Invoke REST API endpoints within workflows using Azure Logic Apps

Steps to Call a REST API Endpoint Using HTTP Request and Response

1. Add a Trigger:
   • Start your Logic App with a trigger. For example:
     • Use the HTTP Request trigger if you want to trigger the workflow via an external HTTP request.
     • Use a Recurrence trigger if you want to run the workflow on a schedule.
2. Add an HTTP Action:
   • In the Logic App Designer, click on + New Step.
   • Search for and select the HTTP action.
3. Configure the HTTP Action:
   • Method: Choose the HTTP method (e.g., GET, POST, PUT, DELETE).
   • URI: Enter the REST API endpoint URL.
   • Headers: Add any required headers (e.g., Content-Type, Authorization).
   • Body: If the method requires a body (e.g., POST or PUT), provide the JSON payload.
4. Handle the Response:
   • Use the output of the HTTP action to process the response (e.g., parse JSON, store data, or send a response back).
5. Return a Response (Optional):
   • If your workflow is triggered by an HTTP request, you can use the Response action to send a response back to the caller.

Example: Call a REST API and Return the Response

Scenario:

You want to create a Logic App that:

1. Accepts an HTTP request with a city name.
2. Calls a weather API to get the current weather for that city.
3. Returns the weather data as an HTTP response.

Steps in Logic App Designer

1. Trigger: When an HTTP request is received
   • This trigger allows the Logic App to be invoked via an HTTP POST request.
   • Add a sample JSON schema to define the expected input:
     

     {
       "type": "object",
       "properties": {
         "city": {
           "type": "string"
         }
       }
     }

2. Action: HTTP
   • Add an HTTP action to call the weather API.
     • Method: GET
     • URI: https://api.weatherapi.com/v1/current.json?key=YOUR_API_KEY&q=@{triggerBody()?['city']}
       • Use dynamic content @{triggerBody()?['city']} to pass the city name from the trigger.
     • Headers: None (unless the API requires authentication).
3. Action: Response
   • Add a Response action to return the weather data to the caller.
     • Status Code: 200
     • Headers:
       • Content-Type: application/json
     • Body: Use the Body output from the HTTP action to return the weather API response.