add clear channel rpc

storage/file.js

@@ -6,6 +6,65 @@ var mkPath = function (env, channelId) {
     return Path.join(env.root, channelId.slice(0, 2), channelId) + '.ndjson';
 };
 
+var getMetadataAtPath = function (Env, path, cb) {
+    var remainder = '';
+    var stream = Fs.createReadStream(path, 'utf8');
+    var complete = function (err, data) {
+        var _cb = cb;
+        cb = undefined;
+        if (_cb) { _cb(err, data); }
+    };
+    stream.on('data', function (chunk) {
+        if (!/\n/.test(chunk)) {
+            remainder += chunk;
+            return;
+        }
+        stream.close();
+        var metadata = chunk.split('\n')[0];
+
+        var parsed = null;
+        try {
+            parsed = JSON.parse(metadata);
+            complete(void 0, parsed);
+        }
+        catch (e) {
+            console.log();
+            console.error(e);
+            complete('INVALID_METADATA');
+        }
+    });
+    stream.on('end', function () {
+        complete(null);
+    });
+    stream.on('error', function (e) { complete(e); });
+};
+
+var getChannelMetadata = function (Env, channelId, cb) {
+    var path = mkPath(Env, channelId);
+    getMetadataAtPath(Env, path, cb);
+};
+
+var clearChannel = function (Env, channelId, cb) {
+    var path = mkPath(Env, channelId);
+    getMetadataAtPath(Env, path, function (e, metadata) {
+        if (e) { return cb(e); }
+        if (!metadata) {
+            return void Fs.truncate(path, 0, function (err) {
+                if (err) {
+                    return cb(err);
+                }
+                cb(void 0);
+            });
+        }
+
+        var len = JSON.stringify(metadata).length + 1;
+        Fs.truncate(path, len, function (err) {
+            if (err) { return cb(err); }
+            closeChannel(Env, channelId, cb);
+        });
+    });
+};
+
 var readMessages = function (path, msgHandler, cb) {
     var remainder = '';
     var stream = Fs.createReadStream(path, 'utf8');
@@ -260,6 +319,12 @@ module.exports.create = function (conf, cb) {
             getChannelSize: function (chanName, cb) {
                 channelBytes(env, chanName, cb);
             },
+            getChannelMetadata: function (channelName, cb) {
+                getChannelMetadata(env, channelName, cb);
+            },
+            clearChannel: function (channelName, cb) {
+                clearChannel(env, channelName, cb);
+            },
         });
     });
     setInterval(function () {