Add support for touch

README.md

@@ -132,7 +132,6 @@ can also implement a feature not a list if you think it would be good.
 
 * Support flags
 * Support multi commands
-* Support touch
 * Support CAS
 * Consistent hashing for keys and/or pluggable hashing algorithm
 

lib/memjs/memjs.js

@@ -384,6 +384,39 @@ Client.prototype.prepend = function(key, value, callback) {
   });
 };
 
+// TOUCH
+//
+// Touch sets an expiration value, given by _expires_, on the given _key_ in
+// memcache. The operation only succeeds if the key is already present. The
+// callback signature is:
+//
+//     callback(err, success)
+Client.prototype.touch = function(key, expires, callback) {
+  this.seq++;
+  var extras = makeExpiration(expires || this.options.expires);
+  var request = makeRequestBuffer(0x1C, key, extras, '', this.seq);
+
+  var logger = this.options.logger;
+  this.perform(key, request, function(err, response) {
+    if (err) {
+      if (callback) { callback(err, null); }
+      return;
+    }
+    switch (response.header.status) {
+    case 0:
+      if (callback) { callback(null, true); }
+      break;
+    case 1:
+      if (callback) { callback(null, false); }
+      break;
+    default:
+      var errorMessage = 'MemJS TOUCH: ' + errors[response.header.status];
+      logger.log(errorMessage);
+      if (callback) { callback(new Error(errorMessage), null); }
+    }
+  });
+};
+
 // FLUSH
 //
 // Flushes the cache on each connected server. The callback signature is:

test/client_test.js

@@ -540,6 +540,48 @@ test('PrependKeyDNE', function(t) {
   });
 });
 
+test('TouchSuccessful', function(t) {
+  var n = 0;
+  var dummyServer = new MemJS.Server();
+  dummyServer.write = function(seq, requestBuf) {
+    var request = MemJS.Utils.parseMessage(requestBuf);
+    t.equal('hello', request.key.toString());
+    t.equal('', request.val.toString());
+    t.equal('\0\0\4\0', request.extras.toString());
+    n += 1;
+    dummyServer.respond({header: {status: 0, opaque: request.header.opaque}});
+  };
+
+  var client = new MemJS.Client([dummyServer]);
+  client.touch('hello', 1024, function(err, val) {
+    t.equal(null, err);
+    t.equal(true, val);
+    t.equal(1, n, 'Ensure touch is called');
+    t.end();
+  });
+});
+
+test('TouchKeyDNE', function(t) {
+  var n = 0;
+  var dummyServer = new MemJS.Server();
+  dummyServer.write = function(seq, requestBuf) {
+    var request = MemJS.Utils.parseMessage(requestBuf);
+    t.equal('hello', request.key.toString());
+    t.equal('', request.val.toString());
+    t.equal('\0\0\4\0', request.extras.toString());
+    n += 1;
+    dummyServer.respond({header: {status: 1, opaque: request.header.opaque}});
+  };
+
+  var client = new MemJS.Client([dummyServer]);
+  client.touch('hello', 1024, function(err, val) {
+    t.equal(null, err);
+    t.equal(false, val);
+    t.equal(1, n, 'Ensure ptouch is called');
+    t.end();
+  });
+});
+
 test('Failover', function(t) {
   var n1 = 0;
   var n2 = 0;