Adam Albrecht

independent ruby & javascript developer in columbus, ohio.

Authorization with Angular.js and UI-Router

While working on an angular.js application recently, I found myself needing some form of authorization logic (not to be confused with authentication / login). I needed to restrict content in my app based on a user’s role as well as some other factors. At first, I created a single AuthService service that dealt with login, authorization, and session management. But this felt messy and violated the Single Responsibility Principle, so I decided to make something cleaner. My goal was for the API to look something like this:

(Warning: lots of coffeescript ahead!)

LoginService.login(email, password).then((u) ->
  Session.setCurrentUser(u)
)
# ... Elsewhere ....
user = Session.getCurrentUser()
authorizer = new Authorizer(user)
authorizer.canAccess(APP_PERMISSIONS.viewAdminSettings) # returns a boolean

By doing it this way, I was fairly sure I could split my formerly monolithic AuthService into 3 separate services that had no dependencies on one another. I won’t go too detailed into the login and session services because they are fairly straight forward. LoginService has one method that simply makes an HTTP request with a username and password and, if successful, returns the user object. Session is a singleton service that, given a user, can create or destroy the current session. But my solution to Authorization was fairly interesting, so I thought I’d share.

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Building your Angular app with Gulp.js

As my work has transitioned from traditional web apps to thick-client Javascript apps (primarily using Angular), Grunt has become essential in my workflow. Grunt is a nice tool and it gets the job done. But there was always something I didn’t like about it that I couldn’t quite articulate until I discovered Gulp.js. Whereas in Grunt, you create a json configuration file, Gulp is just a script. It’s code. And it really fits my programmer brain better. In this post, I’ll convert a basic Gruntfile that compiles and minifies Coffeescript into Gulp.

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Pre-Filling PDF Form Templates in Ruby-on-Rails with PDFtk

In a recent post, I talked about how to generate PDF reports in Rails using Prawn. This approach is great for generating PDF’s with lots of data tables and other variable-length content. But an alternative situation is when you already have a template authored in an application such as Adobe Acrobat and you want to populate it with data from your database. This makes it more difficult to insert variable-length content, but on the plus side, you no longer need to worry about the layout of the document.

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A Better Onboarding Experience in your Angular.js Application

“Onboarding” is one of those things we sometimes forget about when developing an application, but it really deserves more attention. Showing the user how to use your app can be critical in retaining them. Some people might say that if you need onboarding, your app just needs to have a better UX, but I don’t think this is practical in all situations, particularly complex business applications.

For my current Angular app, I wanted a nice way to point out and explain the various features of the application right after signup. I looked through a few javascript plugins such as Tourist.js, Guiders.js, and a few others, but none seemed to work well with angular, so I decided to write my own, which I’m calling ngOnboarding.

ngOnboarding

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Generate Clean, Testable PDF Reports in Ruby/Rails with Prawn

I generally hate PDF’s. The file format is complex and designed to mimic physical paper documents, which really has little to do with the web. But unfortunately, PDF’s are still very common and often expected, particularly when working on businesses applications. I have a legacy ruby-on-rails application with a number of PDF reports and I recently took the time to refactor them in a clean and testable manner. Here’s how I went about that process:

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