Ember Pouch is a PouchDB/CouchDB adapter for Ember Data 2.0+. For older Ember Data versions use Ember Pouch version 3.2.2.
With Ember Pouch, all of your app's data is automatically saved on the client-side using IndexedDB or WebSQL, and you just keep using the regular Ember Data store
API. This data may be automatically synced to a remote CouchDB (or compatible servers) using PouchDB replication.
What's the point?
-
You don't need to write any server-side logic. Just use CouchDB.
-
Data syncs automatically.
-
Your app works offline, and requests are super fast, because they don't need the network.
For more on PouchDB, check out pouchdb.com.
Install and setup
ember install ember-pouch
For ember-data < 2.0:
ember install ember-pouch@3.2.2
For ember-cli < 1.13.0:
npm install ember-pouch@3.2.2 --save-dev
This provides
import PouchDB from 'ember-pouch/pouchdb';
import {Model, Adapter, Serializer} from 'ember-pouch'
Ember-Pouch
requires you to add a @attr('string') rev
field to all your models. This is for PouchDB/CouchDB to handle revisions:
// app/models/todo.js
import Model, { attr } from '@ember-data/model';
export default class TodoModel extends Model {
@attr('string') title;
@attr('boolean') isCompleted;
@attr('string') rev; // <-- Add this to all your models
}
If you like, you can also use Model
from Ember-Pouch
that ships with the rev
attribute:
// app/models/todo.js
import { attr } from '@ember-data/model';
import { Model } from 'ember-pouch';
export default class TodoModel extends Model {
@attr('string') title;
@attr('boolean') isCompleted;
}
Configuring /app/adapters/application.js
A local PouchDB that syncs with a remote CouchDB looks like this:
// app/adapters/application.js
import PouchDB from 'ember-pouch/pouchdb';
import { Adapter } from 'ember-pouch';
let remote = new PouchDB('http://localhost:5984/my_couch');
let db = new PouchDB('local_pouch');
db.sync(remote, {
live: true, // do a live, ongoing sync
retry: true // retry if the connection is lost
});
export default class ApplicationAdapter extends Adapter {
db = db;
}
You can also turn on debugging:
import PouchDB from 'ember-pouch/pouchdb';
// For v7.0.0 and newer you must first load the 'pouchdb-debug' plugin
// see https://github.com/pouchdb/pouchdb/tree/39ac9a7a1f582cf7a8d91c6bf9caa936632283a6/packages/node_modules/pouchdb-debug
import pouchDebugPlugin from 'pouchdb-debug'; // (assumed available via ember-auto-import or shim)
PouchDB.plugin(pouchDebugPlugin);
PouchDB.debug.enable('*');
See the PouchDB sync API for full usage instructions.
EmberPouch Blueprints
Model
In order to create a model run the following command from the command line:
ember g pouch-model <model-name>
Replace <model-name>
with the name of your model and the file will automatically be generated for you.
Adapter
You can now create an adapter using ember-cli's blueprint functionality. Once you've installed ember-pouch
into your ember-cli app you can run the following command to automatically generate an application adapter.
ember g pouch-adapter application
Now you can store your localDb and remoteDb names in your ember-cli's config. Just add the following keys to the ENV
object:
ENV.emberPouch.localDb = 'test';
ENV.emberPouch.remoteDb = 'http://localhost:5984/my_couch';
Relationships
EmberPouch supports both hasMany
and belongsTo
relationships.
Don't save hasMany child ids
To be more in line with the normal ember data way of saving hasMany
- belongsTo
relationships, ember-pouch now has an option to not save the child ids on the hasMany
side. This prevents the extra need to save the hasMany
side as explained below. For a more detailed explanation please read the relational-pouch documentation
This new mode can be disabled for a hasMany
relationship by specifying the option save: true
on the relationship. An application wide setting named ENV.emberPouch.saveHasMany
can also be set to true
to make all hasMany
relationships behave the old way.
Using this mode does impose a slight runtime overhead, since this will use db.find
and database indexes to search for the child ids. The indexes are created automatically for you. But large changes to the model might require you to clean up old, unused indexes.
