Utilisation des mécanismes d’autorisation Lambda API Gateway

// A simple request-based 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, QueryString1
// query parameter, and stage variable of StageVar1 all match
// specified values of 'headerValue1', 'queryValue1', and 'stageValue1',
// respectively.
    
export const handler = function(event, context, callback) {
    console.log('Received event:', JSON.stringify(event, null, 2));
    
    // Retrieve request parameters from the Lambda function input:
    var headers = event.headers;
    var queryStringParameters = event.queryStringParameters;
    var pathParameters = event.pathParameters;
    var stageVariables = event.stageVariables;
        
    // 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 restApiId = apiGatewayArnTmp[0];
    var stage = apiGatewayArnTmp[1];
    var method = apiGatewayArnTmp[2];
    var resource = '/'; // root resource
    if (apiGatewayArnTmp[3]) {
        resource += apiGatewayArnTmp[3];
    }
        
    // Perform authorization to return the Allow policy for correct parameters and 
    // the 'Unauthorized' error, otherwise.

     
    if (headers.HeaderAuth1 === "headerValue1"
        && queryStringParameters.QueryString1 === "queryValue1"
        && stageVariables.StageVar1 === "stageValue1") {
        callback(null, generateAllow('me', event.methodArn));
    }  else {
        callback(null, generateDeny('me', event.methodArn));
    }
}
     
// 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) {
    return generatePolicy(principalId, 'Allow', resource);
}
     
var generateDeny = function(principalId, resource) {
    return generatePolicy(principalId, 'Deny', resource);
}

# A simple request-based 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, QueryString1
# query parameter, and stage variable of StageVar1 all match
# specified values of 'headerValue1', 'queryValue1', and 'stageValue1',
# respectively.

def lambda_handler(event, context):
    print(event)

    # Retrieve request parameters from the Lambda function input:
    headers = event['headers']
    queryStringParameters = event['queryStringParameters']
    pathParameters = event['pathParameters']
    stageVariables = event['stageVariables']

    # Parse the input for the parameter values
    tmp = event['methodArn'].split(':')
    apiGatewayArnTmp = tmp[5].split('/')
    awsAccountId = tmp[4]
    region = tmp[3]
    restApiId = apiGatewayArnTmp[0]
    stage = apiGatewayArnTmp[1]
    method = apiGatewayArnTmp[2]
    resource = '/'

    if (apiGatewayArnTmp[3]):
        resource += apiGatewayArnTmp[3]

    # Perform authorization to return the Allow policy for correct parameters
    # and the 'Unauthorized' error, otherwise.

    if (headers['HeaderAuth1'] == "headerValue1" and queryStringParameters['QueryString1'] == "queryValue1" and stageVariables['StageVar1'] == "stageValue1"):
        response = generateAllow('me', event['methodArn'])
        print('authorized')
        return response
    else:
        print('unauthorized')
        response = generateDeny('me', event['methodArn'])
        return response
    # Help function to generate IAM policy


def generatePolicy(principalId, effect, resource):
    authResponse = {}
    authResponse['principalId'] = principalId
    if (effect and resource):
        policyDocument = {}
        policyDocument['Version'] = '2012-10-17'
        policyDocument['Statement'] = []
        statementOne = {}
        statementOne['Action'] = 'execute-api:Invoke'
        statementOne['Effect'] = effect
        statementOne['Resource'] = resource
        policyDocument['Statement'] = [statementOne]
        authResponse['policyDocument'] = policyDocument

    authResponse['context'] = {
        "stringKey": "stringval",
        "numberKey": 123,
        "booleanKey": True
    }

    return authResponse


def generateAllow(principalId, resource):
    return generatePolicy(principalId, 'Allow', resource)


def generateDeny(principalId, resource):
    return generatePolicy(principalId, 'Deny', resource)

// A simple token-based authorizer example to demonstrate how to use an authorization token 
// to allow or deny a request. In this example, the caller named 'user' is allowed to invoke 
// a request if the client-supplied token value is 'allow'. The caller is not allowed to invoke 
// the request if the token value is 'deny'. If the token value is 'unauthorized' or an empty
// string, the authorizer function returns an HTTP 401 status code. For any other token value, 
// the authorizer returns an HTTP 500 status code. 
// Note that token values are case-sensitive.

export const handler =  function(event, context, callback) {
    var token = event.authorizationToken;
    switch (token) {
        case 'allow':
            callback(null, generatePolicy('user', 'Allow', event.methodArn));
            break;
        case 'deny':
            callback(null, generatePolicy('user', 'Deny', event.methodArn));
            break;
        case 'unauthorized':
            callback("Unauthorized");   // Return a 401 Unauthorized response
            break;
        default:
            callback("Error: Invalid token"); // Return a 500 Invalid token response
    }
};

// Help function to generate an IAM policy
var generatePolicy = function(principalId, effect, resource) {
    var authResponse = {};
    
    authResponse.principalId = principalId;
    if (effect && resource) {
        var policyDocument = {};
        policyDocument.Version = '2012-10-17'; 
        policyDocument.Statement = [];
        var statementOne = {};
        statementOne.Action = 'execute-api:Invoke'; 
        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;
}

# A simple token-based authorizer example to demonstrate how to use an authorization token
# to allow or deny a request. In this example, the caller named 'user' is allowed to invoke
# a request if the client-supplied token value is 'allow'. The caller is not allowed to invoke
# the request if the token value is 'deny'. If the token value is 'unauthorized' or an empty
# string, the authorizer function returns an HTTP 401 status code. For any other token value,
# the authorizer returns an HTTP 500 status code.
# Note that token values are case-sensitive.

import json


def lambda_handler(event, context):
    token = event['authorizationToken']
    if token == 'allow':
        print('authorized')
        response = generatePolicy('user', 'Allow', event['methodArn'])
    elif token == 'deny':
        print('unauthorized')
        response = generatePolicy('user', 'Deny', event['methodArn'])
    elif token == 'unauthorized':
        print('unauthorized')
        raise Exception('Unauthorized')  # Return a 401 Unauthorized response
        return 'unauthorized'
    try:
        return json.loads(response)
    except BaseException:
        print('unauthorized')
        return 'unauthorized'  # Return a 500 error


def generatePolicy(principalId, effect, resource):
    authResponse = {}
    authResponse['principalId'] = principalId
    if (effect and resource):
        policyDocument = {}
        policyDocument['Version'] = '2012-10-17'
        policyDocument['Statement'] = []
        statementOne = {}
        statementOne['Action'] = 'execute-api:Invoke'
        statementOne['Effect'] = effect
        statementOne['Resource'] = resource
        policyDocument['Statement'] = [statementOne]
        authResponse['policyDocument'] = policyDocument
    authResponse['context'] = {
        "stringKey": "stringval",
        "numberKey": 123,
        "booleanKey": True
    }
    authResponse_JSON = json.dumps(authResponse)
    return authResponse_JSON