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