How to setup EXTJS4 store for CRUD Couch DB?

How to calibrate Extjs 4 store for simple CR开发者_运维问答UD from/to couchDb?

There is a demo project that was put together for our last Austin Sencha meetup that shows connecting Ext 4 to both Couch and MongoDB:

https://github.com/coreybutler/JSAppStack

Specifically this class will probably help you get started.

I have developed a library called SenchaCouch to make it easy to use CouchDB as the sole server for hosting both application code and data. Check it out at https://github.com/srfarley/sencha-couch.

I'd like to point out that to fully implement CRUD capabilities with the demo require some modification. CouchDB requires you to append revisions for any update/delete operation. This can also cause some issues with the field attributes in the Ext REST proxy. There is a project called mvcCouch that would be worth taking a look at. This project references a plugin that should help with full CRUD operations against CouchDB.

You'll find a number of subtleties in ExtJS 4's REST proxy that can slow you down. this brief post summarises the major ones:

1. In your Model class, you have to either define a hardcoded 'id' property or use 'idProperty' to specify one column as 'id'.

2. You server side code needs to return the entire updated record(s) to the browser. CouchDB normally returns only an _id and _rev, so you'll have to find a way to get the entire document on your own.

3. Be aware that the format of the record in the "data" must be JSON-formatted.

4. Be sure to implemented at least one Validator in your Model class because, in ExtJS source code AbstractStore.js, you can find the following code, which may always return true for a new created record in RowEditing plugin when the store is set as autoSync = true.

   filterNew: function(item) {
       // only want phantom records that are valid
       return item.phantom === true && item.isValid();
   },
   

This last item is, in my opinion, a design bug. The isValid() function should by rights return true by default, and rely on the developer to throw an error if problems occur.

The end result is that unless you have a validator for every field, the updates never get sent to CouchDB. You won't see any error thrown, it will just do nothing.

I just released two update libs for Sencha Touch and CouchDB respecively(based on S. Farley's previous work). They support nested data writing and basic CRUD.

https://github.com/rwilliams/sencha-couchdb-extjs

https://github.com/rwilliams/sencha-couchdb-touch