Comments on: Getting a class object in Ruby from a string containing that class’ name http://infovore.org/archives/2006/08/02/getting-a-class-object-in-ruby-from-a-string-containing-that-classes-name/ a weblog by Tom Armitage Sun, 08 Apr 2012 09:50:05 +0000 hourly 1 http://wordpress.org/?v=3.3.2 By: Josh Carter http://infovore.org/archives/2006/08/02/getting-a-class-object-in-ruby-from-a-string-containing-that-classes-name/comment-page-1/#comment-161305 Josh Carter Mon, 26 Jul 2010 22:53:59 +0000 http://infovore.org/archives/2006/08/02/getting-a-class-object-in-ruby-from-a-string-containing-that-classes-name/#comment-161305 @btower you really don't want to be eval'ing strings that could come from an untrusted source, lest someone get a class name into your system like "system('rm -rf /')". ;) Thanks for the tips here. I had figured out the issue with creating classes under nested modules, but failed to realize that I could condense my several lines of code using inject (thanks @Mirage). FWIW more recent versions of Ruby have an alias "reduce" that I think is closer to the intent of the method than "inject." @btower you really don’t want to be eval’ing strings that could come from an untrusted source, lest someone get a class name into your system like “system(‘rm -rf /’)”. ;)

Thanks for the tips here. I had figured out the issue with creating classes under nested modules, but failed to realize that I could condense my several lines of code using inject (thanks @Mirage). FWIW more recent versions of Ruby have an alias “reduce” that I think is closer to the intent of the method than “inject.”

]]> By: DSimon http://infovore.org/archives/2006/08/02/getting-a-class-object-in-ruby-from-a-string-containing-that-classes-name/comment-page-1/#comment-161158 DSimon Fri, 11 Jun 2010 16:15:31 +0000 http://infovore.org/archives/2006/08/02/getting-a-class-object-in-ruby-from-a-string-containing-that-classes-name/#comment-161158 This is lovely! It's especially nice because it is much more secure than eval when handling user input. I don't have to worry about some sneaky user trying to get me to load a type named " exec 'rm -rf /' ". Of course, I still have to make sure that the class name specified isn't something unexpected which would have disastrous side effects, but that's way easier than trying to somehow sanitize a call to exec; all I have to do is make sure the input class includes the base type of the classes I expect to deserialize in its ancestors. This is lovely! It’s especially nice because it is much more secure than eval when handling user input. I don’t have to worry about some sneaky user trying to get me to load a type named ” exec ‘rm -rf /’ “.

Of course, I still have to make sure that the class name specified isn’t something unexpected which would have disastrous side effects, but that’s way easier than trying to somehow sanitize a call to exec; all I have to do is make sure the input class includes the base type of the classes I expect to deserialize in its ancestors.

]]> By: Jaydeep Dave http://infovore.org/archives/2006/08/02/getting-a-class-object-in-ruby-from-a-string-containing-that-classes-name/comment-page-1/#comment-160467 Jaydeep Dave Mon, 08 Feb 2010 22:37:35 +0000 http://infovore.org/archives/2006/08/02/getting-a-class-object-in-ruby-from-a-string-containing-that-classes-name/#comment-160467 This is the answer needed maaan....... you have no idea, what you have helped me to build. This is the answer needed maaan……. you have no idea, what you have helped me to build.

]]> By: Frank http://infovore.org/archives/2006/08/02/getting-a-class-object-in-ruby-from-a-string-containing-that-classes-name/comment-page-1/#comment-159535 Frank Sat, 19 Dec 2009 13:47:40 +0000 http://infovore.org/archives/2006/08/02/getting-a-class-object-in-ruby-from-a-string-containing-that-classes-name/#comment-159535 Thanks petef. Just needed that answer! Thanks petef. Just needed that answer!

]]> By: petef http://infovore.org/archives/2006/08/02/getting-a-class-object-in-ruby-from-a-string-containing-that-classes-name/comment-page-1/#comment-157832 petef Tue, 17 Nov 2009 15:33:57 +0000 http://infovore.org/archives/2006/08/02/getting-a-class-object-in-ruby-from-a-string-containing-that-classes-name/#comment-157832 And of course FWIW you can go the other way to define classes from Strings: <code> # Declare all the classes up front to avoid forward references %w(Tom Dick Harry George).each do |c| Tunnel.const_set(c, Class.new) end </code> And of course FWIW you can go the other way to define classes from Strings:


# Declare all the classes up front to avoid forward references
%w(Tom Dick Harry George).each do |c|
Tunnel.const_set(c, Class.new)
end

]]> By: Andrew’s Blog » Getting Reference to a Class with a String Class Name in Ruby http://infovore.org/archives/2006/08/02/getting-a-class-object-in-ruby-from-a-string-containing-that-classes-name/comment-page-1/#comment-145217 Andrew’s Blog » Getting Reference to a Class with a String Class Name in Ruby Sun, 26 Apr 2009 12:38:07 +0000 http://infovore.org/archives/2006/08/02/getting-a-class-object-in-ruby-from-a-string-containing-that-classes-name/#comment-145217 [...] Getting a class object in Ruby from a string containing that class’ name, Programming Ruby [...] [...] Getting a class object in Ruby from a string containing that class’ name, Programming Ruby [...]

]]> By: btower http://infovore.org/archives/2006/08/02/getting-a-class-object-in-ruby-from-a-string-containing-that-classes-name/comment-page-1/#comment-131086 btower Sat, 03 Jan 2009 23:41:11 +0000 http://infovore.org/archives/2006/08/02/getting-a-class-object-in-ruby-from-a-string-containing-that-classes-name/#comment-131086 What makes the non-eval version more maintainable? What makes the non-eval version more maintainable?

]]> By: Michael A http://infovore.org/archives/2006/08/02/getting-a-class-object-in-ruby-from-a-string-containing-that-classes-name/comment-page-1/#comment-126501 Michael A Mon, 15 Dec 2008 19:33:43 +0000 http://infovore.org/archives/2006/08/02/getting-a-class-object-in-ruby-from-a-string-containing-that-classes-name/#comment-126501 Well done Mirage. I've never used inject for any real work but it makes short work of this problem. Well done Mirage. I’ve never used inject for any real work but it makes short work of this problem.

]]> By: xprdr http://infovore.org/archives/2006/08/02/getting-a-class-object-in-ruby-from-a-string-containing-that-classes-name/comment-page-1/#comment-124482 xprdr Wed, 03 Dec 2008 09:59:04 +0000 http://infovore.org/archives/2006/08/02/getting-a-class-object-in-ruby-from-a-string-containing-that-classes-name/#comment-124482 inject is not used for the purpose you are trying to accomplish here. plus there are at least two types of injects: http://www.java2s.com/Code/Ruby/Range/Injectarange.htm and http://www.java2s.com/Code/Ruby/Hash/injectwithregularexpression.htm inject is not used for the purpose you are trying to accomplish here. plus there are at least two types of injects:
http://www.java2s.com/Code/Ruby/Range/Injectarange.htm

and

http://www.java2s.com/Code/Ruby/Hash/injectwithregularexpression.htm

]]> By: Chris Hoeppner http://infovore.org/archives/2006/08/02/getting-a-class-object-in-ruby-from-a-string-containing-that-classes-name/comment-page-1/#comment-124127 Chris Hoeppner Mon, 01 Dec 2008 14:16:32 +0000 http://infovore.org/archives/2006/08/02/getting-a-class-object-in-ruby-from-a-string-containing-that-classes-name/#comment-124127 Time to dig into #inject. It's a method I have not yet understood. Time to dig into #inject. It’s a method I have not yet understood.

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