API and Web Service Introduction

Define API by its components—application, programming, and interface—and explain how interfaces let programs run in applications, offering platform independence and upgrade safety.

Explore the core of APIs by identifying the interface, program, and application across four examples, and learn essentials like XML, JSON, REST, POST, Python, and Postman.

Explore the world of APIs by examining definitions. Use the ebay API in sandbox to search items, learn about endpoints, and understand the role of access tokens.

Explore how API transactions work through a 3-step flow—request, program execution, and response—using Google search and eBay API examples.

Explore how web service requests use urls and query parameters, including q for searches and tbm=isch for image search, with optional parameters that can be omitted.

Explore what an API mashup means by combining elements from multiple APIs into one app, using the Travelocity interface to call many airline APIs for flight times and prices.

Explain what a web service is, and how it differs from an API, highlighting that web services use the web, with XML and JSON data and REST or SOAP protocols.

Advance from the first section by reinforcing what an API is and what a web service is, then dive into the details of APIs.

Learn how APIs use HTTP to form web services over the internet, detailing the four parts of a request—the start line, headers, blank line, and body, including common methods.

Review http basics: an internet api is a web service. http stands for hypertext transfer protocol, with four parts: start line, headers, blank line, and body.

Explore the four parts of HTTP: start line, headers, blank line, and body, in detail with a PowerPoint walkthrough, beginning with the start line.

Explain the HTTP start line in requests and responses, including method, folder, parameters, and version. Show idempotence: get is repeatable, post creates, while put and delete are idempotent.

Identify the HTTP start line in a request: method, the API program folder if it exists, the parameters if you have them, and the HTTP version; POST is not idempotent.

Explore how HTTP headers structure requests and responses, covering common headers such as Accept-Language, Authorization, Cache-Control, Content-Type, Date, and Host, plus Set-Cookie and Expires for caching.

Explore http header lines and learn how header information is structured through a hands-on exercise, using the Google homepage as an example.

Explore the role of the http blank line in http messages. It separates header lines from the body, signaling where headers end and the body begins.

Explore how the http body carries content in requests and responses, and how the content-type header defines json, xml, and other types for APIs.

Explore how the HTTP body carries content in requests and responses, how the Content-Type header describes that content, and why XML and JSON are essential for API data exchange.

Understand how http remains stateless by default, how cookies with session ids and tokens preserve sessions across requests, and how load balancers and app servers enable scalable infrastructure.

Learn how XML, an extensible markup language, uses tags to describe data in APIs, differs from HTML, and how XML schemas (XSD) and W3C standards guide structure, validation, and security.

Create an XML file on your own or based on the pizza XML provided, then save with the .xml extension and open it in a browser.

Explore JSON, the JavaScript object notation that holds data with key-value pairs, using quotes for strings and no quotes for numbers, as Douglas Crockford created it for HTTP using application/json.

Create a JSON file by following the pizza example, write it in a text editor, save as .json or .js, and open it in a browser, preferably Firefox.

Compare XML and JSON for data transport over HTTP, noting XML's power via XSLT and schemas versus JSON's simplicity and rising popularity; learn API requirements and when to choose each.

Compare soap and rest as web services over http, and examine their popularity and job trends.

Explain soap and its form simple object access protocol, then show how it uses HTTP with XML and a WSDL to access a web service, outlining the required HTTP structure.

Explore soap and rest through holiday and soccer data examples, compare rest to soap, and learn to call WSDL-based soap and rest endpoints with Postman and the sport data API.

Explore SOAP basics: stands for simple object access protocol, SOAP APIs use HTTP to transfer XML with a text/xml content-type; WSDL describes the service, and W3C created SOAP.

Explore how REST, the modern API approach, uses HTTP methods like get, post, put, and delete to perform create, read, update, and delete operations, contrasted with SOAP.

Learn what representational state transfer is and how it enables web service APIs over the internet, using HTTP methods like GET, POST, PUT, DELETE, and flexible request bodies.

Learn to call the eBay rest apis in a sandbox, authenticate with a token, and perform a get search for five computer items using the browse api.

Explore REST fundamentals, including Representational State Transfer and the main methods GET, POST, PUT, and DELETE. Learn about flexible HTTP body content types and Roy Fielding, the creator of REST.

Learn how https secures API calls over the internet by encrypting http traffic, protecting data from view, and using the url with a lock to indicate security.

Differentiate authentication from authorization in API use by proving identity with credentials and granting limited access. Explore examples from no authentication to bearer tokens, OAuth, and two-factor authentication.

Explore how native, web, and hybrid apps work, including operating systems, APIs, and app installation, and compare quality, speed, and cost to help choose the right approach for your project.

Explore OAuth 2.0 and its flow for granting limited access to a resource owner's data, with access and refresh tokens and the roles of resource server, authorization server, and client.

Explore the OAuth 2.0 authorization code grant flow, including client registration for a client ID, redirect URI, PKCE, and exchanging authorization codes for access and refresh tokens.

Discover OpenID Connect extends OAuth 2.0 by providing resource owner details via an ID token. Use the OpenID endpoint and JWTs to access that information alongside the access token.

Define https as hyper text transfer protocol secure and explain authentication, authorization, native vs web apps, OAuth, and access tokens.