This document discusses HTTP clients and servers, with a focus on request/response models, common HTTP methods like GET and POST, parameters and bodies that can be included in requests and responses, JSON, and status codes. An example is given of a ride-hailing application where client devices can see ride information and prices from the server storing and providing that data. The structure of URLs and differences between PUT, PATCH, and POST methods are also outlined.

1. OOD with Spring
By Pedram Hajesmaeeli
HTTP

2. Client And Server
● The request response
model
● Client: Handling user
interaction
○ HTML, JS and CSS
○ Android/iOS app
● Server
○ Storing, manipulating and
providing data

3. Example
Ride hailing application
● Ride info seen on
different devices
● Price of rides

4. Sending and
Receiving data
● Request Body
● Query Parameters
● Path Parameters
● HTTP headers
● Response Body
● Response Headers

5. Query and Path
Params
Structure of a URL
● http://foo.com/bars?x=z&a=b
● http://foo.com/bars/{x}
○ http://foo.com/bars/1

6. JSON
Javascript Object Notation

7. HTTP methods
● POST
● PUT
● GET
● DELETE
● PATCH

8. Get and Delete
● Get for retrieving a
resource
● Delete for removing a
resource
● Neither of them should
have request body

9. Post, Put and
Patch
● Post: Create a resource
● Put: Modify a resource
● Patch: Modify a
resource
● Both can have request
bodies

10. Put VS Patch
Example: Updating email of
a user

11. HTTP status
codes - 2XX
Operation successful
Most common ones
● 200: OK
● 201: Created
● 204: No content

12. HTTP status
codes - 4XX
Client Error
Most common ones
● 400: Bad request
● 401: Unauthorized
● 403: Forbidden
● 404: Not found
● 409: Conflict

13. HTTP status
codes
Server Errors
Most common one:
● 500: Internal server
error