Implementing REST services in AngularJS using Restangular

Current web development trends are in favour of AngularJS. The framework is having its momentum and is one of the most popular choices for client side development frameworks. Personally, I like it a lot, it makes my job easier to jump start the web development projects quickly. It is also useful for hybrid mobile applications.

Another thing that has quite a momentum for some time now is implementation and consumption of REST services. REST as an architecture, although it makes things easier after implementation, is an architectural style which is very easy to get it wrong, despite most of the time what we need is simple GET/POST/PUT/DELETE requests.

Restangular is an AngularJS service which makes GET/POST/PUT/DELETE requests simpler and easier. The configuration is easier and can be done in several ways with different initiation settings. Let me try to put an easier demonstration on how to use Restangular on your site and how easy it is to make your AngularJS app consume RESTful service.

Configuration

The first thing to do is to reference restangular in your index.html (refer to official page for installation).

To configure restangular with your AngularJS app, in your app module definition file you configure restangular settings.

Now that we have restangular configured, we can make requests for resource like this:

Alternatively, we can also create services for our resources. For e.g. if I have a resource named students, I would create the service through these lines of code:

then I would add this service as a dependency to the controller that I want to use it in. With this simple service definition, I can now easily initiate GET/POST/PUT/DELETE requests through restangular.

Let us take some examples. We can read all students by requesting

or if I want to read the student with id 1234 I would request

Saving a student is also as easy as getting it

Restangular has the main request types GET/POST/PUT/DELETE almost ready made for us, but also it allows many things to be configured per our needs. We can make custom requests to custom methods, specify parameter names, and many other not so standard things. Please refer to restangular’s github page for detailed specifications.

As it makes RESTful api consumption so simple, currently it is one of my favorite parts of my AngularJS apps.

Implementing loading animation in AngularJS and jQuery

With the advancement of web development technologies, web application are closing the user experience gap with desktop applications very quickly. It is a very common practice to let the user know when the application is busy with a certain task, and one of the most common ways to do this is by showing a loading indicator or a spinning gif. This will let the user know that the application is working and he or she will not try to refresh or press other buttons until the task is finished.

To implement this, before the task is initiated at server, we must show our spinner or any loading animation we want to show, and then when the task is finished (successfully or unsuccessfully) hide the animation. I will show you how you can do it using jQuery and using AngularJS.

Implementing loading animation in jQuery

Let us start with the jQuery. I want to show a spinner whenever I post something to the server from the form, until I receive a response. Let us suppose we have a form like this:

and I have a div with a spinner gif img inside it somewhere in the html

At the beginning, I need to make this hidden, so you can put a css style display:none  or hide it using jquery or whatever way you like most.

There are several forms to determine how to show the spinner and hide it. One way is to bind to subscriptionForm ajaxSend and ajaxComplete events to show and hide the spinner respectively.

This will make the spinner show when a ajax request starts from that form and disappear when the request completes.

If it is the case that you need to make the spinner show for every ajax request made within the page, then you may need to bind the events to the DOM.

You can also make the spinner show as a modal dialog by applying a style like this and adding class ajax-loader to the spinner img element:

This will make the spinner show in a modal dialog and prevent the user from initiating any other requests before this one finishes.

Implementing loading animation in AngualarJS apps

The strategy for implementing the loading animation in AngularJS is little different and requires a bit of a setup. To catch the start and end of requests, in AngularJS we must create http interceptors for request and response. Interceptors will intercept requests before they are handed to the server so we can show our spinner and response before it is handed to the client so we can hide the spinner.

To get the interceptors, we need to register them through an anonymous factory  and inside request and response functions, we need to show and hide the div of spinner respectively.

Interceptors are a useful part of AngularJS which can be used to make several kinds of validations before a request is made or after a response is received (authentication validations, etc.), and one of the tasks we can put here is also to show and hide the spinner when a request has started and completed (please be aware that for the simplicity of the code, I have omitted functions which check for errors on requests).

To make the example more clear, I have create a sample interceptor demo in a Plunker, you may see it here http://plnkr.co/edit/hAg1T8sdsLq5c61iW97f?p=preview

This was a simple post to show you how is implementing loading animation in AngularJS and jQuery done. Of course your scenario may have additional or more complex requirements but this should serve as a basis to set it up.

