Note: I'm a backend (Java) developer by trade and work in Clojure in my spare time, so forgive me for my ignorance.
I'm trying to get my head around Clojurescript and how it could potentially fit in with projects I'm working on, or plan to work on in the future. As I've grown up with the "classic" web development mindset (e.g. Clojure running the backend, distributing data to the frontend via JSON to be processed in JS or returning a HTML page for the browser to render), I'm having trouble trying to understand how Clojurescript might make things better than this model.
Could anyone explain to me what the general approach to Clojurescript/Clojure development would be, seeing as the "Clojurescript One" project moniker signifies that application development will be unified under one language (as such)
What tasks would normally be done in the Clojurescript portion of the application?
What tasks would normally be done in the Clojure (e.g. backend) portion of the application?
Any help would be appreciated, or if anyone can point me towards some diagrams or explanations or anything - that would be great too!
I think Clojure/ClojureScript applications will be structured very similarly to X backend technology + JavaScript.
One big benefit with architecting applications with Clojure and ClojureScript - a richer data format than JSON (you can represent hash-maps and sets with arbitrary keys) without losing compactness.
JavaScript is a fine, fine language but ClojureScript offers quite a few benefits. It's semantically simpler (functional), ships with a rich standard library, a robust battle tested application library (Google Closure), and all the benefits you get from the tasteful application of syntactic abstraction via macros.
That said, it's still very much alpha software and the tooling still needs a lot of work.
A bit of background about me, I have developed with Clojurescript, JQuery, Vaadin, Servlets, JSP, and many other web technologies.
1) Clojurescript is much harder to learn than any other web technology I have used as you need, Java, Clojure, Closure (with an s ;), Closure Lib, and Closurescript specific knowledge.
2) Clojurescript doesn't make sense for a small app. It only makes sense when you will have ALOT of client side processing
3) Clojurescript's only use as far as I see is as a better javascript (which is why it is better suited to larger apps) as the minifier part of Clojurescript is available for javascript too
4) Only the client end would be written in Javascript, the server would be in Clojure/Java servlets
Maybe Ganelon micro-framework (which incidentally I am author of) will suit your needs - the execution model is similiar to Vaadin's: server-side Clojure code pushes UI updates to the browser through AJAX/JavaScript, but we don't store application state in session by default.
The demo and docs are available at http://ganelon.tomeklipski.com/
For me, clojure and clojurescript offers cleaner code than mixed stack. There is only one language to think of and code is quite easy to read.
At the backend clojure does things that java usually would do. Input validation, saving to database and above all, implementing business logic. Our backend also validates incoming / outgoing data by types using prismatic schemas.
Frontend in short: We get pretty code using ClojureScript and it is fast to write. We are using ClojureScript version of material-ui when writing UI components. We have to write less code when compared to the JavaScript and I find our UI component code to be easier to read than JavaScript counterpart. One of the main reasons is shorter closing tags and less noise by coding language. Development with ClojureScript is quite fast.
Of course ClojureScript is used for simple imput validation like RegExp for phone numbers etc.
One of the disadvantages of clojure which you have probably noticed is long lines after giving proper names to the functions. I havent found silver bullet how to cope with that.
As dnolen said: ClojureScript is still developing. It is way better now than it was 6 months ago, so you'll have to keep checking its maturity now and then.
Related
I have a few years experience programming c++ and a little less then that using Qt. I built a data mining software using Qt and I want to make it available online. Unfortunately, I know close to nothing about web programming. Firstly, how easy or hard is this to do and what is the best way to go about it?
Supposing I am looking to hire someone to make me a secure, long-term, extensible, website for an online software service, what skill set should I be looking for?
Edit:
I want to make my question a little more specific:
How can I take a bunch of working c++ functions and port the code so I can run it server side on a website?
Once this is done, would it be easy to make changes to the c++ code and have the algorithm automatically update on the site?
What technologies would be involved? Are there any cloud computing platforms that would be good for something like this?
#Niklaos-what does it mean to build a library and how does one do that?
You might want to have a look at Wt[1]. Its a C++ web framework which is programmed more or less like a desktop GUI application. One of the use cases quoted is to bring legacy apps into the web.
