FreeplaneJrubyInstaller Addon

So, someday I gave some attention to this scripts thing that freeplane had - basically you could write some code that would use the Freeplane API to programatically make freeplane do things. The code was in the Groovy language which is a kind of java-with-some-sugar-that-looks-a-bit-like-ruby, and I did not know groovy nor java, but ruby was (is) my prefered language and I feel very comfortable programming in ruby. So although with no knowledge of Groovy, I could slightly understand the groovy scripts, and managed to make a couple of simple scripts, basically from copy/pasting/modifying from examples of the scripts collection page and got my homemade very-simple-groovy-scripts going on. No big groovy knowledge there, I just did the basic modify-try-and-error cycle which many times is enough for simple things.

Time passed, and sometimes, very rarely, I would notice that my personal usage of freeplane, could be boostered with some little scripty-automation. This lead me to get bolder in making Groovy scripts, and soon enough I got to the point that I had to learn/understand a little more about Groovy to make my scripts more complex - the copy/paste/modify magic was falling short to what I wanted to program.

As it turns out, for another project, I passed the last 6 months of scarse freetime learning C++ from a "renowned" book, and out of boredoom and curiosity I casually took a Java book to my one-week-vacations (instead of C++), and in one week of late-nigh-readings I ended up feeling more capable with Java than I felt with 6 months of C++ reading. And that was the tipping point to drop the study of C++ in favour of Java and use Jruby (Jruby = Java + Ruby) for that other project. The book was Head First Java, and it made a very funny reading :) Take it to your vacations :)

So, luck took me to learning a bit of Java, and I knew that Groovy was like java-with-some-sugar-that-looks-a-bit-like-ruby, so I started to improve my groovy scripts with the new java understanding. And it worked :) To a certain point. I managed to make the more complex scripts that I wanted with Java and Groovy. Still it costed me an enourmous efforth, as I could only do it in scarce free time, which meant sometimes severall weeks between code-session of a few hours, and that was my only practice of java and groovy. It was working, but carried along a steep beginner-overhead for me, far from efficient/productive, and only worth for high-priority-not-very-simple-but-not-too-complex scripts. Yes, a step ahead, but not the last step.

Jruby: Freeplane can also run ruby scripts with Jruby!

On the other hand, I did read in the wiki that it is possible to use other programming languages for scripting (scala, jython, etc) through the JSR 223. With some try-and-error I got jruby to work with freeplane (very simple after all!), and got all excited - using jruby I could write scripts for freeplane in the ruby language (instead of groovy/java). So, I started to think about making an addon to easily enable ruby scripts with freeplane. And that motivation slowly lead to the creation of the FreeplaneJrubyInstaller addon.

My first intention was for the addon to simply install Jruby in Freeplane to enable ruby scripts, and just that.

I had to learn how to make a freeplane addon (which after you read it well, its easy!). Then I noticed that to make freeplane aware of jruby it was just to put jruby-xxx.jar in 'freeplane-user-dir/lib/jruby-xxx.jar', but the jruby-xxx.jar file is +20MBytes in size, which is too much to be packaged inside an addon.mm file (that would give memory problems, both when building the addon myself, and later when others tried to install the addon - a no go), and the alternative was to make a java-downloader-window, that would be executed after the addon was installed in freeplane, and that would simply download the jruby-xxx.jar file from internet. That was not easy but got it done (the right way!) :) Also, I left the default download url pointing to jruby-9.0.4 (the jruby version I use and know it works!) but that can be easily changed in the future to download more recent versions of jruby (if/when they are needed! A prior jruby-9.0.something.jar did not work because of a bug!). And so with the addon installed (and jruby post-downloaded), one could write a freeplane-ruby-script (ex: 'freeplane-user-dir/scripts/my_ruby_script.rb') and then restart freeplane and click in the new menu entry Tools/Scripts/my_ruby_script to run it. In Preferences/Plugins some options had to be enabled (Permit file read operations + Script Classpath = "lib")

So, at this point the addon could install jruby in freeplane. With jruby installed, freeplane could already run ruby scripts. Also, I've seen that it was then possible for other addons to use ruby instead of groovy addon-scripts! (A whole new world to be explored there...) A good accomplishment, great!

Adding to ruby scripts the variables: c, node, ui, logger, textUtils, ...

However the ruby scripts did not had these handy variables defined - c, node, ui, logger, textUtils, ... - they had to be manually extracted from java classes... that's possible but it's annoying to do it in every single script. In groovy scripts these variables just work and that's great, so in ruby scripts the same should happen. That was possible to do using som ruby metaprogramming.

