_serialize method

This commit adds a utility method as a counterpart to the _unserialize
utility method, allowing users to manually serialize data themselves
before sending it to Redis.  This could be useful for calls going through
EVAL, as phpredis can't automatically serialize/unserialize in that case.

Addresses #431

README.markdown

@@ -2990,6 +2990,7 @@ $ret = FALSE if x has been modified between the call to WATCH and the call to EX
 * [clearLastError](#) - Clear the last error message
 * [_prefix](#) - A utility method to prefix the value with the prefix setting for phpredis
 * [_unserialize](#) - A utility method to unserialize data with whatever serializer is set up
+* [_serialize](#) - A utility method to serialize data with whatever serializer is set up
 
 ### eval
 -----
@@ -3139,6 +3140,28 @@ $redis->setOption(Redis::OPT_PREFIX, 'my-prefix:');
 $redis->_prefix('my-value'); // Will return 'my-prefix:my-value'
 ~~~
 
+### _serialize
+-----
+_**Description**_: A utility method to serialize values manually.
+
+This method allows you to serialize a value with whatever serializer is configured, manually.
+This can be useful for serialization/unserialization of data going in and out of EVAL commands
+as phpredis can't automatically do this itself.  Note that if no serializer is set, phpredis
+will change Array values to 'Array', and Objects to 'Object'.
+
+##### *Parameters*
+*value*:  Mixed.  The value to be serialized
+
+##### *Examples*
+~~~
+$redis->setOption(Redis::OPT_SERIALIZER, Redis::SERIALIZER_NONE);
+$redis->_serialize("foo"); // returns "foo"
+$redis->_serialize(Array()); // Returns "Array"
+$redis->_serialize(new stdClass()); // Returns "Object"
+
+$redis->setOption(Redis::OPT_SERIALIZER, Redis::SERIALIZER_PHP);
+$redis->_serialize("foo"); // Returns 's:3:"foo";'
+
 ### _unserialize
 -----
 _**Description**_: A utility method to unserialize data with whatever serializer is set up.

php_redis.h

@@ -142,6 +142,7 @@ PHP_METHOD(Redis, time);
 PHP_METHOD(Redis, getLastError);
 PHP_METHOD(Redis, clearLastError);
 PHP_METHOD(Redis, _prefix);
+PHP_METHOD(Redis, _serialize);
 PHP_METHOD(Redis, _unserialize);
 
 PHP_METHOD(Redis, mset);

redis.c

@@ -245,6 +245,7 @@ static zend_function_entry redis_functions[] = {
      PHP_ME(Redis, clearLastError, NULL, ZEND_ACC_PUBLIC)
 
      PHP_ME(Redis, _prefix, NULL, ZEND_ACC_PUBLIC)
+     PHP_ME(Redis, _serialize, NULL, ZEND_ACC_PUBLIC)
      PHP_ME(Redis, _unserialize, NULL, ZEND_ACC_PUBLIC)
 
      PHP_ME(Redis, client, NULL, ZEND_ACC_PUBLIC)
@@ -6458,6 +6459,35 @@ PHP_METHOD(Redis, _prefix) {
 	}
 }
 
+/*
+ * {{{ proto Redis::_serialize(value)
+ */
+PHP_METHOD(Redis, _serialize) {
+    zval *object;
+    RedisSock *redis_sock;
+    zval *z_val;
+    char *val;
+    int val_free, val_len;
+
+    // Parse arguments
+    if(zend_parse_method_parameters(ZEND_NUM_ARGS() TSRMLS_CC, getThis(), "Oz",
+                                    &object, redis_ce, &z_val) == FAILURE)
+    {
+        RETURN_FALSE;
+    }
+
+    // Grab socket
+    if(redis_sock_get(object, &redis_sock TSRMLS_CC, 0) < 0) {
+        RETURN_FALSE;
+    }
+
+    // Serialize, which will return a value even if no serializer is set
+    val_free = redis_serialize(redis_sock, z_val, &val, &val_len TSRMLS_CC);
+
+    // Return serialized value.  Tell PHP to make a copy if redis_serialize didn't.
+    RETURN_STRINGL(val, val_len, !val_free);
+}
+
 /*
  * {{{ proto Redis::_unserialize(value)
  */

tests/TestRedis.php

@@ -4428,6 +4428,34 @@ class Redis_Test extends TestSuite
     	$this->assertTrue(1 === $this->redis->evalsha($sha));
     }
 
+    public function testSerialize() {
+        $vals = Array(1, 1.5, 'one', Array('here','is','an','array'));
+        
+        // Test with no serialization at all
+        $this->assertTrue($this->redis->_serialize('test') === 'test');
+        $this->assertTrue($this->redis->_serialize(1) === '1');
+        $this->assertTrue($this->redis->_serialize(Array()) === 'Array');
+        $this->assertTrue($this->redis->_serialize(new stdClass) === 'Object');
+
+        $arr_serializers = Array(Redis::SERIALIZER_PHP);
+        if(defined('Redis::SERIALIZER_IGBINARY')) {
+            $arr_serializers[] = Redis::SERIALIZER_IGBINARY;
+        }
+
+        foreach($arr_serializers as $mode) {
+            $arr_enc = Array(); 
+            $arr_dec = Array();
+
+            foreach($vals as $k => $v) {
+                $enc = $this->redis->_serialize($v);
+                $dec = $this->redis->_unserialize($enc);
+
+                // They should be the same
+                $this->assertTrue($enc == $dec);
+            }
+        }
+    }
+
     public function testUnserialize() {
     	$vals = Array(
     		1,1.5,'one',Array('this','is','an','array')