[1] http://www.webtoolkit.eu
Port the functions to Java, easily done from C++, you can even find some tools to help - don't trust them implicitly but they could provide a boost.
See longer answer below.
Wrap them in a web application, and deploy them on Google App-Engine.
Java version of a library would be a jar file.
If you really want to be able to update the algorithm implementation dynamically, then you could implement them in Groovy, and upload changes through a form on your webapp, either as files or as a big text block, need to consider version control.
The effort/skillset involved to perform the task depends on how your wrote your code. If it is in a self-contained library, and has a clean (re-entrant, thread safe) API, you could probably hire a web developer (html/php/asp etc) to write the UI interface to the library for a relatively small cost. The skills required would be dependant on the technologies you wanted to use. For Windows development I would suggest C#/ASP. The applicant would require knowledge of interfacing with native libraries from a managed language. This is assuming that you dont mind the costs of Windows deployment for your application.
On the otherhand, if the library is complex or needs to be re-written to support the extensibility you are looking for, asking here will not get you much.
BTW: here is a great article on Marshalling if you chose to implement using C#/ASP
http://msdn.microsoft.com/en-us/magazine/cc164193.aspx
First, DO NOT USE PHP :D
I used it for some projects (the last one with symphony framework) and i almost shoot my self !
If you are very familiar with C++, ASP .NET could be a good solution because if you like C++ you are going to love C#.
Any ways, I personally use Ruby on Rails for 6 months now and I LOVE IT. I won't write you a book here but the framework is pure gold !
The only problem is that Ruby is a very special language. You will probably be a bit lost a the beginning. But as every one you will learn to love it.
But that was only for the server side. Indeed, there 3 technologies you won't be able to avoid if you want to start to develop web applications.
HTML, CSS and JavaScript are presents every where. This is why i'm thinking you should start by HTML and CSS then JavaScript (with jQuery).
When you've got some basics with these 3 technologies you should be able to choose the server side language.
But you've got to tell you one thing, it's not going to be easy !
PS : Ruby on Rails uses HAML and SASS. These 2 languages replaces HTML and CSS you should have a look at them quickly because they are awesome.
Background:
I have a new site in the design phase and am considering using ColdFusion. The Server is currently set-up with ColdFusion and Python (done for me).
It is my choice on what to use and ColdFusion seems intriguing with the tag concept. Having developed sites in PHP and Python the idea of using a new tool seems fun but I want to make sure it is as easy to use as my other two choices with things like URL beautification and scalability.
Are there any common problems with using ColdFusion in regards to scalability and speed of development?
My other choice is to use Python with WebPy or Django.
ColdFusion 9 with a good framework like Sean Cornfeld's FW/1 has plenty of performance and all the functionality of any modern web server development language. It has some great integration features like exchange server support and excel / pdf support out of the box.
Like all tools it may or may not be the right one for you but the gotchas in terms of scalability will usually be with your code, rarely the platform.
Liberally use memcached or the built in ehache in CF9, be smart about your data access strategy, intelligently chunk returned data and you will be fine performance wise.
My approach with CF lately involves using jQuery extensively for client side logic and using CF for the initial page setup and ajax calls to fill tables. That dramatically cuts down on CF specific code and forces nice logic separation. Plus it cuts the dependency on any one platform (aside from the excellent jQuery library).
To specifically answer your question, if you read the [coldfusion] tags here you will see questions are rarely on speed or scalability, it scales fine. A lot of the questions seem to be on places where CF is a fairly thin layer on another tool like Apache Axis (web services) and ExtJs (cfajax) - neither of which you need to use. You will probably need mod-rewrite or IIS rewrite to hide .cfm
Since you have both ColdFusion and Python available to you already, I would carefully consider exactly what it is you're trying to accomplish.
Do you need a gradual learning curve, newbie-friendly language (easy for someone who knows HTML to learn), great documentation, and lots of features that make normally difficult tasks easy? That sounds like a job for ColdFusion.
