # Put our webfinger server script into a well-known location.
 cp tools/webfinger.php /usr/local/bin/mailinabox-webfinger.php
 chown www-data.www-data /usr/local/bin/mailinabox-webfinger.php
+mkdir -p $STORAGE_ROOT/webfinger/acct;
+chown -R $STORAGE_USER $STORAGE_ROOT/webfinger
 
 # Start services.
 service nginx restart

tools/webfinger.php

 <?php
 	$resource = $_GET['resource'];
 
+	// Parse our configuration file to get the STORAGE_ROOT.
+	$STORAGE_ROOT = NULL;
+	foreach (file("/etc/mailinabox.conf") as $line) {
+		$line = explode("=", rtrim($line), 2);
+		if ($line[0] == "STORAGE_ROOT") {
+			$STORAGE_ROOT = $line[1];
+		}
+	}
+	if ($STORAGE_ROOT == NULL) exit("no STORAGE_ROOT");
+
+	// Turn the resource into a file path. First URL-encode the resource
+	// so that it is filepath-safe.
+	$fn = urlencode($resource);
+
+	// Replace the first colon (it's URL-encoded) with a slash since we'll
+	// break off the files into scheme subdirectories.
+	$fn = preg_replace("/%3A/", "/", $fn, 1);
+
+	// Since this is often for email addresses, un-escape @-signs so they
+	// are not odd-looking. It's filename-safe anyway.
+	$fn = preg_replace("/%40/", "@", $fn);
+
+	// Combine with root path.
+	$fn = $STORAGE_ROOT . "/webfinger/" . $fn . ".json";
+
+	// See if the file exists.
+	if (!file_exists($fn)) {
+		header("HTTP/1.0 404 Not Found");
+		exit;
+	}
+
 	header("Content-type: application/json");
-	echo json_encode(array(
-		subject => $resource,
-	), JSON_PRETTY_PRINT);
+	echo file_get_contents($fn);
+
+	//json_encode(array(
+	//	subject => $resource,
+	//), JSON_PRETTY_PRINT);
 ?>