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RESTful APIs

Team I Tech Talk

Wid Alsadoon - Fariha Marzan - Janet Mbugua - Natalie Yuziuk

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Background

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History

Previously (1999): SOAP (Simple Object Access Protocol)

Handwritten XML document with Remote Procedure Call
Specified endpoint, POST SOAP envelope to endpoint
Notorious for being complex and NOT simple

Then (2000): Roy Fielding & colleagues set to create standard

Uniform interface (HTTP verbs: GET, PUT, POST, DELETE)
Stateless (self-descriptive requests)
Client-Server (Clear boundaries set)
Cacheable
Resource based

Natalie

First off, I’ll start by touching on the history surrounding Rest APIs.

In 1999, before REST, developers used SOAP to integrate was APIs. It was very complex, despite the S in the acronym standing for simple. Developers had to handwrite an XML document with a Remote Procedure Call, or RPC, in the body and then post the envelope to a specified endpoint; It’s a more rigid set of messaging patterns as opposed to REST’s flexible, lightweight implementation.

Roy Fielding and other developers created REST api as a standard so any one server can talk to any other server. Constraints were defined and these universal rules made it simpler for developers to integrate necessary software. You can see here the rules that will be delved into later in the presentation.

From then on, notable moments were the e-commerce giants: eBay and Amazon building their own REST APIs in 2002, followed by Flickr, Facebook, and Twitter in the years after.

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Definition

API (Application Programming Interface):

a set of rules that define how applications or devices connect to and communicate with each other

REST API (Representational State Transfer API):

An API that conforms to the design principles of the REST style; e.g. GET, POST, PUT, DELETE

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Key Features of RESTful APIs

RESTful API is:

Stateless, meaning that each request contains all the information necessary for the server to understand and fulfill the request
Resource-based, meaning that resources are identified by unique URIs (Uniform Resource Identifiers)
Supports a limited set of operations, typically HTTP verbs such as GET, POST, PUT, and DELETE
Designed to be cacheable to improve performance and scalability

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Purpose

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Benefits of RESTful APIs

It is widely used and supported, making it a popular choice for web services
Flexible and can be used in a variety of contexts, from simple web applications to complex enterprise systems
It is easy to understand and use, making it accessible to developers of all skill levels
It promotes good software design practices, such as separation of concerns and modularity

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Motivation

Client and Server Communication is vital to applications!

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Function Usages

GET: allows server to find requested data and sends it back
PUT: server will update an entry in database
POST: permits server to create new entry in database
DELETE: allows server to delete entry in database

Example: GET api.marker.io/?color=Black

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How we’re using Rest API

Express.js used as backend framework for building RESTful APIs with Node.js

Controllers required for each survey type

Natalie:

Before we go into our simple demo that showcases the GET and POST requests from RESTful API, I’ll give a brief overview of how we’re using REST API in our semester long project since it includes all of the main REST operations. Firstly, we add express to our code since it’s used as the backend framework for building RESTful APIs with Node.js. We also require express.router, a class that is used to create modular, mountable route handlers. After this, we add the paths to each of the controllers for each survey type. Our surveys from our project each have their own database collections in mongoDB that store the user id’s, dates, numbers, and other information to be retrieved or used in calculations in the future; an example of the implementation for the personLevelController can be seen on the following slide.

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How we’re using Rest API

GET, POST, DELETE from REST seen above…

PATCH is like PUT, but only updates fields instead of entities (introduced to reduce bandwidth usage)

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How we’re using Rest API

Example of person survey GET; used for retrieving person survey records from Mongo database or throwing error if the action fails

Natalie

This get all records function goes further into a the get all records from db function, where it finally uses a built in mongoose function to check for any documents within the person level collection within the mongo database. All of these layers within the GET request will eventually lead to the request being successfully completed, returning all of the records within the databases’ collection (even if there are none), or will result in an error, giving an alert that something has gone wrong and that the records were not able to be retrieved.

This snippet of code is just one of the many requests that we made in order to connect our surveys to the data in mongoDB, so it’s easy to see how useful the simplicity of RESTful API is. We used the REST api architecture in order to be able to retrieve, delete, edit, and make new records to store in our mongoDB server cluster while keeping our code in a form that will be easy to use with different clients and devices as well.

I also included here a really short clip of the interface using the 4 operations we discussed earlier.

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How we’re using Rest API

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Demo

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Follow Along!

Link: https://github.com/WidAlsa0/RESTful-APIs

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Step 1: Initialize Server

Importing path, express

& body-parser

Initializes the Express server and sets it to a variable called app

Initializes the body-parser plugin

Setting our server to listen on port 5000 for requests

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Step 2: GET data from REST server

Creates function for API to use on request. Calling GET request on ‘/’

Using .sendFile, any file can be sent as a response. In this particular case, the user will access the index.html page when they try to navigate to ‘/’.

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Step 3: Connect to server

If successful, should return a corresponding statement such as:

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Step 4 : POST data to REST server

Then returns the output to the REST server via POST

Within index.html

Creating a power function takes in the requested input and raises it to the power

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Step 4 : POST data to REST server

Add function takes in the requested input and raises it to the power

Multiply function takes in the requested input and raises it to the power

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Demo Clip

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Bad Service Requests

01:

Incorrect spelling of the url, or the parameter passed through is unknown

02:

Request of a nonexistent resource

03:

Too many resource requests

04:

Higher permissions needed (API Key)

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Let’s Try It Out

Choose one of these fun databases to pick from so you can try it!:

https://www.fruityvice.com/#3

Retrieves in depth information of fruits taxology and other information**

https://dukengn.github.io/Dog-facts-API/

Retrieves randomized dog facts. The number amount can be specified in the URL

https://github.com/robertoduessmann/weather-api

Retrieves weather information for a city for a specified time period

https://opentdb.com/api_config.php

Retrieves trivia questions that are customizable on difficulty, topic category, etc**

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Q&A

(Questions?)

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Possible questions:

Alternatives to REST: https://blog.bitsrc.io/not-all-microservices-need-to-be-rest-3-alternatives-to-the-classic-41cedbf1a907