That said, once you get the basics of ColdFusion down, it's easy to transition into an Object Oriented approach (as others have noted, there are a plethora of MVC frameworks available: FW/1, ColdBox, Fusebox, Model-Glue, Mach-ii, Lightfront, and the list goes on...), and there are also dependency management (DI/IoC) frameworks (my favorite of which is ColdSpring, modeled after Java's Spring framework), and the ability to do Aspect-Oriented Programming, as well. Lastly, there are also several ORM frameworks (Transfer, Reactor, and DataFaucet, if you're using CF8 or earlier, or add Hibernate to the list in CF9+).
ColdFusion also plays nicely with just about everything else out there. It can load and use .Net assemblies, provides native access to Java classes, and makes creating and/or consuming web services (particularly SOAP, but REST is possible) a piece of cake. (I think it even does com/corba, if you feel like using tech from 1991...)
Unfortunately, I've got no experience with Python, so I can't speak to its strengths. Perhaps a Python developer can shed some light there.
As for url rewrting, (again, as others have noted) that's not really done in the language (though you can fudge it); to get a really nice looking URL you really need either mod_rewrite (which can be done without .htaccess, instead the rules would go into your Apache VHosts config file), or with one of the IIS URL Rewriting products.
The "fudging" I alluded to would be a url like: http://example.com/index.cfm/section/action/?search=foo -- the ".cfm" is in the URL so that the request gets handed from the web server (Apache/IIS) to the Application Server (ColdFusion). To get rid of the ".cfm" in the URL, you really do have to use a URL rewriting tool; there's no way around it.
From two years working with CF, for me the biggest gotchas are:
If you're mainly coding using tags (rather than CFScript) and formatting for readability, be prepared for your output to be filled with whitespace. Unlike other scripting languages, the whitespace between statements are actually sent to the client - so if you're looping over something 100 times and outputting the result, all the linebreaks and tabs in the loop source code will appear 100 times. There are ways around this but it's been a while - I'm sure someone on SO has asked the question before, so a quick search will give you your solution.
Related to the whitespace problem, if you're writing a script to be used with AJAX or Flash and you're trying to send xml; even a single space before the DTD can break some of the more fussy parsing engines (jQuery used to fall over like this - I don't know if it still does and flash was a nightmare). When I first did this I spent hours trying to figure out why what looked like well formed XML was causing my script to die.
The later versions aren't so bad, but I was also working on legacy systems where even quite basic functionality was lacking. Quite often you'll find you need to go hunting for a COM or Java library to do the job for you. Again, though, this is in the earlier versions.
CFAJAX was a heavy, cumbersome beast last time I checked - so don't bother, roll your own.
Other than that, I found CF to be a fun language to work with - it has its idiosyncracies like everything else, but by and large it was mostly headache free and fast to work with.
Hope this helps :)
Cheers
Iain
EDIT: Oh, and for reasons best known to Adobe, if you're running the trial version you'll get a lovely fat HTML comment before all of your output - regardless of whether or not you're actually outputting HTML. And yes, because the comment appears before your DTD, be prepared for some browsers (not looking at any one in particular!) to render it like crap. Again - perhaps they've rethought this in the new version...
EDIT#2: You also mentioned URL Rewriting - where I used to work we did this all the time - no problems. If you're running on Apache, use mod_rewrite, if you're running on IIS buy ISAPI Rewrite 3.
do yourself the favor and check out the CFWheels project. it has the url rewriting support and routes that you're looking for. also as a full stack mvc framework, it comes with it's own orm.
It's been a few years, so my information may be a little out of date, but in my experience:
Pros:
Coldfusion is easy to learn, and quick to get something up and running end-to-end.
Cons:
As with many server-side scripting languages, there is no real separation between persistence logic, business logic, and presentation. All of these are typically interwoven throughout a typical Coldfusion source file. This can mean a lot more work if you want to make changes to the database schema of a mature application, for example.
There are some disciplines that can be followed to make things a little more maintainable; "Fusebox" was one. There may be others.
I am familiar with both Python and C++ as a programmer. I was thinking of writing my own simple web application and I wanted to know which language would be more appropriate for server-side web development.
Some things I'm looking for:
It has to be intuitive. I recognize that Wt exists and it follows the model of Qt. The one thing I hate about Qt is that they encourage strange syntax through obfuscated means (e.g. the "public slots:" idiom). If I'm going to write C++, I need it to be standard, recognizable, clean code. No fancy shmancy silliness that Qt provides.
