Until now we have advanced in some initial concepts about learning Ruby and some other stuff like Versioning, Installing Ruby, RVM and IRB, now we’ve to know about an important concept in the programming world: Packages

In computer science, a package or library is a collection of non-volatile resources used by computer programs, often for software development. These may include configuration data, documentation, help data, message templates, pre-written code and subroutines, classes, values or type specifications. 

A library is also a collection of implementations of behavior, written in terms of a language, that has a well-defined interface by which the behavior is invoked. For instance, people who want to write a higher-level program can use a library to make system calls instead of implementing those system calls over and over again

Link if you want to know more about packages or libraries

This jargon could be a little confusing if you’re a beginner, so let’s simplify the terms and do an analogy. Let’s suppose that you want to create a webpage and you want to allow people to register and then login via web browser. The good news is you don’t have to create everything from scratch, because someone else encountered this very same challenge in the past and they decided to encapsulate and distribute for free a certain amount of code to be used for other people, which is something awesome! But probably at this point you can have some concerns and make some questions

So let’s try to answer this questions

Why is it a bad idea to write everything from scratch if I’m learning?

You don’t want to reinvent the wheel and create from scratch with all the complexities that this could imply to create something that someone else solved in the past and that is for free. If you’re just learning, there are better places to invest your time. Let’s suppose that you want to implement an authentication method, so if you have the enough time, resources and knowledge you can do it from scratch, but if you don’t have all of these prerequisites, it's better to look for a package or library that can implement this for you

Are there packages or libraries for every possible use case?

It depends. For common use cases like authentication, testing or background jobs there are plenty of solutions already implemented, so you don’t have to do it from scratch. But if you want to create something very unique inside your webpage just in that case you have to create your own solution. One time I heard somebody who said that to create a webpage who does something innovative, you can do it with almost 80% with libraries and the other 20% will be your own proprietary code. For this reason knowledge about libraries is so important, because you can create almost 100% of it using libraries written by others in the past. This almost means that there are packages for almost every possible use case, but not for all of them.

Because there is a concept called “Open-source software (OSS)”. This is one of the most powerful concepts in computer software: Open-source software (OSS) is software that is released under a license in which the copyright holder grants users the rights to use, study, change, and distribute the software and its source code to anyone and for any purpose.

Open-source software may be developed in a collaborative public manner. Open-source software is a prominent example of open collaboration, meaning any capable user is able to participate online in development, making the number of possible contributors indefinite. The ability to examine the code facilitates public trust in the software

Open-source software development can bring in diverse perspectives beyond those of a single company. A 2008 report by the Standish Group stated that adoption of open-source software models has resulted in savings of about $60 billion per year for consumers.

Open source code can be used for studying and allows capable end users to adapt software to their personal needs in a similar way user scripts and custom style sheets allow for web sites, and eventually publish the modification as a fork for users with similar preferences, and directly submit possible improvements as pull requests.

For more info about Open Source click here

This is a good question, and it is fair to say that you’ll never be 100% protected, but there are measures you can take when using 3th Party packages or libraries. First thing is to be sure that you’re in the latest versions of the software, because older versions can have security vulnerabilities. Another important thing is to check the Github repository and see how active are the maintainers releasing new code and bug fixtures. A good idea is to use well known packages or libraries, measured by the number of downloads. 

Yes, this concept of Package or Library applies to almost all modern programming languages. In Ruby you can find RubyGem as a package manager along with Bundler. In javascript you can find NPM and in Python you’ll see Conda or PIP. These tools work as main repositories where package or library creators can deploy their code and the users can download it and install it. It works like a marketplace for Packages. 

Gem is the name that Ruby creators give to the open source packages or libraries built to work with Ruby, so if you find a package that deals with the user authentication in a webpage, we call this package a Gem! 

It's time to introduce the most important Ruby Gem: Rails

Rails itself is a Ruby package or library created by David Heinemeier Hansson who decided to release it publicly in 2004 and it helped hundreds of people to create web pages in an easy, quick and affordable way. It’s simple, each time you need to create a web page you have to go through repetitive steps: create a web server, create the skeleton (Routes, Models, Vies, Controllers, etc) and have every file organized in the same way. Because it is a repetitive and standard process you can encapsulate it in different files and code, synchronize everything and make it easy for public use. This is the best example of a package or library

The site where you can find all the Ruby gems is: https://rubygems.org/

Unfortunately this site does not organize gems by use case, they just organize things alphabetically: https://rubygems.org/gems, but with a quick search in Google you could find a gem according to your use case, for instance:

I think that you got it, it's a matter of search and probably you’ll find a gem for almost all use cases. Here I want to share a good resource to see a list of good Ruby gems: https://www.monocubed.com/ruby-on-rails-gems/

You’ve 2 options to install a Ruby Gem, the first one is globally in your machine, the second one is by project. 

Let’s go again to the RubyGems site: https://rubygems.org/ and then we’ll type “Devise” on the search bar

We’ll choose the first one: “Devise” and we can see that they have at this moment more than 115 million of downloads, so it's pretty popular. 

Lets click on “Devise” and we can see next screenshot

We have some information here, but the most important at this very moment is this one

At the right panel we can see the links for GEMFILE and INSTALL. For now we just want to install globally, not per project, because we don’t have any project yet (we’ll do that in next blog posts), so the link that helps us now to achieve this installation is the one that is under INSTALL. If you copy that in your clipboard, this is the code

gem install devise

That command is the one we’ve to type in our machine. So, let’s do it on our Linux machine (remember that we’ve created a different machine, so please refer to the previous blog posts). 