Multilanguage AngularJS apps

Last two years, almost every project that I have worked on, has had the requirement of multilingual graphical user interface (GUI) and messages. This scenario may be important if your country has a multilingual environment or if you are opening to international markets and want to give your users the best possible user experience. The former is little easier as the number of supported languages is usually lower than the latter.

So, what is the problem definition here. We need to support dynamic language setting in GUI for two types of components:

  1. Labels
  2. Dropdown lists

In order to define the actual language the user is using, we chose to use a route parameter for it. Our route became something like this:

Route parameter :lang enabled us to get the user’s current language by calling

Then, we used angular library angular-translate which happened to be very convenient and easy to use for us. The setup is pretty easy. You include angular-translate.js file in your index.html and require reference to ‘pascalprecht.translate’ when defining your module, e.g.

After this, we create a json file for every language we wanted to define, eg. en.js file will contain the labels for English language (sq.js for Albanian, and so on), and it looks like this:

We also need to tell our app the translation configuration. I like to do this in a separate configuration file which I call translation.js (don’t forget to reference it in index.html) and it looks like this:

If later I want to add a translation for Albanian language, I will create one file sq.js which contain the translations e.g.

and I will add this line of code to the translation.js file

and the new language is automatically supported.

Now, in the controller that we want to use translation, we need to to tell the language to be used and we do it like by getting the param from route and pass it to $translate object:

In the view, we put the dynamic labels and messages by using an angularjs binding and filtering it with translate

Here we are, our labels will be translated automatically based on the route parameter :lang.

The labels are translated, now we need to translate the dropdown lists. To support list translation, as we already had a small number of languages to be supported, we chose to save list values in the database lookup tables in all languages, so basically, every lookup table has a structure similar to this:

id name_en name_sq

and when we return the json object for the lookup values, we return an object similar to the object below and bind it in our controller to a scope variable list

then our html select element will look like this

In this way, our ng-options will get automatically the language from lang parameter set in $scope from the $routeParams and it will automatically get the lookup name for the specific language

This might not be the best way to implement multilanguage angularjs apps but it worked pretty well in our case and in several other projects I have worked on.

Hope it helps to you as well.

I want to create a website

Having your own website is one of the best things you can do if you are planning to have a serious online presence. Of course it is not a silver bullet solution, as it requires constant investment of time creating valuable content and marketing, but it is ultimately the starting point people will check about you online.

So, I want to create a website. What are my options? What should I do next? In this post, I will consider several options you may follow to create your own web site. Fortunately, there are a lot of options available to choose from, starting with ready made solutions which you may set up with very few clicks, to those which require advanced knowledge of some technologies. Unfortunately, I will not be able to list here all available options, but I will try to make a list of options which may suit most of you out there trying to create your own web site.

1. Free blog with WordPress.com

If what you are looking for is just a blogging website and you want it for free, wordpress.com may be the best choice for you. They have a managed wordpress hosting solution for which you may sign up and get your own blogging solution set up with a few clicks. This solution could be a good start if you want to try yourself blogging and create an online presence without investing any money. Though, this free solution comes with some limitations. You get a domain as http://yourname.wordpress.com and few free themes for your site. If you want a custom domain name like www.yourname.com, or a better design for your site you have to pay for it. You are also not allowed to install your own themes (if you already have one, or want to custom build one), but only choose from available ones there (free or paid).

2. Managed hosting with wordpress site

If limitations of wordpress.com do not fit you well, you may decide to go with a managed hosting where you may setup a wordpress site. I happen to prefer wordpress as my CMS of choice, otherwise, you may chose to set up a different CMS with your hosting provider depending on the type of hosting you have and the CMS you have chosen. With a manage hosting, you may chose your own domain, buy or develop a custom theme for your site, and do many more customizations which are not possible with free wordpress.com solution.

There are plenty of companies offering managed hosting solutions, and all of them vary in price and features they offer. Some of the popular hosting companies I have come over are GoDaddy and BlueHost.

3. Managed hosting with a custom solution

Another choice is to have a managed hosting solution with a custom web site developed for you. This is more powerful than above mentioned solutions as you have the option to chose everything (from colors, fonts, to design and features developed), however, it is more expensive. Depending on the market you live, developing a custom web site may cost you from several hundred dollars to several thousand dollars.

