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https://github.com/clarkie/dynogels
DynamoDB data mapper for node.js. Originally forked from https://github.com/ryanfitz/vogels
https://github.com/clarkie/dynogels
aws dynamodb javascript orm
Last synced: 1 day ago
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DynamoDB data mapper for node.js. Originally forked from https://github.com/ryanfitz/vogels
- Host: GitHub
- URL: https://github.com/clarkie/dynogels
- Owner: clarkie
- License: other
- Created: 2016-06-26T11:01:56.000Z (over 8 years ago)
- Default Branch: master
- Last Pushed: 2023-04-14T07:37:02.000Z (almost 2 years ago)
- Last Synced: 2024-10-29T20:55:57.549Z (3 months ago)
- Topics: aws, dynamodb, javascript, orm
- Language: JavaScript
- Homepage:
- Size: 623 KB
- Stars: 490
- Watchers: 14
- Forks: 110
- Open Issues: 51
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# dynogels
[](https://travis-ci.org/clarkie/dynogels)
[](https://coveralls.io/github/clarkie/dynogels)
[](http://badge.fury.io/js/dynogels)
[](https://david-dm.org/clarkie/dynogels)
[](https://david-dm.org/clarkie/dynogels#info=devDependencies)
[](https://snyk.io/test/npm/dynogels)
Dynogels is a [DynamoDB][5] data mapper for [node.js][1]. This project has been forked from
[Vogels](https://github.com/ryanfitz/vogels) and republished to npm under a different name.
## Features
* Simplified data modeling and mapping to DynamoDB types
* Advanced chainable apis for [query](#query) and [scan](#scan) operations
* [Data validation](#data-validation)
* [Autogenerating UUIDs](#uuid)
* [Global Secondary Indexes](#global-indexes)
* [Local Secondary Indexes](#local-secondary-indexes)
* [Parallel Scans](#parallel-scan)
## Installation
npm install dynogels
## Getting Started
First, you need to configure the [AWS SDK][2] with your credentials.
```js
var dynogels = require('dynogels');
dynogels.AWS.config.loadFromPath('credentials.json');
```
When running on EC2 it's recommended to leverage EC2 IAM roles. If you have configured your instance to use IAM roles,
Vogels will automatically select these credentials for use in your application,
and you do not need to manually provide credentials in any other format.
```js
var dynogels = require('dynogels');
dynogels.AWS.config.update({region: "REGION"}); // region must be set
```
You can also directly pass in your access key id, secret and region.
* It's recommended not to hard-code credentials inside an application.
Use this method only for small personal scripts or for testing purposes.
```js
var dynogels = require('dynogels');
dynogels.AWS.config.update({accessKeyId: 'AKID', secretAccessKey: 'SECRET', region: "REGION"});
```
Currently the following region codes are available in Amazon:
| Code | Name |
| -------------- | ------------------------ |
| ap-northeast-1 | Asia Pacific (Tokyo) |
| ap-southeast-1 | Asia Pacific (Singapore) |
| ap-southeast-2 | Asia Pacific (Sydney) |
| eu-central-1 | EU (Frankfurt) |
| eu-west-1 | EU (Ireland) |
| sa-east-1 | South America (Sao Paulo)|
| us-east-1 | US East (N. Virginia) |
| us-west-1 | US West (N. California) |
| us-west-2 | US West (Oregon) |
### Define a Model
Models are defined through the toplevel define method.
```js
var Account = dynogels.define('Account', {
hashKey : 'email',
// add the timestamp attributes (updatedAt, createdAt)
timestamps : true,
schema : {
email : Joi.string().email(),
name : Joi.string(),
age : Joi.number(),
roles : dynogels.types.stringSet(),
settings : {
nickname : Joi.string(),
acceptedTerms : Joi.boolean().default(false)
}
}
});
```
Models can also be defined with hash and range keys.