The code is in the file freeplane.rb (with comments!), you can find it in freeplane_user_dir/addons/freeplaneJrubyInstaller/FreeplaneJrubyCommonEnvironment/lib/freeplane.rb. This file is automatically required by freeplane_jruby_common_environment.rb, so in your freeplane-ruby-script you only need to require "freeplane_jruby_common_environment.rb" to have these variables availabe for use in *any* scope (like global variables).

Just to make this clear:

 * all freeplane-ruby-scripts need to require "freeplane_jruby_common_environment.rb" to use the variables c, node, ui, logger, textUtils, ...
 * certain Preferences have to be enabled

You need to have these freeplane preferences enabled, in Tools/Preferences/Plugins

Rubygems: All ruby scripts share one local gems-home folder

After, I realized that ruby scripts may at somepoint need to use rubygems. Rubygems by default use a default system-wide directory to store all the gems, for all ruby programs (freeplane and non-freeplane). I did not wanted to use that systemwide-default-rubygems-folder, I wanted to use an isolated and self-contained rubygems-folder, where only the gems necessary for the freeplane-ruby-scripts could be stored and read from.

I've investigated about how to use only a local-rubygems-folder... First I started with bundler but it turned out to be an unexpected dead-end for this, and finally concluded that the best solution was to (avoid bundler and) define the environment variables GEM_HOME and GEM_PATH (no dependencies, clean-small code, easily understood) to indicate to rubygems that it should only load gems from a specific local gem-home folder. The result of using GEM_HOME and GEM_PATH is that the freeplane-ruby-scripts only see and only use the gems present in this local gem-home folder. Great, gems containment and isolation achieved :)

I've decided to place the local gem-home folder in freeplane_user_dir/addons/freeplaneJrubyInstaller/FreeplaneJrubyCommonEnvironment/gem_home. The code that makes this local gem-home ready to use in scripts, is in the file 'only_gem_home.rb' file, you can find it in 'freeplane_user_dir/addons/freeplaneJrubyInstaller/FreeplaneJrubyCommonEnvironment/lib/only_gem_home.rb'. This file is automatically required by freeplane_jruby_common_environment.rb, so in your freeplane-ruby-script you only need to require "freeplane_jruby_common_environment.rb" to only use gems from this local gem-home.

Just to make this clear:

 * all freeplane-ruby-scripts need to require "freeplane_jruby_common_environment.rb" to use the local gem_home folder. After that line, the gems (installed in gem_home) can be require'd normally in your script (ex: require 'awesome_print')
 * all freeplane-ruby-scripts will use one common rubygems folder, which is the local gem_home folder, located in freeplane_user_dir/addons/freeplaneJrubyInstaller/FreeplaneJrubyCommonEnvironment/gem_home

NOTE: If you want to manage (list/install/uninstall/...) gems to/from the local gem_home then have a look and edit the files freeplane_user_dir/addons/freeplaneJrubyInstaller/FreeplaneJrubyCommonEnvironment/gem.bat or gem.sh

NOTE2: If you are making an addon with ruby-scripts that needs more gems, then instead of adding gems into the common .../FreeplaneJrubyCommonEnvironment/gem_home of all freeplane-ruby-script, its better for you to package your own independent addon_gem_home folder, with a modified only_gem_home.rb pointing to the addon_gem_home folder. This is easier and garantees that your addon be deployed and executed with exactly the same gems that you want (instead of relying on the common .../FreeplaneJrubyCommonEnvironment/gem_home which is intended to serve as a common base for the non-addon freeplane-ruby-scripts, and may even be tinkered by curious users out there :) )

So, at this point the addon was capable of installing Jruby, and then freeplane-ruby-scripts could be run from menu Tools/Scripts/my_ruby_script The freeplane-ruby-script should have a require "freeplane_jruby_common_environment.rb" that defines the variables c, node, ui, ... and also enables the gems (installed in gem_home) that thereafter can be required normally by the script.

Great :)

RubyLiveDebugger

Well, with all that ready, the next step would be to write some freeplane ruby scripts! And, as it happens to everyone who programs, at some point you'll find an error and debug your code for that error... When an error is found during execution of your ruby script, a short error-message-window will show up in freeplane (which tipically will not show the line number of the error). On the other hand the error will also be logged into the freeplane log file (freeplane_user_dir/logs/log.0), where you may find the line number of the error among other usefull info such as the ruby exception raised. So keep in mind that the log file will have more info about the error than what is shown in the small error-message-window that pops up.

