Is there a good tool to debug Perl-based web applications? Output to stderr or stdout don't count as tool.
Yup, I've got the perfect tool for you.
CGI::Inspect lets you inspect and debug a running Perl web application.
Read more about the module on the developer's website.
Or check out the slides from a presentation about it at YAPC::NA 2009.
The Komodo IDE supports remote debugging for just this sort of thing.
The EPIC plugin for Eclipse will also let you do this.
In CGI, you can
use CGI::Carp qw(fatalsToBrowser);
It will display any fatal message in your browser.
With Mason, leave the default error option, which outputs the call stack in your browser.
Let's not assume, like the first answer, that the module being used is CGI, but rather provide something that will work across anything that is supported by/supports PSGI/Plack.
Perhaps combine Plack::Middleware::Debug (to display information about the active request and response, perhaps adding the Log4perl panel) and Devel::hdb to debug the running code in a separate tab.
Also available (I haven't tried it though) is InteractiveDebugger
Anything you try should be run in a single process, non-forking server like HTTP::Server::PSGI or HTTP::Server::Simple::PSGI for development and debugging instead of something like Starman.
Late to the party on this one, but I felt some other tools should be called out in case anyone else stumbles upon this question.
The Perl command line debugger is perfectly serviceable, but occasionally hard to use, and has a fairly steep learning curve, especially for those who are used to GUI tools.
Devel::hdb is a great tool for this. It integrates with the existing debugging functionality in Perl, so you can start the application with -d:hdb as a flag, and then you can hit a web based endpoint to start stepping through the application easily. It supports breakpoints, watch expressions, and stepping, so it can help you figure out where an issue is on a somewhat live application.
As mentioned earlier, ActiveState's Komodo IDE (not Edit) has a built in graphical debugger, that can work on a local instance or against a remote server. The remote server must have some libraries installed, and activated within the code to work. It's not invasive, but it should be known. Also, Komodo costs money, but they do provide a trial period. It'll work on Windows, OS X or Linux. ActiveState's Perl Dev Kit has an independent debugger as well, but I haven't used it in years.
Related
Everything that I have coded upto this point has been launched from Command Prompt or the IDE itself. I would like the ability to deploy an application such that launching it doesn't require a tutorial for novices. .exe, .apk, .app, ELF. Double-click and go.
I recall creating .exe files from Python as being restrictivly difficult. I was thinking C# and found .net/maui. It doesn't support linux, which I could maybe look past, but it also doesn't appear to support creating .exe files.
Java is more low level than I would like to deal with. Learning a new language that runs virtually could be the solution. I havn't done much investigating as this wouldn't be the ideal. (Edit: JVM requires an additional install, so that's not going to work.)
I don't have any experience with web developement, but it seems like a promising route none the less. It is not clear to me if I can create a local icon-launchable webpage that will run an application in your browser sans-server. Additionally, I am not sure how far my known languages will take me before I have to then learn CSS or whatever.
Thoughts?
Electron seems to be popular choice for cross-platform development in case you don't mind developing with JavaScript.
QT is another cross-platform framework that was around for a long time.
Specifically for .NET, there's MAUI (mobile-focused, no Linux), Avalonia UI, Eto Forms, AlterNET UI. The last one is desktop-only and still in beta.
I have recently started working with Perl. Googling reveals a number of editors but I am unable to find an editor that will help me navigate a large body of Perl source code. One of the features that I am looking for is the ability of the IDE to integrate with different modules and allow me to jump from one to another. If possible, it will also help if one can see the which function calls what.
I used source insight for C programming and it provides these very useful features. Am looking for similar features in perl.
Help appreciated
Have you looked at Padre? It is a Perl IDE developed by the Perl community.
I'm just giving EPIC a chance.
http://www.epic-ide.org/
Its an Eclipse plugin utilizing a mighty IDE. The advantage I see in using EPIC over Padre is the fact that eclipse can do all sorts of languages and I don't have to get used to multiple different editors every time.
Another great aproach for Perl programming is using emacs. Yes ... its old but I had quite some joy while getting into Perl.
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Roman
Komodo IDE, from Active State is also quite good. I haven't used any other Perl IDEs so cannot make comparisons. Most of the features that you are looking for I believe are available in Komodo.
On a side note: The feature that I most appreciated in Komodo was visual debugging.
I mainly use jEdit for Perl programming.
The PerlSideKick plugin, allows you to navigate huge Perl modules (mainly just a plugin for the SideKick plugin).
But there's not much to give you that easy Shift+click navigation you get from Eclipse. jEdit is 100% programmable through Beanshell macros (and JavaScript and Python and JRuby...). So, you can do some of this yourself. So there would be work involved.
For example, it been close enough for me to create "Selection macros" that will allow certain actions on the package or name either highlighted or at the caret. For example, open up the module indicated by the package name.
The Navigator plugin will at least remember where you were last across files.
You might be able to do cross-module navigation through one of the tags plugins
So this won't get you all the way you'd want to go, but it will get you some of the way, and for $0.
It has the most configurable source highlighting this side of writing Emacs-LISP.
It does FTP and remote editing cleaner than most editors I've used.
You can build up a library of Beanshell (shorthand Java) scripts that really help you get what you want done.
Just remember that this recommendation comes with caveats. I have found EPIC quite sub-standard for my use.
I have a bunch of related Perl scripts that I would like to put together in one convenient place. So I was thinking of building a GUI and incorporating the scripts. I'm using Strawberry Perl on Windows XP and have just installed Tk from cpan about fifteen minutes ago. Before I go for it, I want some sound advice either for or against it.