```js
var BlogPost = dynogels.define('BlogPost', {
hashKey : 'email',
rangeKey : ‘title’,
schema : {
email : Joi.string().email(),
title : Joi.string(),
content : Joi.binary(),
tags : dynogels.types.stringSet(),
}
});
```
You can pass through validation options to Joi like so:
```js
var BlogPost = dynogels.define('BlogPost', {
hashKey : 'email',
rangeKey : 'title',
schema : {
email : Joi.string().email(),
title : Joi.string()
},
validation: {
// allow properties not defined in the schema
allowUnknown: true
}
});
```
### Create Tables for all defined models
```js
dynogels.createTables(function(err) {
if (err) {
console.log('Error creating tables: ', err);
} else {
console.log('Tables have been created');
}
});
```
When creating tables you can pass specific throughput settings or stream specification for any defined models.
```js
dynogels.createTables({
'BlogPost': {readCapacity: 5, writeCapacity: 10},
'Account': {
readCapacity: 20,
writeCapacity: 4,
streamSpecification: {
streamEnabled: true,
streamViewType: 'NEW_IMAGE'
}
}
}, function(err) {
if (err) {
console.log('Error creating tables: ', err);
} else {
console.log('Tables has been created');
}
});
```
You can also pass operational options using the `$dynogels` key:
* `pollingInterval`: When creating a table, Dynogels must poll the DynamoDB server to detect when table creation has completed. This option specifies the *minimum* poll interval, in milliseconds. (Default: 1000)
```js
dynogels.createTables({
$dynogels: { pollingInterval: 100 }
}, function(err) {
if (err) {
console.log('Error creating tables: ', err);
} else {
console.log('Tables has been created');
}
});
```
### Delete Table
```js
BlogPost.deleteTable(function(err) {
if (err) {
console.log('Error deleting table: ', err);
} else {
console.log('Table has been deleted');
}
});
```
### Get Dynamo API Parameters
You can get the raw parameters needed for the DynamoDB [CreateTable API](https://docs.aws.amazon.com/amazondynamodb/latest/APIReference/API_CreateTable.html):
```js
var parameters = BlogPost.dynamoCreateTableParams();
var dynamodb = new AWS.DynamoDB();
dynamodb.createTable(params, (err)=>{ ... });
```
### Schema Types
Vogels provides the following schema types:
* String
* Number
* StringSet
* NumberSet
* Boolean
* Date
* UUID
* TimeUUID
#### UUID
UUIDs can be declared for any attributes, including hash and range keys. By
Default, the uuid will be automatically generated when attempting to create
the model in DynamoDB.
```js
var Tweet = dynogels.define('Tweet', {
hashKey : 'TweetID',
timestamps : true,
schema : {
TweetID : dynogels.types.uuid(),
content : Joi.string(),
}
});
```
#### Data Validation
Dynogels automatically validates the model against the schema before attempting to save it, but you can also call the `validate` method to validate an object before saving it. This can be helpful for a handler to validate input.
```js
var Tweet = dynogels.define('Tweet', {
hashKey : 'TweetID',
timestamps : true,
schema : {
TweetID : dynogels.types.uuid(),
content : Joi.string(),
}
});
const tweet = new Tweet({ content: 123 })
const fail_result = Tweet.validate(tweet)
console.log(fail_result.error.name) // ValidationError
tweet.set('content', 'This is the content')
const pass_result = Tweet.validate(tweet)
console.log(pass_result.error) // null
```
### Configuration
You can configure dynogels to automatically add `createdAt` and `updatedAt` timestamp attributes when
saving and updating a model. `updatedAt` will only be set when updating a record
and will not be set on initial creation of the model.
```js
var Account = dynogels.define('Account', {
hashKey : 'email',
// add the timestamp attributes (updatedAt, createdAt)
timestamps : true,
schema : {
email : Joi.string().email(),
}
});
```
If you want dynogels to handle timestamps, but only want some of them, or want your
timestamps to be called something else, you can override each attribute individually:
```js
var Account = dynogels.define('Account', {
hashKey : 'email',
// enable timestamps support
timestamps : true,
// I don't want createdAt
createdAt: false,
// I want updatedAt to actually be called updateTimestamp
updatedAt: 'updateTimestamp'
schema : {
email : Joi.string().email(),
}
});
```
You can override the table name the model will use.
