Check out the GitHub Gist and the second comment for more info.

Here are my bingo_cards for this year.

Delegation is used when you want to forward a method call from on class/model to an associated class/model. The Ruby on Rails Guides use the example of a User model which has a Profile associated with it. This is a great example with a little subtlety which I overlooked. If you aren't famaliar with delegation, go ahead and get yourself learned. I won't wait for you though. This is text just come back when you're up to speed.

The Setup

Let's say we've got a Rails app with Drivers and Trucks. On the show page for drivers, we show the truck number, if that driver is in a truck. Easy-peasy:

# app/views/drivers/show.html.haml
 
.truck_number
  -if @driver.truck
    = @driver.truck.number
  -else
    Not Driving any Truck

NBD. Here's our problem:

The Problem

As when any good application which acts as a font-end for a database, we track history on all edits, etc. So, when we update the Driver in a Truck, we want to add history for the Truck and the Driver. If the Driver is already in another Truck we want to show, in his history, that he moved from Truck 1001 into Truck 2002. We'll say we have a create_history method included into our Entity classes whose declaration looks something like:

def create_history(attribute, prev_value, new_value)

So, we want to call something like:

@truck.driver.create_history('Truck Number', @driver.truck.number, @truck.number)

Jackpot! Works perfectly. We get the old Truck number (1001) from the @driver instance and the new Truck number (2002) directly from the @truck instance. We are geniuses.
Hold the phone though. What if that Driver didn't have a previous truck... Spoiler Alert:

NoMethodError: undefined method 'number' for nil:NilClass

I guess we could check that a Truck exists each time we want to access any attributes for Driver.truck. But, really, what do we expect Driver.truck.number to be if the Driver is not in a Truck? Nil would work...

Delegate: for science!

I'll allow it. Let's delegate and allow_nil:

# app/models/driver.rb
 
class Driver < ActiveRecord::Model
  # ...
  delegate :number, :to => :truck, :prefix => true, :allow_nil => true
  # ...
end

Works! Now, we've got history showing: Driver had no Truck and moved into Truck 2002. Geniusness times 2. Delegation to perferction.

Sometime later...

Instead of the Truck number, maybe we want to store the id of the Truck in the history. Perhaps we know the truck number may change over time and want to link up the correct Truck record. Seems easy:

delegate :id, :to => :truck, :prefix => true, :allow_nil => true

But, when our Driver doesn't have a 'previous' truck:

RuntimeError - Called id for nil, which would mistakenly be 4 -- if you really wanted the id of nil, use object_id

WTF? I allowed nil. I know he doesn't have a previous truck. I just want my nil back and I'll go about my business. Let's get our hard hats on and get digging into the source. I'll save you some googling and just tell you that the Delegation module is in ActiveSupport in the Core Extensions under Module. Scroll, scroll, scroll. There! Line 136! They(we)(whomever) are only rescuing from NoMethodErrors. Calling id on nil raises a RuntimeError, which isn't rescued and bubbles up to us. This is me stomping my feet and wining. My knee jerk reaction was to just rescue RuntimeErrors too:

rescue NoMethodError, RuntimeError

We're gonna be Famous

It works! AND, how cool are we? We get to submit a bug fix to Rails. Uber-cool. Uh-oh, uneasyness...crap... It just doesn't feel right to just catch any old RuntimeError and possibly, silently fail to nil. However, the urge to try and submit a simple 'fix' to Rails was strong. Instead, I started doing more research into delegate and Ruby Exception handling. Here's what I've come up with:

The Moral of the Story

You should delegate when you want to hide an architectural aspect and expose the expected abstraction. In the Ruby on Rails Guides example, we expect a user to have a name through @user.name even through name actually resided in Profile. However, in our example, a Driver isn't expected to have a truck_id. A truck has an id, but a driver does not have a truck_id.

One of the classic 'bad smells' in code for refactoring is using a temporary variable in place a a query. Ruby and its optional parantheses, blurs the lines between variable, attribute and method. It's easy to forget what you are doing and assume everything is an attribute. Why shouldn't a Driver have a truck_id? The same reason a Truck doesn't have a CDL. But, we can query the truck_id for the Truck associated with a Driver with a method.

