Add unref() method to RedisClient that will call unref() on the socke…

…t connection, allowing it to close when unused. This is experimental because it does not yet understand the Redis protocol, so subscriptions or blocking operations will not work correctly.

README.md

@@ -264,6 +264,26 @@ want to do this:
 `client.end()` is useful for timeout cases where something is stuck or taking too long and you want
 to start over.
 
+## client.unref()
+
+Call `unref()` on the underlying socket connection to the Redis server, allowing the program to exit once no more commands are pending.
+
+This is an **experimental** feature, and only supports a subset of the Redis protocol. Any commands where client state is saved on the Redis server, e.g. `*SUBSCRIBE` or the blocking `BL*` commands will *NOT* work with `.unref()`.
+
+```js
+var redis = require("redis")
+var client = redis.createClient()
+
+/*
+    Calling unref() will allow this program to exit immediately after the get command finishes. Otherwise the client would hang as long as the client-server connection is alive.
+*/
+client.unref()
+client.get("foo", function (err, value){
+    if (err) throw(err)
+    console.log(value)
+})
+```
+
 ## Friendlier hash commands
 
 Most Redis commands take a single String or an Array of Strings as arguments, and replies are sent back as a single String or an Array of Strings.

index.js

@@ -121,6 +121,20 @@ RedisClient.prototype.initialize_retry_vars = function () {
     this.attempts = 1;
 };
 
+RedisClient.prototype.unref = function () {
+    trace("User requesting to unref the connection");
+    if (this.connected) {
+        trace("unref'ing the socket connection");
+        this.stream.unref();
+    }
+    else {
+        trace("Not connected yet, will unref later");
+        this.once("connect", function () {
+            this.unref();
+        })
+    }
+};
+
 // flush offline_queue and command_queue, erroring any items with a callback first
 RedisClient.prototype.flush_and_error = function (message) {
     var command_obj;

test-unref.js

@@ -0,0 +1,12 @@
+var redis = require("./")
+//redis.debug_mode = true
+var PORT = process.argv[2] || 6379;
+var HOST = process.argv[3] || '127.0.0.1';
+
+var c = redis.createClient(PORT, HOST)
+c.unref()
+c.info(function (err, reply) {
+  if (err) process.exit(-1)
+  if (!reply.length) process.exit(-1)
+  process.stdout.write(reply.length.toString())
+})

test.js

@@ -10,6 +10,7 @@ var redis = require("./index"),
     assert = require("assert"),
     crypto = require("crypto"),
     util = require("./lib/util"),
+    fork = require("child_process").fork,
     test_db_num = 15, // this DB will be flushed and used for testing
     tests = {},
     connected = false,
@@ -2013,6 +2014,23 @@ tests.reconnectRetryMaxDelay = function() {
     });
 };
 
+tests.unref = function () {
+    var name = "unref";
+    var external = fork("./test-unref.js");
+    var done = false;
+    external.on("close", function (code) {
+        assert(code == 0, "test-unref.js failed");
+        done = true;
+    })
+    setTimeout(function () {
+        if (!done) {
+            external.kill();
+        }
+        assert(done, "test-unref.js didn't finish in time.");
+        next(name);
+    }, 100);
+};
+
 all_tests = Object.keys(tests);
 all_start = new Date();
 test_count = 0;