How to efficiently cache web service requests-response pairs in JSON format

I find a interesting problem when working with web service in JSON format.

Assume there's web service. accept several parameters. each parameter has different value set. You can get the response by passing different request parameters.

The request is in JSON format. Because there're so many different 开发者_开发技巧combination of request parameters. For performance optimization, I want to cache the request and response pair. and store it into local database. If there's big hash table, I may want to store the request as key, the response as value.

I am thinking the MongoDB maybe a solution. But I am not sure. Is it possible to store request-response as key-value pair in these kind of database? So I can cache the result and response to user immediately.

Thank you.

You won't get any benefit from that level of caching unless your code and database have spectacularly bad performance (in which case you have bigger problems than setting up a cache).

You can use JSON as a key with any key/value store, though it probably makes sense to use a hash as the cache key rather than using the JSON string directly, and a non-persistent in-memory cache with memcached or redis will work a lot better than a complete document database like MongoDB.

Where you will run into big problems with this approach is managing cache expiry - to get real time updates, you need to know exactly which cached objects are affected by a change to a given object. That's easy if the request is a simple get by ID, but next to impossible in the scenario you describe.

The other way to manage cache is expiry is to delete objects from the cache after a given time. This assumes that it is acceptable to show stale data after an update. Caches usually have support for expiry built in. Databases generally don't.