Fun PouchDB

Thin wrapper around PouchDB for convenient server use

The common scenario is, you have a Node.js application, usually a server. You need just a few basic things:

1. Open some databases by name
2. Let me specify any design docs I need, as a JavaScript object
3. Let me provide a simple throws/doesn't-throw function to validate a doc
4. Everything should always be synced with Cloudant

Usage:

var DB = require('fun-pouchdb').defaults({prefix: __dirname})

DB('my_db', function(er, my_db) {
  console.log('At this point, my_db is a plain PouchDB object')
})

Or as a list of names to open at once.

DB(['users', 'web', 'billing'], function(er, dbs) {
  // The databases are in the dbs object, by name.
  dbs.users.get('some_doc', function() { /* etc */ })
  dbs.web
  dbs.billing // etc.
})

However, the most common thing to do in a real world application is to provide a bunch of names, plus design docs and validation functions. Basically, you have a big definition of all your databases, plus the design docs you need (for views), plus validation functions. Placing this all together in Node.js code is a great way to ensure that it is well-tested.

// Define all the DBs needed for this app. The key is the database name, and
// the value is the options for that database.
var opts = {}

// Make an "inventory" database with default options.
opts.inventory = {}

// A "ddoc" option will ensure that design document will be in the database.
opts.users = { ddoc: {_id:'_design/foo', views: {}} }

// Or provide several ddocs in an array.
opts.web = {
  ddocs: [
    // First one
    {_id:'_design/foo', views: {}},

    // Second one. Note, the map function is a real function.
    { _id:'_design/bar',
      views: {
        by_name: {
          map: function(doc) { emit(doc.name) }
        }
      }
    }
  ]
}

// In reality, you will want at least a simple pass/fail validation function,
// to prevent a bug or something getting a bad document into the DB.
opts.web.validate = check_web_document

// This doc checker simply throws an Error if anything looks wrong. You can call
// console.log() or logging.
//
// Of course, you export this function and write lots of good unit tests.
function check_web_document(doc) {
  console.log('Checking web document: %s', doc._id)

  if (doc.type != 'web')
    throw new Error(`Document type must be "web": ${doc._id}`)

  if (doc.a && doc.b && doc.c && doc.a + doc.b != doc.c)
    throw new Error(`Bad arithmetic A plus B should equal C`)

  // Et cetera.
}

Now send that to DB, and you will get the same friendly object full of PouchDB instances, but with all of your design documents and validation in place.

DB(opts, function(er, dbs) {
  dbs.users.put({name:'John Doe'}, function(er, response) {
    console.log('Stored a doc in the users DB')
  })

  // This will fail the A+B=C validation test.
  dbs.web.put({type:'web', a:5, b:3, c:53}, function(er, response) {
    console.log('Error: %s', response.name) // Error: forbidden
    console.log(response.exception) // Prints the full Error object
  })
})

Automatic Cloudant Sync

If you provide an option, "cloudant": {"account":"my-cloudant-account", "password":"my-password"} then the database will be kept in sync with its counterpart in your Cloudant account. The DB name is the same.

Note, Fun PouchDB does not sync design documents. They are considered to be part of your application code. You should manage it in Git, with your application.