After all that, I should have just written a query method in Driver as such:

def truck_id
  self.truck.id if self.truck
end

Too easy...

I've been half-heartedly looking for another solution every few weeks, but haven't found anything other than a few Perl scripts (I'm not really famaliar with perl). So, yesterday I decided to write a ruby script to send auto-responses. I wanted to use text files to hold each autoresponse. Then, I'd just move them int and out of a folder to activate and deactivate them. I also took advantage of the 'new' folder within the vmail structure to reply to mail newer than the autoresponder config file.

The format of the config files is:

email_address_to_respond_from

subject of response

message of response

The message can be multiple lines until the end of the file.

For each config file in the directory, the script parses the file for the above information. Then it will check that user's new mail folder for files. Any new mail file which was modified (sent) after the modification date of the config file is parsed to get the sender's address(es)*. A new e-mail is composed using benprew's pony gem and sent to each of the senders. Finally, the script 'touches' the config file to move the modification date newer than the messages for which it just responded.

The nifty parts of the script are iterating over a directory listing of files:

Dir.new(directory_path).each { |filename| puts filename }

and using the stat method of a file object to get the modified dateTime:

file.stat.mtime

and lastly, using the FileUtils module to 'touch' a file:

FileUtils.touch "#{file_path}/#{file_name}"

Here's the full source:

require 'fileutils'
require 'rubygems'
require 'pony'


# Set absolute path for config file directory
conf_path = "/home/auto-responses"

#for each config file (autoresponder)
Dir.new(conf_path).each do |response_file|
  # don't act on this file or linux '.' listings
  unless response_file[0,1] == "." || response_file == "auto-response-script.rb"
    #create a file for reading
    file = File.new("#{conf_path}/#{response_file}")
    
    # get the last modified time of the current config file
    last_date = file.stat.mtime

    # e-mail address to respond from is first line
    address = file.gets.chomp
   
    #skip blank lines
    begin 
      line = file.gets
    end while line == "\n"

    # subject is next
    base_subject = "#{line.chomp} (Auto-Response)"

    #skip blank lines
    begin 
      line = file.gets
    end while line == "\n"

    # take all the rest of the lines as the message
    message = line
    while line = file.gets 
      message << line
    end

    # write parsed info to output (for log file)
    puts address
    #puts last_date
    #puts subject
    #puts message

    # split the e-mail address into user and domain to put into vmail path    
    user = address.split('@')[0]
    domain = address.split('@')[1]
    #puts user
    #puts domain

    # build the vmail path to the new mail message files
    mail_path = "/home/vmail/#{domain}/#{user}/new"
    
    #for each new mail file
    Dir.new(mail_path).each do |mail_file|
      #don't act on the linux '.' listings
      unless mail_file[0,1] == "."
        # get mail file for reading
        mail = File.new(mail_path + '/' + mail_file)
        
        #log mail filename and mod times (for debugging)
        puts mail_file
        puts "mail_file_time: #{mail.stat.mtime}"
        puts "conf_file_time: #{last_date}"
        
        # act only if mail file is newer
        if mail.stat.mtime > last_date
        
          # initialize flags for From and Subject lines in message
          found_from = false
          found_subject = false
          
          #get first line from email message
          line = mail.gets
          begin
            # regex to check if line starts with 'From:'
            # if so, store as from
            if line =~ /^From:/i && !found_from
              found_from = true
              from = line
            end
            
            # regex to check if line starts with 'Subject:'
            # if so, append the base_subject from above and store as subject
            if line =~ /^Subject:/i && !found_subject
              found_subject = true
              subject = "Re: #{line.chomp} - #{base_subject}"
            end
            
            #get next line
            line = mail.gets
          # loop over lines until both from AND subject are foud OR there are no more lines
          end while (!found_from && !found_subject) || line
          
          # use the base subject if couldn't find message subject
          subject = base_subject unless found_subject

          
          #puts "From line: #{from}"
          
          # take the From line and split on spaces
          # each 'word' which contains an @ (and isn't mailer-deamon) store into the to array
          to = Array.new
          from.split(' ').each do |name|
            if(name =~ /@/  && !(name =~ /MAILER.DAEMON/i))
              to << name 
            end
          end

