JSON (JavaScript Object Notation) is an open standard file and data interchange format. If you’ve worked with any modern web application or API, you’ve probably used JSON.
JSON is supported by most programming languages, and typically native objects and arrays are encoded as JSON (serialized), before being sent over the network or written to a file. Parsing JSON, or deserialization, is the opposite of this process.
Storing JSON in Azure Cache for Redis Enterprise let’s you work with JSON values directly, without the need for multiple operations to retrieve, update or access values within the data. When working with JSON in your cache, there’s no need to serialize and deserialize data.
The RedisJSON module provides JSON support for Redis. RedisJSON lets you store, update, and retrieve JSON values in a Redis database, similar to any other Redis data type.
Azure Cache for Redis Enterprise includes RedisJSON. Once enabled, your cache becomes a powerful, superfast in-memory JSON document store.
Completing this lab will provide you with an understanding of:
Quickstart: Create a Redis Enterprise cache
Please note: When creating your Redis Enterprise cache, in the Advanced tab, select the “RedisJson” and “RediSearch” modules. This will force you to select the “Enterprise” Clustering Policy.
Lets imagine a scenario where we are working for an online food order company. Redis and Microsoft are running a developer meetup and have decided to order in some food 🍕 and refreshments 🥤 for the guests.
Let’s consider what a typical JSON object might look like that contains the data for the order:
{
"orderNumber": 0,
"deliveryAddress": "",
"orderTotal": 0.0,
"paid": false,
"shipped": false,
"items":[
{
"sku": "",
"description": "",
"quantity": 0,
"price": 0
}
]
}
To create JSON in Redis, use the JSON.SET command. For example, to create an empty object:
JSON.SET order $ '{}'
To check the value, use JSON.GET:
JSON.GET order
Now let’s delete it:
JSON.DEL order
We could create our example JSON document above using one command, but let’s build up our object incrementally. Here we start with an empty object:
Using JSON.SET, you can choose to overwrite data or work with values using JSONPath (hence the $ - this denotes the root of the JSON object). For example, let’s start with this inital object containing a few properties:
JSON.SET order $ '{"deliveryAddress": "Microsoft UK, Thames Valley Park, Reading", "orderTotal": 0.00, "paid": false}'
Note If you found ERR unknown command JSON.SET please ensure you have have Enterprise SKU.
Now let’s add some top-level keys and values:
JSON.SET order $.orderNumber 6379
JSON.SET order $.orderDateTime 1682424000000
And a placeholder for the items ordered:
JSON.SET order $.items []
Let’s check a couple of our property types:
JSON.TYPE order $.orderDateTime
JSON.TYPE order $.items
Let’s add some items to our food order:
JSON.SET order $.items '[{"sku": "pizza001", "description": "margherita", "quantity": 4, "price": 8.50},{"sku": "pizza003", "description": "funghi", "quantity": 2, "price": 11.00},{"sku": "drinks008", "description": "Camden Hells Lager", "quantity": 16, "price": 4.00}]'
We can append additional items to the collection of pizza orders as follows:
JSON.ARRAPPEND order $.items '{"sku": "pizza002", "description": "prosciutto", "quantity": 2, "price": 13.00}'
We can increment individual values. Let’s say we want to increase the number of drinks. Here we will increment the existing number by eight:
JSON.NUMINCRBY order $.items[2].quantity 8
JSON.SET order $.shipped 'false'
We can toggle boolean values:
JSON.TOGGLE order $.shipped
As you can see from these examples, working with JSON via the Redis CLI is efficient and intuitive once you are familiar with commands and syntax.
There are many client libraries available for different programming languages.
For .NET developers:
In the example above we used the Redis CLI to execute RedisJSON commands. To see how we can leverage RedisJSON in applications, there are two examples provided in Github.
To get started, clone the following repository:
git clone https://github.com/Redislabs-Solution-Architects/redis-msft-labs.git
Change your directory to the following:
cd redis-json-example
Now run this command:
dotnet run
This is a simple console application to demonstrate how a JSON document can be created using .NET. In the example the NRedisStack package has been added to the project.
Notice how the methods map to Redis CLI commands that were used earlier in the lab.
The second example is a simple web API. It’s based on the example ‘Todo API’ from Microsoft but uses Redis and RedisJSON for persistence:
cd redis-api-example
This example shows how typical CRUD operations used by web services can be achieved using Redis OM.
Redis OM provides high-level abstractions for using Redis in .NET, making it easy to model and query your Redis domain objects.
To start the web service:
dotnet run
Now, navigate to
https://localhost:7127/swagger/index.html