```js
var Event = dynogels.define('Event', {
hashKey : 'name',
schema : {
name : Joi.string(),
total : Joi.number()
},
tableName: 'deviceEvents'
});
```
if you set the tableName to a function, dynogels will use the result of the function as the active table to use.
Useful for storing time series data.
```js
var Event = dynogels.define('Event', {
hashKey : 'name',
schema : {
name : Joi.string(),
total : Joi.number()
},
// store monthly event data
tableName: function () {
var d = new Date();
return ['events', d.getFullYear(), d.getMonth() + 1].join('_');
}
});
```
After you've defined your model you can configure the table name to use.
By default, the table name used will be the lowercased and pluralized version
of the name you provided when defining the model.
```js
Account.config({tableName: 'AccountsTable'});
```
You can also pass in a custom instance of the aws-sdk DynamoDB client
```js
var dynamodb = new AWS.DynamoDB();
Account.config({dynamodb: dynamodb});
// or globally use custom DynamoDB instance
// all defined models will now use this driver
dynogels.dynamoDriver(dynamodb);
```
### Saving Models to DynamoDB
With your models defined, we can start saving them to DynamoDB.
```js
Account.create({email: '[email protected]', name: 'Foo Bar', age: 21}, function (err, acc) {
console.log('created account in DynamoDB', acc.get('email'));
});
```
You can also first instantiate a model and then save it.
```js
var acc = new Account({email: '[email protected]', name: 'Test Example'});
acc.save(function (err) {
console.log('created account in DynamoDB', acc.get('email'));
});
```
Saving models that require range and hashkeys are identical to ones with only
hashkeys.
```js
BlogPost.create({
email: '[email protected]',
title: 'Expanding the Cloud',
content: 'Today, we are excited to announce the limited preview...'
}, function (err, post) {
console.log('created blog post', post.get('title'));
});
```
Pass an array of items and they will be saved in parallel to DynamoDB.
```js
var item1 = {email: '[email protected]', name: 'Foo 1', age: 10};
var item2 = {email: '[email protected]', name: 'Foo 2', age: 20};
var item3 = {email: '[email protected]', name: 'Foo 3', age: 30};
Account.create([item1, item2, item3], function (err, acccounts) {
console.log('created 3 accounts in DynamoDB', accounts);
});
```
Use expressions api to do conditional writes
```js
var params = {};
params.ConditionExpression = '#i <> :x';
params.ExpressionAttributeNames = {'#i' : 'id'};
params.ExpressionAttributeValues = {':x' : 123};
User.create({id : 123, name : 'Kurt Warner' }, params, function (error, acc) { ... });
```
Use the `overwrite` option to prevent over writing of existing records.
* By default `overwrite` is set to true, allowing create operations to overwrite existing records
```js
// setting overwrite to false will generate
// the same Condition Expression as in the previous example
User.create({id : 123, name : 'Kurt Warner' }, {overwrite : false}, function (error, acc) { ... });
```
### Updating
When updating a model the hash and range key attributes must be given, all
other attributes are optional
```js
// update the name of the [email protected] account
Account.update({email: '[email protected]', name: 'Bar Tester'}, function (err, acc) {
console.log('update account', acc.get('name'));
});
```
`Model.update` accepts options to pass to DynamoDB when making the updateItem request
```js
Account.update({email: '[email protected]', name: 'Bar Tester'}, {ReturnValues: 'ALL_OLD'}, function (err, acc) {
console.log('update account', acc.get('name')); // prints the old account name
});
// Only update the account if the current age of the account is 22
Account.update({email: '[email protected]', name: 'Bar Tester'}, {expected: {age: 22}}, function (err, acc) {
console.log('update account', acc.get('name'));
});
// setting an attribute to null will delete the attribute from DynamoDB
Account.update({email: '[email protected]', age: null}, function (err, acc) {
console.log('update account', acc.get('age')); // prints null
});
```
To ensure that an item exists before updating, use the `expected` parameter to check the existence of the hash key. The hash key must exist for every DynamoDB item. This will return an error if the item does not exist.
