Google today released Protocol Buffers. Protocol Buffers is their “language-neutral, platform-neutral, extensible mechanism for serializing structured data”. In general it’s pretty interesting stuff, and looking over the docs, seems pretty well thought out.
I agree XML is bulky and wasteful for the task. There’s a reason why many web developers prefer JSON rather than actual XML when using xmlHttpRequest: XML parsing can be a real performance killer. JSON in my mind is currently the winner in this department since it’s light weight, simple, and a can be interpreted by pretty much any language on the planet (may need to install a module, gem, extension, or include a class). The downside to JSON is that it doesn’t really allow you to define structure. JSON also is still not binary format, so you have a performance penalty to parse the string. The upside is that JSON is rather easy for humans to read (great for debugging). The NY Times even made a database abstraction layer called DBSlayer that interfaces using JSON.
Serialized PHP has become somewhat popular (Yahoo Developer Network API’s support it), but it’s language specific, though interpreters that can read/write it exist for other languages including Perl, Python and Java. It’s also somewhat complicated for what it provides. At a glance it’s a string of garbage until you break it down.
It looks like Google already has support for Java, Python, and C++. It’s only a matter of time before Perl, PHP, and Ruby get support for Protocol Buffers as well.
I could see Protocol Buffers being pretty useful in combination with Memcached.
It’s great to see Google open sourcing stuff like this.