HTTP methods and CRUD mapping in Node.js - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to use the HTTP method for creating a new resource.

Node.js

app.[1]('/items', (req, res) => { res.send('Create item'); });

Drag options to blanks, or click blank then click option'

AGET

BPOST

CPUT

DDELETE

Attempts:

3 left

💡 Hint

Common Mistakes

Using GET instead of POST

Using DELETE to create resources

The POST method is used to create new resources on the server.

2fill in blank

medium

Complete the code to use the HTTP method for reading a resource.

Node.js

app.[1]('/items/:id', (req, res) => { res.send('Read item'); });

Drag options to blanks, or click blank then click option'

APOST

BPUT

CPATCH

DGET

Attempts:

3 left

💡 Hint

Common Mistakes

Using POST to read data

Using DELETE to read data

The GET method is used to read or retrieve data from the server.

3fill in blank

hard

Fix the error in the code by choosing the correct HTTP method for updating a resource.

Node.js

app.[1]('/items/:id', (req, res) => { res.send('Update item'); });

Drag options to blanks, or click blank then click option'

APUT

BPOST

CGET

DDELETE

Attempts:

3 left

💡 Hint

Common Mistakes

Using POST to update

Using GET to update

The PUT method is used to update an existing resource completely.

4fill in blank

hard

Fill both blanks to handle partial updates and deletions of a resource.

Node.js

app.[1]('/items/:id', (req, res) => { res.send('Partial update'); });
app.[2]('/items/:id', (req, res) => { res.send('Delete item'); });

Drag options to blanks, or click blank then click option'

APATCH

BPOST

CDELETE

DPUT

Attempts:

3 left

💡 Hint

Common Mistakes

Using PUT for partial updates

Using POST for deletion

PATCH is used for partial updates, and DELETE is used to remove resources.

5fill in blank

hard

Fill all three blanks to complete the CRUD operations with correct HTTP methods.

Node.js

app.[1]('/items', (req, res) => { res.send('Create item'); });
app.[2]('/items/:id', (req, res) => { res.send('Read item'); });
app.[3]('/items/:id', (req, res) => { res.send('Delete item'); });

Drag options to blanks, or click blank then click option'

APOST

BGET

CDELETE

DPUT

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing GET and POST

Using PUT for deletion

POST creates, GET reads, and DELETE removes resources in REST APIs.

Practice

1. Which HTTP method is typically used to retrieve data from a server in a RESTful API?

easy

A. GET

B. POST

C. PUT

D. DELETE

Solution

1. Step 1: Understand HTTP methods and their purposes

   In RESTful APIs, GET is used to read or retrieve data from the server.

2. Step 2: Match the method to the action

   POST creates, PUT updates, and DELETE removes data, so only GET fits retrieving data.

3. Final Answer:

   GET -> Option A

4. Quick Check:

   Read = GET [OK]

Hint: GET is for reading data, like looking at a book [OK]

Common Mistakes:

• Confusing POST with GET
• Using DELETE to fetch data
• Thinking PUT retrieves data

2. Which of the following Express route definitions correctly handles updating a resource using the HTTP method for update?

easy

A. app.get('/item/:id', handler)

B. app.post('/item/:id', handler)

C. app.put('/item/:id', handler)

D. app.delete('/item/:id', handler)

Solution

1. Step 1: Identify the HTTP method for updating

   Updating a resource uses the PUT method in RESTful APIs.

2. Step 2: Match Express method to HTTP method

   Express uses app.put() to handle PUT requests, so app.put('/item/:id', handler) is correct.

3. Final Answer:

   app.put('/item/:id', handler) -> Option C

4. Quick Check:

   Update = PUT = app.put() [OK]

Hint: Use app.put() for updates in Express routes [OK]

Common Mistakes:

• Using app.post() for updates
• Using app.get() for updates
• Confusing app.delete() with update

3. Consider this Express code snippet:

app.delete('/user/:id', (req, res) => {
  res.send(`Deleted user ${req.params.id}`);
});

// Client sends DELETE request to /user/42

What will the server respond with?

medium

A. "Updated user 42"

B. "Deleted user 42"

C. "Created user 42"

D. 404 Not Found

Solution

1. Step 1: Understand the route and HTTP method

   The route listens for DELETE requests on /user/:id. The client sends a DELETE request to /user/42.

2. Step 2: Analyze the response sent

   The handler sends back the string Deleted user 42 using the id from the URL.

3. Final Answer:

   "Deleted user 42" -> Option B

4. Quick Check:

   DELETE request responds with deletion message [OK]

Hint: DELETE routes respond with deletion confirmation [OK]

Common Mistakes:

• Confusing DELETE with POST response
• Expecting 404 instead of success message
• Mixing up URL parameters

4. What is wrong with this Express route for creating a new item?

app.get('/items', (req, res) => {
  // code to add new item
  res.send('Item created');
});

medium

A. Missing route parameter for item ID

B. Route path should be '/item' not '/items'

C. Response message is incorrect

D. GET method should not be used to create data

Solution

1. Step 1: Identify the HTTP method used

   The route uses GET, which is meant for reading data, not creating.

2. Step 2: Match method to CRUD action

   Creating new data should use POST, so using GET here is incorrect.

3. Final Answer:

   GET method should not be used to create data -> Option D

4. Quick Check:

   Create = POST, not GET [OK]

Hint: Use POST to create, not GET [OK]

Common Mistakes:

• Using GET to create resources
• Ignoring HTTP method semantics
• Assuming route path is the issue

5. You want to build an Express API that allows clients to create, read, update, and delete "products". Which set of route definitions correctly maps HTTP methods to CRUD actions?

hard

A. app.post('/products', createHandler); app.get('/products/:id', readHandler); app.put('/products/:id', updateHandler); app.delete('/products/:id', deleteHandler);

B. app.get('/products', createHandler); app.post('/products/:id', readHandler); app.put('/products', updateHandler); app.delete('/products', deleteHandler);

C. app.put('/products', createHandler); app.get('/products/:id', readHandler); app.post('/products/:id', updateHandler); app.delete('/products/:id', deleteHandler);

D. app.delete('/products', createHandler); app.put('/products/:id', readHandler); app.post('/products/:id', updateHandler); app.get('/products/:id', deleteHandler);

Solution

1. Step 1: Match each CRUD action to correct HTTP method

   Create = POST, Read = GET, Update = PUT, Delete = DELETE.

2. Step 2: Check route paths and handlers

   app.post('/products', createHandler); app.get('/products/:id', readHandler); app.put('/products/:id', updateHandler); app.delete('/products/:id', deleteHandler); uses POST /products for create, GET /products/:id for read, PUT /products/:id for update, and DELETE /products/:id for delete, which is correct.

3. Final Answer:

   app.post('/products', createHandler); app.get('/products/:id', readHandler); app.put('/products/:id', updateHandler); app.delete('/products/:id', deleteHandler); -> Option A

4. Quick Check:

   POST=create, GET=read, PUT=update, DELETE=delete [OK]

Hint: Remember CRUD: POST, GET, PUT, DELETE order [OK]

Common Mistakes:

• Mixing POST and GET methods
• Using wrong paths for actions
• Assigning update to POST instead of PUT