Create API and Lambda function

After creating the User pool, we create an API and a Lambda function to handle user registration and login requests.

  1. Open template.yaml file in source of fcj-book-shop-sam-ws3.zip file that downloaded in preparation

    • Add the following script under the LambdaInvokePermission
    • Replace all APP_INTERGATION with CLIENT_ID which recorded from the previous step 
        Login:
    Type: AWS::Serverless::Function
    Properties:
      FunctionName: login
      CodeUri: fcj-book-shop/login
      Handler: login.lambda_handler
      Runtime: python3.9
      Architectures:
        - x86_64
      Environment:
        Variables:
          CLIENT_ID: "APP_INTERGATION"

  Register:
    Type: AWS::Serverless::Function
    Properties:
      FunctionName: register
      CodeUri: fcj-book-shop/register
      Handler: register.lambda_handler
      Runtime: python3.9
      Architectures:
        - x86_64
      Environment:
        Variables:
          CLIENT_ID: "APP_INTERGATION"

  ConfirmUser:
    Type: AWS::Serverless::Function
    Properties:
      FunctionName: confirm_user
      CodeUri: fcj-book-shop/confirm_user
      Handler: confirm_user.lambda_handler
      Runtime: python3.9
      Architectures:
        - x86_64
      Environment:
        Variables:
          CLIENT_ID: "APP_INTERGATION"
      DeployFunction

  2. The directory structure is as follows:

    fcj-book-shop-sam-ws3
├── fcj-book-shop
│   ├── login
│   │   └── login.py
│   ├── register
│   │   └── register.py
│   ├── confirm_user
│   │   └── confirm_user.py
│   ├── ...
│
└── template.yaml
    • Create login folder in fcj-book-shop-sam-ws3/fcj-book-shop/ folder
    • Create login.py file and copy the following code to it
    import json
import boto3
import botocore.exceptions
import os


client = boto3.client('cognito-idp')
def initiate_auth(client_id, username, password):
    try:
        response = client.initiate_auth(
            AuthFlow='USER_PASSWORD_AUTH',
            ClientId=client_id,
            AuthParameters={
                "USERNAME": username,
                "PASSWORD": password,
            }
        )
        print(response)

    except Exception as e:
        return None, e.__str__()

    return response, None

def lambda_handler(event, context):
    user_infor = json.loads(event['body'])
    error = ""
    message = ""
    client_id = os.getenv("CLIENT_ID")


    resp, msg = initiate_auth(client_id, user_infor['username'], user_infor['password'])
    print(resp)

    if msg is not None:
        message = "Login fail!"
        statusCode = 400
    elif resp["AuthenticationResult"]:
        message = "Login sccessful!"
        statusCode = 200
    else:
        message = "Login fail!"
        statusCode = 400


    # TODO implement
    return {
            'statusCode': statusCode,
            'body': message,
            'headers': {
                'Content-Type': 'application/json',
                "Access-Control-Allow-Headers": "Access-Control-Allow-Headers, Origin, Accept, X-Requested-With, Content-Type, Access-Control-Request-Method,X-Access-Token, XKey, Authorization",
                "Access-Control-Allow-Origin": "*",
                "Access-Control-Allow-Methods": "GET,PUT,POST,DELETE,OPTIONS"
            }
    }
    • Create register folder in fcj-book-shop-sam-ws3/fcj-book-shop/ folder
    • Create register.py file and copy the following code to it
    import json
import boto3
import os

client = boto3.client('cognito-idp')

def lambda_handler(event, context):
    user_infor = json.loads(event['body'])
    client_id = os.getenv("CLIENT_ID")
    error = None
    try:
        resp = client.sign_up(
            ClientId=client_id,
            Username=user_infor['username'],
            Password=user_infor['password']
            )

    except Exception as e:
        error = e.__str__()

    if error is None:
        message = "Register successful!"
        statusCode = 200
    else:
        message = "Register fail!"
        statusCode = 400
        print(error)

