It is a form's responsibility to process the request it was submitted with

How forms are being validated should not be a task that is part of the
controller action, but should be handled by the form base class as it is
most of the time the same procedure. Now a controller action just sets
up the form to use, calls handleRequest() and acts upon its return value.
(e.g. calling handleRequest() from another form or any redirection)

refs #5525

library/Icinga/Web/Form.php

@@ -190,6 +190,30 @@ class Form extends Zend_Form
         return array();
     }
 
+    /**
+     * Perform actions after this form was submitted using a valid request
+     *
+     * Intended to be implemented by concrete form classes.
+     *
+     * @param   Request     $request    The valid request used to process this form
+     */
+    public function onSuccess(Request $request)
+    {
+
+    }
+
+    /**
+     * Perform actions after this form was submitted using an invalid request
+     *
+     * Intended to be implemented by concrete form classes.
+     *
+     * @param   Request     $request    The invalid request supposed to process this form
+     */
+    public function onFailure(Request $request)
+    {
+
+    }
+
     /**
      * Add a submit button to this form
      *
@@ -292,6 +316,37 @@ class Form extends Zend_Form
         return parent::setDefaults($defaults);
     }
 
+    /**
+     * Process the given request using this form
+     *
+     * @param   Request     $request    The request to be processed
+     *
+     * @return  null|bool               True in case the request was handled and valid,
+     *                                  false if invalid and null if it was not handled
+     */
+    public function handleRequest(Request $request)
+    {
+        if (strtolower($request->getMethod()) === $this->getMethod()) {
+            $formData = $request->{'get' . $request->isPost() ? 'Post' : 'Query'}();
+            if ($this->wasSent($formData)) {
+                $this->populate($formData); // Necessary to get isSubmitted() to work
+                if ($this->isSubmitted()) {
+                    if ($this->isValid($formData)) {
+                        $this->onSuccess($request);
+                        return true;
+                    } else {
+                        $this->onFailure($request);
+                    }
+                } else {
+                    // The form can't be processed but we want to show validation errors though
+                    $this->isValidPartial($formData);
+                }
+
+                return false;
+            }
+        }
+    }
+
     /**
      * Return whether the submit button of this form was pressed
      *