Use the Dapr API

In this guide, you’ll simulate an application by running the sidecar and calling the state management API directly. After running Dapr using the Dapr CLI, you’ll:

• Save a state object.
• Read/get the state object.
• Delete the state object.

Learn more about the state building block and how it works in our concept docs.

Pre-requisites

• Install Dapr CLI.
• Run dapr init.

Step 1: Run the Dapr sidecar

The dapr run command normally runs your application and a Dapr sidecar. In this case, it only runs the sidecar since you are interacting with the state management API directly.

Launch a Dapr sidecar that will listen on port 3500 for a blank application named myapp:

dapr run --app-id myapp --dapr-http-port 3500

Since no custom component folder was defined with the above command, Dapr uses the default component definitions created during the dapr init flow.

Step 2: Save state

Update the state with an object. The new state will look like this:

[
  {
    "key": "name",
    "value": "Bruce Wayne"
  }
]

Notice, that objects contained in the state each have a key assigned with the value name. You will use the key in the next step.

Save a new state object using the following command:

• HTTP API (Bash)
• HTTP API (PowerShell)

curl -X POST -H "Content-Type: application/json" -d '[{ "key": "name", "value": "Bruce Wayne"}]' http://localhost:3500/v1.0/state/statestore

Invoke-RestMethod -Method Post -ContentType 'application/json' -Body '[{ "key": "name", "value": "Bruce Wayne"}]' -Uri 'http://localhost:3500/v1.0/state/statestore'

Step 3: Get state

Retrieve the object you just stored in the state by using the state management API with the key name. In the same terminal window, run the following command:

• HTTP API (Bash)
• HTTP API (PowerShell)

curl http://localhost:3500/v1.0/state/statestore/name 

Invoke-RestMethod -Uri 'http://localhost:3500/v1.0/state/statestore/name'

Step 4: See how the state is stored in Redis

Look in the Redis container and verify Dapr is using it as a state store. Use the Redis CLI with the following command:

docker exec -it dapr_redis redis-cli

List the Redis keys to see how Dapr created a key value pair with the app-id you provided to dapr run as the key’s prefix:

keys *

Output:
1) "myapp||name"

View the state values by running:

hgetall "myapp||name"

Output:
1) "data"
2) "\"Bruce Wayne\""
3) "version"
4) "1"

Exit the Redis CLI with:

exit

Step 5: Delete state

In the same terminal window, delete thename state object from the state store.

• HTTP API (Bash)
• HTTP API (PowerShell)

curl -v -X DELETE -H "Content-Type: application/json" http://localhost:3500/v1.0/state/statestore/name

Invoke-RestMethod -Method Delete -ContentType 'application/json' -Uri 'http://localhost:3500/v1.0/state/statestore/name'