Javascript best practices with web sockets - javascript

I am going to make my website more interactive with websockets to update content without having to refresh. On server side, my Play! application is well structured, I have a controller per page. But in javascript, would you write a file for each page like
websocket_page1.js ...
websocket_page2.js
...
Or something else ?
I will have stuff like a header with facebook like notification icons, some feeds with infinite scrolling, some action buttons.
More generally, is there any JS code writing convention like there is a structure for the Play! project ?
thanks,
Julien

There is no preferred way to structure your Javascript in Play. This imposes some more work upon you, but also leaves you more flexible. If you need an opinionated approach to Javascript, there's a lot for you out there: from backbone.js to AngularJS. Some are easier to use, some are smaller, some provide a stronger structure. Just have a look through them.
You should also at least have a look at Ractive.js. Haven't used it so far, but it sounds awesome.
But, well, to come back to your question: you don't need some JS framework. Just do what you think fits your project. These frameworks might help you, but at the end of the day, it's up to you.

Related

Cramming tons of HTML in to one page

I am helping to design a HTML client for a game that I am collaborating with others on.
This client is going to need to have multiple scenes/pages like the login, the lobby, the actual game page, etc.
Normally, I would be just fine with navigating in and out of pages. However, the client needs to have a constant connection with the server via a Websocket, so therefore it cannot navigate away from the page.
Option 1: Put everything in one file
Rather than having each scene in its own separate page, just cram all the HTML together.
Then, when one scene is needed, simply hide all the other scenes.
I do not think that this way is the way to go: from what I know about HTML and web practices, this is not a very smart practice.
Option 2: jQuery's .load()
Using jQuery's handy-dandy .load method, an external HTML file can be easily loaded into the current HTML file.
To me, this seems that this might be the best way. However, I am not very familiar with how this method acts, so I do not know if this will cause bumps in the road ahead.
Option 3: ???
This is where I need help. Unless one of the two above options is the best way, what is the best option for my situation?
Notes
I am not looking for speed here; it's okay if there is some delay between loads.
Not sure about your backend but it seems like you are looking for a single page app solution.
I recommend AngularJS, currently maintained by Google.
Others have mentioned Angular, but I'll just throw out the recommendation of KnockoutJS as well. Knockout has a less steep learning curve than AngularJS, and though it doesn't have as many features as Angular does, the latest version does have better browser support.
Both Knockout and Angular have excellent documentation and tutorials available via their websites.
I would recommend Angular 2. Since you seem like a beginner in front-end (correct me if I am wrong), starting with Angular 2 would be great over 1 because then you can learn this really good JS framework only once. It will help you keep everything organized and will prevent you from making your markup messy.

Lift, Play! or BlueEyes (with a bunch of Javascript Frameworks)