The less non-C++ or Python code I have to write, the better. The thing about Django (Python web framework) is that it requires you pretty much write the HTML by hand. I think it would be great if HTML forms took more of a wxWidgets approach. Wt is close to this but follows the Qt model instead of wxWidgets.
I'm typically writing video games with C++ and I have no experience in web development. I want to write a nice web site for many reasons. I want it to be a learning experience, I want it to be fun, and I want to easily be able to concentrate on "fun stuff" (e.g. less boilerplate, more meat of the app).
Any tips for a newbie web developer? I'm guessing web app frameworks are the way to go, but it's just a matter of picking one.
I would go with Wt because:
You already know C++
It has a nice layout system, so you don't need to know lots of HTML
It is very well written and a pleasure to code in
Your deployed apps will handle 50 times the load of the python app on less hardware (from experience with pylons apps, 10,000 times the load of a plone app :P)
It has all the libraries that the guy in the first question says it doesn't and more
In built development webserver
Templating language
ORM
unit testing help
open-id and user+password authentication
A brilliant widget library
Web 2.0 isn't an after thought; it wasn't designed on a Request+Response model like all the python frameworks (as far as I know), but on an event driven interactive model.
It uses WebSockets if available
Falls back to normal ajax gracefully if not
Falls back to http for browsers like linx
It is more like coding a gui app than a web app, which is probably what you're used to
It is statically typed and therefore less error prone. Does def delete(id): take an int or a string ?
The unit tests (on my apps at least) take 10-100 times less time than my python app unit tests to run (including the compile time)
It has a strong and friendly community. All my email list posts are answered in 0-3 days.
If you'd like to avoid writing HTML, you could try GWT. However, in my experience, using an intermediate framework to generate HTML and ECMAScript never works anywhere near as well as hand-writing the pages.
[edit] nikow mentions in the comments that Pyjamas is a port of GWT to Python.
Regarding the language, if given the choice between C++ and Python I would pick Python 100% of the time. Even ignoring the obvious difference in abstraction between those languages, Python simply has more useful libraries than C++. You don't have to write your own development-oriented web server -- Django comes with one. You don't need to write a custom template library -- Python has Genshi. Django comes with a capable ORM layer, or for even more control you can use SQLAlchemy. It's barely a contest.
Django is good point to start web development it is great framework
If you look for C++ take a look on CppCMS, it is much more close to Django, it is not like Wt that mimics Qt.
In any case, it is really depends on your needs. C++ can be used for embedded or high performance web applications, but for medium range web sites Django would be better. (and I'm developer of CppCMS)
I think you better go firt python in your case, meanwhile you can extend cppCMS functionalities and write your own framework arround it.
wt was a good idea design, but somehow not that suitable.
If you are exploring Python frameworks (based on the excepted answer I think you are) I think you really owe it to yourself to check out CherryPy. When you write CherryPy apps, you really are just writing Python apps. The framework gets out of your way in a real hurry. Your free to choose your own templating, ORM (if you choose to use ORM), etc. Seriously, take 10 or 20 minutes and give it a look.
The only reason you might want to use C++ over Python is when speed is paramount.
If this is going to be your first web-app, you'll probably be ok with just Python, and your development speed will be orders of magnitude better than with CPP.
Django's templating language is far from powerless, to me it actually seems very pythonic. You actually can write pure python in a template(although this is generally not recommended).
Even better, it's possible to replace Django's templating system with the one you like.
My personal favourite language for this is HAML.
Here's some data on this:
Is there a HAML implementation for use with Python and Django
Having looked several ones, like django, pylos, web2py, wt. My recommendation is web2py. It's a python version of "ruby on rails" and easy to learn.
I know that some big players have embraced it and are actually exposing some of their services in APP compliant way, already. However, I haven't found many other (smaller) players in this field. Do you know any web application/service that uses APP as its public API protocol? What is your own take on AtomPub? Do you have any practical experiences using it? What are its limitations and drawbacks? Do you prefer AtomPub as your REST style or do you have some other favourite one? And why?
