Added some information about Exceptions.

Author: Phil Sturgeon

_posts/03-03-01-Exceptions.md

@@ -0,0 +1,64 @@
+---
+isChild: true
+---
+
+## Exceptions
+
+Exceptions are a standard part of most popular programming languages, but they are often overlooked by PHP programmers. 
+Languages like Ruby are extremely Exception heavy, so whenever something goes wrong such as a HTTP request failing, or 
+a DB query goes wrong, or even if an image asset could not be found, Ruby (or the gems being used) will throw an 
+exception to the screen meaning you instantly know there is a mistake. 
+
+PHP itself is fairly lax with this, and a call to `file_get_contents()` will usually just get you a `FALSE` and a warning.
+Many older PHP frameworks like CodeIgniter will just return a false, log a message to their proprietary logs and maybe 
+let you use a method like `$this->upload->get_error()` to see what went wrong. The problem here is that you have to go 
+looking for a mistake and check the docs to see what the error method is for this class, instead of having it made extremely 
+obvious.
+
+Another problem is when classes automatically throw an error to the screen and exit the process. When you do this you 
+stop another developer from being able to dynamically handle that error. Exceptions should be throw to make a developer aware 
+of an error, then they can choose how to handle this. E.g:
+
+{% highlight php %}
+<?php
+$email = new Fuel\Email;
+$email->subject('My Subject');
+$email->body('How the heck are you?');
+$email->to('[email protected]', 'Some Guy');
+
+try
+{
+    $email->send();
+}
+catch(Fuel\Email\ValidationFailedException $e)
+{
+    // The validation failed
+}
+catch(Fuel\Email\SendingFailedException $e)
+{
+    // The driver could not send the email
+}
+{% endhighlight %}
+
+### SPL Exceptions
+
+An Exception by default has no meaning and the most common to give it meaning is by setting its name:
+
+{% highlight php %}
+<?php
+class ValidationException extends Exception {}
+{% endhighlight %}
+
+This means you can add multiple catch blocks and handle different Exceptions differently. This can lead to 
+the creation of a <em>lot</em> of custom Exceptions, some of which could have been avoided using the SPL Exceptions 
+provided in the [SPL extension][splext]. 
+
+If for example you use the `__call()` Magic Method and an invalid method is requested then instead of throwing a standard 
+Exception which is vague, or creating a custom Exception just for that, you could just `throw new BadFunctionCallException;`.
+
+* [Read about Exceptions][exceptions]
+* [Read about SPL Exceptions][splexe]
+
+[exceptions]: http://php.net/manual/en/language.exceptions.php
+[splexe]: http://php.net/manual/en/spl.exceptions.php
+[splext]: /#standard_php_library

_posts/03-03-01-Namespaces.md renamed to _posts/03-04-01-Namespaces.md

@@ -11,31 +11,31 @@ CLI PHP programs are powerful because you can use your app's code directly witho
 Try running PHP from your command line:
 
 {% highlight bash %}
-    > php -i
+php -i
 {% endhighlight %}
 
 The `-i` option will print your PHP configuration just like the [`phpinfo`][phpinfo] function. There are a number of other useful [command line options][cli-options], too.
 
 Let's write a simple "Hello, $name" CLI program. To try it out, create a file named `hello.php`, as below.
 
 {% highlight php %}
-    <?php
-    if($argc != 2) {
-        die("Usage: php hello.php [name].\n");
-    }
-    $name = $argv[1];
-    echo "Hello, $name\n";
+<?php
+if($argc != 2) {
+    die("Usage: php hello.php [name].\n");
+}
+$name = $argv[1];
+echo "Hello, $name\n";
 {% endhighlight %}
 
 PHP sets up two special variables based on the arguments your script is run with. [`$argc`][argc] is an integer variable containing the argument *count* and [`$argv`][argv] is an array variable containing each argument's *value*. The first argument is always the name of your PHP script file, in this case `hello.php`.
 
 To run our script, above, from the command line:
 
 {% highlight bash %}
-    > php hello.php
-    Usage: php hello.php [name]
-    > php hello.php world
-    Hello, world
+php hello.php
+Usage: php hello.php [name]
+php hello.php world
+Hello, world
 {% endhighlight %}
 
 

_posts/03-04-01-Standard-PHP-Library.md renamed to _posts/03-05-01-Standard-PHP-Library.md

@@ -7,19 +7,19 @@ More importantly, `PDO` allows you to safely inject foreign input (e.g. IDs) int
 Let's assume a PHP script receives a numeric ID as a query parameter. This ID should be used to fetch a user record from a database. This is the `wrong` way to do this:
 
 {% highlight php %}
-    <?php
-    $pdo = new PDO('sqlite:users.db');
-    $pdo->query("SELECT name FROM users WHERE id = " . $_GET['id']); // <-- NO!
+<?php
+$pdo = new PDO('sqlite:users.db');
+$pdo->query("SELECT name FROM users WHERE id = " . $_GET['id']); // <-- NO!
 {% endhighlight %}
 
 This is terrible code. You are inserting a raw query parameter into a SQL query. This will get you hacked in a heartbeat. Instead, you should sanitize the ID input using PDO bound parameters.
 
 {% highlight php %}
-    <?php
-    $pdo = new PDO('sqlite:users.db');
-    $stmt = $pdo->prepare('SELECT name FROM users WHERE id = :id');
-    $stmt->bindParam(':id', filter_input(INPUT_GET, 'id', FILTER_SANITIZE_NUMBER_INT), PDO::PARAM_INT);
-    $stmt->execute();
+<?php
+$pdo = new PDO('sqlite:users.db');
+$stmt = $pdo->prepare('SELECT name FROM users WHERE id = :id');
+$stmt->bindParam(':id', filter_input(INPUT_GET, 'id', FILTER_SANITIZE_NUMBER_INT), PDO::PARAM_INT);
+$stmt->execute();
 {% endhighlight %}
 
 This is correct code. It uses a bound parameter on a PDO statement. This escapes the foreign input ID before it is introduced to the database preventing potential SQL injection attacks.