Note: We have to run this command outside the IRB console, if you run this command inside the IRB you’ll get an error. To exit the IRB console just type “exit”

$ ssh -p 22 -i ~/.ssh/ubuntu-webserver-rails.pem [email protected]

$ gem install devise

Output

Fetching rack-2.2.3.gem

Fetching zeitwerk-2.5.3.gem

Fetching warden-1.2.9.gem

Fetching thor-1.2.1.gem

Fetching method_source-1.0.0.gem

Fetching concurrent-ruby-1.1.9.gem

Fetching tzinfo-2.0.4.gem

Fetching i18n-1.8.11.gem

Fetching activesupport-7.0.1.gem

Fetching nokogiri-1.13.0-x64-mingw32.gem

Fetching crass-1.0.6.gem

Fetching loofah-2.13.0.gem

Fetching rails-html-sanitizer-1.4.2.gem

Fetching rails-dom-testing-2.0.3.gem

Fetching rack-test-1.1.0.gem

Fetching erubi-1.10.0.gem

Fetching devise-4.8.1.gem

Fetching builder-3.2.4.gem

Fetching actionview-7.0.1.gem

Fetching actionpack-7.0.1.gem

Fetching railties-7.0.1.gem

Fetching responders-3.0.1.gem

Fetching orm_adapter-0.5.0.gem

Fetching bcrypt-3.1.16.gem

Successfully installed rack-2.2.3

Successfully installed warden-1.2.9

Successfully installed zeitwerk-2.5.3

Successfully installed thor-1.2.1

Successfully installed method_source-1.0.0

Successfully installed concurrent-ruby-1.1.9

Successfully installed tzinfo-2.0.4

Successfully installed i18n-1.8.11

Successfully installed activesupport-7.0.1

Successfully installed nokogiri-1.13.0-x64-mingw32

Successfully installed crass-1.0.6

Successfully installed loofah-2.13.0

Successfully installed rails-html-sanitizer-1.4.2

Successfully installed rails-dom-testing-2.0.3

Successfully installed rack-test-1.1.0

Successfully installed erubi-1.10.0

Successfully installed builder-3.2.4

Successfully installed actionview-7.0.1

Successfully installed actionpack-7.0.1

Successfully installed railties-7.0.1

Successfully installed responders-3.0.1

Successfully installed orm_adapter-0.5.0

Temporarily enhancing PATH for MSYS/MINGW...

Building native extensions. This could take a while...

Successfully installed bcrypt-3.1.16

Successfully installed devise-4.8.1

Parsing documentation for rack-2.2.3

Installing ri documentation for rack-2.2.3

Parsing documentation for warden-1.2.9

Installing ri documentation for warden-1.2.9

Parsing documentation for zeitwerk-2.5.3

Installing ri documentation for zeitwerk-2.5.3

Parsing documentation for thor-1.2.1

Installing ri documentation for thor-1.2.1

Parsing documentation for method_source-1.0.0

Installing ri documentation for method_source-1.0.0

Parsing documentation for concurrent-ruby-1.1.9

Installing ri documentation for concurrent-ruby-1.1.9

Parsing documentation for tzinfo-2.0.4

Installing ri documentation for tzinfo-2.0.4

Parsing documentation for i18n-1.8.11

Installing ri documentation for i18n-1.8.11

Parsing documentation for activesupport-7.0.1

Installing ri documentation for activesupport-7.0.1

Parsing documentation for nokogiri-1.13.0-x64-mingw32

Installing ri documentation for nokogiri-1.13.0-x64-mingw32

Parsing documentation for crass-1.0.6

Installing ri documentation for crass-1.0.6

Parsing documentation for loofah-2.13.0

Installing ri documentation for loofah-2.13.0

Parsing documentation for rails-html-sanitizer-1.4.2

Installing ri documentation for rails-html-sanitizer-1.4.2

Parsing documentation for rails-dom-testing-2.0.3

Installing ri documentation for rails-dom-testing-2.0.3

Parsing documentation for rack-test-1.1.0

Installing ri documentation for rack-test-1.1.0

Parsing documentation for erubi-1.10.0

Installing ri documentation for erubi-1.10.0

Parsing documentation for builder-3.2.4

Installing ri documentation for builder-3.2.4

Parsing documentation for actionview-7.0.1

Installing ri documentation for actionview-7.0.1

Parsing documentation for actionpack-7.0.1

Installing ri documentation for actionpack-7.0.1

Parsing documentation for railties-7.0.1

Installing ri documentation for railties-7.0.1

Parsing documentation for responders-3.0.1

Installing ri documentation for responders-3.0.1

Parsing documentation for orm_adapter-0.5.0

Installing ri documentation for orm_adapter-0.5.0

Parsing documentation for bcrypt-3.1.16

Installing ri documentation for bcrypt-3.1.16

Parsing documentation for devise-4.8.1

Installing ri documentation for devise-4.8.1

Done installing documentation for rack, warden, zeitwerk, thor, method_source, concurrent-ruby, tzinfo, i18n, activesupport, nokogiri, crass, loofah, rails-html-sanitizer, rails-dom-testing, rack-test, erubi, builder, actionview, actionpack, railties, responders, orm_adapter, bcrypt, devise after 89 seconds

24 gems installed

Because it is the first time we install a gem, we’ll end up with other dependencies installed. As you can see, Devise uses 24 of them. In a previous post we talked about Dependency Managers, so you can check it out to understand this more in detail

Now you may be asking about what makes the “Devise” gem that is so popular? Devise deal with user authentication in webapps, and if you think a bit about it, is a repetitive process, something that you’ll need almost always in your web apps, and you don’t have to write this functionality from scratch. That way is so popular. 

This is enough for this post, next time we’ll be using Ruby Gems a lot, so if you don't get it now, don’t worry, just keep your learning peace

Thanks for reading 

DanielM