```js
Account.update(
{ email: '[email protected]', name: 'FooBar Testers' },
{ expected: { email: { Exists: true } } },
(err, acc) => {
console.log(acc.get('name')); // FooBar Testers
}
);
Account.update(
{ email: '[email protected]', name: 'Bar Tester' },
{ expected: { email: { Exists: true } } },
(err, acc) => {
console.log(err); // Condition Expression failed: no Account with that hash key
}
);
```
This is essentially short-hand for:
```js
var params = {};
params.ConditionExpression = 'attribute_exists(#hashKey)';
params.ExpressionAttributeNames = { '#hashKey' : 'email' };
```
You can also pass what action to perform when updating a given attribute
Use $add to increment or decrement numbers and add values to sets
```js
Account.update({email : '[email protected]', age : {$add : 1}}, function (err, acc) {
console.log('incremented age by 1', acc.get('age'));
});
BlogPost.update({
email : '[email protected]',
title : 'Expanding the Cloud',
tags : {$add : 'cloud'}
}, function (err, post) {
console.log('added single tag to blog post', post.get('tags'));
});
BlogPost.update({
email : '[email protected]',
title : 'Expanding the Cloud',
tags : {$add : ['cloud', 'dynamodb']}
}, function (err, post) {
console.log('added tags to blog post', post.get('tags'));
});
```
$del will remove values from a given set
```js
BlogPost.update({
email : '[email protected]',
title : 'Expanding the Cloud',
tags : {$del : 'cloud'}
}, function (err, post) {
console.log('removed cloud tag from blog post', post.get('tags'));
});
BlogPost.update({
email : '[email protected]',
title : 'Expanding the Cloud',
tags : {$del : ['aws', 'node']}
}, function (err, post) {
console.log('removed multiple tags', post.get('tags'));
});
```
Use the expressions api to update nested documents
```js
var params = {};
params.UpdateExpression = 'SET #year = #year + :inc, #dir.titles = list_append(#dir.titles, :title), #act[0].firstName = :firstName ADD tags :tag';
params.ConditionExpression = '#year = :current';
params.ExpressionAttributeNames = {
'#year' : 'releaseYear',
'#dir' : 'director',
'#act' : 'actors'
};
params.ExpressionAttributeValues = {
':inc' : 1,
':current' : 2001,
':title' : ['The Man'],
':firstName' : 'Rob',
':tag' : dynogels.Set(['Sports', 'Horror'], 'S')
};
Movie.update({title : 'Movie 0', description : 'This is a description'}, params, function (err, mov) {});
```
### Deleting
You delete items in DynamoDB using the hashkey of model
If your model uses both a hash and range key, then both need to be provided
```js
Account.destroy('[email protected]', function (err) {
console.log('account deleted');
});
// Destroy model using hash and range key
BlogPost.destroy('[email protected]', 'Hello World!', function (err) {
console.log('post deleted')
});
BlogPost.destroy({email: '[email protected]', title: 'Another Post'}, function (err) {
console.log('another post deleted')
});
```
`Model.destroy` accepts options to pass to DynamoDB when making the deleteItem request
```js
Account.destroy('[email protected]', {ReturnValues: 'ALL_OLD'}, function (err, acc) {
console.log('account deleted');
console.log('deleted account name', acc.get('name'));
});
Account.destroy('[email protected]', {expected: {age: 22}}, function (err) {
console.log('account deleted if the age was 22');
});
```
Use expression apis to perform conditional deletes
```js
var params = {};
params.ConditionExpression = '#v = :x';
params.ExpressionAttributeNames = {'#v' : 'version'};
params.ExpressionAttributeValues = {':x' : '2'};
User.destroy({id : 123}, params, function (err, acc) {});
```
### Loading models from DynamoDB
The simpliest way to get an item from DynamoDB is by hashkey.
