How to pass API Gateway query parameters to AWS Lambda?

First - make sure that you have set up Lambda proxy integration in API Gateway. Once that's done, you can access API Gateway parameters such as queryStringParameters or pathParameters in your Lambda function by using the event object.

Here's a Node.js example:

Copy code
exports.handler = async (event) => {
  // Get the querystring and route parameters from the event
  const queryParams = event.queryStringParameters;
  const routeParams = event.pathParameters;

  // Use the querystring and route parameters in your logic
  // ...

  // Return a response
  return {
    statusCode: 200,
    body: JSON.stringify({
      // Data to return in the response
    }),
  };
};

The following example from AWS docs shows the structure of an event that API Gateway sends to a Lambda proxy integration:

{
  "resource": "/my/path",
  "path": "/my/path",
  "httpMethod": "GET",
  "headers": {
    "header1": "value1",
    "header2": "value2"
  },
  "multiValueHeaders": {
    "header1": ["value1"],
    "header2": ["value1", "value2"]
  },
  "queryStringParameters": {
    "parameter1": "value1",
    "parameter2": "value"
  },
  "multiValueQueryStringParameters": {
    "parameter1": ["value1", "value2"],
    "parameter2": ["value"]
  },
  "requestContext": {
    "accountId": "123456789012",
    "apiId": "id",
    "authorizer": {
      "claims": null,
      "scopes": null
    },
    "domainName": "id.execute-api.us-east-1.amazonaws.com",
    "domainPrefix": "id",
    "extendedRequestId": "request-id",
    "httpMethod": "GET",
    "identity": {
      "accessKey": null,
      "accountId": null,
      "caller": null,
      "cognitoAuthenticationProvider": null,
      "cognitoAuthenticationType": null,
      "cognitoIdentityId": null,
      "cognitoIdentityPoolId": null,
      "principalOrgId": null,
      "sourceIp": "IP",
      "user": null,
      "userAgent": "user-agent",
      "userArn": null,
      "clientCert": {
        "clientCertPem": "CERT_CONTENT",
        "subjectDN": "www.example.com",
        "issuerDN": "Example issuer",
        "serialNumber": "a1:a1:a1:a1:a1:a1:a1:a1:a1:a1:a1:a1:a1:a1:a1:a1",
        "validity": {
          "notBefore": "May 28 12:30:02 2019 GMT",
          "notAfter": "Aug  5 09:36:04 2021 GMT"
        }
      }
    },
    "path": "/my/path",
    "protocol": "HTTP/1.1",
    "requestId": "id=",
    "requestTime": "04/Mar/2020:19:15:17 +0000",
    "requestTimeEpoch": 1583349317135,
    "resourceId": null,
    "resourcePath": "/my/path",
    "stage": "$default"
  },
  "pathParameters": null,
  "stageVariables": null,
  "body": "Hello from Lambda!",
  "isBase64Encoded": false
}

How to pass API Gateway query parameters to AWS Lambda?

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