Guide HTTP Client

HTTP Client

ARO provides HTTP client capabilities for making requests to external services and APIs.

Making HTTP Requests

Use the Request action to make HTTP requests. The preposition determines the HTTP method:

• from - GET request
• to - POST request
• via METHOD - Explicit method (PUT, DELETE, PATCH)

GET Requests

Use from preposition to make GET requests:

(* Simple GET request *)
Create the <url> with "https://api.example.com/users".
Request the <users> from the <url>.

POST Requests

Use to preposition to make POST requests:

(* POST with data from context *)
Create the <user-data> with { name: "Alice", email: "alice@example.com" }.
Create the <api-url> with "https://api.example.com/users".
Request the <result> to the <api-url> with <user-data>.

Other HTTP Methods

Use via preposition with method specifier for PUT, DELETE, PATCH:

(* PUT request *)
Request the <result> via PUT the <url> with <update-data>.

(* DELETE request *)
Request the <result> via DELETE the <url>.

(* PATCH request *)
Request the <result> via PATCH the <url> with <partial-data>.

Response Handling

The Request action automatically parses JSON responses. After a request, these variables are available:

Variable	Description
result	Parsed response body (JSON as map/list, or string)
result.statusCode	HTTP status code (e.g., 200, 404)
result.headers	Response headers as map
result.isSuccess	Boolean: true if status 200-299

Create the <api-url> with "https://api.example.com/users".
Request the <response> from the <api-url>.

(* Access response metadata *)
Extract the <status> from the <response: statusCode>.
Extract the <is-ok> from the <response: isSuccess>.

(* Access response body - response IS the parsed body *)
Extract the <first-user> from the <response: 0>.

Complete Example

(* Fetch weather data from Open-Meteo API *)

(Application-Start: Weather Client) {
    Log "Fetching weather..." to the <console>.

    Create the <api-url> with "https://api.open-meteo.com/v1/forecast?latitude=52.52&longitude=13.41&current_weather=true".
    Request the <weather> from the <api-url>.

    Log <weather> to the <console>.

    Return an <OK: status> for the <startup>.
}

Implementation Notes

• Uses Foundation's URLSession for HTTP requests
• Compatible with both interpreter (aro run) and compiled binaries (aro build)
• Default timeout: 30 seconds
• Automatically parses JSON responses
• Thread-safe for concurrent requests
• Available on macOS and Linux (not Windows)

See Also

• I/O Services Specification - HTTP client specification
• Examples/HTTPClient - Working example