The only place where I found informations on G-WAN web server was the project web site and it looked very much like advertisement.
What I would really know is, for someone who is proficient with C, if it is as easy to use and extend that other architectures. For now I would mostly focus on scripting abilities.
Are C scripts on GWAN easy to write ?
Can you easily update and upload new C scripts to the server (say as easily than some PHP or Java pages on other architectures) ? Do you have to restart the server when doing so ?
Can you easily extend it with third party or existing C libraries ?
Any other feedback welcome.
Well, now G-WAN is available under Linux, I am using it for more than 6 months.
The C scripts are fully-ANSI C compatible so there is no difference for any seasonned C programmer.
To update them on the server, you can edit them directly in the /csp folder (remotely via SSH) or locally on a test machine (and copy them later): G-WAN reloads scripts on-the-fly when they have been changed on disk (no server stop required).
G-WAN C scripts can use any existing library (starting with all those under /usr/lib) without any configuration or interface: you just have to write a '#pragma link' followed by the name of the library at the top of your script.
What I found really useful is the ability to edit C scripts and refresh the view in the Internet browser to see how my code works.
If there is a compilation error, then G-WAN outputs the line in the source code (just like any C compiler).
But where it enters the extraordinary area, is when you have a C script crash: here also it gives you THE LINE NUMBER IN THE SOURCE CODE (with the faulty call and the backtrace).
Kind of black-magic when you are used to Apache modules.
My experience with G-WAN and its C scripts are:
The G-WAN community is very small. Questions you have are mostly answered by its single developer.
I consider the API not mature: it's not as "clean" as Java APIs.
The limitation, but at the same time the power, of C: it's a systems programming language. So writing application logic in it must be done carefully.
You generally need to be a good developer to get good results: if you do something wrong, the server crashes fast and hard (Unix-style).
I've written some scripts now, to try out G-WAN. Overall, it's been very "productive": not much bugs and it works if you follow the guidelines and don't want to do too much funky stuff you expect it to have, like mature web servers. However, I have got the feeling I'm reinventing the wheel a lot of times.
G-WAN also support scripts written in other programming languages (C++, Objective-C, Java, etc.) so you will benefit from whatever native libraries each language implements.
For C scripts, well, the /usr/lib directory lists more than 1,500 libraries that G-WAN can re-use with a simple #pragma link "library".
I found it neat to be able to write a Web application with a part in C, another in C++ and a third one in Java!
Benchmark shown how G-wan fare poorly at handling these tests.
http://joshitech.blogspot.sg/2012/04/performance-nginx-netty-cppcms.html
I have been using G-Wan for about two years. I consider it highly stable and production ready for static files. I have a number of static sites running for over a year with no issues.
I have built some small scale dynamic sites in C with it as demos/test projects. A bittorrent tracker and a real time analytics platform both using the KV Store for data backing.
In my view building large scale dynamic sites in G-Wan is possible but only with a significant investment in development and support. G-Wan is better suited to building robust highly scalable "enterprise grade" applications than tossing something together over a weekend.
I use G-Wan for a CMS http://solicms.com but for now, I use Ruby as primary language.
I have used G-wan for some preliminary testing and it does benchmark well. I have found a few points of concern that make it so that I will not likely use it for any of my projects. I have found that it seems to cache responses for about 0.5secs to speedup the responses/second and I can't have only some of the responses hitting the application code. Also the key/value store is great for cache and temporary data storage but I'm not sure how well it will work as a real back-end storage method.
Related
I have been trying to decide if my web project is a candidate for implementation using PSGI, but I don't really see what good it would do for my application at this stage.
I don't really understand all the fuss. To me PSGI seems like a framework that provides a common interface between different Apache modules which lets you move your application between them. e.g Easily move your application from running on mod_perl to fastcgi, and provide the application support for running on both options.
Is that right, or have I missed something?
As I and the team I am a part of not only develop the application, but also pretty much do maintenance and setup of servers I don't see the value for us of being able to run on fastcgi, cgi, and mod_perl, we do just fine with just mod_perl.
Have I misunderstood the PSGI functionality, or is it just not suitable for my project?
Forget the Apache bit. It's a way of writing your application so that the choice of webserver becomes less relevant. At $work we switched to Plack/PSGI after finding our app running with very high CPU load after upgrading to Apache2 - benchmarking various Apache configs and NYTProf'ing were unable to determine the reason, and using PSGI and the Starman webserver worked out much better for us.
Now everything is handled in one place by our PSGI app (URL re-writes, static content, expiry headers, etc) rather than Apache configuration, so it's a) Perl, and b) easily tested via our standard /t/ scripts. Also our tests are now testing exactly what a user sees, rather than just the basic app itself.
