Resources and methods in AWS - Mini Project: Build & Apply

AWS API Gateway: Resources and Methods Setup

📖 Scenario: You are building a simple API using AWS API Gateway. This API will have a resource path and a method to handle HTTP requests.Think of this like setting up a new phone line (resource) and deciding what kind of calls (methods) it can take.

🎯 Goal: Create an AWS API Gateway REST API with a resource path /products and add a GET method to it.

📋 What You'll Learn

Create a REST API named StoreAPI

Add a resource with path part products

Add a GET method to the /products resource

💡 Why This Matters

🌍 Real World

APIs are the backbone of modern applications. Setting up resources and methods in API Gateway allows you to create scalable and secure APIs for your services.

💼 Career

Cloud engineers and developers often need to configure API Gateway resources and methods to expose backend services securely and efficiently.

1

Create the REST API

Create a REST API named StoreAPI using AWS SDK or AWS CLI syntax. Assign it to a variable called api.

AWS

# Your code here to create a REST API named StoreAPI and assign it to api

Hint

Use create_rest_api method with name='StoreAPI'.

2

Add the /products resource

Add a resource with path part products to the REST API stored in api. Assign the new resource to a variable called products_resource.

AWS

api = apigateway.create_rest_api(name='StoreAPI')
# Your code here to add a resource with path part 'products' and assign it to products_resource

Hint

Use create_resource with restApiId=api['id'], parentId=api['rootResourceId'], and pathPart='products'.

3

Add GET method to /products

Add a GET method to the products_resource. Use authorizationType='NONE' and assign the method response to a variable called get_method.

AWS

api = apigateway.create_rest_api(name='StoreAPI')
products_resource = apigateway.create_resource(restApiId=api['id'], parentId=api['rootResourceId'], pathPart='products')
# Your code here to add a GET method with authorizationType 'NONE' and assign it to get_method

Hint

Use put_method with restApiId=api['id'], resourceId=products_resource['id'], httpMethod='GET', and authorizationType='NONE'.

4

Add integration for GET method

Add a MOCK integration to the GET method on products_resource. Use type='MOCK' and assign the integration response to a variable called get_integration.

AWS

api = apigateway.create_rest_api(name='StoreAPI')
products_resource = apigateway.create_resource(restApiId=api['id'], parentId=api['rootResourceId'], pathPart='products')
get_method = apigateway.put_method(restApiId=api['id'], resourceId=products_resource['id'], httpMethod='GET', authorizationType='NONE')
# Your code here to add a MOCK integration to the GET method and assign it to get_integration

Hint

Use put_integration with restApiId=api['id'], resourceId=products_resource['id'], httpMethod='GET', type='MOCK', and integrationHttpMethod='GET'.

Practice

1. What does a resource represent in AWS API Gateway?

easy

A. A URL path that clients can access

B. A backend database connection

C. A security policy for API access

D. A method to deploy the API

Solution

1. Step 1: Understand the role of resources in API Gateway

   Resources define the URL paths that clients use to reach your API endpoints.

2. Step 2: Differentiate resources from other components

   Resources are not backend connections, security policies, or deployment methods; they are URL paths.

3. Final Answer:

   A URL path that clients can access -> Option A

4. Quick Check:

   Resource = URL path [OK]

Hint: Resources are the API's URL paths clients call [OK]

Common Mistakes:

• Confusing resources with backend services
• Thinking resources are security settings
• Mixing resources with deployment steps

2. Which HTTP method is correctly defined in AWS API Gateway to retrieve data?

easy

A. GET

B. POST

C. DELETE

D. PUT

Solution

1. Step 1: Identify the HTTP method for data retrieval

   GET is the standard HTTP method used to retrieve or read data from a resource.

2. Step 2: Confirm other methods' purposes

   POST creates data, DELETE removes data, and PUT updates data, so they are not for retrieval.

3. Final Answer:

   GET -> Option A

4. Quick Check:

   GET = retrieve data [OK]

Hint: GET method is for reading data from resources [OK]

Common Mistakes:

• Using POST instead of GET to fetch data
• Confusing DELETE with data retrieval
• Mixing PUT with GET for reading data

3. Given this API Gateway setup: a resource /items with a POST method integrated to a Lambda function. What happens when a client sends a POST request to /items?

medium

A. The API Gateway returns a static mock response

B. The API Gateway returns a 404 Not Found error

C. The Lambda function is triggered to process the request

D. The request is ignored because POST is not allowed

Solution

1. Step 1: Understand the integration of POST method with Lambda

   The POST method on the /items resource is connected to a Lambda function, so requests trigger that function.

2. Step 2: Analyze the client request effect

   When a client sends a POST request to /items, API Gateway forwards it to Lambda for processing.

3. Final Answer:

   The Lambda function is triggered to process the request -> Option C

4. Quick Check:

   POST + Lambda integration = Lambda triggered [OK]

Hint: POST method triggers Lambda if integrated [OK]

Common Mistakes:

• Assuming POST is not allowed without checking method setup
• Thinking API Gateway returns 404 if resource exists
• Confusing mock responses with Lambda integration

4. You created a resource /users and added a GET method, but clients get a 403 Forbidden error when calling it. What is the most likely cause?

medium

A. The client is using POST instead of GET

B. The resource path is misspelled

C. The API Gateway is not deployed

D. The method does not have an integration configured

Solution

1. Step 1: Check method integration setup

   A 403 Forbidden often means the method exists but lacks proper integration or permissions.

2. Step 2: Rule out other causes

   If the resource path was misspelled, the error would be 404. If API Gateway was not deployed, the error would differ. Using POST instead of GET would cause a 405 Method Not Allowed.

3. Final Answer:

   The method does not have an integration configured -> Option D

4. Quick Check:

   403 Forbidden = missing integration or permissions [OK]

Hint: 403 often means method lacks integration or permissions [OK]

Common Mistakes:

• Confusing 403 with 404 or 405 errors
• Ignoring deployment status
• Assuming client method is always correct

5. You want to create an API with a resource /orders that supports both GET and POST methods. The GET method returns a mock response, and the POST method triggers a Lambda function. Which configuration correctly sets this up?

hard

A. Create /orders resource; add GET and POST methods both with MOCK integration

B. Create /orders resource; add GET method with MOCK integration; add POST method with Lambda integration

C. Create /orders resource; add GET method with Lambda integration; add POST method with MOCK integration

D. Create /orders resource; add GET and POST methods both with Lambda integration

Solution

1. Step 1: Match method to integration type

   The GET method should use MOCK integration to return a static response without backend calls.

2. Step 2: Configure POST method to trigger Lambda

   The POST method must be integrated with Lambda to process incoming data.

3. Step 3: Verify the correct combination

   Create /orders resource; add GET method with MOCK integration; add POST method with Lambda integration correctly assigns MOCK to GET and Lambda to POST on the /orders resource.

4. Final Answer:

   Create /orders resource; add GET method with MOCK integration; add POST method with Lambda integration -> Option B

5. Quick Check:

   GET=MOCK, POST=Lambda [OK]

Hint: GET with MOCK, POST with Lambda for mixed behavior [OK]

Common Mistakes:

• Swapping MOCK and Lambda integrations between methods
• Using same integration for both methods incorrectly
• Forgetting to create the resource before methods