I find myself in a bit of a conundrum. I'm building a new, modern, web-based application and not only do I have to pick a technology, I have to pick an architecture. I think it is fair to say that these days its a tough choice because we have more options than we did even 5 years ago.
First things first, I've made the decision that Scala will be the server-side language. I have my reasons, and this is not a Scala versus XYZ post - that choice has been made. I've also sucummed to the fact that we're on the web, in the cloud, so I'm not even going to try and get away from Javascript. Maybe I will with CoffeeScript, but I will be writing Browser-hosted code.
Now, assuming Scala, most people would probably jump to either Play! or Lift. Probably Play! given it's endorsement from Typesafe, but I think I have another more important question that needs answering first. What's the architecture? If I want a very rich client, do I really need more than a simple stateless service layer based on the fact that we'll have a tonne of Javascript anyway? I'm not sure it'll be a single-page webapp, but is something like BlueEyes potentially the right choice? Lift and Play! are much more heavyweight in that they take on much more responsibility. They generate the HTML and for these frameworks, the browser is pretty dumb. Things like routing, validation, Ajax and Comet support are all server-side concerns. Because the browser is more capable today, rich, interactive features are normally implemented by generating and injecting Javascript from the server.
My question boils down to this. Do I go with a traditional Lift/Play! framework where the server takes on both the client and server responsibility or do I go with a rich client + REST-style service layer where the client takes a more prominent role in the application? An architecture where the client deals with routing, validation, binding, etc. I'm seeing frameworks like KnockOut.js, Sammy.js, Sproutcore, Backbone.js,... I'm not going to list them all but suffice to say that they all take on some of these framework features from a client-side perspective.
If I choose Play!, am I giving up some of that rich UI? What about situations where I want to provide service API's for integration/mashup/mobile purposes? How would Play! help me here? Clearly BlueEyes plays well here. I think I need a service layer regardless.
If I choose BlueEyes, what does my client code look like? How many of these Javascript-based frameworks do I need to give me what I need? I still want most of my business-logic in my service layer, but routing, binding.. all that UI stuff would be a concern of the client.
I'm not sure there is a right or wrong answer, but I think this community can probably point me in the right direction.
I also posted this to my blog at http://www.andyczerwonka.com/picking-a-web-technology-isnt-as-easy-as-it-u-45228
If all you want is a REST API on the backend, then Lift, Play! or Blueye will work just fine. But I'll just point the advantages of using Lift.
It is not true that Lift tries to impose doing both, the front and back end. We support REST-only use of Lift and it is encourage for the right project.
While Lift comes with jQuery and blueprint, you can use any javascript library and css framework, there is currently a lot of people on the mailing list showing how they use twitter boostrap with Lift. See this Lift module that helps integrating Bootstrap.
With Lift, you can start stateless, and if along the way you find that your needs change, you can go statefull. You can even mix and match them on the same application.
Want some modern looking UI? Lift's comet support is one, if not the best one, out there. Very simple to use, proven and tested on many browsers/workloads. I have written several posts showcasing Lift's comet support.
If you decide to use Lift for both, front and back end, you get for free an application that is secured by default, no need to worry about xss, xsrf, or many of the top 10 OWASP security vulnerabilities.
Need commercial support, there is a growing list here
Need training? There is a Basic training coming up in London and the founder of Lift also provides other training sessions.
There are several books about Lift available. Lift in Action , Simply Lift and Exploring Lift
There is a very active community ready to help.
Who uses Lift? Just to name a few: Foursquare , OpenStudy , The Guardian UK, StackMob and many more.
Well, I should stop here, but in short, Lift is an awesome framework that has a lot to offer, you take as much or as little as you need.
The Play 2.0 Beta contains a sample application that is exactly what you are looking for (ZenContacts).
Its server side is just a bunch of restful interfaces while its client side leverages coffeescript etc. to build a rich user interface.
As far as I know, both Play! and Lift can be used as basically a "back end", and you can use HTML5+CSS+JS as your "front end"; they do not necessarily restrict your ability to create the front end you desire, so rejecting them for that reason would be silly. Notice things like knockout.js advertise that they "work with any web framework". However, it might be true that they are more "heavyweight" than what you need.
I have never heard of BlueEyes before, but it appears to be aimed at a particular kind of use case. If that fits your bill, then it will probably be the most streamlined solution to your problem.
But if this is something you plan to actually put on the web, "routing, validation, binding, etc" practically need to be handled by the back end; I simply cannot imagine any of these things (securely) being handled by code that runs in the client's browser. Also, if your users choose to disable JavaScript, your website would be completely unusable.
If I choose Play!, am I giving up some of that rich UI?
What exactly you mean by rich UI? more javascript on the frontend?
If you consider - HTML5+CSS3+jQuery as a rich UI - then these work very well with any "backend" (Lift/Play).
The other thing which you might want to consider is the maturity of the framework.
Like you mentioned Play 2.0 supports Scala natively, has endorsement of Typesafe and is rapidly being adopted.
Plus you can expose RESTful services easily and consume then in the frontend (one of your requirement).
Leaning towards HTML5+CSS3+jQuery + Play 2.0 :)
just my thoughts..
What's the architecture?
Play! strongly encourages your server to use an MVC architecture, creating packages in a standard pattern:
app/
controllers/
Application.scala
views/
Application/
index.scala.html
models/
public/
images/
stylesheets/
javascripts/
This makes it easier to follow the architecture than to break it.
I can't speak for either Lift or BlueEyes, but afaik neither of them encourage an architecture as strongly.
Definately have a look at http://twitter.github.com/finagle before making up yiir mind. Finagle can take care of most of your backend stuff. It's desinged around a very flexible architecture that separates concerns cleverly using filters.
I have looked at apache click, wicket, a little bit Lift (feel a bit like wicket), and then play 1.2.4. So far so good with Play. Really beautiful approach to the web development. Keep up the nice work, play! team.