It may well not be relevant to you if you're happy with Apache and mod_perl, and I'm sure others will be able to give much better answers, but for us not having to deal with anything Apache-related again is such a relief in itself. The ease of testing, and the ability to just stick in a Data::Dumper and see what's going on rather than wrestling with ModRewrite and friends, is a great boon.
Borrowing from a recent blog post by chromatic, Why PSGI/Plack Matters (Testing), here's what it is:
It's a good idea borrowed from Python's WSGI and Ruby's Rack but made Perlish; it's a simple formalizing of a pattern of web application development, where the entry point into the application is a function reference and the exit point is a tuple of header information and a response body.
That's it. That's as simple as it can be, and that simplicity deceives a lot of people who want to learn it.
An important benefit is, ibid.,
Given a Plack application, you don't have to deploy to a web server—even locally—to test your application as if it were deployed … Plack and TWMP (and Plack::Test) use the well-defined Plack pattern to make something which was previously difficult into something amazingly easy. They're not the first and they won't be the last, but they do demonstrate the value of Plack.
Started wrote an answer and after 50 lines I deleted it. Simply because it is impossible tell (in short) why is PSGI extremely cool. I'm new in PSGI too, but zilion things now are much easier as before in my apache/mod_perl era.
I can give you next advices:
read the Plack advent calendar - all days, step-by-step. You must understand the basic philosophy, what is good on onions and so on... :)
search CPAN for "Plack::Middleware::" - and read the first few lines in each. Here are MANY. (Really should be somewhere some short overview for each one, unfortunately don't know any faster way. Simply it is good to know, what middlewares are already developed. (For example, you sure will need the Plack::Middleware::Session, or Plack::Middleware::Static and so on...)
read about Plack::Builder (already done, when you done with the advent calendar) :)
try write some apps with it and will find than Plack is like the first sex - now you didn't understand that you could live without it.
ps:
If was here something like "Perl Oscar", will sure nominating MyiagavaSan. :)
Things have changed way too much in the bussines logic for our Flex 3 customer extranet application, so I have received the permision to make a fresh start... with low date pressure (I know, you envy me...).
Instead choosing the obvious Flex 4 path, it seems that Perl/Catalyst fits very, very well in this brand new scenary, but I don´t want to lose some goodies:
We have just ONE set of .swf modules, so all clients load the same actual files in a shared path.
They are Virtual Hosts.
Each domain directory has a index.php. It loads a personalization file with passwords AND the "real" shared index.php that loads the shared .swf.
No crossdomain problems because the .swf thinks that its in the true domain, thanks to the Apache virtual link.
All personalization inside the .swf (bussines data and visual prefs) are loaded dinamically from preferences in a database
It seems that I can do the same with Catalyst, isn´t it? Even easier, because I can make the perl app to respond "globally" to the same arguments in different vhosts, so everything can be decide at runtime
But the great advantage of Flex is that I have all the logic and preferences already loaded in the client, so the work in the server and the data transference is really, really low. The only data that travels is pure bussines data. No preferences, no pages, no nothing. And the app always know WHO the client is, so the queries are really, really clean.
So here are my two questions:
Is the Persistence in Perl/Catalyst a way to manage something similar?
I have read a lot of posts, here and there, about unclosed processes and threads, even cron programmed restarting of the server... as a "solution", and similar performance problems.
Must I manage such things to have a stable server?
It sounds ike a time bomb, and we are now very, very proud of our server perceived performance with a litle investment.
Thank you in advance
The nice thing about Catalyst is that it is very easy to plug all sorts of nice things from CPAN into your application. You need Authentication/Authorization, Session management, database handling, PDF generation, Excel parsing....? If you can think of it, someone on CPAN has probably done it already and published it for the world to use.
It is not exactly clear to me what you want the server to do. If it's just providing data to your SWF application through JSON or something similar, Perl Dancer (http://perldancer.org/) might also be interesting to look at, it's like Catalyst on a diet. Both Catalyst and Dancer have built in PSGI support allowing you to run it in any way you like.
Myself, I have just recently finished a project for ABN AMRO Bank Luxembourg in which I used Catalyst as the backend solution for an ExtJS application. The application is run under FastCGI and is extremely robust and stable. i don't know where you heard that Catalyst processes are leaky and need to be restarted, but that's just nonsense. Of course, if you program leaks yourself you might get yourself in problems, but the framework itself is very stable. Also, because of using Catalyst I was able to develop a very complex application is a very short time. I don't know how I could have managed it without Catalyst.