ℹ️ This mode is the default from version 5 onwards. Before that it was called dontsave
and dontsavehasmany
Saving child ids
When you do save child ids on the hasMany
side, you have to follow the directions below to make sure the data is saved correctly.
Adding entries
When saving a hasMany
- belongsTo
relationship, both sides of the relationship (the child and the parent) must be saved. Note that the parent needs to have been saved at least once prior to adding children to it.
// app/controllers/posts/post.js
import Controller from '@ember/controller';
import { action } from '@ember/object';
export default class PostController extends Controller {
@action addComment(comment, author){
//Create the comment
const comment = this.store.createRecord('comment',{
comment: comment,
author: author
});
//Add our comment to our existing post
this.model.comments.pushObject(comment);
//Save the child then the parent
comment.save().then(() => this.model.save());
}
}
Removing child ids
When removing a hasMany
- belongsTo
relationship, the children must be removed prior to the parent being removed.
// app/controller/posts/admin.js
import Controller from '@ember/controller';
import { action } from '@ember/object';
import { all } from 'rsvp';
export default class AdminController extends Controller {
@action deletePost(post){
//collect the promises for deletion
let deletedComments = [];
//get and destroy the posts comments
post.comments.then((comments) => {
comments.map((comment) => {
deletedComments.push(comment.destroyRecord());
});
});
//Wait for comments to be destroyed then destroy the post
all(deletedComments).then(() => {
post.destroyRecord();
});
}
}
Query and QueryRecord
query and queryRecord are relying on pouchdb-find
db.createIndex(index [, callback])
Create an index if it doesn't exist.
// app/adapters/application.js
function createDb() {
...
db.createIndex({
index: {
fields: ['data.name']
}
}).then((result) => {
// {'result': 'created'} index was created
});
return db;
};
store.query(model, options)
Find all docs where doc.name === 'Mario'
// app/routes/smasher.js
import Route from '@ember/routing/route';
export default class SmasherRoute extends Route {
model() {
return this.store.query('smasher', {
filter: { name: 'Mario' }
});
}
}
Find all docs where doc.name === 'Mario' and doc.debut > 1990:
// app/routes/smasher.js
import Route from '@ember/routing/route';
export default class SmasherRoute extends Route {
model() {
return this.store.query('smasher', {
filter: {
name: 'Mario'
debut: { $gt: 1990 }
}
});
}
}
Sorted by doc.debut descending.
// app/routes/smasher.js
import Route from '@ember/routing/route';
export default class SmasherRoute extends Route {
model() {
return this.store.query('smasher', {
filter: {
name: 'Mario',
debut: { '$gte': null }
},
sort: [
{ debut: 'desc' }
]
})
}
}
Limit to 5 documents.
// app/routes/smasher.js
import Route from '@ember/routing/route';
export default class SmasherRoute extends Route {
model() {
return this.store.query('smasher', {
filter: {
name: 'Mario',
debut: { '$gte': null }
},
sort: [
{ debut: 'desc' }
],
limit: 5
})
}
}
Skip the first 5 documents
// app/routes/smasher.js
import Route from '@ember/routing/route';
export default class SmasherRoute extends Route {
model() {
return this.store.query('smasher', {
filter: {
name: 'Mario',
debut: { '$gte': null }
},
sort: [
{ debut: 'desc' }
],
skip: 5
})
}
}
Note that this query would require a custom index including both fields data.name
and data.debut
. Any field in sort
must also be included in filter
. Only $eq
, $gt
, $gte
, $lt
, and $lte
can be used when matching a custom index.
store.queryRecord(model, options)
Find one document where doc.name === 'Mario'
// app/routes/smasher.js
import Route from '@ember/routing/route';
export default class SmasherRoute extends Route {
model() {
return this.store.queryRecord('smasher', {
filter: { name: 'Mario' }
});
}
}
Attachments
Ember-Pouch
provides an attachments
transform for your models, which makes working with attachments as simple as working with any other field.
