This is an AWS Lambda function that implements Basic authentication scheme to control access to API methods in Amazon API Gateway. It is to be configured as an API Gatewy Lambda authorizer.

BasicAuthnAuthorizer.js

exports.handler =  function(event, context, callback) {
    const username = process.env['username'];
    const password = process.env['password'];
    
    var token = event.authorizationToken;
    
    var encodedCreds = token.split(' ')[1];
    var plainCreds = (new Buffer(encodedCreds, 'base64')).toString().split(':');
    var p_username = plainCreds[0];
    var p_password = plainCreds[1];

    if (!(p_username === username && p_password === password)) {
        return callback('Unauthorized');
    }

    let authResponse = {};
    authResponse.principalId = username;
    var policyDocument = {};
    policyDocument.Version = '2012-10-17'; 
    policyDocument.Statement = [];
    var statementOne = {};
    statementOne.Action = 'execute-api:Invoke'; 
    statementOne.Effect = 'Allow';
    statementOne.Resource = event.methodArn;
    policyDocument.Statement[0] = statementOne;
    authResponse.policyDocument = policyDocument;
    
    callback(null, authResponse);
};