Good luck with you project
Rob
I'm moving away from strict Android development and wanting to create iPhone applications. My understanding is that I can code the backend of iOS applications in C/C++ and also that I can use the NDK to include C/C++ code in Android apps. My question however is how? I've googled quite a bit and I can't find any clear and concise answers.
When looking at sample code for the NDK, it seems that all the function names etc. are Android (or at least Java) specific and so I would not be able to use this C/C++ backend to develop an iPhone frontend?
I'd appreciate some clarification on this issue and if at all available some code to help me out? (even just a simple Hello World that reads a string from a C/C++ file and displays it in an iOS and Android app).
Thanks guys
Chris
Note that I almost exclusively work on "business/utility/productivity" applications; things that rely heavily on fairly standard UI elements and expect to integrate well with their platform. This answer reflects that. See Mitch Lindgren's comment to Shaggy Frog's answer for good comments for game developers, who have a completely different situation.
I believe #Shaggy Frog is incorrect here. If you have effective, tested code in C++, there is no reason not to share it between Android and iPhone, and I've worked on projects that do just that and it can be very successful. There are dangers that should be avoided, however.
Most critically, be careful of "lowest common denominator." Self-contained, algorithmic code, shares very well. Complex frameworks that manage threads, talk on the network, or otherwise interact with the OS are more challenging to do in a way that doesn't force you to break the paradigms of the platform and shoot for the LCD that works equally badly on all platforms. In particular, I recommend writing your networking code using the platform's frameworks. This often requires a "sandwich" approach where the top layer is platform-specific and the very bottom layer is platform-specific, and the middle is portable. This is a very good thing if designed carefully.
Thread management and timers should also be done using the platform's frameworks. In particular, Java uses threads heavily, while iOS typically relies on its runloop to avoid threads. When iOS does use threads, GCD is strongly preferred. Again, the solution here is to isolate the truly portable algorithms, and let platform-specific code manage how it gets called.
If you have a complex, existing framework that is heavily threaded and has a lot of network or UI code spread throughout it, then sharing it may be difficult, but my recommendation still would be to look for ways to refactor it rather than rewrite it.
As an iOS and Mac developer who works extensively with cross-platform code shared on Linux, Windows and Android, I can say that Android is by far the most annoying of the platforms to share with (Windows used to hold this distinction, but Android blew it away). Android has had the most cases where it is not wise to share code. But there are still many opportunities for code reuse and they should be pursued.
While the sentiment is sound (you are following the policy of Don't Repeat Yourself), it's only pragmatic if what you can share that code in an efficient manner. In this case, it's not really possible to have a "write once" approach to cross-platform development where the code for two platforms needs to be written in different languages (C/C++/Obj-C on iPhone, Java for Android).
You'll be better off writing two different codebases in this case (in two different languages). Word of advice: don't write your Java code like it's C++, or your C++ code like it's Java. I worked at a company a number of years ago who had a product they "ported" from Java to C++, and they didn't write the C++ code like it was C++, and it caused all sorts of problems, not to mention being hard to read.
Writing a shared code base is really practical in this situation. There is some overhead to setting up and keeping it organized, but the major benefits are these 1) reduce the amount of code by sharing common functionality 2) Sharing bug fixes to the common code base. I'm currently aware of two routes that I'm considering for a project - use the native c/c++ (gains in speed at the expense of losing garbage collection and setting targets per processor) or use monodroid/monotouch which provide c# bindings for each os's platform functionality (I'm uncertain of how mature this is.)
If I was writing a game using 3d I'd definitely use approach #1.
I posted this same answer to a similar question but I think it's relevant so...
I use BatteryTech for my platform-abstraction stuff and my project structure looks like this:
On my PC:
gamename - contains just the common code
gamename-android - holds mostly BatteryTech's android-specific code and Android config, builders point to gamename project for common code
gamename-win32 - Just for building out to Windows, uses code from gamename project
On my Mac:
gamename - contains just the common code
gamename-ios - The iPhone/iPad build, imports common code
gamename-osx - The OSX native build. imports common code.
And I use SVN to share between my PC and Mac. My only real problems are when I add classes to the common codebase in Windows and then update on the mac to pull them down from SVN. XCode doesn't have a way to automatically add them to the project without scripts, so I have to pull them in manually each time, which is a pain but isn't the end of the world.
All of this stuff comes with BatteryTech so it's easy to figure out once you get it.
Besides using C/C++ share so lib.
If to develop cross-platform apps like game, suggest use mono-based framework like Unity3D.
Else if to develop business apps which require native UI and want to share business logic code cross mobile platforms, I suggest use Lua embedded engine as client business logic center.
The client UI is still native and get best UI performance. i.e Java on Android and ObjectC on iOS etc.
