chapter 11 hell

What web application are not limited to other than delivering static html page

They need to send and receive data between the browser (or another client) and the server in the real time

Define web api

Interact that allows allows different software and application to communicate and exchange data over the web, typically using HTTP

What does Web api typical use?

Http

What does web api provide clearly define

A way for clients to request, modify and work with application data

What are some clients examples

Web browsers, mobile apps, smartwatch apps, other server

How do you design these app effectively as a developer

Using REST

What does REST stand for

REpresentational State Transfer

What is REST

A guiding principle when designing app

What is not rest

a protocol, format, or strict rulebook

What does Restful API principle follow

The three main prince-Les of how web component should interact with the internet

How many main principals is there

3

What are those 3 principals

Stateless communication, Resource based structure, Use of HTTP method

What is stateless communication

Every request is independent and contains all the information the
server needs.

What is Resource based structure

data and functionality are organized into distinct resources, each with a unique URL.

What is Use of HTTP method

Standard HTTP verbs indicate the desired actual on the resource

What are some HTTP verbs

GET, POST, PUT, DELETE

HOWS DOEs a restful web API presents all the server available resource

Clear and structure way

What is the RESTFUL web API presenting

Al, the server available resource

What happens after a RESTFUL web API presents the available resource in the server?

Making it a obvious way clients can access and how to interact with them

How is each resource defined

By a unique url

How can the resource be mani-ukated

Using standard HTTP methods

What are some form resources can take on

JSON, HTML, PLAIN TEXT/XML, images, videos, or other files

Why would a resource take a form of a JSON

Structured data exchange

Why would a resource take a form of a HTML

For web pages

Why would a resource take a form of a Plain text / xml

For simpler or legacy data formats

Why would a resource take a form of a images, videos, or other files

For media content

What do some resource require

Authentication or permission to access certain data

the API’s structure and available endpoints are fully _____

Visible

What are the benefits of having api structure and available endpoints fully visible for the clients

Clients can see what is possible even if they can’t access everything

What clarity would be provided having api structure and available endpoints fully visible for the developer

helps developers understand the system,

know which actions are allowed, and integrate with it reliably

In a restful api what is presented as resource

Data

In a restful api what can you do to data presented as resource

Created retrieved update delete

What is the operation collectively called when you create, retrieved, update, delete resources

CRUD

What does the C stand and what’s the operation performed in crud

Create A resource - Post request

What does the R stand and what’s the operation performed in crud

Read A resource - get request

What does the U stand and what’s the operation performed in crud

Update A resource - put or patch request

What does the D stand and what’s the operation performed in crud

delete A resource - Delete request

In a RESTful API for a site with songs, what would be the method, url and request if I want to get a list of all songs

Get, /songs, 200 OK

In a RESTful API for a site with songs, what would be the method, url and request if I want to get all rock songs from 202

Get, /songs?genre=rock&year=2020, 200 OK

In a RESTful API for a site with songs, what would be the method, url and request if I want to get a songs with ID 202

Get, /songs/202, 200 OK

In a RESTful API for a site with songs, what would be the method, url and request if I want to get lyrics for songs with ID 202

Get, /songs/202/lyrics, 200 OK

In a RESTful API for a site with songs, what would be the response if I want to get a non existing songs with ID 0

404 not found

In a RESTful API for a site with songs, what would be the method, url and request if I want to create a new song

Post, /songs, 201 created

In a RESTful API for a site with songs, what would be the method, url and request if I want tp update song with 202

PUT, /songs/202, 204 no content

In a RESTful API for a site with songs, what would be the method, url and request if I want tp update song with 202

Delete, /songs/202, 204 no content

In a RESTful API for a site with songs, what would be the method, url and request if I want tp get top 10 songs

Get, /songs/top?limit=10, 200 OK

In a RESTful API for a site with songs, what would be the method, url and request if I get all songs by artist with id 45

Get, /artist/45/songs, 200 OK

Whats are the six architectural constrains to a truly designed RESTful API

Client-server, stateless, cacheable, uniform interface, layered system, code on demand (optional)

Does the client and server share or separate responsibilities

seperate responsibilities

Why does the client and server have separate responsibilities

So changes doesn’t affect each other

What is server duties

Store the data, rules, and logic, and provide information (rep of resort Ed) in response to client requests

What is client duties

Makes requests to the server and does something useful with the response.

How does the client and server see each other

Black boxes

What does it mean when the client and server see each other as Black boxes

where each knows the API (the
interface) but not the internal implementation of the other

In some cases, what may the client learn

the client learn the API dynamically from the server

What benefit does this separation Between the client and server provide

Flexibility

What can different types of clients do with the same server

Interact

What comprises does the server have when changing how it stores or manage data

There’s no disadvantages it doesn’t affect the client

Will adding New components or services disrupt the system

No

IN rest, what does each request from the client include and what is done with that item

information the server needs to process it and respond

What memory does the server keep of the previous request or client session state

None

Why does the server doesn’t keep any memory of previous requests or client
session state

treats every request as independent

Why it’s better treating every request as independent

Easier to add more server to handle additional requests, which improves scalability

Imagine a product search: GET /products?type=book . The server might return only the first 10 results. What would we do if we want more.

