Riot

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APIs

Client <--> REST API <--> Resource

API sends data to client from the resource

GET retrieves data and sends it to the client - often via JSON or XML

PUT inserts data into the resource then returns the result to the client

Represntational State Transfer - architecture design constraints that produce efficient, reliable and scalable systems

rest is not a specific technology

Web Application - each page is a view representing the current state - application sends URI (universal resource identifier) request for a resource to the API, then uses the data to build the view

Application Programming Interface (API) - set of rules and features in a prgoram enabling it to interact with other items, such as software or hardware

URI - URL is a subset of URI. Like URIs, URLS is a unique identifier, but also provides a method of access (such as http:// or ftp://

Within REST APIs, we can use URLs or URNs (Universal resource names - just name of the resource). Both of these are types of URIs

REST Constraints

1. Client-Server architecture - The client manages user interface concerns while the server manages data storage concerns

a. this allows for a complete separation between the content and its representation

b. this also means that multiple clients can interact with the REST server at once

2. Statelessness - no client information or content can be stored on the server

a. in some cases (like authentication keys), the information must be passed to a database and stored for a set period of time.

3. Cacheability - All REST responses must be clearly marked as cacheable or not cacheable. this ensures caching works as expected on the client end.

4. Layered System - The client cannot know - and shouldn't care - whether it's connected directly to the server to an intermediary like a CDN or mirror. This helps with security and scalability

5. Code on Demand - Servers are allowed to transfer executable code like JS and compiled components for clients

6. Uniform interface

6.1 Resource Identification requests - the URI must specify what source its looking for and what format the response should use (i.e. asking for a SQL table in JSON or XML)

6.2 resource manipulation through representations - once a cient has a representation of a resource, it can modify or delete the resource

this essentially means that the client can control what's stored on the server

6.3 Self descriptive messages - Ech representation must describe its own data format - without that, the data can't be reliabvly parsed

6.4 Must use Hypermedia as the engine of the application - Once a client has access to a rest service, it should be able to discover all available resources nd methods hrough the hyperlinks provided (i.e. the resource returned describes it's use)