```js
Account.get('[email protected]', function (err, acc) {
console.log('got account', acc.get('email'));
});
```
Perform the same get request, but this time peform a consistent read.
```js
Account.get('[email protected]', {ConsistentRead: true}, function (err, acc) {
console.log('got account', acc.get('email'));
});
```
`Model.get` accepts any options that DynamoDB getItem request supports. For
example:
```js
Account.get('[email protected]', {ConsistentRead: true, AttributesToGet : ['name','age']}, function (err, acc) {
console.log('got account', acc.get('email'))
console.log(acc.get('name'));
console.log(acc.get('age'));
console.log(acc.get('email')); // prints null
});
```
Get a model using hash and range key.
```js
// load up blog post written by Werner, titled DynamoDB Keeps Getting Better and cheaper
BlogPost.get('[email protected]', 'dynamodb-keeps-getting-better-and-cheaper', function (err, post) {
console.log('loaded post by range and hash key', post.get('content'));
});
```
`Model.get` also supports passing an object which contains hash and range key
attributes to load up a model
```js
BlogPost.get({email: '[email protected]', title: 'Expanding the Cloud'}, function (err, post) {
console.log('loded post', post.get('content'));
});
```
Use expressions api to select which attributes you want returned
```js
User.get({ id : '123456789'},{ ProjectionExpression : 'email, age, settings.nickname' }, function (err, acc) {});
```
### Query
For models that use hash and range keys Vogels provides a flexible and
chainable query api
```js
// query for blog posts by [email protected]
BlogPost
.query('[email protected]')
.exec(callback);
// same as above, but load all results
BlogPost
.query('[email protected]')
.loadAll()
.exec(callback);
// only load the first 5 posts by werner
BlogPost
.query('[email protected]')
.limit(5)
.exec(callback);
// query for posts by werner where the tile begins with 'Expanding'
BlogPost
.query('[email protected]')
.where('title').beginsWith('Expanding')
.exec(callback);
// return only the count of documents that begin with the title Expanding
BlogPost
.query('[email protected]')
.where('title').beginsWith('Expanding')
.select('COUNT')
.exec(callback);
// query the first 10 posts by [email protected] but only return
// the title and content from posts where the title starts with 'Expanding'
// WARNING: See notes below on the implementation of limit in DynamoDB
BlogPost
.query('[email protected]')
.where('title').beginsWith('Expanding')
.attributes(['title', 'content'])
.limit(10)
.exec(callback);
// sorting by title ascending
BlogPost
.query('[email protected]')
.ascending()
.exec(callback)
// sorting by title descending
BlogPost
.query('[email protected]')
.descending()
.exec(callback)
// All query options are chainable
BlogPost
.query('[email protected]')
.where('title').gt('Expanding')
.attributes(['title', 'content'])
.limit(10)
.ascending()
.loadAll()
.exec(callback);
// Traversing Map Data Types
Account
.query('[email protected]')
.filter('settings.acceptedTerms').equals(true)
.exec(callback);
```
**Warning, limit is applied first before the where filter. The limit value limits the scanned count,
not the number of returned items. See #12**
Vogels supports all the possible KeyConditions that DynamoDB currently
supports.
```js
BlogPost
.query('[email protected]')
.where('title').equals('Expanding')
.exec();
// less than equals
BlogPost
.query('[email protected]')
.where('title').lte('Expanding')
.exec();
// less than
BlogPost
.query('[email protected]')
.where('title').lt('Expanding')
.exec();
// greater than
BlogPost
.query('[email protected]')
.where('title').gt('Expanding')
.exec();
// greater than equals
BlogPost
.query('[email protected]')
.where('title').gte('Expanding')
.exec();
// attribute doesn't exist
BlogPost
.query('[email protected]')
.where('title').null()
.exec();
// attribute exists
BlogPost
.query('[email protected]')
.where('title').exists()
.exec();
BlogPost
.query('[email protected]')
.where('title').beginsWith('Expanding')
.exec();
BlogPost
.query('[email protected]')
.where('title').between('[email protected]', '[email protected]')
.exec();
```
Query Filters allow you to further filter results on non-key attributes.
