This package provides support for the RediSearch module, which adds indexing and querying support for data stored in Redis Hashes or as JSON documents with the RedisJSON module.
Should be used with redis
/@redis/client
.
For complete examples, see search-hashes.js
and search-json.js
in the examples folder.
Before we can perform any searches, we need to tell RediSearch how to index our data, and which Redis keys to find that data in. The FT.CREATE command creates a RediSearch index. Here's how to use it to create an index we'll call idx:animals
where we want to index hashes containing name
, species
and age
fields, and whose key names in Redis begin with the prefix noderedis:animals
:
await client.ft.create('idx:animals', {
name: {
type: SchemaFieldTypes.TEXT,
SORTABLE: true
},
species: SchemaFieldTypes.TAG,
age: SchemaFieldTypes.NUMERIC
}, {
ON: 'HASH',
PREFIX: 'noderedis:animals'
});
See the FT.CREATE
documentation for information about the different field types and additional options.
Once we've created an index, and added some data to Redis hashes whose keys begin with the prefix noderedis:animals
, we can start writing some search queries. RediSearch supports a rich query syntax for full-text search, faceted search, aggregation and more. Check out the FT.SEARCH
documentation and the query syntax reference for more information.
Let's write a query to find all the animals where the species
field has the value dog
:
const results = await client.ft.search('idx:animals', '@species:{dog}');
results
looks like this:
{
total: 2,
documents: [
{
id: 'noderedis:animals:4',
value: {
name: 'Fido',
species: 'dog',
age: '7'
}
},
{
id: 'noderedis:animals:3',
value: {
name: 'Rover',
species: 'dog',
age: '9'
}
}
]
}
RediSearch can also index and query JSON documents stored in Redis using the RedisJSON module. The approach is similar to that for indexing and searching data in hashes, but we can now use JSON Path like syntax and the data no longer has to be flat name/value pairs - it can contain nested objects and arrays.
As before, we create an index with the FT.CREATE
command, this time specifying we want to index JSON documents that look like this:
{
name: 'Alice',
age: 32,
coins: 100
}
Each document represents a user in some system, and users have name, age and coins properties.
One way we might choose to index these documents is as follows:
await client.ft.create('idx:users', {
'$.name': {
type: SchemaFieldTypes.TEXT,
SORTABLE: 'UNF'
},
'$.age': {
type: SchemaFieldTypes.NUMERIC,
AS: 'age'
},
'$.coins': {
type: SchemaFieldTypes.NUMERIC,
AS: 'coins'
}
}, {
ON: 'JSON',
PREFIX: 'noderedis:users'
});
Note that we're using JSON Path to specify where the fields to index are in our JSON documents, and the AS
clause to define a name/alias for each field. We'll use these when writing queries.
Now we have an index and some data stored as JSON documents in Redis (see the JSON package documentation for examples of how to store JSON), we can write some queries...
We'll use the RediSearch query language and FT.SEARCH
command. Here's a query to find users under the age of 30:
await client.ft.search('idx:users', '@age:[0 30]');