4. Private hosting

Private hosting is an advanced solution, mostly suitable for companies, where you get a private server rented for you from a hosting company. The hosting company creates the server (be it real hardware server or a virtual one), connects it to internet, but leaves the management of the server environment to you. This has huge advantages as you control what is installed in the server, what features do you want to offer, and it is very easy if you want to add some unsupported technology to your solution. However, it is also very expensive and requires technical skills of system administration and system security as this task is on you now.

5. Cloud solution

Cloud solution is a superset of private hosting. If you choose to have a cloud solution with one of the biggest market players in this industry (Microsoft Azure, Amazon AWS, Google Cloud Computing), then you not only have the server on your control, but a whole IT infrastructure. You have the possibility to create virtual servers, website hosting, email services, active directory services, storage and backup services, and many other IT infrastructure components as a service. This powerful solution requires you to have a very good understanding of IT infrastructure configuration, but as a benefit, you get a flexible IT architecture which can scale up and down as needed and you pay for what you use.

Conclusions

Which one is right for you? Well, it depends. Your needs define what is best for you, but generally speaking, amongst these, number 2 and number 5 are my favorites. So, if I want to create a website for myself, or you are an individual or a business who wants to have a blog or a personal/company site which is for online presence, then I think option number two is the best choice as it has the possibility to scale up with a custom solution or stay with a WordPress or a specific CMS. If you have a startup which is offering a SaaS or any other solution that you expect to have increasing demand, then I think option number five is the best as it offers you the possibility to start small and grow as needed. Of course these come with the complexity of knowledge required, but it will be worthy to invest in that direction.

Developing hybrid mobile apps with Phonegap, AngularJS, Bootstrap

In this post I am going to talk about developing hybrid mobile apps with Phonegap, AngularJS, Bootstrap. In my post Develop mobile applications using web development skills, I pointed out a list of possible frameworks which can be used to create a hybrid mobile app. My favorite choice so far is using Cordova/Phonegap (Read my post on my opinion about Cordova/Phonegap) in combination with a hybrid app development framework. In my previous mobile applications I have developed, I used to use jQuery mobile as my framework of choice for developing the UI of my apps. Nowadays, I have switched to another combination, which is:

Cordova/Phonegap + AngularJS + Bootstrap

The hybrid mobile app architecture with Phonegap, AngularJS, Bootstrap looks like this:

The presentation layer is built with Bootstrap framework, the app domain is modelled using AngularJS, and the is packaged using Cordova/Phonegap to a native app. Let us go through the components of this hybrid mobile app architecture and describe them.

Bootstrap

Bootstrap is a mobile-first responsive front-end framework. What this mean? Bootstrap has an easy to use responsive grid which allows you to position your layout in a well structured responsive way. As the framework is built with mobile use in mind, it responds well to different screen sizes and adapts the layout of the app easily to different screen sizes. This is a good possibility to use the very same implementation for tablet and mobile devices of different screen sizes. And it is not only the grid that makes it special. It helps you manage typography, responsive images, forms, form validation messages, notification messages, responsive tables, and a good number of UI components. You can download it from getbootstrap.com.

AngularJS

AngularJS

AngularJS

A very powerful, full-featured JavaScript MVW framework. With AngularJS framework, you can give a structure to your app domain model and manage your app logic in a very flexible way. Everything is organized around a model which is displayed through a View. Views can be well structured templated HTML code styled and organized using Bootstrap. Controllers organize the communication between the View, Services, and all other parts. The framework supports a good routing mechanism, which can also be extended by other extension libraries for more powerful functionalities. There are a plethora of extension libraries for AngularJS which add value to the framework by filling in the gaps of the framework. You can get AngularJS from angularjs.org.

 

Cordova/Phonegap

Cordova is an Apache project which creates an underlying platform for developing multiplatform mobile applications. In our case, it makes possible the AngularJS+Bootstrap web app to be packaged to a native mobile app which can be published to the mobile markets and be instlalled in mobile devices. Adobe PhoneGap is a distribution of Cordova.

Basically what Cordova does is to make possible the web app to run inside a WebView component of a native app, we can say it as a native package of a web app. You can do the packaging using Cordova Command Line Interface (CLI) or using Adobe PhoneGap Build which does not require any installations.

The most powerful feature of Cordova in my opinion is the extension possibility by plugins. By installing specific plugins, you get access to device’s hardware such as camera, compass, geolocation, as well as other device specific APIs such as contacts, media, notifications, etc. Very powerful plugins such as barcode reading, push notifications, and many more, can give your application good features by writing few lines of code.

