APIG Event Source¶
API Gateway (APIG) is an API hosting service that helps enterprises to build, manage, and deploy APIs at any scale. With APIG, your function can be invoked through HTTPS by using a custom REST API and a specified backend. You can map each API operation (such as, GET and PUT) to a specific function. APIG invokes the relevant function when an HTTPS request is sent to the API backend.
For more information about how to use HTTPS calls to trigger functions, see :Using an APIG (Dedicated) trigger.
Example APIG Event¶
{
"body": "eyJuYW1lIjogIk9wZW5UZWxla29tQ2xvdWQifQ==",
"requestContext": {
"apiId": "bc1dcffd-aa35-474d-897c-d53425a4c08e",
"requestId": "11cdcdcf33949dc6d722640a13091c77",
"stage": "RELEASE"
},
"queryStringParameters": {
"responseType": "html"
},
"httpMethod": "GET",
"pathParameters": {},
"headers": {
"accept-language": "q=0.5,en-US;q=0.3,en;q=0.2",
"accept-encoding": "gzip, deflate, br",
"x-forwarded-port": "443",
"x-forwarded-for": "103.218.216.98",
"accept": "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8",
"upgrade-insecure-requests": "1",
"host": "host",
"x-forwarded-proto": "https",
"pragma": "no-cache",
"cache-control": "no-cache",
"x-real-ip": "103.218.216.98",
"user-agent": "Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:57.0) Gecko/20100101 Firefox/57.0"
},
"path": "/",
"isBase64Encoded": true
}
Parameter description¶
Parameter |
Type |
Description |
|---|---|---|
body |
String |
Actual request body in string format (Base64 encoded). |
requestContext |
Map |
Request information, including the API gateway configuration, request ID, authentication information, and source. |
httpMethod |
String |
HTTP method |
queryStringParameters |
Map |
Query strings configured in APIG and their actual values |
pathParameters |
Map |
Path parameters configured in APIG and their actual values |
headers |
Map |
Complete headers |
path |
String |
Complete path |
isBase64Encoded |
Boolean |
Default value: true (see Notes below) |
Notes¶
When calling a function using APIG, isBase64Encoded is valued true by default, indicating that the request body transferred to FunctionGraph is encoded using Base64 and must be decoded for processing.
The function must return characters strings by using the following structure.
{ "isBase64Encoded": "true|false", "statusCode": "httpStatusCode", "headers": {"headerName":"headerValue"}, "body": "..." }
Example¶
const { APIGEvent, APIGResponse } = require("apig-event");
exports.initializer = function (context, callback) {
const logger = context.getLogger();
logger.info("Function initialized");
callback(null, "");
};
exports.handler = async function (event, context) {
const logger = context.getLogger();
logger.info("Function Name:", context.getFunctionName());
const apigEvent = new APIGEvent(event);
const isBase64Encoded = event.isBase64Encoded || false;
const body = apigEvent.getBody();
logger.info("APIG Event body:", body);
let responseType = "default";
if (
apigEvent.getQueryStringParameters() &&
apigEvent.getQueryStringParameters().responseType
) {
responseType = apigEvent.getQueryStringParameters().responseType;
}
let output = "";
if (responseType === "html") {
output = new APIGResponse(
200,
"",
{ "Content-Type": "text/html; charset=utf-8" },
false,
);
output.setBody(
"<html><h1>Welcome to use FunctionGraph</h1></html>",
isBase64Encoded,
);
} else if (responseType === "json") {
output = new APIGResponse(
200,
"",
{ "Content-Type": "application/json" },
false,
);
try {
const parsedBody = JSON.parse(body.replace(/\\\"/g, '"'));
output.setBody(parsedBody, isBase64Encoded);
} catch (e) {
output.setBody({ error: "Invalid JSON input" }, isBase64Encoded);
}
} else {
output = new APIGResponse(
200,
"",
{ "Content-Type": "text/html; charset=utf-8" },
false,
);
output.setBody(
"<html>Please construct the url with query parameters responseType=html, responseType=json</html>",
isBase64Encoded,
);
}
logger.info("returning:", output);
return output;
};