Add a DS.attr('attachments')
field to your model. Provide a default value for it to be an empty array.
// myapp/models/photo-album.js
import { attr } from '@ember-data/model';
import { Model } from 'ember-pouch';
export default class PhotoAlbumModel extends Model {
@attr('attachments', {
defaultValue: function() {
return [];
}
}) photos
}
Here, instances of PhotoAlbum
have a photos
field, which is an array of plain Ember.Object
s, which have a .name
and .content_type
. Non-stubbed attachment also have a .data
field; and stubbed attachments have a .stub
instead.
Attach new files by adding an Ember.Object
with a .name
, .content_type
and .data
to array of attachments.
// somewhere in your controller/component:
myAlbum.photos.addObject(Ember.Object.create({
'name': 'kitten.jpg',
'content_type': 'image/jpg',
'data': btoa('hello world') // base64-encoded `String`, or a DOM `Blob`, or a `File`
}));
Sample app
Tom Dale's blog example using Ember CLI and EmberPouch: broerse/ember-cli-blog
Notes
LocalStorage
Currently PouchDB doesn't use LocalStorage unless you include an experimental plugin. Amazingly, this is only necessary to support IE ≤ 9.0 and Opera Mini. It's recommended you read more about this, what storage mechanisms modern browsers now support, and using SQLite in Cordova on the PouchDB adapters page.
CouchDB
From day one, CouchDB and its protocol have been designed to be always Available and handle Partitioning over the network well (AP in the CAP theorem). PouchDB/CouchDB gives you a solid way to manage conflicts. It is "eventually consistent," but CouchDB has an API for listening to changes to the database, which can be then pushed down to the client in real-time.
To learn more about how CouchDB sync works, check out the PouchDB guide to replication.
Sync and the ember-data store
Out of the box, ember-pouch includes a PouchDB change listener that automatically updates any records your app has loaded when they change due to a sync. It also unloads records that are removed due to a sync.
However, ember-pouch does not automatically load new records that arrive during a sync. The records are saved in the local database, but ember-data is not told to load them into memory. Automatically loading every new record works well with a small number of records and a limited number of models. As an app grows, automatically loading every record will negatively impact app responsiveness during syncs (especially the first sync). To avoid puzzling slowdowns, ember-pouch only automatically reloads records you have already used ember-data to load.
If you have a model or two that you know will always have a small number of records, you can tell ember-data to automatically load them into memory as they arrive. Your PouchAdapter subclass has a method unloadedDocumentChanged
, which is called when a document is received during sync that has not been loaded into the ember-data store. In your subclass, you can implement the following to load it automatically:
unloadedDocumentChanged: function(obj) {
let recordTypeName = this.getRecordTypeName(this.store.modelFor(obj.type));
this.db.rel.find(recordTypeName, obj.id).then((doc) => {
this.store.pushPayload(recordTypeName, doc);
});
},
Plugins
With PouchDB, you also get access to a whole host of PouchDB plugins.
For example, to use the pouchdb-authentication
plugin like this using ember-auto-import
:
import PouchDB from 'ember-pouch/pouchdb';
import auth from 'pouchdb-authentication';
PouchDB.plugin(auth);
Relational Pouch
Ember Pouch is really just a thin layer of Ember-y goodness over Relational Pouch. Before you file an issue, check to see if it's more appropriate to file over there.
Offline First
Saving data locally using PouchDB is one part of making a web application Offline First. However, you will also need to make your static assets available offline.
There are two possible approaches to this. The first one is using the Application Cache (AP) feature. The second one is using Service Workers (SW). The Application Cache specification has been removed from the Web standards. Mozilla now recommends to use Service Workers instead.
Most browser vendors still provide support for Application Cache and are in the process of implementing Service Workers. So depending on the browsers you target, you should go for one or the other. You can track the progress via caniuse.com.
1. Application Cache
You can use broccoli-manifest to create an HTML5 appcache.manifest
file. This By default, will allow your index.html and assets
directory to load even if the user is offline.
