austin day of rest - introduction

Introduction to the WordPress REST API Nick Batik

Nick Batik PleiadesServices.com

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What Is an API?

http://pleiadesservices.com/



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What Is an API?• API is short for Application Program Interface.

• An agreed set of standardized ways that a particular software program can be used;

• The rules define how one program can talk to a another, and how it will respond.




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What Is an API?

ApplicationAPI

I WantInformati

onFrom You

What info I want

The app’s info

I HaveInformati

onFor You

What info the app needs

Did the app accept it?




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Classic Problems of APIs• How do you know the rules?

• The content is different for each rule

• You can’t change the rules




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What is REST?• Uniform Interface

• Resources

• Representations

• Hypermedia (Links)

• Metadata




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What is REST?• Stateless

• Cacheable

• Client-Server

• Layered System

• Code on Demand (optional)




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What is a REST API?

A REST API defines a set of functions developers can use to perform requests and receive responses via HTTP protocol such as GET and POST.




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What is a REST API?

Databases have 4 primary function - CRUD:

• Create

• Read

• Update

• Delete




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What is a REST API?

The REST API implements the 4 main database functions in through the HTTP protocol:

• Create = PUT with a new URI

• POST to a base URI returning a newly created URI

• Read = GET

• Update = PUT with an existing URI

• Delete = DELETE




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What is a REST API?

REST API turns the internet into the world’s largest database




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Acronym, Initialization, and Other Jargon•HTTP Verbs

•HTTP Methods

•URLS, routes and Endpoints

•Representations

•Response Codes

•JSON




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HTTP Verbs•GET

•PUT

•DELETE

•POST

• HEAD

•OPTIONS




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HTTP Methods•Safe methods

•Unsafe methods

•Idempotent methods




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URLs, routes and Endpoints•Routes are URLs

•Endpoints - actions taken (HTTP verb) on the URL

e.g. GET http://example.com/wp-json/wp/v2/posts/123POST http://example.com/wp-json/wp/v2/posts/123

•“GET” and “POST” are endpoints

•“wp/v2/posts/123” is the route

•/wp-json/ is the API “base”




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URLs, routes and Endpoints

You can expose services in different endpoints:

http://www.example.com/soaphttp://www.example.com/jsonhttp://www.example.com/xml




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Representations•The HTTP client and HTTP server exchange information about resources identified by URLs

•Both request and response contain a representation of the resource

•The header and the body are part of the representation

•HTTP headers contain metadata, defined by the HTTP spec



https://en.wikipedia.org/wiki/List_of_HTTP_header_fields


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Representations•The HTTP response should specify the content type of the body, example possibilities include:

•HTML

•XML

•XHTML

•SOAP+XM

•JSON



http://www.freeformatter.com/mime-types-list.html


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Response Codes

•405 Method Not Allowed

•409 Conflict

•410 Gone

•500 Internal Server Error

•501 Not Implemented

•200 OK

•201 Created

•400 Bad Request

•401 Unauthorized

•404 Not Found




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JSON•JSON: JavaScript Object Notation.

•JSON is a syntax for storing and exchanging data.

•Human readable / writable

•Machine parse-able




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JSON - Example

{"employees":[

{"firstName":"John", "lastName":"Doe"},

{"firstName":"Anna", "lastName":"Smith"},

{"firstName":"Peter", "lastName":"Jones"}

]}




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JSON - Example

{"menu": { "id": "file", "value": "File", "popup": { "menuitem": [ {"value": "New", "onclick": "CreateNewDoc()"}, {"value": "Open", "onclick": "OpenDoc()"}, {"value": "Close", "onclick": "CloseDoc()"} ] }}}




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The WordPress Implementation of REST API• WordPress as a Data Store

• WordPress as an Editing Interface

• Access and Authentication




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The WordPress Implementation of REST API

WordPress as a Data Store

https://css-tricks.com/thoughts-on-an-api-first-wordpress/




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The WordPress Implementation of REST APIWordPress as an Editing Interface

•WYSIWYG / Text Editor

•Media Library

•Plugin Functionality

•Database Customization

•Custom Interfaces such as Calypso




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The WordPress Implementation of REST API

Access and Authentication

•cookie authentication

•OAuth authentication

•basic authentication




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WordPress REST API – Conclusion•Open WordPress to new front-end platforms

•Heralds a new era in content exchange

•Introduces new levels of complexity



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