The RedisDocument mixin for Modinha defines a collection of persistence methods that map cleanly between HTTP semantics and Redis data structures.
Suppose we've defined an Account model with Modinha like so:
var Modinha = require('modinha')
, RedisDocument = require('modinha-redis').RedisDocument
var Account = Modinha.define('accounts', {
email: { type: 'string', required: true, unique: true },
role: { type: 'string', secondary: true, enum: ['admin', 'editor', 'author'] },
hash: { type: 'string', private: true }
});
Account.extend(RedisDocument);
RedisDocument will add the following persistence methods to the Account document.
HTTP MODEL METHOD
GET /accounts Account.list(options, callback)
GET /accounts/id Account.get(ids, options, callback)
POST /accounts Account.insert(data, options, callback)
PUT /accounts/id Account.replace(id, data, options, callback)
PATCH /accounts/id Account.patch(id, data, options, callback)
DELETE /accounts/id Account.delete(id, callback)
Extending Account with RedisDocument will also define the following properties on Account.schema:
_id: { type: 'string', required: true, default: Model.defaults.uuid },
created: { type: 'number', order: true, default: Model.defaults.timestamp },
modified: { type: 'number', order: true, default: Model.defaults.timestamp }
Since we defined unique
and secondary
properties on email and role, respectively, the mixin will also generate property specific methods for those indexes.
Account.getByEmail(email, callback)
Account.listByRole(role, callback)
We can index in a variety of ways with Redis hashes and sorted sets. For example, we could explicitly define our unique email index like so:
Account.defineIndex({
type: 'hash',
key: 'accounts:email',
field: 'email',
value: '_id'
});
This tells the model to store an account's _id
property in a hash named accounts:email
with email as the field name. Because this is a very common use of the hash type index, the mixin also provides a helper method for defining unique indices:
Account.indexUnique('email');
This is equivalent to adding unique: true
to the property definition in our schema.
Sorted set indices get a little more interesting. We have a great deal of flexibility in how we can index our models. For example, suppose we have a Video
model that has a category
property and a likes
property. We want to retrieve a list of videos for a specific category, sorted by the number of likes.
Video.defineIndex({
type: 'sorted',
key: ['videos:#:$', 'category', 'category'],
score: 'likes',
member: '_id'
});
When we index the following instance...
{
_id: 'r4nd0m',
name: 'Awesome Presentation',
url: 'https://youtube.com/wh4t3v3r'
category: 'conferences',
likes: 777
}
... the object's _id
will be added to a sorted set in Redis called videos:category:conferences
, with a score of 777. Notice the key
property of the index definition: ['videos:#:$', 'category', 'category']
. The first element of this array is a template for a key name. In the template, the placeholders #
and $
will be replaced in order according to the remaining elements of the array. #
will be replaced literally with element and $
will be used to access a property on the object being indexed.
Like the hash-type index, there are a few very common indexing patterns for sorted sets. The mixin provides higher level methods for defining these, and in some cases, they can be created as part of a schema definition. Some examples:
Model.indexSecondary(propertyName, [score]);
Video.indexSecondary('category', 'likes'); // Same as previous example
Model.indexReference(propertyName, ReferencedModel, [score]);
Comment.indexReference('videoId', Video); // multi.zadd('videos:ID:comments', comment.created, comment._id);
Model.indexOrder(propertyName);
Comment.indexOrder('likes');
// video schema
{
name: { type: 'string', unique: true },
url: { type: 'string', unique: true },
category: { type: 'string', enum: ['tutorial', 'presentation'], secondary: true },
likes: { type: 'string', order: true }
}
Unique values are enforced by the insert
, replace
, and patch
methods. If you write custom methods, you can use Account.enforceUnique(callback)
(for example) to generate a UniqueValueError.
The default timestamp methods define an ordered index for created and modified. Account.list(options, callback)
uses the accounts:created
index by default to deliver reverse chronological account listings.
Copyright (c) 2015 Anvil Research, Inc. http://anvil.io
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