My other option is to translate the Perl scripts into VB and use Visual Studio 2008, but that might be too much hassle for an outcome that might end up all the same had I just stuck with Perl & Tk.
I haven't looked yet, but maybe there is a module for Visual Studio that would allow me to invoke Perl scripts?
The main requirements are:
It must be able to communicate with MySQL
It must be able to fetch & parse XML files from the internet
It must be transportable, scalable, and sustainable
What direction would you take?
I've built Perl/Tk apps on Windows before and found it just fine, including using PAR to package everything up for distribution to others. It was nice being able to do most of my development on a proper Linux system and have things just magically work on Windows :) The only gotcha I encountered is that Tk doesn't play well with ithreads.
I personally would recommend wxPerl over Tk. It has native looking widgets, at least in my view leads to cleaner code and you can use wxGlade as a GUI designer.
If you haven't programmed with Perl/Tk I would think that Tkx (developed by Activestate) would be a better option. Tkx is a thin layer over Tcl/Tk, which gives it access to the new themed widgets in Tcl/Tk so your application would look better.
Perl/Tk has a lot more documentation around, but the module itself does not seem to be developed anymore. The documentation for Tkx is very sparse but by following the Tkx tutorial files on CPAN, it should be easy to get started.
WxWidgets (available for Perl via wxPerl) is an excellent graphical toolkit, but wxPerl only implements a subset of the available widgets.
PAR is convenient but if you go with Perl/Tk, the result will not run natively on OS X. (Users will need to run X11 first, which is problematic, especially with more recent version of OS X). If you go with Tkx, you can get native application on Mac OSX. Also, ActiveStates's PDK gives you a simple way to package everything to deploy to Windows, Linux, and OS X.
For reference, see the the software (AntConc and AntWordProfiler) at the following site http://www.antlab.sci.waseda.ac.jp/software.html, where AntConc was developed using Perl/Tk and AntWordProfiler was developed using Tkx.
The Process class allows to start new processes from a C# (WPF/Winforms) frontend.
I guess that way you can keep your Perl scripts and use the nice Visual Studio GUI builder.
Are there good GUI builder for Perl GUI libraries, especially for WxPerl?
For Wx:
WxGlade
Any Wx tool that generates XRC files.
For Tk:
Zooz
SpeTcl
wxDesigner is the only one I know. I have never used it though.
It's still fairly new, but the Padre editor has an in-development Padre::Plugin::FormBuilder plugin that takes a wxFormBuilder project file and generates pure-Perl dialog classes.
Check out wxformbuilder. You can design your GUI there and generate an XRC file which wxPerl can then be configured to load.
There is The GUI Loft for Win32::GUI, but of course it's not portable off of Win32.
Of the GUI editors that I have tried briefly, wxGlade seems the most natural to use, but it still doesn't seem to have the "drag and drop" functionality that I grew to love when working with Java in Eclipse or Netbeans. Don't get me wrong, I love Perl, but would still really like to see a nice WYSIWYG GUI editor.
I would recommend simply using web-based interfaces for everything. If you went with this approach, you could even run a local (i.e. on a Desktop) web server for "standalone" applications.
In like manner, ActiveState decided to focus on Web-based development instead of continuing work on their GUI editor
Is Perl a good option for writing (possibly and partially) platform independent desktop applications? I know there are interesting widget libraries like GTK2 Perl and wxWidgets but I'm not familiar with development on Windows.
Is it possible to write a good application with Perl and those tools, maybe embedding everything needed to avoid asking the user to install external (and probably non conventional for many) libraries? Are there examples of this kind of apps around?
Sort of. You can certainly write Perl scripts that provide a Tk GUI that will work on any platform, and you can even package the libraries they need to work with PAR to put together an application that will run anywhere with an appropriate version of perl installed without requiring the end use to install a bunch of stuff from CPAN to get it to work.
However, an application that will run anywhere without requiring an existing perl installation (and it's probably not safe to assume the average Windows user will have perl) isn't really viable. One solution would be to distribute an "everywhere but Windows" version that simply uses PAR to include the necessary libraries, and a PAR::Packer-built version for Windows, which would be a fully-functional .exe including the perl interpreter and the libraries.
EDIT: following daotoad's response, it does appear that ActiveState's PerlApp can build cross-platform binaries for for Windows, Mac OS X, Linux, Solaris, and AIX; I haven't tried this but if it works as advertised it would seem to meet your requirements.
My employer uses ActiveState's PerlApp to produce executable versions of our apps with great success.
We tested PAR and PerlApp before selecting our packaging method. At that time, PerlApp had faster load times. Several versions of each tool have come and gone since then, so I would recommend testing with each before selecting a tool.
Executable packaging has been very effective for us.
There are a few portability issues issues with Perl, but if you pay attention to perlport, it's easy to avoid most issues. Our biggest problems are always with Win32. From time to time, some simple thing will require stupid, bizarre work-arounds or digging into Win32 API for a platform specific hack.
We have used both Wx and Tk guis.
Frozen Bubble is a well known and widely available app you can look at.
Check out PAR (available via CPAN) with respect to your bundling requirement.
Consider having a look at Padre for an example of a complex application written in perl using Wx.
So yes. All of your requirements are achievable, including portability.
I am working on the module XUL::Gui on CPAN, which uses Firefox to display cross platform gui apps from Perl. It is under development, but stable, and may be complete enough for your needs. You can build your gui in HTML and/or XUL (the Mozilla gui language that Firefox itself is written in), and then style everything with CSS. Let me know if you have any feature requests.