bquery/docs/7. Caching.md

bquery is a useful node module to fetch web page, which use css selector to fetch and structure this html page content.

---
category: reference
heading: 'Caching'
---

noodle includes an in memory cache for both queried pages and the query 
results to help with the speed of requests.

This cache can be configured in the `noodlejs/lib/config.json` file.

This cache is included in the noodle library core not at its web service.

Caching is done on a singular query basis and not per all queries in a request.

By default the page cache and results cache's individual items have a life time 
of an hour. With a cache itself having total size of 124 recorded items in 
memory at one time. A cache is also cleared entirely on a weekly basis.

These values can all be changed from noodle's json config.

## HTTP caching headers

The noodle web service includes `Expires` header. This is always set to the 
oldest to expire query result in a result set.

Take not however that the browser [may not cache](http://stackoverflow.com/questions/626057/is-it-possible-to-cache-post-methods-in-http) POST requests to the noodle server.