lambda-auth.js

exports.handler = function(event, context, callback) {
    console.log('Received event:', JSON.stringify(event, null, 2));

   // A simple REQUEST authorizer example to demonstrate how to use request
   // parameters to allow or deny a request. In this example, a request is
   // authorized if the client-supplied HeaderAuth1 header and QueryString1 query parameter
   // in the request context match the specified values of
   // of 'headerValue1' and 'queryValue1' respectively.

   // Retrieve request parameters from the Lambda function input:
   var headers = event.headers;
   var queryStringParameters = event.queryStringParameters;
   var stageVariables = event.stageVariables;
   var requestContext = event.requestContext;

   // Parse the input for the parameter values
   var tmp = event.methodArn.split(':');
   var apiGatewayArnTmp = tmp[5].split('/');
   var awsAccountId = tmp[4];
   var region = tmp[3];
   var ApiId = apiGatewayArnTmp[0];
   var stage = apiGatewayArnTmp[1];
   var route = apiGatewayArnTmp[2];

   // Perform authorization to return the Allow policy for correct parameters and
   // the 'Unauthorized' error, otherwise.
   var authResponse = {};
   var condition = {};
    condition.IpAddress = {};

   if (headers.headerauth1 === "headerValue1") {
        callback(null, generateAllow('me', event.methodArn));
    }  else {
        callback("Unauthorized");
    }
}

// Helper function to generate an IAM policy
var generatePolicy = function(principalId, effect, resource) {
   // Required output:
   var authResponse = {};
    authResponse.principalId = principalId;
   if (effect && resource) {
       var policyDocument = {};
        policyDocument.Version = '2012-10-17'; // default version
       policyDocument.Statement = [];
       var statementOne = {};
        statementOne.Action = 'execute-api:Invoke'; // default action
       statementOne.Effect = effect;
        statementOne.Resource = resource;
        policyDocument.Statement[0] = statementOne;
        authResponse.policyDocument = policyDocument;
    }
   // Optional output with custom properties of the String, Number or Boolean type.
   authResponse.context = {
       "stringKey": "stringval",
       "numberKey": 123,
       "booleanKey": true
    };
   return authResponse;
}

var generateAllow = function(principalId, resource) {
   return generatePolicy(principalId, 'Allow', resource);
}

var generateDeny = function(principalId, resource) {
   return generatePolicy(principalId, 'Deny', resource);
}