2. Service Workers
We recommend using Ember Service Worker to get started with Service Workers for your web application. The website provide's an easy to follow guide on getting started with the addon.
You can also take a look at Martin Broerse his ember-cli-blog configuration for the plugin.
Security
An easy way to secure your Ember Pouch-using app is to ensure that data can only be fetched from CouchDB – not from some other server (e.g. in an XSS attack).
You can use the content-security-policy plugin to enable Content Security Policy in Ember CLI. You also will have to set the CSP HTTP header on your backend in production.
To use, add a Content Security Policy whitelist entry to /config/environment.js
:
ENV.contentSecurityPolicy = {
"connect-src": "'self' http://your_couch_host.com:5984"
};
CORS setup (important!)
To automatically set up your remote CouchDB to use CORS, you can use the plugin add-cors-to-couchdb:
npm install -g add-cors-to-couchdb
add-cors-to-couchdb http://your_couch_host.com:5984 -u your_username -p your_password
Multiple models for the same data
Ember-data can be slow to load large numbers of records which have lots of relationships. If you run into this problem, you can define multiple models and have them all point to the same set of records by defining documentType
on the model class. Example (in an ember-cli app):
// app/models/post.js
import { attr, belongsTo, hasMany } from '@ember-data/model';
import { Model } from 'ember-pouch';
export default class PostModel extends Model {
@attr('string') title;
@attr('string') text;
@belongsTo('author') author;
@hasMany('comments') comments;
}
// app/models/post-summary.js
import { attr } from '@ember-data/model';
import { Model } from 'ember-pouch';
export default class PostSummaryModel extends Model {
@attr('string') title;
}
PostSummary.reopenClass({
documentType: 'post'
})
export default PostSummary;
The value for documentType
is the camelCase version of the primary model name.
For best results, only create/update records using the full model definition. Treat the others as read-only.
Multiple databases for the same model
In some cases it might be desirable (security related, where you want a given user to only have some informations stored on his computer) to have multiple databases for the same model of data.
Ember-Pouch
allows you to dynamically change the database a model is using by calling the function changeDb
on the adapter.
function changeProjectDatabase(dbName, dbUser, dbPassword) {
// CouchDB is serving at http://localhost:5455
let remote = new PouchDB('http://localhost:5455/' + dbName);
// here we are using pouchdb-authentication for credential supports
remote.login( dbUser, dbPassword).then(
function (user) {
let db = new PouchDB(dbName)
db.sync(remote, {live:true, retry:true})
// grab the adapter, it can be any ember-pouch adapter.
let adapter = this.store.adapterFor('project');
// this is where we told the adapter to change the current database.
adapter.changeDb(db);
}
)
}
Eventually Consistent
Following the CouchDB consistency model, we have introduced ENV.emberPouch.eventuallyConsistent
. This feature is on by default. So if you want the old behavior you'll have to disable this flag.
findRecord
now returns a long running Promise if the record is not found. It only rejects the promise if a deletion of the record is found. Otherwise this promise will wait for eternity to resolve.
This makes sure that belongsTo relations that have been loaded in an unexpected order will still resolve correctly. This makes sure that ember-data does not set the belongsTo to null if the Pouch replicate would have loaded the related object later on. (This only works for async belongsTo, sync versions will need this to be implemented in relational-pouch)
Installation
git clone
this repositorynpm install
Running
ember server
- Visit your app at http://localhost:4200.
Running Tests
ember test
ember test --server
Building
ember build
For more information on using ember-cli, visit http://www.ember-cli.com/.
Credits
This project was originally based on the ember-data-hal-adapter by @locks, and I really benefited from his guidance during its creation.
And of course thanks to all our wonderful contributors, here and in Relational Pouch!
Changelog
- 7.0.0
- Use ember-auto-import and pouchdb-browser to ease the installation process
- relational-pouch@4.0.0
- Use Octane Blueprints
- 6.0.0
- Switch to PouchDB 7.0.0
- 5.1.0
- Don't unloadRecord a deleted document in onChange, only mark as deleted. This fixes some bugs with hasMany arrays corrupting in newer ember-data versions. Not unloading records also seems safer for routes that have that model active.