          # create comma separated list of email addresses; stripping angle brackets
          to = to.join(',').gsub('<','').gsub('>','')

          # log to whom sending mail
          puts "Sending to: #{to}"
          
          # don't send mail to nobody
          unless to == "" || to == 'invalid@emailaddress.com'
            Pony.mail(:to => to, :from => address, :subject => subject, 
              :body => message )
          else
            puts "To is invalid"
          end
        else
          # log that the mail file is not newer than the conf file
          puts "From: #{mail_file} is not newer"
        end
        # separate the mail messages in the log
        puts "------------\n\n"
      end
    end
    
    # update the auto response file's mod time
    FileUtils.touch "#{conf_path}/#{response_file}"
  end
end

Here's how it all works. When you install the Dropox client software on your computer, it will create a Dropbox folder with all your stuff in it. Add, delete or edit any file in this folder and Dropbox will sync it up to their servers, plus download the changes to any other computer running the Dropbox client with your account. It's kind of cool to have your desktop and laptop running next to each other and watch them download the changes instantly.

Back to business, I know what you are thinking, "All these files are in one Dropbox folder (and subfolders). My config file needs to be in my home directory. I still have to copy from my Dropbox to my home." Well, let's let the computer do the copying. Actually, let's not even waste time and space copying. Let's create a symlink to make the config files appear to be in your home folder but actually be stored in the Dropbox folder.

First, open a terminal, navigate to the Dropbox folder and create a new subfolder; I called mine 'configs.'

$ cd ~/Dropbox
$ mkdir configs
$ cd configs

Now, let's move the config file from the home folder into the Dropbox/configs folder and navigate to the home folder.

$ mv ~/.ttytterrc ~/Dropbox/configs/.ttytterrc
$ cd ~/

Here's the magic. We'll create a symlink (like a shortcut in Windows) which will make it appear that the file is in your home directory, but Dropbox will still keep track of it.

$ ln -s ~/Dropbox/configs/.ttytterrc ~/.ttytterrc

Rough Spot: If you get a file exists error, the link will not overwrite an existing file. Remove the file from where you are creating the link into (the home dir in our case).

Do this on all your computers, then you can edit the file directly from my home directory on any computer and the changes will be automatically propagated to all my other computers instantaneously.

Here are some other ideas for this technique which I haven't tried, but might be cool.

• Thunderbird Profile
• Media Library
• Flat data files

If you have any more or try one of these, let me know in the comments!

I generally use Vim to code web applications. My site at work run on PHP and at home I'm working with Ruby on Rails. So, I'll be looking for something to specifically help with that, but who knows what I'll find.

.vimrc

.vimrc is a file in your home directory. It contains a script which runs each time you start Vim. You can setup your configurations, preferences and plugins in here. The .vimrc is the starting point for fine tuning your Vim to exactly how you want it. If you are a beginner, I would recommend finding some more advanced users' .vimrc's and, at least, check them out, if not start using them for yourself. I started with Todd Werth's .vimrc file. He keeps his in a separate folder and uses a symlink to put them in his home folder. I strongly recommend this as well. You can automatically sync your .vimrc (or any other files) across computers with Dropbox. See how in my post on how to Use Dropbox to keep your preferences across Computers.

Here are some useful lines to start you out:

" Set tabs to 2 sapces
set softtabstop=2
set shiftwidth=2
set tabstop=2
set expandtab

" Wildmenu - show a tab completion matches list
set wildmenu
set wildmode=list:longest,full

Again, search the google machine and checkout github for more samples and if you find anything cool, let me know in the comments.

Plugins

Autoclose

This first plugin automatically closes quotes, parenthesis, brackets, etc. for you. If you type a single quote, another single quote is added after the cursor. You can type an end paren to move the cursor after the autoclosed characters. This is helpful after nested autocloses. For instance, in PHP, I often find myself passing array values to a function:
run_trail($locmotives['lionel|'])
This pipe in the above example is the cursor position after the last l in lionel. I can simply hit ) and the cursor will jump out of the single quote, square bracket AND end paren. Simple.

