HTTP request methods for IoT (GET, POST, PUT) in IOT Protocols - Mini Project: Build & Apply

HTTP Request Methods for IoT (GET, POST, PUT)

📖 Scenario: You are working with a simple IoT device that communicates with a server using HTTP methods. The device can request data, send new data, and update existing data on the server.

🎯 Goal: Build a small program that simulates sending HTTP GET, POST, and PUT requests to a server for an IoT device. You will create the data, configure the request type, implement the request logic, and display the result.

📋 What You'll Learn

Create a dictionary called device_data with keys temperature and humidity and values 22 and 45 respectively

Create a variable called http_method and set it to the string "GET"

Write a function called send_request that takes method and data as parameters and returns a string describing the action

Call send_request with http_method and device_data and print the result

💡 Why This Matters

🌍 Real World

IoT devices often communicate with servers using HTTP methods to send sensor data or request commands. Understanding these methods helps in building and debugging IoT applications.

💼 Career

Knowing how to simulate and handle HTTP requests is essential for IoT developers and DevOps engineers managing IoT infrastructure and APIs.

1

Create the IoT device data

Create a dictionary called device_data with the exact keys and values: 'temperature': 22 and 'humidity': 45.

IOT Protocols

# Create the device_data dictionary with temperature and humidity
# Your code here

Hint

Use curly braces {} to create a dictionary with the keys and values exactly as shown.

2

Set the HTTP method

Create a variable called http_method and set it to the string "GET".

IOT Protocols

device_data = {'temperature': 22, 'humidity': 45}
# Set the http_method variable to "GET"
# Your code here

Hint

Use double quotes around GET to create a string.

3

Write the request sending function

Write a function called send_request that takes parameters method and data. The function should return:
- "Getting data: {data}" if method is "GET"
- "Posting data: {data}" if method is "POST"
- "Putting data: {data}" if method is "PUT"
Use an if-elif-else structure.

IOT Protocols

device_data = {'temperature': 22, 'humidity': 45}
http_method = "GET"
# Define the send_request function below
# Your code here

Hint

Use if, elif, and else to check the method and return the correct string using f-strings.

4

Call the function and print the result

Call the function send_request with http_method and device_data as arguments. Print the returned string.

IOT Protocols

device_data = {'temperature': 22, 'humidity': 45}
http_method = "GET"

def send_request(method, data):
    if method == "GET":
        return f"Getting data: {data}"
    elif method == "POST":
        return f"Posting data: {data}"
    elif method == "PUT":
        return f"Putting data: {data}"
    else:
        return "Unknown method"

# Call send_request with http_method and device_data, then print the result
# Your code here

Hint

Use print(send_request(http_method, device_data)) to show the result.

Practice

1. Which HTTP method is used to retrieve data from an IoT device without changing it?

easy

A. POST

B. DELETE

C. PUT

D. GET

Solution

1. Step 1: Understand the purpose of GET

   GET is designed to fetch or read data without modifying it on the server or device.

2. Step 2: Compare with other methods

   POST sends new data, PUT updates existing data, DELETE removes data. Only GET fetches without change.

3. Final Answer:

   GET -> Option D

4. Quick Check:

   GET = fetch data without change [OK]

Hint: GET fetches data, POST sends new, PUT updates existing [OK]

Common Mistakes:

• Confusing POST with GET as both send data
• Thinking PUT fetches data
• Using DELETE instead of GET for retrieval

2. Which of the following is the correct syntax to send data using POST method in an HTTP request for IoT?

easy

A. PUT /device/data HTTP/1.1\nContent-Type: application/json\n\n{"temp": 22}

B. POST /device/data HTTP/1.1\nContent-Type: application/json\n\n{"temp": 22}

C. GET /device/data HTTP/1.1\nContent-Type: application/json\n\n{"temp": 22}

D. DELETE /device/data HTTP/1.1\nContent-Type: application/json\n\n{"temp": 22}

Solution

1. Step 1: Identify the method for sending new data

   POST is used to send new data to the server or device, so the request line must start with POST.

2. Step 2: Check the syntax correctness

   The syntax includes the method, path, HTTP version, headers, and body. POST /device/data HTTP/1.1\nContent-Type: application/json\n\n{"temp": 22} correctly uses POST with JSON data.

3. Final Answer:

   POST /device/data HTTP/1.1\nContent-Type: application/json\n\n{"temp": 22} -> Option B

4. Quick Check:

   POST sends data with correct syntax [OK]

Hint: POST method starts the request line to send data [OK]

Common Mistakes:

• Using GET method to send data
• Missing Content-Type header
• Using DELETE or PUT instead of POST for new data

3. Given this HTTP request to update a device setting:

PUT /device/settings HTTP/1.1\nContent-Type: application/json\n\n{"mode": "eco"}

What is the expected result on the device?

medium

A. The device mode is updated to 'eco'.

B. The device sends back current settings without change.

C. A new device setting is created without replacing existing ones.

D. The device deletes the current settings.

Solution

1. Step 1: Understand the PUT method purpose

   PUT replaces or updates existing data on the device with the provided data.

2. Step 2: Analyze the request body

   The JSON body sets "mode" to "eco", so the device's mode setting will be updated accordingly.

3. Final Answer:

   The device mode is updated to 'eco'. -> Option A

4. Quick Check:

   PUT updates existing data [OK]

Hint: PUT updates or replaces existing data on device [OK]

Common Mistakes:

• Thinking PUT only adds new data without replacing
• Confusing PUT with GET which fetches data
• Assuming DELETE is used to update data

4. You wrote this HTTP request to update sensor data:

POST /sensor/data HTTP/1.1\nContent-Type: application/json\n\n{"humidity": 45}

But the device does not update the data. What is the likely error?

medium

A. The JSON body is invalid.

B. Content-Type header is missing.

C. POST is incorrect; PUT should be used to update existing data.

D. GET method should be used instead of POST.

Solution

1. Step 1: Identify the purpose of the request

   The request aims to update existing sensor data, which requires the PUT method.

2. Step 2: Check the method used

   POST is for sending new data, not updating. Using POST here causes the device to ignore the update.

3. Final Answer:

   POST is incorrect; PUT should be used to update existing data. -> Option C

4. Quick Check:

   Use PUT to update data, not POST [OK]

Hint: Use PUT to update, POST to create new data [OK]

Common Mistakes:

• Using POST instead of PUT for updates
• Ignoring Content-Type header importance
• Confusing GET with POST for data changes

5. An IoT device API supports GET, POST, and PUT methods. You want to add a new temperature reading and then update the device's configuration mode. Which sequence of HTTP requests should you use?

hard

A. POST to add temperature, then PUT to update configuration

B. PUT to add temperature, then POST to update configuration

C. GET to add temperature, then PUT to update configuration

D. POST to add temperature, then POST to update configuration

Solution

1. Step 1: Identify method for adding new data

   POST is used to send new data, so adding a temperature reading requires POST.

2. Step 2: Identify method for updating existing data

   PUT updates or replaces existing data, so updating configuration mode requires PUT.

3. Step 3: Determine correct sequence

   First POST to add new reading, then PUT to update configuration.

4. Final Answer:

   POST to add temperature, then PUT to update configuration -> Option A

5. Quick Check:

   POST new data, PUT update existing [OK]

Hint: POST adds new, PUT updates existing; order matters [OK]

Common Mistakes:

• Using PUT to add new data
• Using POST to update existing data
• Using GET for data changes