The development process

As we described the architecture parts, let us start with the process of developing hybrid mobile apps with Phonegap, AngularJS, Bootstrap. We start with creating a sample application  which shows you your current location coordinates and demonstrate the development process. The easiest way to start the app development is by creating initial template using Cordova/Phonegap CLI. We do this through this command (if you do not have cordova cli installed, here is the link showing how to do it: https://cordova.apache.org/docs/en/4.0.0/guide_cli_index.md.html)

The create command requires 3 arguments:

  1. The directory name to be created for generation of the project, in our case “blogSample”
  2. The second argument is the project identifier, in our case “com.ariancelina.blogSample”. Usually it is used as a reversed domain name identifier
  3. The third argument is the display title of the application, in our case “BlogSample”

In this sample code, I used phonegap to create the app. The command equally applies to cordova as well.

If you already had phonegap installed and the app was created successfully, inside blogSample directory you should have a config.xml file and four other directories (hooks, platforms, plugins, and www). Platforms folder contains builds for specific platforms, plugins directory contains installed plugins, and WWW directory contains all our web code (AngularJS + Bootstrap + other files).

To read our location coordinates we need to install the Geolocation plugin (Find the list of plugins) and we do that by executing this command:

Now that we have the initial structure, we need to add platforms to which we want to deploy, but to do that, we need to be inside out app directory, which in our case is blogSample. Adding ios platform is done using the command

After the platform is added, we can build our app using

We can repeat last two commands for all other supported platforms like android, windows phone, etc.

If we want to test our app, we can go to directory blogSample/platforms/ios and lunch BlogSample.xcodeproj and run the app in simulator or existing device.

We have our platform set up, now let us add the AngularJS and Bootstrap files. After we download these (download AngularJS as a zip file so you get all parts of it), we put inside blogSample/www/js directory AngularJS and Bootstrap js files: jquery-1.11.2.min.js (jquery is a dependency of bootstrap and can be downloaded from jquery.com)angular.min.js, angular-route.min.js and bootstrap.min.js. Inside blogSample/www/css directory we put bootstrap.min.css and bootstrap-theme.min.css files. And the last part here is to link these files in our main file index.html. We put css code in head section:

and near the closing body tag we link the javascript files

Now we have the setup ready and we can start coding the logic. We need three things to define to make it work, we need an angular route config which allows us to navigate from page to page, then we need an angular controller, and a view which will display the user his/her current location.

We start with the app.js file which contains the initialization of the js app. This file also is the place where the initialization events are placed. In our case, it looks like this:

We start by defining our angular app, blogSample (line 1). We initiate it and  define the modules which we need (ngRoute, ui.bootstrap). There are other interesting things happening here. As we are used to use jquery ready function to react when the page is loaded and ready for use, here we have onDeviceReady event which is fired when the app is loaded and we can start using it. Inside this event, we will get the current position of the device through this line of code

The getCurrentPosition function which gets the current latitude and longitude of the device, needs two functions as parameters, first being the function that is called if the current location can be obtained successfully, and the latter for errors. The error function is used to report the unavailability of the location. The success function is used to read the coordinates and bind them to our angular app, blogSample through this function

Now that we have our app setup ready, let us define two views, one about page and the other showing location information. Showing the coordinates inside the view is done using

AngularJS will substitute the values inside curly braces with current coordinates set in onSuccess function. But views do not access application level values. We usually link a controller with a view, and view is limited to the scope of that controller, so we need to define a controller to glue the coordinates to the view. The controller will look like:

and finally we add the router configuration to bind the controller to the view and enable the user moving between pages. The router has this code:

The router part defines one default url and ‘/about’ url. The default url ‘/’ binds to main.html view, and the ‘/about’ url binds to about.html view.

Now that we have all the building pieces in place, we need to add the reference of last created files in index.html and the references will look like this:

Now that everything is on place, we can deploy our app to the phone for testing, or run it in a simulator. Running the application is different depending on the platform. You may use the simulators that can be started from phonegap, by xcode, eclipse, or android studio, but for any serious app development, I would strongly suggest you try your app in a real device. I will not go into details about deployment as it is out of scope of this post, but in the simplest scenario, you may go to platforms folder inside  your phonegap project folder, and open the project of the specific platform and run the project from the respective ide.

The complete source code of this application can be found on GitHub https://github.com/acelina/phonegapWithAngularJs, you may download it and try it on your computer.