Building websites using JavaScript frameworks

I have learned and can read/write code in JavaScript. I am a backend engineer by profession and want to learn how to build websites. I have gone to the point where I can build wireframes and start writing basic HTML. I've never succeeded in creating a complete webpage, because they always looked awful midway through.
I've seen many JavaScript frameworks (like Bootstrap, Backbone.js, and others) that one can use to create websites.
Which framework(s), if any, should I use? Which would you recommend I use to start building websites (and why, if applicable)?
I wouldn't recommend you using a JavaScript-framework to build your entire website. I would only recommend JavaScript to enhance your website with cool features.
I'm not sure what type of website we're talking about, but if you're planning on getting traffic from search engines — think twice.
Google aren't that good at reading content embedded in JavaScript. Meaning: your SEO will be terrible if you choose to build the website entirely in JavaScript.
HTML/CSS is easy, man. I'm sure you'll be able to learn that in a one day — tops! You're a backend engineer by profession for gods sake, HTML can't possibly be that hard to get a grasp of :)
I was in your exact shoes not so long ago - I'm a programmer and had no issues picking up the backend programming that is required of websites, but when designing the web page is something I just could not do. I would end up with terrible looking web pages which was very discouraging.
One great way to get around this is use HTML/CSS templates - there are plenty free ones available. Download one you like, then go through the CSS and change as much of it as you need to personalise your site. This process will also give you a great understanding of how CSS works, and how it should be used to design a page.
After doing this a couple of times, you will be confident/able enough to design a webpage from scratch. If not, continue using the templates. No harm in that.
As others have already mentioned, for a powerful, dynamic website you will need a server side language as well. Javascript frameworks like jQuery are nice for the front-end for the website. For the back-end you can try CakePHP, CodeIgniter etc., or just code the back-end from scratch. Doesn't seem that would be a problem for you.
Some sites that provide free HTML/CSS templates:
CSS Creme
FreeTemplatesOnline
Most of them are optimized for 1024x768 which might seem a little outdated for a few. Try tweaking the CSS code to make the template suitable for your purposes - change images, width etc.
You can't exactly build a website using JavaScript. You could, but that would be very inefficient...I recommend going through some HTML tutorials, as you (and the websites you build in the future) will benefit a lot from the fact that you use HTML primarily, and enhance it with JavaScript. After all, JavaScript can't do much in comparison to HTML (since in order to build a site with JavaScript (or my interpretation of what that is), you need to have a basic understanding of HTML).
Unless I misunderstood your question, then that's about it. Frameworks like jQuery can really enhance a page and make it beautiful and, fortunately, much more user-friendly.
You can't create a website (at least a dynamic one) without a server side language. There you can pull from a number of languages.
If you are just a JavaScript fan, then you can use server-side JavaScript code as Node.js. On the client side you can use jQuery and you can have a supporting database like MySQL.

Decision about web application architecture

I am facing a decision about the web application architecture I am going to work on.
We are a small team and actually I will work on it alone (everybody work on something else).
This application will consist of front-end build on the ExtJS library
and it will use the model "load page, build GUI and never refresh".
On the web "desktop" there will be a lot of data windows, map views (using openlayers + GeoExt) and other stuff.
GUI should be flexible and allow every user to modify (and persist) the layout to fit his/her needs.
It should be possible to divide the application into modules / parts / ... and then let users in specific groups use only the specific modules. In other words, each group of users
can have different GUI available on the web "desktop".
Questions are:
First of all, is this approach good?
There will be a lot of AJAX calls from clients,
may be this could be a problem.
How to handle code complexity on client side?
So far I have decided to use dojo.require / dojo.provide feature and divide the client side code into modules
(for production they will be put together using dojo build system)
I am thinking about to use kind of IoC container on client side, but not sure which one yet.
It is very likely that I will write one for myself, it should not be difficult in dynamic language like JavaScript.
How to handle AJAX calls on server ?
Should I use WCF on server side ? Or just ordinary ashx handler ?
How to handle code complexity on server side ?
I want to use Spring.NET. May be this approach could help with modularity problem.
Data access - here I am pretty sure what to use:
For DAL classes I will use nHibernate. Then I compose them with business classes using Spring.NET.
I would really appreciate some advice about which way to go.
I know about a lot of technologies, but I have used only little part of it.
I don't have time to explore all of them and be fine with the decision.
We do this type of single page interface where I work on a pretty large scale for our clients. (Our site is not an internet site)
This seems to work pretty well for us. The more js you have the more difficult it gets to maintain, so have as many automated js tests as you can and try to break up your js logic in an mvc fashion. 4.0 is supposed to make this much easier.
Ext 4.0 has this built in if you are trying to limit the code you bring down. If you have the same users day after day, then I think it would be best to just bring all the source down (compressed and minified) and cache it.
We've found asmx to work really well. I have nothing against wcf, but last I looked it seemed like more trouble than it was worth. I know they have made many improvements recently. asmx just works though (with a few request header changes and managing the "d." on the client side).
Our Server side data access layer is pretty complex, but the interface for the ajax calls is pretty simple. You have not really given enough info to answer this part. I would start as simple as possible and refactor often.
We are also using nHibernate. Works fine for us. We have built a DDD model around it. It can take a lot of work to get that right though (not sure if we have it right after months of working at it).
If I were you I'd start with just extjs, your web service technology, and nHibernte.
I would recommend ASP.NET MVC 3 with Razor instead of a lot Javascript and calls to Service you can just do ajax calls to an Action in a Controller and that will let you have more maintainable code and use a IoC like Ninject. EF instead of NHibernate.
But it's your decision.
I would look into using a tool like Google Closure Compiler, especially if you're dealing with a very large project. I don't have too much experience with ExtJS, but large projects in JavaScript are hard and something like Closure Compiler tends to make it easier.