```js
BlogPost
.query('[email protected]')
.where('title').equals('Expanding')
.filter('tags').contains('cloud')
.exec();
```
Expression Filters also allow you to further filter results on non-key attributes.
```javascript
BlogPost
.query('[email protected]')
.filterExpression('#title < :t')
.expressionAttributeValues({ ':t' : 'Expanding' })
.expressionAttributeNames({ '#title' : 'title'})
.projectionExpression('#title, tag')
.exec();
```
See the queryFilter.js [example][0] for more examples of using query filters
#### Global Indexes
First, define a model with a global secondary index.
```js
var GameScore = dynogels.define('GameScore', {
hashKey : 'userId',
rangeKey : 'gameTitle',
schema : {
userId : Joi.string(),
gameTitle : Joi.string(),
topScore : Joi.number(),
topScoreDateTime : Joi.date(),
wins : Joi.number(),
losses : Joi.number()
},
indexes : [{
hashKey : 'gameTitle', rangeKey : 'topScore', name : 'GameTitleIndex', type : 'global'
}]
});
```
Now we can query against the global index
```js
GameScore
.query('Galaxy Invaders')
.usingIndex('GameTitleIndex')
.descending()
.exec(callback);
```
When can also configure the attributes projected into the index.
By default all attributes will be projected when no Projection pramater is
present
```js
var GameScore = dynogels.define('GameScore', {
hashKey : 'userId',
rangeKey : 'gameTitle',
schema : {
userId : Joi.string(),
gameTitle : Joi.string(),
topScore : Joi.number(),
topScoreDateTime : Joi.date(),
wins : Joi.number(),
losses : Joi.number()
},
indexes : [{
hashKey : 'gameTitle',
rangeKey : 'topScore',
name : 'GameTitleIndex',
type : 'global',
projection: { NonKeyAttributes: [ 'wins' ], ProjectionType: 'INCLUDE' } //optional, defaults to ALL
}]
});
```
Filter items against the configured rangekey for the global index.
```js
GameScore
.query('Galaxy Invaders')
.usingIndex('GameTitleIndex')
.where('topScore').gt(1000)
.descending()
.exec(function (err, data) {
console.log(_.map(data.Items, JSON.stringify));
});
```
#### Local Secondary Indexes
First, define a model using a local secondary index
```js
var BlogPost = dynogels.define('Account', {
hashKey : 'email',
rangeKey : 'title',
schema : {
email : Joi.string().email(),
title : Joi.string(),
content : Joi.binary(),
PublishedDateTime : Joi.date()
},
indexes : [{
hashKey : 'email', rangeKey : 'PublishedDateTime', type : 'local', name : 'PublishedIndex'
}]
});
```
Now we can query for blog posts using the secondary index
```js
BlogPost
.query('[email protected]')
.usingIndex('PublishedIndex')
.descending()
.exec(callback);
```
Could also query for published posts, but this time return oldest first
```js
BlogPost
.query('[email protected]')
.usingIndex('PublishedIndex')
.ascending()
.exec(callback);
```
Finally lets load all published posts sorted by publish date
```js
BlogPost
.query('[email protected]')
.usingIndex('PublishedIndex')
.descending()
.loadAll()
.exec(callback);
```
Learn more about [secondary indexes][3]
### Scan
Vogels provides a flexible and chainable api for scanning over all your items
This api is very similar to the query api.