    # TODO implement
    return {
            'statusCode': statusCode,
            'body': message,
            'headers': {
                'Content-Type': 'application/json',
                "Access-Control-Allow-Headers": "Access-Control-Allow-Headers, Origin, Accept, X-Requested-With, Content-Type, Access-Control-Request-Method,X-Access-Token, XKey, Authorization",
                "Access-Control-Allow-Origin": "*",
                "Access-Control-Allow-Methods": "GET,PUT,POST,DELETE,OPTIONS"
            },
    }
    • Create confirm_user folder in fcj-book-shop-sam-ws3/fcj-book-shop/ folder
    • Create confirm_user.py file and copy the following code to it
    import json
import boto3
import os

client = boto3.client('cognito-idp')

def lambda_handler(event, context):
    user_infor = json.loads(event['body'])
    client_id = os.getenv("CLIENT_ID")
    user_pool_id = os.getenv("USER_POOL_ID")
    error = None
    try:
        resp = client.confirm_sign_up(
            ClientId=client_id,
            Username=user_infor['username'],
            ConfirmationCode=user_infor['code']
            )
    except Exception as e:
        error = e.__str__()

    if error is None:
        message = "Confirm successful!"
        statusCode = 200
    else:
        message = "Confirm fail!"
        statusCode = 400
        print(error)

    # TODO implement
    return {
            'statusCode': statusCode,
            'body': message,
            'headers': {
                'Content-Type': 'application/json',
                "Access-Control-Allow-Headers": "Access-Control-Allow-Headers, Origin, Accept, X-Requested-With, Content-Type, Access-Control-Request-Method,X-Access-Token, XKey, Authorization",
                "Access-Control-Allow-Origin": "*",
                "Access-Control-Allow-Methods": "GET,PUT,POST,DELETE,OPTIONS"
            },
    }

  3. Run the below commands:

    sam build
sam deploy --guided

    DeployFunction

  4. Add the following script under the delete method of BookApi

              /login:
            post:
              responses:
                "200":
                  description: 200 response
                  headers:
                    Access-Control-Allow-Origin:
                      type: string
              x-amazon-apigateway-integration:
                uri:
                  Fn::Sub: "arn:aws:apigateway:${AWS::Region}:lambda:path/2015-03-31/functions/${Login.Arn}/invocations"
                responses:
                  default:
                    statusCode: 200
                    responseParameters:
                      method.response.header.Access-Control-Allow-Origin: "'*'"
                passthroughBehavior: when_no_match
                httpMethod: POST #always POST
                type: aws_proxy
          /register:
            post:
              responses:
                "200":
                  description: 200 response
                  headers:
                    Access-Control-Allow-Origin:
                      type: string
              x-amazon-apigateway-integration:
                uri:
                  Fn::Sub: "arn:aws:apigateway:${AWS::Region}:lambda:path/2015-03-31/functions/${Register.Arn}/invocations"
                responses:
                  default:
                    statusCode: 200
                    responseParameters:
                      method.response.header.Access-Control-Allow-Origin: "'*'"
                passthroughBehavior: when_no_match
                httpMethod: POST #always POST
                type: aws_proxy
          /confirm_user:
            post:
              responses:
                "200":
                  description: 200 response
                  headers:
                    Access-Control-Allow-Origin:
                      type: string
              x-amazon-apigateway-integration:
                uri:
                  Fn::Sub: "arn:aws:apigateway:${AWS::Region}:lambda:path/2015-03-31/functions/${ConfirmUser.Arn}/invocations"
                responses:
                  default:
                    statusCode: 200
                    responseParameters:
                      method.response.header.Access-Control-Allow-Origin: "'*'"
                passthroughBehavior: when_no_match
                httpMethod: POST #always POST
                type: aws_proxy

    DeployFunction DeployFunction

  5. Add the following script under the Login function

          Events:
        Login:
          Type: Api
          Properties:
            Path: /login/
            Method: post
            RestApiId:
              Ref: BookApi

    DeployFunction

    • Add the following script under the Register function
          Events:
        Register:
          Type: Api
          Properties:
            Path: /register/
            Method: post
            RestApiId:
              Ref: BookApi

    DeployFunction

    • Add the following script under the ConfirmUser function
          Events:
        ConfirmUser:
          Type: Api
          Properties:
            Path: /confirm_user/
            Method: post
            RestApiId:
              Ref: BookApi

    DeployFunction

  6. Run the below commands:

    sam build
sam deploy --guided
    • Enter “y” if asked “Login may not have authorization defined, Is this okay? [y/N]: "
    • Enter “y” if asked “Register may not have authorization defined, Is this okay? [y/N]: "
    • Enter “y” if asked “ConfirmUser may not have authorization defined, Is this okay? [y/N]: " DeployFunction We have completed the implementation of the APIs and Lambda functions.