HTTP request methods for IoT (GET, POST, PUT) in IOT Protocols - Step-by-Step Execution

Process Flow - HTTP request methods for IoT (GET, POST, PUT)

Start IoT Device

↓

Choose HTTP Method

↓

Request Data

↓

Receive Response

↓

End

The IoT device starts and chooses an HTTP method: GET to request data, POST to send new data, or PUT to update existing data. Each sends a request and waits for a response.

Execution Sample

IOT Protocols

GET /sensor/temp
POST /sensor/data {"value":22}
PUT /sensor/config {"mode":"auto"}

Three HTTP requests from an IoT device: GET to read temperature, POST to send sensor data, PUT to update sensor configuration.

Process Table

Step	HTTP Method	Request Sent	Server Action	Response Received
1	GET	GET /sensor/temp	Server returns current temperature	200 OK {"temp":21}
2	POST	POST /sensor/data {"value":22}	Server stores new sensor data	201 Created
3	PUT	PUT /sensor/config {"mode":"auto"}	Server updates sensor config	200 OK
4	END	-	-	All requests completed

💡 All HTTP requests processed and responses received

Status Tracker

Variable	Start	After Step 1	After Step 2	After Step 3	Final
Request	-	GET /sensor/temp	POST /sensor/data {"value":22}	PUT /sensor/config {"mode":"auto"}	-
Response	-	200 OK {"temp":21}	201 Created	200 OK	-
Server State	Initial	Temperature sent	Data stored	Config updated	Updated

Key Moments - 2 Insights

Why does the GET request receive data but POST and PUT do not?

GET requests data from the server, so the response includes data (see Step 1). POST sends new data, and PUT updates data, so their responses confirm success without returning data (Steps 2 and 3).

What is the difference between POST and PUT in these requests?

POST adds new data to the server (Step 2), while PUT updates existing data (Step 3). This is why POST returns '201 Created' and PUT returns '200 OK'.

Visual Quiz - 3 Questions

Look at the execution table, what response does the GET request receive?

A 201 Created

B 200 OK {"temp":21}

C 404 Not Found

D 500 Internal Server Error

💡 Hint

Check Step 1 in the execution_table under 'Response Received'

At which step does the server update the sensor configuration?

A Step 3

B Step 1

C Step 2

D Step 4

💡 Hint

Look at the 'Server Action' column in the execution_table

If the POST request sent different data, how would the response change?

A Response would be '404 Not Found'

B Response would be '200 OK'

C Response would still be '201 Created'

D Response would be '500 Internal Server Error'

💡 Hint

POST confirms data creation with '201 Created' regardless of data content (see Step 2)

Concept Snapshot

HTTP methods for IoT:
GET: Request data from server, receives data in response.
POST: Send new data to server, response confirms creation.
PUT: Update existing data on server, response confirms update.
Each method has a specific role in IoT communication.

Full Transcript

This visual execution shows how an IoT device uses HTTP methods GET, POST, and PUT. First, the device sends a GET request to read temperature data, and the server responds with the current temperature. Next, the device sends a POST request with new sensor data; the server stores it and confirms creation. Then, the device sends a PUT request to update sensor configuration; the server updates and confirms success. The execution table tracks each step's request, server action, and response. Variables like Request, Response, and Server State change accordingly. Key moments clarify why GET returns data while POST and PUT confirm actions, and the difference between POST and PUT. The quiz tests understanding of responses and server updates. This helps beginners see how IoT devices communicate using HTTP methods step-by-step.

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