```js
// scan all accounts, returning the first page or results
Account.scan().exec(callback);
// scan all accounts, this time loading all results
// note this will potentially make several calls to DynamoDB
// in order to load all results
Account
.scan()
.loadAll()
.exec(callback);
// Load 20 accounts
Account
.scan()
.limit(20)
.exec();
// Load All accounts, 20 at a time per request
Account
.scan()
.limit(20)
.loadAll()
.exec();
// Load accounts which match a filter
// only return email and created attributes
// and return back the consumed capacity the request took
Account
.scan()
.where('email').gte('[email protected]')
.attributes(['email','created'])
.returnConsumedCapacity()
.exec();
// Load All accounts, if settings.acceptedTerms is true
Account
.scan()
.where('settings.acceptedTerms').equals(true)
.exec();
// Returns number of matching accounts, rather than the matching accounts themselves
Account
.scan()
.where('age').gte(21)
.select('COUNT')
.exec();
// Start scan using start key
Account
.scan()
.where('age').notNull()
.startKey('[email protected]')
.exec()
```
Vogels supports all the possible Scan Filters that DynamoDB currently supports.
```js
// equals
Account
.scan()
.where('name').equals('Werner')
.exec();
// not equals
Account
.scan()
.where('name').ne('Werner')
.exec();
// less than equals
Account
.scan()
.where('name').lte('Werner')
.exec();
// less than
Account
.scan()
.where('name').lt('Werner')
.exec();
// greater than equals
Account
.scan()
.where('name').gte('Werner')
.exec();
// greater than
Account
.scan()
.where('name').gt('Werner')
.exec();
// name attribute doesn't exist
Account
.scan()
.where('name').null()
.exec();
// name attribute exists
Account
.scan()
.where('name').notNull()
.exec();
// contains
Account
.scan()
.where('name').contains('ner')
.exec();
// not contains
Account
.scan()
.where('name').notContains('ner')
.exec();
// in
Account
.scan()
.where('name').in(['[email protected]', '[email protected]'])
.exec();
// begins with
Account
.scan()
.where('name').beginsWith('Werner')
.exec();
// between
Account
.scan()
.where('name').between('Bar', 'Foo')
.exec();
// multiple filters
Account
.scan()
.where('name').equals('Werner')
.where('age').notNull()
.exec();
```
You can also use the new expressions api when filtering scans
```javascript
User.scan()
.filterExpression('#age BETWEEN :low AND :high AND begins_with(#email, :e)')
.expressionAttributeValues({ ':low' : 18, ':high' : 22, ':e' : 'test1'})
.expressionAttributeNames({ '#age' : 'age', '#email' : 'email'})
.projectionExpression('#age, #email')
.exec();
```
### Parallel Scan
Parallel scans increase the throughput of your table scans.
The parallel scan operation is identical to the scan api.
The only difference is you must provide the total number of segments
**Caution** you can easily consume all your provisioned throughput with this api
```js
var totalSegments = 8;
Account.parallelScan(totalSegments)
.where('age').gte(18)
.attributes('age')
.exec(callback);
// Load All accounts
Account
.parallelScan(totalSegments)
.exec()
```
More info on [Parallel Scans][4]
### Batch Get Items
`Model.getItems` allows you to load multiple models with a single request to DynamoDB.
DynamoDB limits the number of items you can get to 100 or 1MB of data for a single request.
Vogels automatically handles splitting up into multiple requests to load all
items.
```js
Account.getItems(['[email protected]','[email protected]', '[email protected]'], function (err, accounts) {
console.log('loaded ' + accounts.length + ' accounts'); // prints loaded 3 accounts
});
// For models with range keys you must pass in objects of hash and range key attributes
var postKey1 = {email : '[email protected]', title : 'Hello World!'};
var postKey2 = {email : '[email protected]', title : 'Another Post'};
BlogPost.getItems([postKey1, postKey2], function (err, posts) {
console.log('loaded posts');
});
```
`Model.getItems` accepts options which will be passed to DynamoDB when making the batchGetItem request
```js
// Get both accounts, using a consistent read
Account.getItems(['[email protected]','[email protected]'], {ConsistentRead: true}, function (err, accounts) {
console.log('loaded ' + accounts.length + ' accounts'); // prints loaded 2 accounts
});
```
### Streaming api
dynogels supports a basic streaming api in addition to the callback
api for `query`, `scan`, and `parallelScan` operations.