Autoclose is developed by Karl Guertin and can be found at http://www.vim.org/scripts/script.php?script_id=1849

See ya Soon!

It basically boils down to editing your /etc/ssh/ssh_config file and adding the following:

/etc/ssh/ssh_config
ServerAliveInterval 5

The number is the number of seconds to send the small keep alive which keeps the connection open. Ubuntu Blog suggests changing it from 5 to 240 or 300 (4 or 5 minutes).

1. Get the PianoBar source.

I downloaded the .tar.gz from http://6xq.net/html/00/17.html and extracted it with
tar -xzf PromyLOPh-pianobar-e079b45.tar.gz

2. Try to Make the PianoBar source.

I say try because for me it didn't work. I was missing some of the required dependencies. But, you might not be missing the same ones as me. So, try to make it and then follow the instructions below for the dependencies you are missing.
cd PromyLOPh-pianobar-e079b45/
cmake .

3. Get and install libao

Libao is a cross-platform audio library for playing audio. I followed these instructions from Linux from Scratch to install it. Download the source from that page. Extract the .tar.gz:
tar -xzf libao-0.8.8
Then, from withing the libao-0.8.8 directory, configure the library with:
./configure --prefix=/usr && make
Finally, install it as root:
sudo make install && sudo install -v -m644 README /usr/share/doc/libao-0.8.8
Then, I retried step 2 to see that I didn't need the LIBAO anymore.

4. Install FAAD2

Download the bootstrapped .tar.gz from AudioCoding.com.
Extract the .tar.gz with:
tar -xzf faad2-2.7
There are installation instructions in the INSTALL file in the extracted folder. I'll summarize what worked for me.
Configure it:
./configure
Make it:
make
Install it:
sudo make install
Then, I tried to make pianobar again. It still said it couldn't find libmad, but it turned out I didn't need it.

5. Install PianoBar.

After running the cmake from the extracted PianoBar folder, you should see that the object files were made. Then, run make:
make
And install:
sudo make install
If all goes well, you will be able to run it:
./src/pianobar
Enter your pandora username/email address and password.
Choose your station.
Hear music!

6. PianoBar config

You can change the configuration of PianoBar to switch up the keyboard short cuts and automatically login on run. To do this, you need to create and edit a file named 'config' in the .config/pianobar/ within your home directory.
vim ~/.config/pianobar/config
To automatically login, add the following two lines
user = pandoraUserName
password = pandoraPassword
I also found that changing the "Loving Song" keyboard short cut from + to = worked out better, since I didn't have to press Shift+=.
act_songlove = =

Style Configurator

The Style Configurator is a dialog within Notepad++ accessible through the Settings menu. The really great thing about the Configurator is that the styles you choose are updated live in your code. So, open up a file with a lot of code. Then open the Configurator and move it over to another screen. If you don't have more than one monitor, check the Transparency box in the lower right and you will be able to see through the Configurator. The slider there sets the Transparency level. Now you can see all of your code and pick styles for them.

Start with the very first 'language,' Global Styles. These not only include default styles of text but many of the stuff around your code, such as line number margin, inactive and active tab color, and the edge. The edge is great to keep your lines of code to a certain length for printing or displaying in a terminal. I also set the global font to Consolas. Also, be sure to set the current line color and selected text background color.

Now you are ready to style for you language. I usu PHP mostly at work so I'll go though that one. Hopefully, I'll be familiar with Ruby soon enough to write a post about Ruby styles.

• QUESTION MARK - This is the style of the opening and closing php tags ('')
• DEFAULT - Text that doesn't match any of the other styles will be this.
• STRING - Any string enclosed with double quotes
• STRING VARIABLE - variables enclosed withing literal strings: "The Count is $count"
• SIMPLESTRING - These are string enclosed with single quotes. (I used a very similar green to STRING)
• WORD - These are the keywords of PHP. There are a bunch defined. You can also define some of your own in the blank box.
• NUMBER - Number literals, including array indices
• VARIABLE - Any word started with a $
• COMMENT - Text between matching multi-line comments ('/*' and '*/')
• COMMENTLINE - Text on a line after and including two forward slashes (//)
• OPERATOR - Operators (+,=,-,etc.), matched parenthesis, brackets, curly brackets and logical operators

Stylers.xml

The stylers.xml file contains all the settings from the Configurator used by Notepad++. In addition to using the Configurator, you can manually edit this file. Or, download one from the web. The Notepad++ site has some under Theme Files. Joy Boner (read the About page) has 60 themes. I didn't check any of these out, but it might be worth a shot if you really don't want to set your own styles.

