REST API - Post

This function block sends JSON POST requests to a HTTP server address and returns the server response. It is designed for integration with external REST APIs while keeping the user interface responsive.

📥 Inputs

Enable Condition — Logic signal to start a POST request when True.

Server Address — Text input for the full server endpoint (use full URL starting with http:// or https://).

Response Data ID — Optional key name to extract a specific field from a JSON response.

Post Data — Generic data payload that will be sent as JSON in the request body.

📤 Outputs

Status Code — HTTP status code returned by the server.

Error — Error message or reason when the request fails.

Response — Server response body or the extracted value when Response Data ID is provided.

🕹️ Controls

Timeout (s) — Number of seconds to wait before the request times out (adjust to suit slow/fast servers).

🎨 Features

• Asynchronous requests: POST operations run in the background so the interface remains responsive.

• Optional response parsing: If you provide a Response Data ID the block will attempt to return that specific field from a JSON response.

• Simple integration: Accepts a generic payload so you can send images, numbers, text or structured data prepared by other blocks.

⚙️ Running mechanism

When Enable Condition is True and a valid Server Address is provided, the block sends a POST request with the Post Data payload. The request uses the configured Timeout (s) and runs without blocking the UI. When the server responds, the block updates its outputs with Status Code, Error (if any), and Response (or the selected response field).

📝 Usage instructions

1. Provide the target endpoint in Server Address (include http:// or https://).

2. Connect or prepare the payload on the Post Data input (use other blocks to build structured data if needed).

3. Use a logic signal on Enable Condition to trigger sending (e.g., manual toggle or a conditional block).

4. Optionally set Response Data ID to extract a specific field from the server's JSON response.

5. Adjust Timeout (s) if the server is slow or to avoid long waits.

💡 Tips and Tricks

• Use Logic Input or Rising Edge to control when the request is sent (single-shot triggers or manual control).

• Prepare structured payloads with Data to JSON before feeding into Post Data for reliable JSON formatting.

• Use String Input to provide the Server Address or Number Input for numeric fields inside the payload.

• Log or persist responses with CSV Export or Image Logger (if your payload/response contains images or timestamps).

• Pair with REST API - Get when you need both POST and GET interactions with the same service (e.g., send data then poll for results).

• Include Date-Time or Date-Time List in your payload to timestamp requests.

• Use Debug Input to inspect the request payload or server response during development.

🛠️ Troubleshooting

• No response / network error: Verify that Server Address is correct, reachable from the machine, and includes the protocol (http/https). Check firewall or network settings.

• Authentication required: Ensure the target API accepts unauthenticated POSTs or add whatever authentication the service needs outside of this block (e.g., via headers managed by the server).

• Invalid JSON or unexpected response: Use Data to JSON to ensure payload is valid JSON, and check the API documentation for expected field names. If you requested a specific Response Data ID and the field is missing, the Response output may be empty.

• Timeouts: Increase Timeout (s) for slow endpoints or check server load. If requests frequently time out, test the service separately to confirm responsiveness.

• Repeated triggers: If you only want to send a single POST per event, use Rising Edge to convert a continuous True signal into a single trigger.

If you need examples of how to chain this block with data formatting, logging or trigger controls, combine it with blocks such as Data to JSON, Logic Input, Rising Edge, CSV Export, and REST API - Get for common integration patterns.