Function Compute:Use an HTTP trigger to invoke a function

Format

Function Compute maps the incoming HTTP request to an event object with the following structure:

{
    "version": "v1",
    "rawPath": "/example",
    "body": "Hello FC!",
    "isBase64Encoded": false,
    "headers": {
        "header1": "value1",
        "header2": "value1,value2"
    },
    "queryParameters": {
        "parameter1": "value1",
        "parameter2": "value1,value2"
    },
    "requestContext": {
        "accountId": "123456*********",
        "domainName": "<http-trigger-id>.<region-id>.fcapp.run",
        "domainPrefix": "<http-trigger-id>",
        "http": {
            "method": "GET",
            "path": "/example",
            "protocol": "HTTP/1.1",
            "sourceIp": "11.11.11.**",
            "userAgent": "PostmanRuntime/7.32.3"
        },
        "requestId": "1-64f6cd87-*************",
        "time": "2023-09-05T06:41:11Z",
        "timeEpoch": "1693896071895"
    }
}

Parameters

Mapping logic

Function Compute maps the HTTP request to the event object as follows:

• HTTP request headers → event.headers

• HTTP query parameters → event.queryParameters

• Request context (request ID, timestamp, caller identity) → event.requestContext

• POST request body → event.body

Base64 encoding

Function Compute checks the Content-Type header to decide whether to Base64-encode the request body.

Request mapping examples

curl -v "https://example.cn-hangzhou.fcapp.run?parameter1=value1&parameter2=value2"

curl -v -H "Content-Type: application/json" -d '{"message": "Hello"}' "https://example.cn-hangzhou.fcapp.run"

Format

Your function output is parsed into a response struct before being mapped to the HTTP response:

{
    "statusCode": 200,
    "headers": {
        "Content-Type": "application/json",
        "Custom-Header-1": "Custom Value"
    },
    "isBase64Encoded": false,
    "body": "{\"message\":\"Hello FC!\"}"
}

Mapping logic

Function Compute maps your function output to the HTTP response based on whether the output is valid JSON containing a statusCode field.

When the output is valid JSON with `statusCode`:

When the output is valid JSON without `statusCode`, or is not JSON:

Function Compute uses the following defaults:

Response mapping examples

The following examples show how function output flows through parsing to the final HTTP response.

Base64 decoding

If your function returns valid JSON with isBase64Encoded set to true, Function Compute Base64-decodes the body before mapping it to the HTTP response body. If decoding fails, Function Compute returns the body value directly without reporting an error.

Response headers

Function Compute automatically adds the X-Fc-Request-Id header to every response. This header uniquely identifies the request and is useful for tracing logs and diagnosing errors.

Error handling

HTTP trigger invocations and direct API invocations handle function errors differently.

When a function invoked via HTTP trigger encounters an error, the client receives a response like:

HTTP/1.1 502 Bad Gateway
Content-Disposition: attachment
Content-Type: application/json
X-Fc-Request-Id: 1-64f6df91-fe144d52e4fd27afe3d8dd6f
Content-Length: 21

Internal Server Error

Use the X-Fc-Request-Id value to look up the full error details in your function's invocation logs.