```js
var stream = Account.parallelScan(4).exec();
stream.on('readable', function () {
console.log('single parallel scan response', stream.read());
});
stream.on('end', function () {
console.log('Parallel scan of accounts finished');
});
var querystream = BlogPost.query('[email protected]').loadAll().exec();
querystream.on('readable', function () {
console.log('single query response', stream.read());
});
querystream.on('end', function () {
console.log('query for blog posts finished');
});
```
### Dynamic Table Names
dynogels supports dynamic table names, useful for storing time series data.
```js
var Event = dynogels.define('Event', {
hashKey : 'name',
schema : {
name : Joi.string(),
total : Joi.number()
},
// store monthly event data
tableName: function () {
var d = new Date();
return ['events', d.getFullYear(), d.getMonth() + 1].join('_');
}
});
```
### Logging
A [Bunyan](https://www.npmjs.com/package/bunyan) logger instance can be provided to either dynogels itself or individual models. Dynogels requests are logged at the `info` level.
Other loggers that implement `info` and `warn` methods can also be used. However, [Winston](https://www.npmjs.com/package/winston) uses a different parameter signature than bunyan so the log messages are improperly formatted when using Winston.
```js
const bunyan = require('bunyan');
const logger = bunyan.createLogger(
{
name: 'globalLogger',
level:'info'
})
dynogels.log = logger;
```
```js
const bunyan = require('bunyan');
const accountLogger = bunyan.createLogger(
{
name: 'modelLogger',
level:'info'
})
var Account = dynogels.define('Account', {
hashKey: 'email',
log: accountLogger
}); // INFO level on account table
```
* [Bunyan log levels](https://github.com/trentm/node-bunyan#levels)
## Examples
```js
var dynogels = require('dynogels');
var Account = dynogels.define('Account', {
hashKey : 'email',
// add the timestamp attributes (updatedAt, createdAt)
timestamps : true,
schema : {
email : Joi.string().email(),
name : Joi.string().required(),
age : Joi.number(),
}
});
Account.create({email: '[email protected]', name : 'Test Account'}, function (err, acc) {
console.log('created account at', acc.get('created')); // prints created Date
acc.set({age: 22});
acc.update(function (err) {
console.log('updated account age');
});
});
```
See the [examples][0] for more working sample code.
### Support
Dynogels is provided as-is, free of charge. For support, you have a few choices:
- Ask your support question on [Stackoverflow.com](http://stackoverflow.com), and tag your question with **dynogels**.
- If you believe you have found a bug in dynogels, please submit a support ticket on
the [Github Issues page for dynogels](http://github.com/clarkie/dynogels/issues). We'll get to them as soon as we can.
- For general feedback message me on [twitter](https://twitter.com/clarkieclarkie)
- For more personal or immediate support, I’m available for hire to consult on your project.
[Contact](mailto:[email protected]) me for more detals.
### Maintainers
- [Clarkie](https://github.com/clarkie) ([@clarkieclarkie](https://twitter.com/clarkieclarkie))
- [Ryan Fitzgerald](http://github.com/ryanfitz) ([@ryanfitz](https://twitter.com/theryanfitz))
### License
(The MIT License)
Copyright (c) 2016 Ryan Fitzgerald
Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:
The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
[0]: https://github.com/clarkie/dynogels/tree/master/examples
[1]: http://nodejs.org
[2]: http://aws.amazon.com/sdkfornodejs
[3]: http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/LSI.html
[4]: http://aws.typepad.com/aws/2013/05/amazon-dynamodb-parallel-scans-and-other-good-news.html
[5]: http://aws.amazon.com/dynamodb