Over this past weekend I began templating a project structure that we use at my day/evening/night job to allow developers to simply execute a script and provide a few parameters to initialize a new development project (including build script, fxcop analysis, unit testing, visual studio projects, etc.).  I didn’t think this would take that long despite being relatively new to the Ruby world.

Oddly enough, I had trouble finding similar examples on the interwebs – even StackOverflow didn’t have the answer!  The horror, the horror!

No matter, I’m a developer after all and should be, better be capable of handling this simple script.  I decided to start simple and just use the directory global searching method to recursively get everything within my project template’s directory:

def packageInitiator( startDirectory )  
    Dir.glob( startDirectory ).each do | path | 
        puts path
    end
end  
packageInitiator( './**/*' )

OK, good start.  Now I have all the items (files and directories) within my current executing directory.  I figured it would be easy to then replace the templated text in the directory and file paths at that point.

Not so fast!

The global directory search - Dir.glob() – actually traverses the directory structure and returns an array of all the file/directory names within the executing directory.  Take a look at the ruby documentation on the it here.  What ended up happening was that as I changed directory names using a top-down approach, I was invalidating paths used later in the loop.  For example, /project/store is the first directory to change in the example structure below:

Original Directory Structure

• /project/store/  - [first to change]
• /project/store/hats
• /project/store/jackets

When we try to change /project/store/hats ruby throws an error because the root path /project/store would have changed.  The fix for this was simple,reverse the array and go from bottom-up:

def packageInitiator( startDirectory )   
    directoryItems = Dir.glob( startDirectory ).reverse
    directoryItems.each do | path | 
        puts path
    end
end  
packageInitiator( './**/*' )

Better.  Time to add the logic to replace the placeholders I put in the file and directory names.  At this point I don’t care about whether the item is a file or directory so I treat them the same:

def packageInitiator( startDirectory, patternToReplace )   
    directoryItems = Dir.glob( startDirectory ).reverse
    directoryItems.each do | path | 
        if( path.include? patternToReplace )
            oldPath = File.dirname(path)
            newPath = oldPath + '/' + File.basename( path ).gsub( patternToReplace, 'MyNewProjectName' )

            File.rename( path, newPath )    
        end
    end
end  
packageInitiator( './**/*', '{projectName}' )

Much better.  Now I need to determine if I am dealing with a file or a directory since I will need to replace the contents of files where I find the placeholder text as well.  Turns out that was pretty darn simple.

Final Script

def replaceFileContents( path, patternToReplace, newProjectName )
    fileContents = File.read ( path )
    fileContents = fileContents.gsub( patternToReplace, newProjectName )
    File.open( path, 'w' ) { | file | file.puts fileContents }
end  
def packageInitiator( startDirectory, patternToReplace, newProjectName )   
    directoryItems = Dir.glob( startDirectory ).reverse
    directoryItems.each do | path | 

        # ignoring ruby scripts so I don't change contents of this file
        if( FileTest.file? ( path ) and File.extname( path ) != '.rb' )
                replaceFileContents( path, patternToReplace, newProjectName )
        end

        if( path.include? patternToReplace )
            oldPath = File.dirname(path)
            newPath = oldPath + '/' + File.basename( path ).gsub( patternToReplace, newProjectName )

            File.rename( path, newPath )    
        end

    end
end  
packageInitiator( './**/*', '{projectName}', 'MyNewProjectName' )

I can think of a lot of ways to improve this for more complicated scenarios, but this worked just fine for my needs.  Hopefully this helps someone else too.  And as I mentioned previously, I’m relatively new to Ruby and welcome and constructive feedback or suggestions for improvement that any Ruby experts have for me.