Sunday, August 29, 2010

Error installing ruby-debug-base19

The ruby-debug19 gems are used for interactive debugging with Ruby 1.9 (the gems without 19 on the end are for Ruby 1.8). To use the debugging feature in Rubymine (which is awesome if you haven't tried it yet) you need to install these gems (ruby-debug-base19 and ruby-debug-ide19). I had previously used these with no problems, but yesterday when I tried installing ruby-debug-base19 on a new Ubuntu 10 system with Ruby 1.9.1 yesterday I got the following error:

gcc -I. -I/usr/local/include/ruby-1.9.1/i686-linux -I/usr/local/include/ruby-1.9.1/ruby/backward -I/usr/local/include/ruby-1.9.1 -I. -DHAVE_VM_CORE_H -DHAVE_ISEQ_H -DHAVE_INSNS_INC -DHAVE_INSNS_INFO_INC -DHAVE_EVAL_INTERN_H -I/usr/local/include/ruby-1.9.1/ruby-1.9.1-p376 -fPIC -O2 -g -Wall -Wno-parentheses -o breakpoint.o -c breakpoint.c
gcc -I. -I/usr/local/include/ruby-1.9.1/i686-linux -I/usr/local/include/ruby-1.9.1/ruby/backward -I/usr/local/include/ruby-1.9.1 -I. -DHAVE_VM_CORE_H -DHAVE_ISEQ_H -DHAVE_INSNS_INC -DHAVE_INSNS_INFO_INC -DHAVE_EVAL_INTERN_H -I/usr/local/include/ruby-1.9.1/ruby-1.9.1-p376 -fPIC -O2 -g -Wall -Wno-parentheses -o ruby_debug.o -c ruby_debug.c
ruby_debug.c: In function ‘ruby_method_ptr’:
ruby_debug.c:141: error: ‘rb_method_entry_t’ undeclared (first use in this function)
ruby_debug.c:141: error: (Each undeclared identifier is reported only once
ruby_debug.c:141: error: for each function it appears in.)
ruby_debug.c:141: error: ‘method’ undeclared (first use in this function)
ruby_debug.c:142: warning: implicit declaration of function ‘rb_method_entry’
ruby_debug.c: In function ‘debug_event_hook’:
ruby_debug.c:719: error: ‘rb_method_entry_t’ undeclared (first use in this function)
ruby_debug.c:719: error: ‘me’ undeclared (first use in this function)
make: *** [ruby_debug.o] Error 1

Apparently version 0.11.24 of ruby-debug-base19 was released on August 22, 2010, and it won't install correctly on Ruby 1.9.1. This version fixed support in Ruby 1.9.2, but broke 1.9.1 support. I went back to the previous version and it works fine. So to install the ruby-debug19 gems on a Ruby 1.9.1 system, run these two commands:

sudo gem install ruby-debug-base19 -v=0.11.23
sudo gem install ruby-debug-ide19

One important note! If you've already attempted to install the latest version of ruby-debug-base19 and gotten the failure, ruby-debug-ide19 may fail, even if you install the working version of ruby-debug-base19. You have to actually delete the files for 0.11.24 of ruby-debug-base19, and then reinstall ruby-debug-ide19. For me on a Ubuntu system where Ruby was compiled from source:

sudo rm -rf /usr/local/lib/ruby/gems/1.9.1/gems/ruby-debug-base19-0.11.24
sudo gem install ruby-debug-ide19

Also this bug has been reported on as ticket #28512.

Thursday, August 26, 2010

Rails 2.3.8 automatically escaping HTML when you don't want it to

I was upgrading my application to Rails 2.3.8 from 2.3.5 and found a pretty annoying bug in Rails 2.3.8. This bug HAS BEEN FIXED in Rails 2.3.9, so simply install Rails 2.3.9 to get around this problem. However, there are a lot of other problems with Rails 2.3.9, read my posting at Upgrade to Rails 2.3.9 session no longer works for a killer bug for me. Other problems have been reported too. I'm just sticking with 2.3.5.

The bug is that when you concatenate HTML strings in helper methods, Rails will automatically HTML escape the string under certain conditions. There is NO way to tell Rails not to do this. Here is an example that reproduces the problem. Add these two methods to your application helper:

Then simply output the outer_helper method in one of your views:

  <%= outer_helper %>

This is the result:
about to call inner_helper method

inside p content tag

a space should be between the following words: hello&nbsp;worldmore <span style="font-weight:bold;">dirty HTML</span>
inside div content tag

outside of inner_helper method in p tag

This is obviously not what it should be producing. Rails 3 automatically escapes HTML rendered, but you can simply call .html_safe on the output to mark that you don't want it to escape, or call raw(string), from what I've read. But these don't exist in Rails 2.3.8. This bug has been fixed in this commit to the Rails code, which has been included in Rails 2.3.9.

The blog posting at shows some ways you can get around this, but in my opinion you shouldn't have to work around this. Just stick with 2.3.5, or if you're brave you can try 2.3.9.

Friday, August 20, 2010

Gem for getting Google static maps

I've created a gem for getting maps from the Google Maps static API service called googlestaticmap. With static maps, you can specify parameters for a map, from image size, image type, and markers, path lines, and polygons to draw on the map, and in one http get to Google, retrieve the map. This is great for mobile sites where many visitors won't be able to use the Google Maps 2D API. It's also great if you have a map image that you want people to see, but don't want to load all of the Google maps javascript on your page.

To install the gem, simply type "gem install googlestaticmap" (the gem is on gemcutter, and I believe you need version 1.3.6 or higher of Rubygems to get gems from there). Documentation for the gem is at with several examples of how to use it. Also if you want to see the source, it's on Github at