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

Concept Flow - Example requests and responses

Client prepares request

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Send HTTP request to server

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Server receives request

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Server processes request

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Server sends HTTP response

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Client receives response

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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

Step	Action	Request/Response Content	Result
1	Client prepares GET request	GET /users/123 HTTP/1.1 Host: api.example.com	Request ready to send
2	Client sends request	Request sent to server	Waiting for response
3	Server receives request	GET /users/123 HTTP/1.1	Request accepted
4	Server processes request	Look up user with ID 123	User found: {"id":123,"name":"Alice"}
5	Server sends response	HTTP/1.1 200 OK Content-Type: application/json {"id":123,"name":"Alice"}	Response sent
6	Client receives response	HTTP/1.1 200 OK Content-Type: application/json {"id":123,"name":"Alice"}	Response received
7	Client processes response	Parse JSON body	User data available: id=123, name=Alice
8	End	No more actions	Process complete

💡 Client has received and processed the server's response, completing the request cycle.

Variable Tracker

Variable	Start	After Step 4	After Step 6	Final
request	empty	GET /users/123 HTTP/1.1	GET /users/123 HTTP/1.1	sent
response	empty	empty	HTTP/1.1 200 OK with JSON body	received and parsed
user_data	none	none	none	{"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

Look at the execution_table, what is the content of the response at Step 6?

A HTTP/1.1 200 OK with JSON body {"id":123,"name":"Alice"}

B GET /users/123 HTTP/1.1 request

C Empty response

D Error message

💡 Hint

Check the 'Request/Response Content' column at Step 6 in execution_table.

At which step does the server find the user data?

A Step 2

B Step 4

C Step 6

D Step 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?

A Request would not be sent

B Response would be HTTP 200 OK with empty body

C Response would be HTTP 404 Not Found

D Client 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.