I also put my personal stylers.xml as a gist on github. Feel free to fork it.

If you have any other Notepad++ styling tips, comment below!

--Chris

]]> http://chrismar035.com/2010/01/08/notepad-color-configurator-and-styler-xml/feed/ 4 http://chrismar035.com/2009/12/18/getting-and-parsing-e-mail-with-php/ http://chrismar035.com/2009/12/18/getting-and-parsing-e-mail-with-php/#comments Fri, 18 Dec 2009 16:24:29 +0000 Chris M http://chrismar035.com/?p=4 Here's my Problem:
My website sends text files to a partner's site via FTP. Our partner site sends us the results of their processing the file in an e-mail. This e-mail is a the direct output from their processing script. Or, the relevant details are buried in a bunch of garbled text.

My Solution:
I first looked at message piping, but my hosting provider doesn't provide an easy way to do this.
Then I found this PHP class from PHP classes, which handles the interactions with the server. You do have to create an account with PHP classes to download the files. If you e-mail me directly, I could send them to you.
It's easy enough to get working quickly.

$pop3->hostname="localhost";    // POP 3 server host name 
 
$user="username";                    // Authentication user name 
$password="password";             // Authentication password  
 
$pop3->debug=1;                    // Output debug information
$pop3->html_debug=1;            // Debug information is in HTML

Edit the test_pop3.php file. All you need to do is change the sever name, user name and password to get rolling. After you see the full output and it's getting the mail correctly, I recommend setting the debug and html_debug values to 0. This will cut out the unnecessary text of the interaction with the server and just show you the messages and what's going on.

One hangup of this class, the body of the message is an array and the message was repeated twice in the array.

array(14) {
  [0]=> string(30) "--0016e6d99d7ed848e5047b02e012"
  [1]=> string(44) "Content-Type: text/plain; charset=ISO-8859-1"
  [2]=> string(0) ""
  [3]=> string(71) "This is a test. If this were an actual message, important text would be"
  [4]=> string(5) "here."
  [5]=> string(0) ""
  [6]=> string(30) "--0016e6d99d7ed848e5047b02e012"
  [7]=> string(43) "Content-Type: text/html; charset=ISO-8859-1"
  [8]=> string(0) ""
  [9]=> string(77) "This is a test. If this were an actual message, important text would be here."
  [10]=> string(4) ""
  [11]=> string(0) ""
  [12]=> string(32) "--0016e6d99d7ed848e5047b02e012--"
  [13]=> string(0) ""
}

Luckily, the part boundaries are included in the array which makes it fairly easy to split the array and just get the message once.

$oneBody = array();
$delimiter = $body[0];
$oneBody_i = 0;
for($body_i=3; $body_i<count($body); $body_i++) // starts on 3 to skip the top of the body stuff
{
	if($body[$body_i] == $delimiter)
	    break;
	$oneBody[$oneBody_i] = $body[$body_i];
	$oneBody_i++;
}

I needed to run some regular expressions on the body and imploded it into a single string.

$bodyString = implode('', $oneBody);

Now I have the body of my e-mail message as a string variable ready for processing. Alternatively, you can change the first parameter in implode( to a line break if you need to display the message not as one long string.

Lastly, once you process your messages, you don't need them anymore.

if(($error=$pop3->DeleteMessage($index))=="")
	echo "<PRE>Marked message $index for deletion.</PRE>\n";

The DeleteMessage( method will mark messages for deletion when you close the connection to your mail server. Please note that this method does not immediately delete the messages and messages can still be 'un-deleted' until the connection is closed. The ResetDeletedMessages( method is used to un-mark all messages for deletion.

Happy Parsing!!

--Chris

]]> http://chrismar035.com/2009/12/18/getting-and-parsing-e-mail-with-php/feed/ 0