I know, these are many questions, not just one. The thing I'm interested here in is simple, though - how did the APP standard hit the market and particularly how does it seem with its adoption among web developers?
The company that I work for, is developing a lot of RESTful services.
However none of them expose public APIs.(In the sense that all services are internally consumed by our own clients). The reason why we went for REST architectural style was that we wanted our services to be easily consumable and more importantly scale well.
From my own practical experience I have come to the conclusion that HTTP + ATOM syndication format is a good idea, provided you want to keep things flexible(In terms of different content model, attaching and extending meta data associated with payloads, uniform parsing etc). ATOM ensures that everybody interprets the payload in an uniform manner without any scope for ambiguity.
However if one does not have any such complex requirements or does not forsee such requirements then the ATOM format could be a bit of an overhead. (For instance elements like Author,Title etc make sense more in the blogging/RSS world and may not make sense in your particular problem domain).
Also if the goal is to just serialize data structures at one end and reconstruct it at the other end, then most web frameworks(like WCF) have custom formats which are more appealing.
So in my opinion ATOM Pub is good if you need flexiblity in terms of data representation and if the playing field is huge with different kind of client.
However if you have a good knowledge of potential clients and server/client usage patterns then custom formats might be a good idea.
If the client is browser based then formats like JSON are very appealing.
Hope this answers your question.
My own research so far:
Wordpress supports AtomPub as its API protocol since version 2.3
GData is probably the biggest shot in the AtomPub field so far
Habari - new promising blogging system promotes APP as one of its main features
BlogSvc.net - an AtomPub
server, blog engine for .NET
platform, written in C#
Jangle - an open source project
designed to facilitate API access to
Library Systems
There's also mod_atom - an Apache module that stores entries in the filesystem.
Last time I checked (2007 or so) Atompub was fairly complex to implement. While you can whip together something that emits valid Atom feeds during the lunch break, implementing AtomPub was a fairly big undertaking.
That might have changed due to better libraries and tools but still it might be too complex to be implemented by smaller sides just because it's cool.
And the lack of killer AtomPub client applications puts little or no pressure on server operators to offer an AtomPub interface.
I m just starting using gwt and so far so good, however after reading some sample code I wonder is it necesary to have a high level of test coverage? (I can see that most code is declarative and then add some attributes I can see the sense in checking so me particular attributes are there but not all)
Also i would be interested to know anything about what are the gotchas in TDDing with GWT
I m using eclipse so also if you are really happy with some particualrs add ins for GWT I would be happy to hear about that
Thanks for the input
edit: maybe I m asking a very wide question, but even little pieces of information will help
I come from having nvelocity views with jquery/extJs/prototype/scriptaculous and this is a bit different
When designing GWT applications to be easily testable, it's best to move as much logic out of the view as possible. Use a design pattern which makes GUI testing easier such as Model-View-Presenter (MVP), which is used widely in building desktop applications (The C#/.NET folks have written a lot about this pattern.)
You can use GWTTestCases to test remote communication and code that ultimately executes raw JavaScript (most of the GWT core classes require this, especially widgets). However, these tests are slow to execute, so you should prefer designs which put all that logic in objects that can be tested in plain ol' JUnit TestCases.
For more information about writing GWT applications test-first, I've written an article for Better Software magazine, which is available as a PDF online at my blog.
I think the best reference at the moment would be this Testing Methodologies Using Google Web Toolkit
I think you asked a pretty broad question, which is part of the reason why you didn't get a reply for a while.
Compared to traditional AJAX web development, one could argue a GWT application requires less testing. Because the GWT team has worked so hard to make sure that its widgets work consistently across all web browsers, you don't have to worry about cross-browser compatibility nearly as much for your own application.
That frees you up to focus on your own application. Create a separate test case for each of your own custom widgets and test that they behave as you expect, and then write higher-level tests for each module. Take the extra step to make your tests fully automatable - that way every time you make a change or are about to release, it's easy to run all of your tests.
http://code.google.com/docreader/#p=google-web-toolkit-doc-1-5&s=google-web-toolkit-doc-1-5&t=DevGuideJUnitIntegration