And there you go reading the log file for the line number of your error, then opening the ruby script and rechecking that line and trying to mentally recompute and fing the error. And thats ok, but there is a better way currently availabe in ruby - there is this gem called Pry that is used normally to debug a program live while it is still executing (its a REPL launched inside a running program). Pry is very usefull, you just put a line of code in the middle of your program where you want, and then run your program and when the program execution gets to that line it waits for you to interact with it (read variables, change variables, call methods, etc, it's live conding inside your program in that point). Have a look a some youtube videos to understand it better, or wait 5 min to read this to the end and then it try yourself, its pretty easy to use.

However Pry expects the program to be launched from a terminal and reuses the terminal's stdin/stdout to interact with the user, but we are running a ruby program with jruby which is called from java and the program stdin/stdout is who-knows-where... :) the stdout at least seems to be logged into the log files, but stdin is out-of-reach. For these cases (and other similar that happen in the ruby universe, like daemon processes), there is another gem called Pry-remote which uses tcp/ip to communicate between a pry-remote-server listening on 127.0.0.1:9876, to which its possible to connect with a pry-remote-client. The pry-remote-server is attached to the ruby program, and waits a connection from the pry-remote-client. The pry-remote-client is executed from another terminal, and will connect to the pry-remote-server via Tcp/Ip and use the client-terminal stdin/stdout to allow the user to interact with the ruby program (attached to pry-remote-server). So, using pry + pry-remote, we can debug a freeplane-ruby-script in the middle of its execution, from an external terminal that is running the pry-remote-client, and inspect the running freeplane-ruby-script to see its variables value and try new commands.

Using pry-remote implies severall things:

1) have the freeplane-ruby-script execute a pry-remote command (in the line where the debug will occur). This will start the pry-remote-server which will stay listening and waiting for a tcp connection in 127.0.0.1:9876
2) in a separate terminal window, launch the pry-remote-client (using java + jruby + the pry-remote gem)
3) finally once pry-remote-client is openned and connected, the user can debug the freeplane-ruby-script using that terminal (typing in keyboard, reading in screen). Tab is very usefull (autocompletion!)

As can be seen, manually setting up a pry-remote debug session is a bit daunting... and repeating it every time we want to debug something is not pleasant... So I automated it programatically so that a script-developer would not need to think about all this, and instead would only need to call a special command inside the freeplane-ruby-script where one wants to open a debug window: RubyLiveDebugger.open_debug_here(binding)

You can put in multiple lines the RubyLiveDebugger.open_debug_here(binding) - each time one of those lines is executed, a debug window will open for you to debug the ruby script in that point of execution.

To exit from a debug session, its mandatory to send the command !!@ Only exit with !!@' and never with 'exit' or 'quit' or closing the debug window directly. This is necesary for the pry-remote-server process to cleanup and properly release/continue the execution of the ruby script past the debug line.

The RubyLiveDebugger class is defined in file ruby_live_debugger.rb located in freeplane_user_dir/addons/freeplaneJrubyInstaller/FreeplaneJrubyCommonEnvironment/lib/ruby_live_debugger.rb This file is automatically required by freeplane_jruby_common_environment.rb, so in your freeplane-ruby-script you only need to require "freeplane_jruby_common_environment.rb" to have available the RubyLiveDebugger.open_debug_here(binding) command

Just to make this clear:

 * all freeplane-ruby-scripts need to require "freeplane_jruby_common_environment.rb" to use the debug command RubyLiveDebugger.open_debug_here(binding)
 * all freeplane-ruby-scripts can use debug at any place of the script - just put in a line RubyLiveDebugger.open_debug_here(binding) and when the script is executed it will open a debug window in that point of the script.
 * certain Preferences have to be enabled

Certain Preferences need to be enabled for a script to be able to use the RubyLiveDebugger:

Normal freeplane users that don't code ruby script, and are only concerned about executing ruby scripts, the RubyLiveDebugger is not usefull, after all RubyLiveDebugger is kind-of a developer-tool for programming ruby scripts.

... ...

To make it easy for every script, to require all these files at once, I made one single file thats the only one that need to be required by every ruby script - the 'freeplane_jruby_common_environment' (in 'freeplane_user_dir/lib/freeplane_jruby_common_environment.rb').

So you should put in the start of your ruby scripts the following:

TODO: continue here

in freeplane the groovy scripts we have these very handy global variables defined:

FreeplaneJrubyInstaller Addon

Contents

This page is still a work in progress

Introduction

How to install the FreeplaneJrubyInstaller Addon in Freeplane

The making of the FreeplaneJrubyInstaller addon - a long story

Jruby: Freeplane can also run ruby scripts with Jruby!

Adding to ruby scripts the variables: c, node, ui, logger, textUtils, ...

Rubygems: All ruby scripts share one local gems-home folder

RubyLiveDebugger

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