The logic is shared with same Lua scripts for all platform.
So the Lua layer is similar as client services (compare to server side services).
-- Anderson Mao, 2013-03-28
Though I don't use these myself as most of the stuff I write won't port well, I would recommend using something like Appcelerator or Red Foundry to build basic applications that can then be created natively on either platform. In these cases, you're not writing objective-c or java, you use some kind of intermediary. Note that if you move outside the box they've confined you to, you'll need to write your own code closer to the metal.
So, there are several languages which will allow you to create a website, as long as you configure the server(s) well enough.
To my knowledge, there is:
PHP
ASP.NET
Ruby(on rails, what is
that all about?)
And thusly, my knowledge is limited. Ruby and ASP, I've only heard of, never worked with. If there are other languages, I suppose they have some way to make files containing the needed html. It would then suffice to add a line to the Apache config to associate the file-extension.
And if other languages: are there any notable characteristics about the one(s) you mention?
ANY language can be use to make a dynamic website - you could do it in COBOL or FORTRAN if you were twisted enough. Back in the olden days (about 10 years ago) most dynamic websites were done with CGI scripts - all you needed was a program that could read data from standard input and write data (usually HTML) to standard output.
Most modern languages have libraries and frameworks to make it easier. As well as the languages you have already mentioned, Java, C# and Python are probably the most common in use today.
Typically a web framework will have:
a way of mapping URLs to a class or function to handle the request
a mechanism for extracting data from a request and converting it into an easy to use form
a template system to easily create HTML by filling in the blanks
an easy way to access a database, such as an ORM
mechanisms to handle caching, redirections, errors etc
You can find a comparison of popular web frameworks on wikipedia.
How can you forget Java ? :)
Python
It runs on Windows, Linux/Unix, Mac OS X, and has been ported to the Java and .NET virtual machines.
Python is a perfect scripting language for web applications, e.g. via mod_python for the Apache web server. With Web Server Gateway Interface a standard API has been developed to facilitate these applications. Web application frameworks or application servers like Django, Pylons, TurboGears, web2py and Zope support developers in the design and maintenance of complex applications. Around libraries like NumPy, Scipy and Matplotlib, Python is a standard in scientific computing.
Among the users of Python are YouTube and the original BitTorrent client. Large organizations that make use of Python include Google, Yahoo!, CERN, NASA,and ITA.
This could be for your interest.
Virtually thru CGI all programming languages that produce output may use for web page generation.
Basically, you can use any language (if you are hosting your own server)
Very closely related and very interesting is this article where LISP has been used to build a very succesfull website.
Python has a 3rd party module CherryPy which can be used with or without a http server.
Amongst others: Erlang (YAWS, Mochiweb), Python
JSP has the advantage that it automatically wraps your code in a servlet, compiles that to bytecodes, then uses the just-in-time Java compiler to recompile critical sections into native object code. Not aware of any alternative which allows optimizes your work automatically in this way.
Also allows you to develop and deploy on any combination of Windows, Mac OS X, or Linux.
If you'd like to choose one for the beginning, you should check out PHP first. It gives you the basic clues about how dynamic sites work in general.
After you've become familiar with the basics, I recommend ASP.NET.
Fist off, you should know that ASP.NET is a technology and not a language. (It actually supports any language that can be used on the .NET platform.) Also it is not to be confused with classic ASP. (The old ASP was much more like PHP.)
ASP.NET is very easy to begin with, and after you have some clues about its concepts, you can always dig deeper and customize everything in it. The http://asp.net site is a very good starting point, if you are to learn it. I think it is really worth the effort, because even if you choose not to stick to it, it will give you some interesting ideas and concepts.
I tell you its most important advantages:
The code is compiled (and NOT interpreted like PHP), and it has a very good performance. (In a performace comparsion, it is 10-15 times faster. http://www.misfitgeek.com/pages/Perf_Stat_0809.htm)
It can be run on Windows without effort, and on Linux / Mac / etc using the Mono project.
It implements the Separation of Concerns principle very well.
It has most of the general functionality you'll need built-in. (Such as membership, roles, database management, and so on.)
Every time I see Ruby or Python discussed in the context of web development, it's always with a framework (Rails for Ruby, Django for Python). Are these frameworks necessary? If not, is there a reason why these languages are often used within a framework, while Perl and PHP are not?
I can only speak towards Ruby - but, no, you don't need a framework to run Ruby based pages on the web. You do need a ruby enabled server, such as Apache running eruby/erb. But, once you do, you can create .rhtml files just like RoR, where it processes the inline ruby code.
