1，今天在hacknews上看到很多人對messagepack的爭論。首先了解什麼是MessagePack：MessagePack is a binary-based efficient object serialization library. It enables to exchange structured objects between many languages like JSON. But unlike JSON, it is very fast and small.
2，MessagePack的主要用途，作者解釋說有兩大用途：一是Space-efficient storage for Memcache entries (Pinterest)，節省空間類型的mamcache應用；另一個是用於RPC傳輸， This use case is fairly close to my original intent. When one is designing an RPC system, one of the first tasks is to specify and implement a communication protocol. This process can get pretty hairy as you need to worry about a lot of low-level issues like Endian-ness. By using MessagePack, one can skip designing and implementing a communication protocol entirely and accelerate development.
3,爭議的地方是MessagePack的benchmark說，他比protocolBuffer，Json快很多倍。但是有人不相信，做個javasript下的測試（json與messagePack）。發現MessagePack僅是壓縮後的數據比json少10%左右，而壓縮和解壓時間則和json的解析器比起來要費時很多。
4，“MsgPack vs. JSON: Cut your client-server exchange traffic by 50% with one line of code”這篇文章使用了messagePack做服務器的優化，降低服務器的數據量，更加合理的利用帶寬。作者強調了他們寧願浪費客戶端的0.5ms—1ms，但是服務器使用ruby的MessagePack解析器，效率能夠比JSON快5倍。
The difference to JSON is, that MsgPack is binary-based - this gives the possibility to make the exchanged data a) smaller and use less bytes, I guess we all know the advantages of that, however there is an even bigger advantage: b) It is faster to parse and encode, having a parser parse 40 bytes takes about twice as long as parsing 20 bytes.
復制代碼 代碼如下:
myJSONString = JSON.stringify(myObject);
myObject = JSON.parse(myJSONString);
var myByteArray = msgpack.pack(myObject);
myObject = msgpack.unpack(myByteArray);
MessagePack作者也認為MessagePack may not be the best choice for client-side serialization as described by the blog author.引用2的作者有點小悲劇。
5，BSon是Json的二進制形式，但是與JSon有語法不兼容的地方。但是MessagePack保證語義上能夠做到一致。
6，場景需求不同，導致技術的應用有所差異。
PHP試用MessagePack
It's like JSON. but fast and small.
這句吸引了我，去瞧了下。
官網：http://msgpack.org
官方的安裝方法忽悠人，msgpack目錄下根本沒php目錄...只看到csharp,erlang,go,java,ruby等目錄。
復制代碼 代碼如下:
git clone https://github.com/msgpack/msgpack.git
cd msgpack/php
phpize
./configure && make && make install
還是在PHP官網擴展找到了：http://pecl.php.net/package/msgpack
最後更新時間：2012-09-14，昨天的版本。
附安裝過程：
復制代碼 代碼如下:
wget http://pecl.php.net/get/msgpack-0.5.2.tgz
tar zxf msgpack-0.5.2.tgz
cd msgpack-0.5.2
/usr/local/hx/php/bin/phpize
./configure --with-php-config=/usr/local/hx/php/bin/php-config
make && make install
然後把msgpack.so加到php.ini裡，重啟php，完成安裝。
開始測試：
$data = array(0=>'abcdefghijklmnopqrstuvwxyz',1=>'廈門','abc'=>'1234567890');
分別對其msgpack_pack，json_encode，serialize，長度為：50,62,87
然後分別執行10000次，耗時：9.95 毫秒，17.45 毫秒，8.85 毫秒
解開執行10000次，耗時：14.76 毫秒，23.93 毫秒，14.61 毫秒
msgpack的性能至少超過json50%，雖然和serialize其實速度差不多，但serialize占用空間明顯比較多。
另外，GBK的程序方便了，中文也可以msgpack_pack，用json的話還要批量轉換成utf-8之後才能json_encode。
引用：
1，MessagePack官方網站
2，MsgPack vs. JSON: Cut your client-server exchange traffic by 50% with one line of code
HN評論地址：http://news.ycombinator.com/item?id=4090831
3，My thoughts on MessagePack
HN評論地址：http://news.ycombinator.com/item?id=4092969
4 JS下MessagePack與JSON性能對比
HN評論地址：http://news.ycombinator.com/item?id=4091051
