Book Image

Angular Services

By : Sohail Salehi
Book Image

Angular Services

By: Sohail Salehi

Overview of this book

A primary concern with modern day applications is that they need to be dynamic, and for that, data access from the server side, data authentication, and security are very important. Angular leverages its services to create such state-of-the-art dynamic applications. This book will help you create and design customized services, integrate them into your applications, import third-party plugins, and make your apps perform better and faster. This book starts with a basic rundown on how you can create your own Angular development environment compatible with v2 and v4. You will then use Bootstrap and Angular UI components to create pages. You will also understand how to use controllers to collect data and populate them into NG UIs. Later, you will then create a rating service to evaluate entries and assign a score to them. Next, you will create "cron jobs" in NG. We will then create a crawler service to find all relevant resources regarding a selected headline and generate reports on it. Finally, you will create a service to manage accuracy and provide feedback about troubled areas in the app created. This book is up to date for the 2.4 release and is compatible with the 4.0 release as well, and it does not have any code based on the beta or release candidates.
Table of Contents (15 chapters)
Angular Services
About the Author
About the Reviewer
Customer Feedback

Cron job versus Interval/Timeout

As you know, there are native JavaScript functions such as setInterval() or setTimeout(), which can run certain tasks periodically. But the main reason that they are not practical here is their limited lifespan. In other words, their life depends on the JavaScript host (mostly browsers) that executes them. Kill the browser process and they are long dead. This is not ideal, because we need a reliable process that runs in the background - possibly forever - and gathers news and sends emails without requiring to leave a browser window open 24/7.

For that reason, we need something on the system level and Cron jobs sound like a perfect choice for this matter. System administrators have been using them for decades and all we need is to run a command with a bunch of parameters inside a terminal window. With this solution, we can achieve our goal in three steps:

  1. First we need to generate a .js file so we can call it from the command line. We can continue creating TypeScript...