lambdaauthorizer

index.js

exports.handler = (event, context, callback) => {
    
    console.log('Received event:', JSON.stringify(event, null, 2));
    
    
    var headers = event.headers;
    console.log('headers: ', JSON.stringify(headers));
   
    // Parse the input for the parameter values
    var tmp = event.routeArn.split(':');
    console.log('tmp: ', JSON.stringify(tmp));
    var apiGatewayArnTmp = tmp[5].split('/');
    console.log('apiGatewayArnTmp: ', JSON.stringify(apiGatewayArnTmp));
    var awsAccountId = tmp[4];
    console.log('awsAccountId: ', JSON.stringify(awsAccountId));
    var region = tmp[3];
    console.log('region: ', JSON.stringify(region));
    var restApiId = apiGatewayArnTmp[0];
    console.log('restApiId: ', JSON.stringify(restApiId));
    var stage = apiGatewayArnTmp[1];
    console.log('stage: ', JSON.stringify(stage));
    var method = apiGatewayArnTmp[2];
    console.log('method: ', JSON.stringify(method));
    var resource = '/'; // root resource
    console.log('resource: ', JSON.stringify(resource));
    if (apiGatewayArnTmp[3]) {
        resource += apiGatewayArnTmp[3];
    }
    
    console.log('resource 2 : ', JSON.stringify(resource));    
    // Perform authorization to return the Allow policy for correct parameters and 
    // the 'Unauthorized' error, otherwise.
    //var authResponse = {};
    //var condition = {};
    //condition.IpAddress = {};
    
    const readJSONFileFromS3 = require('s3-service');
 
    const params = {
        Bucket: 'azureupload',
        Key: 'applications.json',
    };
    const apikey = headers['x-header-apikey']
    const appid = headers['x-header-appid'];
    console.log("apikey :" + apikey)
    
     
    if (apikey || appid ) {
        const applications =  readJSONFileFromS3.handler(params)
        //console.log("applications123 :" + applications.then(result=>{console.log(JSON.parse(result.Body)['x-header-apikey'])}))
        applications.then(result=>{
		  if (headers['x-header-apikey'] === JSON.parse(result.Body)['x-header-apikey'] && headers['x-header-appid'] === JSON.parse(result.Body)['x-header-appid']) {
             callback(null, generateAllow('me', event.routeArn));
          }  
		  else {
               callback("Unauthorized");
          }
          })
        
    }
}




// Help 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) {
    console.log(generatePolicy(principalId, 'Allow', resource))
    return generatePolicy(principalId, 'Allow', resource);
}
     
var generateDeny = function(principalId, resource) {
    return generatePolicy(principalId, 'Deny', resource);
}