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Rest APIprogramming~10 mins

Example requests and responses in Rest API - Step-by-Step Execution

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Concept Flow - Example requests and responses
Client prepares request
Send HTTP request to server
Server receives request
Server processes request
Server sends HTTP response
Client receives response
Client processes response
This flow shows how a client sends a request to a server and receives a response back.
Execution Sample
Rest API
GET /users/123 HTTP/1.1
Host: api.example.com


Response:
HTTP/1.1 200 OK
Content-Type: application/json

{"id":123,"name":"Alice"}
A client requests user data with ID 123 and the server responds with user details in JSON.
Execution Table
StepActionRequest/Response ContentResult
1Client prepares GET requestGET /users/123 HTTP/1.1 Host: api.example.comRequest ready to send
2Client sends requestRequest sent to serverWaiting for response
3Server receives requestGET /users/123 HTTP/1.1Request accepted
4Server processes requestLook up user with ID 123User found: {"id":123,"name":"Alice"}
5Server sends responseHTTP/1.1 200 OK Content-Type: application/json {"id":123,"name":"Alice"}Response sent
6Client receives responseHTTP/1.1 200 OK Content-Type: application/json {"id":123,"name":"Alice"}Response received
7Client processes responseParse JSON bodyUser data available: id=123, name=Alice
8EndNo more actionsProcess complete
💡 Client has received and processed the server's response, completing the request cycle.
Variable Tracker
VariableStartAfter Step 4After Step 6Final
requestemptyGET /users/123 HTTP/1.1GET /users/123 HTTP/1.1sent
responseemptyemptyHTTP/1.1 200 OK with JSON bodyreceived and parsed
user_datanonenonenone{"id":123,"name":"Alice"}
Key Moments - 3 Insights
Why does the client wait after sending the request?
After sending the request (Step 2), the client waits because it needs the server to process the request and send back a response (see Step 3 and 4 in execution_table).
What does the server do when it receives the request?
The server looks up the requested data (user with ID 123) and prepares the response (Step 4 and 5 in execution_table).
How does the client use the response data?
The client parses the JSON response body to extract user details (Step 7 in execution_table), making the data usable in the application.
Visual Quiz - 3 Questions
Test your understanding
Look at the execution_table, what is the content of the response at Step 6?
AHTTP/1.1 200 OK with JSON body {"id":123,"name":"Alice"}
BGET /users/123 HTTP/1.1 request
CEmpty response
DError message
💡 Hint
Check the 'Request/Response Content' column at Step 6 in execution_table.
At which step does the server find the user data?
AStep 2
BStep 4
CStep 6
DStep 7
💡 Hint
Look for 'Server processes request' in execution_table.
If the user ID was not found, how would the response change in the execution_table?
ARequest would not be sent
BResponse would be HTTP 200 OK with empty body
CResponse would be HTTP 404 Not Found
DClient would not receive any response
💡 Hint
Think about standard HTTP status codes for missing resources.
Concept Snapshot
Example requests and responses:
- Client sends HTTP request (GET, POST, etc.)
- Server processes and sends HTTP response
- Response includes status code and data (often JSON)
- Client parses response to use data
- Common status codes: 200 OK, 404 Not Found
- Requests and responses form the communication cycle
Full Transcript
This visual execution shows how a client sends an HTTP GET request to a server to get user data. The client prepares the request, sends it, and waits. The server receives the request, looks up the user with ID 123, and sends back a response with status 200 OK and JSON data. The client receives and parses this response to get the user details. This cycle is the basic pattern of REST API communication.