Writing a single page client-side only webpage

I'm considering to try out an idea, mostly for fun, and my question is if this is reasonable and if there are any libraries or frameworks that could make this experiment a little easier.
So, the idea: Basically it is to write a new UI for a website I've developed, but doing it with client-side code only. I can read/write data using ajax, since my existing website has an API that allows me to perform all kinds of queries. This allows me to use JavaScript for the whole thing and theoretically put all of the code in a single file.
Obviously there are limitations to circumvent; bookmarking, page refreshing, the back-button etc. But these limitations are what makes it interesting, right? :) I'm not so worried about search engine indexing, since one has to be logged in to use the site anyway.
The site itself is not overly complex, but it is not simple either. There are four different levels of users, multiple languages and quite a lot of data to be presented.
Is this a bad idea? If so, why would you advice against it? And do you know of any JavaScript frameworks or libraries that could make this easier? (And no, I'm not looking for an abstraction like Google Web Toolkit; I would like something purely JavaScript)
One of my coworkers did this. A nice feature of this concept was that you don't have a ton of POSTS whenever the user 'changes pages', since they are actually not ever changing a page until they submit their data for the final time. He did this for product registration software, which was nice. Our servers were only taking a hit when the user initially requested the page, and then when they submitted it.
The major, MAJOR downside to this concept is that most web developers are not expecting this. My coworker (and you) have a cool idea - but unless it is well implemented, with comments, 100% valid HTML, and a host of other good design principles in place, it can be confusing since most web developers have basically never seen this done before. His site was a nightmare to work with, as he did not actually know what engineering web software meant, and it was all slapped together. My organization never pursued this (potentially useful) idea because his implementation was so poor.
So, when I looked at this idea here were the trade-off I came up with:
1.) You cannot require any server-side interaction during intermediate pages.
2.) The initial page loading is longer, but there are no intermediate page requests (better optimization).
3.) This is vastly different than anything anyone usually does, which means you need to be especially careful with documentation.
4.) This design concept facilitates totally stand-alone web software to be easily deployed without the web.
5.) You might be increasing complexity for avoiding page loads, but maybe not. I'm not sure.
All together, I think it just depends on what you want to accomplish. My coworker really just wanted to see if he could do it, which he could. However, how he did it was really pretty bad, to the point where everyone else connected his poor implementation with a poor idea it was fairly sad.
Mostly, I think if you follow good web design practices this wouldn't be too bad of a thing to pursue. What are your goals though?
I'm sorry I couldn't directly answer all of your questions. I hope my experiences are still helpful in answering if I think it is a bad idea or not.
-Brian J. Stinar-
SproutCore is one of the best out there when it comes to really being built from the ground up for single-page, potentially complex applications. Unlike some others like GWT or Cappucino, SproutCore is really about using JavaScript directly. They aren't the only one though. You might also want to look at JavaScriptMVC and qooxdoo.
Personally, I've built an extremely large and complex single-page application using JavaScript. It is currently around 100,000 lines (including comments/whitespace). To give a sense of scale, jQuery is around 6,000. To reach that size, I built my own framework, build tools etc. and it is extremely maintainable. You're asking if it can work, and I can tell you that it does, but you do need a little infrastructure if you're looking at doing something big. (BTW, there's a lot of lazy loading - its not 100,000 lines all at once!)
I also wouldn't really recommend this method for anything other than a web application. As pointed out, its still difficult for SEO, and may be strange for some users.
You're looking for ExtJS
I did my site like that in jquery, backed by spring mvc 3. For me it works fine and you have a lightweight, flashy feling while on it.
If you have time to dig in javascript seriously... it is really good exercise.
The only thing I really need to add is SEO, since spiders see only intial html. If it is important for you, i think backend static files and sitemap would be good enough solution.
I found something very light-weight that provides the basic needed functionally without forcing you into a whole framework. It's called Sammy and is inspired by Ruby's Sinatra: http://code.quirkey.com/sammy/
Very recommended!
Alternative: code the same in Java. Take a look to ItsNat
Think in JavaScript but code the same in Java in server with the same DOM APIs, in server is way easier to manage your application without custom client/bridges because UI and data are together.
Regarding SEO, bookmarking etc in single page there are solutions, take a look to the Single Page Interface Manifesto

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