We must include all the necessary information to get the next set such as
GET /products?type=book&start=25
GET /products?type=book&page=2
GET /products?type=book&limit=25&offset=25

What is the difference between non-restful system and restful system when handling servers

non-RESTful systems often rely on server-side session state. The server
remembers what the client was doing, allowing requests like:
GET /products?type=book
GET /nextPage
GET /nextPage

We have a non restful request,
GET /products?type=book
GET /nextPage
GET /nextPage
What rule does this violate?

Statelessness, server keeps track of the client’s progress

We have a non restful request,
GET /products?type=book
GET /nextPage
GET /nextPage
What would happen if it crashes and compare this to stateless system.

server crashes, the client may lose its session and have to start over. A stateless system, on the other hand, is more robust and scalable

Since each request contains all the information the server needs, how many requests can the server handle

Any

What would happen to stateless system if one server fail.

another can take over without interrupting the client’s interactions.

What does A REST server explicitly indicate

A response can be cached

How is cache headers done in REST

Using HTTP headers (Cache-Control or Expires)

If a response is cacheable, what can the server also specify

How long it’s remains valid

What happens when a client has a valid cached copy

it can reuse it instead of making a new
request

What are the benefits of reusing a valid cache copy

reduces network traffic and server load. Making the system more scalable
and efficient.

consider an image-hosting website. The server stores both images and metadata (e.g., filename, upload date, tags, or description). While metadata may change, the image files themselves usually do not.
How will the server can mark the images and metadata and what are the benefits of doing this.

Images as cacheable for longer periods, while metadata may have shorter cache times or no caching at all. Clients and intermediaries can reuse large, unchanging resources efficiently

What are the benefits of RESTful system using a uniforms interface for the API

predictable, easy to understand, and interoperable across different systems

What are the key aspects of RESTFUL system uniform interface

Identification of Resources, Manipulation of resources through representations, Self-descriptive message, HATEOAS

REST is centered around resources, which are any entities that can be named< what are some of those examples

images, user profiles, orders, or real-time data streams

How are resources created and how are they identified

dynamically generated by the server and uniquely identifiable by a URL that remains constant for its lifetime

Do urls represent nouns or verb?

Nouns

What happen if an API use verbs in the url such as /removeProduct or /updateProduct

Generally are not RESTFUL

In Rest what does the client interacts with the resource

The information, not the resource itself ir it storage mechanism

How is this information formatted in REST when the client interacts with the information and why

JSON and contains all the data needed to understand and work with it

What does the server handle in regards to Manipulation of resources through representations

The actual storage and management of the resource (e.g., by using a database, files, or even other servers)

Does the client need to know how it done when the server handles the storage and the management of the resource? And why?

No as this separation allows the server to
change its internal implementation without affecting the client

What does the client and server do after receiving the resource information

Display the product or let a user interact
with it. The server may later change its internal storage (e.g., move from a database to a file system), but the client still receives the same JSON format, so its code doesn’t break.

In a RESTful system, every request and response should contain enough of what

information to be understood on its own, without relying on previous messages.

In a RESTful system, every message should contain ____ type? And why

each message should contain a data type, which tells the receiver what kind of data it is receiving (e.g., "Content-Type" in HTTP).

Why should RESTFUL system follow the formal meaning of the HTTP verbs

Because these verbs have well-known meanings, clients and servers can interact consistently, which contributes to a uniform interface

What does HATEOAS stand for

Hypermedia As The Engine Of Application State

What does hypermedia links in the server response act in REST and why

Signpost. The client doesn’t need to “know” all URLs in advance; it can simply follow the links provided by the server

Where can the client start to discover and navigate other resources dynamically using hyperlinks?

An inital url

What are the benefits of HATEOAS approach in the client side

Explore relationship(e.g., how a product is linked to its reviews or manufacturer), discover related resources (e.g., similar products), and interact with the system without hardcoding any URLs.

What would be a example of HATEOAS for both client and sever side

a client requests the first page of products like this: GET /products
The server can respond with JSON including products and links:
{
"products": [
{ "id": 101,
"name": "Wireless Mouse",
"price": 29.99,
"links": {
"reviews": "/products/101/reviews"
,
"similar": "/products?category=accessories" }},
{ "id": 102,
"name": "Mechanical Keyboard",
"price": 79.99,
"links": {
"reviews": "/products/102/reviews",
"similar": "/products?category=keyboards" }}],
"links": {
"nextPage": "/products?start=10" }

From this server JSOn file, how would you see reviews for the mouse

{
"products": [
{ "id": 101,
"name": "Wireless Mouse",
"price": 29.99,
"links": {
"reviews": "/products/101/reviews"
,
"similar": "/products?category=accessories" }},
{ "id": 102,
"name": "Mechanical Keyboard",
"price": 79.99,
"links": {
"reviews": "/products/102/reviews",
"similar": "/products?category=keyboards" }}],
"links": {
"nextPage": "/products?start=10" }

To see reviews for the mouse, the client follows /products/101/reviews, to see similar products it follows /products?category=accessories, to see the next page of products it follows /products?start=10

For fully RESTful systems that implement HATEOAS, does the client hardcode url

No it discovers all actions dynamically through the links provided in the responses

Why don’t REST API fully use hypermedia content often

APIs still expect the client to know URLs in advance and don’t provide hypermedia links

For fully RESTful systems that implement HATEOAS, are they considered RESTful even if they use HTTP verbs and URL

No

In REST, the system can be composed of multiple layers of servers or services it the client interact with what as a whole

the system as a whole and never needs to know how many layers exist or how they are structured