The short answer is no, they are not necessary. In ruby you have .erb templates that can be used in a similar way as you use PHP pages. You can write a site in ruby or Python using several technologies (Rails-like frameworks, Templates or even talking directly with the HTTP library and building the page CGI-style).
Web frameworks like Python's Django or Ruby's Rails (there are many) just raise the level of abstraction from the PHP's or ASP's, and automate several process (like login, database interaction, REST API's) which is always a good thing.
"Need" is a strong word. You can certainly write Python without one, but I wouldn't want to.
Python wasn't designed (like PHP was, for example) as a direct web scripting language, so common web-ish things like connecting to databases isn't native, and frameworks are handy.
EDIT: mod_python exists for Apache, so if you're merely looking to write some scripts, then Python doesn't need a framework. If you want to build an entire site, I'd recommend using one.
From a Pythonic point of view, you'd absolutely want to use one of the frameworks. Yes, it might be possible to write a web app without them, but it's not going to be pretty. Here's a few things you'll (probably) end up writing from scratch:
Templating: unless you're writing a really really quick hack, you don't want to be generating all of your HTML within your Python code -- this is a really poor design that becomes a maintainability nightmare.
URL Processing: splitting a URL and identifying which code to run isn't a trivial task. Django (for example) provides a fantastic mechanism to map from a set of regular expressions to a set of view functions.
Authentication: rolling your own login/logout/session management code is a pain, especially when there's already pre-written (and tested) code available
Error handling: frameworks already have a good mechanism in place to a) help you debug your app, and b) help redirect to proper 404 and 500 pages.
To add to this, all of the framework libraries are all heavily tested (and fire tested). Additionally, there are communities of people who are developing using the same code base, so if you have any questions, you can probably find help.
In summary, you don't have to, but unless your project is "a new web framework", you're probably better off using one of the existing ones instead.
Framework? Heck, you don't even need a web server if you're using Python, you can make one in around three lines of code.
As to the why:
The most plausible thing I can think of is that Perl and PHP were developed before the notion of using frameworks for web apps became popular. Hence, the "old" way of doing things has stuck around in those cultures. Ruby and Python became popular after frameworks became popular, hence they developed together. If your language has a good framework (or more than one) that's well supported by the community, there's not much reason to try to write a Web App without one.
A framework isn't necessary per se, but it can certainly speed development and help you write "better" code. In PHP, there are definitely frameworks that get used like CakePHP, and in Perl there are many as well like Mason and Catalyst.
The frameworks aren't necessary. However, a lot of developers think frameworks ease development by automating a lot of things. For example, Django will create a production-ready backend for you based on your database structure. It also has lets you incorporate various plugins if you choose. I don't know too much about Rails or Perl frameworks, but PHP frameworks such as Zend, Symfony, Code Igniter, CakePHP, etc are used widely.
Where I work at we rolled our own PHP framework.
Are these frameworks necessary?
No. They, like any 'framework', are simply for speeding up development time and making the programmer's job easier.
If not, is there a reason why these languages are often used within a framework, while Perl and PHP are not?
PHP and Perl were popular languages for building web sites well before the idea of using frameworks was. Frameworks like Rails are what gave Ruby it's following. I'm not sure that Python or Ruby were that common as web languages before they were backed by frameworks.
These days, even PHP/Perl web developement should be backed by a framework (of which there are now many).
By no means are those development frameworks required. But as with most development environments, your productivity will increase exponentially if you have a supported framework to reference and build your applications on. It also decreases the training needed to bring others up to speed on your applications if they already have a core understanding of the framework that you use.
For python, the answer is No you don't have to. You can write python directly behind your web server very easily, take a look at mod_python for how to do it.
A lot of people like frameworks because they supply a lot of the boilerplate code in a reliable form so you don't have to write it yourself. But, like any code project, you should choose the tools and frameworks on their merit for your problem.
You can certainly write CGI scripts in either language and do things "raw".
The frameworks (ideally) save the trouble of writing a pile of code for things that other people have already handled (session handling, etc.).
The decision probably comes down to what you need to do. If the framework has the features you need, why not use it. If the framework is going to require extensive modifications, it might be easier to roll your own stuff. Or check out a different framework.
The python library has numerous modules for doing cgi, parsing html, cookies, WSGI, etc:
http://docs.python.org/library/index.html
PHP has a lot of frameworks. Probably more then most. In Ruby most use Rails so thats what you hear, and Django for Python is mentioned more then not.
But with PHP you have many to choose from.
List of web application frameworks
Any language that can "print" can be used to generate web pages, but frameworks handle a lot of the HTML generation for you. They let you concentrate more on the content and less on the details of coding the raw HTML.