- 5.0.1
- Adapter
fixDeleteBug
flag. Defaults totrue
. Fixes emberjs/data#4963 and related issues that don't seem to work well with server side delete notifications. - Track newly inserted records, so
unloadedDocumentChanged
is not called for those. Otherwise a race-condition can occur where onChange is faster than the save. This can result in the document being inserted in the store viaunloadedDocumentChanged
before the save returns to ember-data. This will result in an assert that the id is already present in the store.
- Adapter
- 5.0.0
- 5.0.0-beta.6
- 5.0.0-beta.5
- Add pouchdb.find.js from pouchdb #208
- createIndex promises should be done before removing #208
- Change sudo to required (see travis-ci/travis-ci#8836) #208
- Ignore same revision changes #189
- 5.0.0-beta.4
- 5.0.0-beta.3
- 5.0.0-beta.2
- version fix #196
- 5.0.0-beta.1
- Eventually consistency added: documents that are not in the database will result in an 'eternal' promise. This promise will only resolve when an entry for that document is found. Deleted documents will also satisfy this promise. This mirrors the way that couchdb replication works, because the changes might not come in the order that ember-data expects. Foreign keys might therefor point to documents that have not been loaded yet. Ember-data normally resets these to null, but keeping the promise in a loading state will keep the relations intact until the actual data is loaded.
- 4.3.0
- Bundle pouchdb-find #191
- 4.2.9
- Lock relational-pouch version until pouchdb-find bugs are solved
- 4.2.8
- Update Ember CLI and PouchDB #186
- 4.2.7
- Fix
_shouldSerializeHasMany
deprecation #185
- Fix
- 4.2.6
- 4.2.5
- 4.2.4
- Fix attachments typo in README #170
- 4.2.3
- Update pouchdb to the latest version
- Minor typofix #166
- 4.2.2
- Update pouchdb to the latest version
- 4.2.1
- Fix
Init
some more - Fix
Init
_super.Init
error
- Fix
- 4.2.0
- Switch to npm versions
- 4.1.0
- async is now true when not specified for relationships
- hasMany relationship can have option dontsave
- 4.0.3
- Fixes #158
- 4.0.2
- 4.0.0
- 3.2.2
- 3.2.1
- Fix(Addon): Call super in init #129
- 3.2.0
- Make adapter call a hook when encountering a change for a record that is not yet loaded #108
- 3.1.1
- Bugfix for hasMany relations by @backspace (#111).
- 3.1.0
- Database can now be dynamically switched on the adapter (#89). Thanks to @olivierchatry for this!
- Various bugfixes by @backspace, @jkleinsc, @rsutphin, @mattmarcum, @broerse, and @olivierchatry. See the full commit log for details. Thank you!
- 3.0.1
- Add blueprints for model and adapter (see above for details). Thanks @mattmarcum (#101, #102) and @backspace (#103).
- 3.0.0
- Update for compatibility with Ember & Ember-Data 2.0+. The adapter now supports Ember & Ember-Data 1.13.x and 2.x only.
- 2.0.3
- Use Ember.get to reference the PouchDB instance property in the adapter (
db
), allowing it to be injected (#84). Thanks to @jkleinsc! - Indicate to ember-data 1.13+ that reloading individual ember-pouch records is never necessary (due to the change watcher that keeps them up to date as they are modified) (#79, #83).
- Use Ember.get to reference the PouchDB instance property in the adapter (
- 2.0.2 - Use provide
findRecord
for ember-data 1.13 and later thanks to @OleRoel (#72) - 2.0.1 - Fixed #62 thanks to @rsutphin (deprecated
typekey
in Ember-Data 1.0.0-beta.18) - 2.0.0 - Ember CLI support, due to some amazing support by @fsmanuel! Bower and npm support are deprecated now; you are recommended to use Ember CLI instead.
- 1.2.5 - Last release with regular Bower/npm support via bundle javascript in the
dist/
directory. - 1.0.0 - First release