# REST API - Get This function block performs a HTTP GET request to a web server and provides the result to the rest of your system. Use it to fetch JSON or plain-text data from REST endpoints and forward the response to other blocks for parsing, logging or storage. ## đŸ“Ĩ Inputs `Enable Condition` When True the block will attempt to fetch data from the given server address. Use this to control when requests are made. `Server Address` Full URL of the server or API endpoint to query (e.g., ). `Response Data ID` Optional key or path to extract a specific value from a JSON response. Leave empty to return the whole response. ## 📤 Outputs `Status Code` HTTP status code returned by the server. `Error` Error message when the request failed or server returned an error. `Response` The body of the server response. This may be plain text or a parsed JSON value depending on the endpoint and the `Response Data ID` input. ## 🕹ī¸ Controls `Timeout (s)` Maximum time (in seconds) to wait for the server to respond before treating the request as failed. Default is 2 seconds. ## đŸŽ¯ Features * Non-blocking execution: requests are performed without freezing the user interface, so other blocks and controls stay responsive while waiting for the response. * Optional response extraction: provide a `Response Data ID` to pick a single field from a JSON response when you only need a specific value. * Error reporting: common failures (connection errors, timeouts, non-OK status codes) are surfaced through the `Error` output and the system log. * Adjustable timeout: prevents long waits from stalling your flow by tuning the `Timeout (s)` control. ## 📝 Usage Instructions 1. Provide a boolean signal to `Enable Condition` when you want the request to run. 2. Enter the endpoint URL into `Server Address`. 3. If the endpoint returns JSON and you only need a single value, set `Response Data ID` to the JSON key you want (leave empty to receive the whole response). 4. Adjust `Timeout (s)` if the server is slow or if you want quicker failure handling. 5. Read results from the `Status Code`, `Error`, and `Response` outputs and connect them to subsequent blocks for parsing, saving or alerting. ## 📊 Evaluation When enabled and provided a valid server address, the block issues a GET request and updates its outputs when a response arrives or when an error occurs. If no response is available, default outputs are provided so downstream blocks can continue operating. ## 💡 Tips and Tricks * To trigger a single request when a condition first becomes True, combine with the `Rising Edge` block to convert a sustained True signal into a single trigger. * If you need to POST data after inspecting a GET response, pair this block with the `REST API - Post` block. * Use `Parse Data Dictionary` or `Data to JSON` to extract and format structured data from the `Response` output before saving or forwarding. * To log or save repeated API responses, connect outputs to `CSV Export` or `SQL-DB Operations` for persistent storage. * Use `Debug Input` to display and inspect the raw outputs during development and troubleshooting. * To forward fetched data to message brokers or IoT systems, connect the results to `MQTT Publish`. ## 🛠ī¸ Troubleshooting * Problem: No response or timeout. * Check the URL in `Server Address` and verify network access to the server. Increase `Timeout (s)` for slow servers. * Problem: Error output contains an HTTP status or message. * Inspect `Status Code` to determine if the server reported a client or server error (4xx/5xx). Confirm the endpoint and any required authentication with the API provider. * Problem: Response is JSON but required value not found. * Verify the correct key or path is provided in `Response Data ID`. If the structure is nested, use a parsing block like `Parse Data Dictionary` to navigate the JSON. * Problem: Requests run too frequently or during undesired times. * Control the request timing with `Logic Input`, `Rising Edge`, or other flow-control blocks to ensure requests are sent only when needed. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.augelab.com/function-blocks/input-output/communication/rest-api-get.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.