Improve exception handling, introduce autoloading

5 files changed, 124 insertions, 26 deletions

diff --git a/index.php b/index.php
index 8c9ef11..f8ef302 100644
--- a/index.php
+++ b/index.php
@@ -4,21 +4,38 @@ declare(strict_types=1);
 
 namespace AugustOffensive;
 
-// y u no autoload
-include 'private/Model/Connection.php';
-include 'private/Model/Query.php';
-include 'private/Model/Result.php';
-include 'private/View/Main.php';
-include 'private/Controller/Controller.php';
+// Borrowed and modified from PSR-4 Closure Example
+spl_autoload_register(
+    function ($class) {
+        $prefix = 'AugustOffensive\\';
+        $relative_class = substr($class, strlen($prefix));
+
+        // find file in /private/ in respective namespace path
+        $file = __DIR__ . '/private/' . str_replace('\\', '/', $relative_class) . '.php';
+
+        // if the file exists, require it
+        if (file_exists($file)) {
+            require $file;
+        }
+    }
+);
 
 use AugustOffensive\View;
-use AugustOffensive\Model;
+use AugustOffensive\Controller;
+
+try {
+    // initiate connection and build front-end
+    $connection = Controller\Controller::initiateConnection();
+    $view = new View\Main($connection);
 
-// initiate connection and build front-end
-$connection = new Model\Connection();
-$view = new View\Main($connection);
+    // get results of query from front-end
+    $result = $view->generateResult();
 
-// get results of query from front-end
-$result = $view->generateResult();
+    echo $result;
+} catch (\Exception $err) {
+    // catch all exceptions and let the controller generate the error
+    $error = Controller\Controller::errorResult($err);
 
-echo $result;
+    // pass generated error result to output
+    echo View\Main::generateOutput($error);
+}
diff --git a/private/Controller/Controller.php b/private/Controller/Controller.php
index 188345a..586be15 100644
--- a/private/Controller/Controller.php
+++ b/private/Controller/Controller.php
@@ -12,6 +12,20 @@ use AugustOffensive\Model;
 class Controller
 {
     /**
+     * Initiates connection with the database.
+     *
+     * While errors are ideally handled by the controller, this instantiation
+     * will likely throw a \PDOException which should be handled by the front-
+     * end due to this being a fatal error and generally unrecoverable.
+     *
+     * @return Model\Connection
+     */
+    public static function initiateConnection (): Model\Connection
+    {
+        return new Model\Connection();
+    }
+
+    /**
      * Creates and returns a Query object.
      *
      * If the creation results in an error, a different query object is
@@ -29,9 +43,9 @@ class Controller
         array $content
     ): Model\Query {
         try {
-            return new Model\Query ($path, $request, $content);
+            return new Model\Query($path, $request, $content);
         } catch (\Exception $err) {
-            return new Model\Query (array(), "", array("ERROR" => $err->getMessage()));
+            return new Model\Query(array(), "", array("ERROR" => $err->getMessage()));
         }
     }
 
@@ -48,9 +62,31 @@ class Controller
         array $result
     ): Model\Result {
         try {
-            return new Model\Result ($resultType, $result);
+            return new Model\Result($resultType, $result);
         } catch (\Exception $err) {
-            return new Model\Result ("ERROR", array($err->getMessage()));
+            return new Model\Result("ERROR", array($err->getMessage()));
+        }
+    }
+
+    /**
+     * Obtain the error result based on the exception that was thrown.
+     *
+     * @param \Exception $err the error that was thrown.
+     *
+     * @return Model\Result
+     */
+    public static function errorResult (\Exception $err): Model\Result
+    {
+        $errorType = "";
+        // Juggle error: objective is to sort error type
+        try {
+            throw $err;
+        } catch (\PDOException $e) {
+            $errorType = "DATABASE_ERROR";
+        } catch (\Exception $e) {
+            $errorType = "ERROR";
         }
+
+        return new Model\Result($errorType, array("error" => $err->getMessage()));
     }
 }
diff --git a/private/Model/Connection.php b/private/Model/Connection.php
index 48cf4fb..4afa330 100644
--- a/private/Model/Connection.php
+++ b/private/Model/Connection.php
@@ -19,6 +19,7 @@ class Connection
     public function __construct ()
     {
         // Establish connection to db
+        // breaks side-effect rule
         include 'creds.php';
 
         try {
@@ -34,7 +35,7 @@ class Connection
         } catch (\PDOException $err) {
             // we destroy $cred as quickly as possible
             $cred = null;
-            die(json_encode(array("Result-Type" => "ERROR", "Content" => array($err->getMessage()))));
+            throw $err; // throw for Controller to catch
         }
         return $this;
     }
diff --git a/private/View/Main.php b/private/View/Main.php
index 1dcd760..746c2bb 100644
--- a/private/View/Main.php
+++ b/private/View/Main.php
@@ -18,6 +18,9 @@ class Main
     /** @var Model\Result $result the Result object to be sent to the client. */
     private $result;
 
+    /** @var string TYPE The type of output the client should receive. */
+    private const TYPE = "json";
+
     /**
      * Prepares the output and environment for the front end of the service.
      *
@@ -27,8 +30,6 @@ class Main
      */
     public function __construct (Model\Connection $connection)
     {
-        header("Content-Type: application/json");
-
         $this->query = Controller\Controller::createQuery(
             explode('/', trim($_SERVER['PATH_INFO'] ?? '/api', '/')),
             $_SERVER['REQUEST_METHOD'],
@@ -58,7 +59,7 @@ class Main
     }
 
     /**
-     * Communicates with the controller to generate the JSON result.
+     * Communicates with the controller to generate the output.
      *
      * @return string
      */
@@ -69,10 +70,19 @@ class Main
             array()
         );
 
-        // generate result
-        return json_encode(array(
-            "Result-Type" => $this->result->getResultType(),
-            "Content" => $this->result->getResult()
-        ));
+        return self::generateOutput($this->result);
+    }
+
+    /**
+     * Creates output of the result based on the defined constant TYPE.
+     *
+     * @param Model\Result $result The result to be sent to the client.
+     *
+     * @return string
+     */
+    public static function generateOutput (Model\Result $result): string
+    {
+        $type = self::TYPE;
+        return Output::$type($result);
     }
 }
diff --git a/private/View/Output.php b/private/View/Output.php
new file mode 100644
index 0000000..fe42c15
--- /dev/null
+++ b/private/View/Output.php
@@ -0,0 +1,34 @@
+<?php
+
+declare(strict_types=1);
+
+namespace AugustOffensive\View;
+
+use AugustOffensive\Model;
+
+/**
+ * Output formats for Results that are returned to the client.
+ */
+class Output
+{
+    /**
+     * Formats the result into JSON.
+     *
+     * @param Model\Result $result The result to return to the client.
+     * @param bool $prepare Whether to set the content type of the response (default true).
+     *
+     * @return string
+     */
+    public static function json (Model\Result $result, bool $prepare = true): string
+    {
+        // breaks side effect rule?
+        if ($prepare) {
+            header("Content-Type: application/json");
+        }
+
+        return json_encode(array(
+            "Result-Type" => $result->getResultType(),
+            "Content" => $result->getResult()
+        ));
+    }
+}