RMagick on Mac OSX

When installing RMagick, I found that X11 hadn't been installed. It's on the developer CD, which I didn't have handy, so here's what I did.

1) read the notes here:

http://developer.apple.com/opensource/tools/runningx11.html

2) Downloaded and installed Xcode and X11SDK from Apple Developers Center.

3) I still needed X11.app, so I downloaded and installed that from:

http://xanana.ucsc.edu/xtal/x11.html

4) Downloaded and installed rm_install from:


http://rubyforge.org/projects/rmagick/

This will install ImageMagick and RMagick with all dependencies.

I originally had downloaded ImageMagick binary and got this error when trying to install RMagick gem:

"Can't install RMagick. Can't find libMagick or one of the dependent libraries. Check the config.log file for more detailed information."

Info on the error here:


http://rubyforge.org/forum/message.php?msg_id=4066

Ruby on Rails - script/console

A nice and easy way to check you validation rules...

With a table called users with fields user_name, password, and email, we can add simple validation to the model User.

validates_uniqueness_of :user_name, :email
validates_length_of :user_name, :within => 4..20
validates_length_of :password, :within => 4..20
validates_length_of :email, :maximum => 50
validates_format_of :user_name,
                    :with => /^[A-Z0-9_]*$/i,
                    :message => "must contain only letters, " +
                                      "numbers and underscores"
validates_format_of :email,
                    :with => /@/,
                    :message => "must be a valid email address"

Then using script/console, we can check our validation:

First, try to add a bad record:

$ script/console
Loading development environment.
>> user = User.new(:user_name => "pooh bear",
?> :password => "pb",
?> :email => "poohbear_at_100akerwood.com")
=> #"pooh bear", "password"=>"pb", "email"=>"poohbear_at_100akerwood.com"}>
>> user.save
=> false

Then you can inspect the errors individually with errors.on method:

>> user.errors.on(:user_name)
=> "must contain only letters, numbers and underscores"
>> user.errors.on(:password)
=> "is too short (minimum is 4 characters)"
>> user.errors.on(:email)
=> "must be a valid email address"

or all at once with errors.full_messages method:

>> user.errors.full_messages
=> ["Screen name must contain only letters, numbers and underscores", "Password is too short (minimum is 4 characters)", "Email must be a valid email address"]
>>  

PHP PEAR: MDB2

The PEAR DB class has been deprecated and replaced with MDB2.

MDB2 doesn't come with the MySQL driver out to the box, so you need to install that separately:

$ pear install MDB2
$ pear install MDB2_Driver_mysql

Here's a simple select, using the default fetchmode of MDB2_FETCHMODE_ORDERED.

<?
require_once "MDB2.php";

$dsn = 'mysql://my_username:@my_password@127.0.0.1/my_db';

$options = array(
    'debug' => 2,
    'result_buffering' => false,
);

$mdb2 =& MDB2::factory($dsn, $options);
if (PEAR::isError($mdb2)) {
    die($mdb2->getMessage());
}

// Proceed with a query...
$res =& $mdb2->query('SELECT * FROM my_table');

// Always check that result is not an error
if (PEAR::isError($res)) {
    die($res->getMessage());
}

// Iterate through result set (assume default fetchmod is MDB2_FETCHMODE_ORDERED)
while (($row = $res->fetchRow())) {
    echo $row[0] . " " . $row[1] . "<br/>\n";
}

?>

The three possible fetchmode values are:
1) MDB2_FETCHMODE_ORDERED (query results returned as array - column numbers are keys)
2) MDB2_FETCHMODE_ASSOC (query results returned as hash/associative array - column names are keys)
3) MDB2_FETCHMODE_OBJECT (query results returned as object - column names as properties)


To change the default fetchmode and use MDB2_FETCHMODE_ASSOC instead, use the setFetchMode method:

$mdb2->setFetchMode(MDB2_FETCHMODE_ASSOC);

and then iterate through the results:

while ($row = $res->fetchRow()) {
    echo $row['column_name_a'] . ' ' . $row['column_name_b'] . "<br/>\n";
}

Or you can change it per call:

while ($row = $res->fetchRow(MDB2_FETCHMODE_ASSOC)) {
    echo $row['client_abbrv'] . ' ' . $row['client_name'] . "<br/>\n";
}

Here's an example of the first method:

<?
require_once "MDB2.php";

$dsn = 'mysql://my_username:@my_password@127.0.0.1/my_db';

$options = array(
    'debug' => 2,
    'result_buffering' => false,
);

$mdb2 =& MDB2::factory($dsn, $options);
if (PEAR::isError($mdb2)) {
    die($mdb2->getMessage());
}

// Set the fetchmode
$mdb2->setFetchMode(MDB2_FETCHMODE_ASSOC);

// Proceed with a query...
$res =& $mdb2->query('SELECT * FROM my_table');

// Always check that result is not an error
if (PEAR::isError($res)) {
    die($res->getMessage());
}

// Iterate through result set
while ($row = $res->fetchRow()) {
    echo $row['column_name_a'] . ' ' . $row['column_name_b'] . "<br/>\n";
}

?>

You can insert data with a prepared statement:

<?
require_once "MDB2.php";

$dsn = 'mysql://my_username:@my_password@127.0.0.1/my_db';

$options = array(
    'debug' => 2,
    'result_buffering' => false,
);

$mdb2 =& MDB2::factory($dsn, $options);
if (PEAR::isError($mdb2)) {
    die($mdb2->getMessage());
}

// Insert
$statement = $mdb2->prepare('INSERT INTO clients VALUES (?, ?)');
$data = array($var1, $var2);
$statement->execute($data);
$statement->free();
?>

These are just the basics...read all the goodness here:

http://pear.php.net/manual/en/package.database.mdb2.php

PHP PEAR: MDB2 Error: connect failed (localhost MySQL)

I ran into a persistent connect error when trying to connect to localhost MySQL database with MDB2.

Instead of:

dsn: mysql://my_username:my_password@localhost/my_db

use:

dsn: mysql://my_username:my_password@127.0.0.1/my_db

Viewing Ruby Gem documentation

1) Command line

$ ri <gem_name>

2) Browser (http://localhost:8808)

$ gem_server

Emulate PHP5 str_split() in PHP4

/* emulate the php5 str_split function
* array str_split( string $string [, int $split_length])
* Converts a string to an array
* If the optional split_length param is specified, the returned array
* will be broken down into chunks with each being split_length in
* length, otherwise each chuck will be one character in length.
* False is returned if split_length is less than 1. If the split_length
* length exceeds the length of string, the entire string is returned
* as the first (and only) array element.
*/

If you want to use optional split_length:

function str_split($str, $l=1) {
  $str_array = explode("\r\n", chunk_split($str,$l));
  return $str_array;
}

Or optionally, if you just need the simple split (split_length=1):

function str_split($str) {
  $str_array=array();
  $len=strlen($str);
  for($i=0; $i<$len; $i++) {
    $str_array[]=$str{$i};
  }
  return $str_array;
}

Gem List

Here's a command to list all your installed Gems:

gem list | grep '^[a-zA-Z]'