Allow developers to handle form submission separately.

README.md

@@ -45,6 +45,7 @@ UndefinedOffset\NoCaptcha\Forms\NocaptchaField:
     default_type: "image" #Default captcha type (optional, image or audio, defaults to image)
     default_size: "normal" #Default size (optional, normal, compact or invisible, defaults to normal)
     default_badge: "bottomright" #Default badge position (bottomright, bottomleft or inline, defaults to bottomright)
+    default_handle_submit: true #Default setting for whether nocaptcha should handle form submission. See "Handling form submission" below.
     proxy_server: "" #Your proxy server address (optional)
     proxy_port: "" #Your proxy server address port (optional)
     proxy_auth: "" #Your proxy server authentication information (optional)
@@ -124,6 +125,50 @@ $captchaField->setMinimumScore(0.2);
 For more information about version 3, including how to implement custom actions
 see https://developers.google.com/recaptcha/docs/v3
 
+## Handling form submission
+By default, the javascript included with this module will add a submit event handler to your form.
+
+If you need to handle form submissions in a special way (for example to support front-end validation),
+you can choose to handle form submit events yourself.
+
+This can be configured site-wide using the Config API
+```yml
+UndefinedOffset\NoCaptcha\Forms\NocaptchaField:
+    default_handle_submit: false
+```
+
+Or on a per form basis:
+```php
+$captchaField = $form->Fields()->fieldByName('Captcha');
+$captchaField->setHandleSubmitEvents(false);
+```
+
+With this configuration no event handlers will be added by this module to your form. Instead, a
+function will be provided called `nocaptcha_handleCaptcha` which you can call from your code
+when you're ready to submit your form. It has the following signature:
+```js
+function nocaptcha_handleCaptcha(form, callback)
+```
+`form` must be the form element, and `callback` should be a function that finally submits the form,
+though it is optional.
+
+In the simplest case, you can use it like this:
+```js
+document.addEventListener("DOMContentLoaded", function(event) {
+    // where formID is the element ID for your form
+    const form = document.getElementById(formID);
+    const submitListener = function(event) {
+        event.preventDefault();
+        let valid = true;
+        /* Your validation logic here */
+        if (valid) {
+            nocaptcha_handleCaptcha(form, form.submit.bind(form));
+        }
+    };
+    form.addEventListener('submit', submitListener);
+});
+```
+
 ## Reporting an issue
 
 When you're reporting an issue please ensure you specify what version of

javascript/NocaptchaField_noHandler_v2.js

@@ -0,0 +1,27 @@
+var _noCaptchaFields=_noCaptchaFields || [];
+
+// form isn't necessary for v2, but we have it here to keep the function signature consistent.
+function nocaptcha_handleCaptcha(form, callback) {
+    if (callback) {
+        callback();
+    }
+};
+
+function noCaptchaFieldRender() {
+    var render = function(field) {
+        var options={
+            'sitekey': field.getAttribute('data-sitekey'),
+            'theme': field.getAttribute('data-theme'),
+            'type': field.getAttribute('data-type'),
+            'size': field.getAttribute('data-size'),
+            'badge': field.getAttribute('data-badge'),
+        };
+
+        var widget_id = grecaptcha.render(field, options);
+        field.setAttribute("data-widgetid", widget_id);
+    }
+
+    for(var i=0;i<_noCaptchaFields.length;i++) {
+        render(document.getElementById('Nocaptcha-'+_noCaptchaFields[i]));
+    }
+}

javascript/NocaptchaField_noHandler_v3.js

@@ -0,0 +1,9 @@
+function nocaptcha_handleCaptcha(form, callback) {
+  var input = document.getElementById('Nocaptcha-' + form.getAttribute('id'));
+  grecaptcha.execute(input.getAttribute('data-sitekey'), {action: 'submit'}).then(function (token) {
+      input.value = token;
+      if (callback) {
+        callback();
+      }
+  });
+};

src/Forms/NocaptchaField.php

@@ -82,6 +82,14 @@ class NocaptchaField extends FormField {
      */
     private static $default_size='normal';
 
+    /**
+     * Whether form submit events are handled directly by this module.
+     * If false, a function is provided that can be called by user code submit handlers.
+     * @var boolean
+     * @default true
+     */
+    private static $default_handle_submit = true;
+
     /**
      * Recaptcha Site Key
      * Configurable via Injector config
@@ -150,6 +158,13 @@ class NocaptchaField extends FormField {
      */
     protected $minimumScore;
 
+    /**
+     * Whether form submit events are handled directly by this module.
+     * If false, a function is provided that can be called by user code submit handlers.
+     * @var boolean
+     */
+    private $handleSubmitEvents;
+
     /**
      * Creates a new Recaptcha 2 field.
      * @param string $name The internal field name, passed to forms.
@@ -165,6 +180,7 @@ public function __construct($name, $title=null, $value=null) {
         $this->_captchaType=self::config()->default_type;
         $this->_captchaSize=self::config()->default_size;
         $this->_captchaBadge=self::config()->default_badge;
+        $this->handleSubmitEvents = self::config()->default_handle_submit;
     }
 
     /**
@@ -180,44 +196,71 @@ public function Field($properties=array()) {
             user_error('You must configure Nocaptcha.site_key and Nocaptcha.secret_key, you can retrieve these at https://google.com/recaptcha', E_USER_ERROR);
         }
 
-        $form = $this->getForm();
-
         if ($this->config()->get('recaptcha_version') == 2) {
-            $exemptActionsString = implode("' , '", $form->getValidationExemptActions());
+            $this->configureRequirementsForV2();
+        } else {
+            $this->configureRequirementsForV3();
+        }
 
+        return parent::Field($properties);
+    }
+
+    /**
+     * Configure any javascript and css requirements that are specific for recaptcha v2.
+     */
+    protected function configureRequirementsForV2()
+    {
+        Requirements::customScript(
+            "(function() {\n" .
+                "var gr = document.createElement('script'); gr.type = 'text/javascript'; gr.async = true;\n" .
+                "gr.src = ('https:' == document.location.protocol ? 'https://www' : 'http://www') + " .
+                "'.google.com/recaptcha/api.js?render=explicit&hl=" .
+                Locale::getPrimaryLanguage(i18n::get_locale()) .
+                "&onload=noCaptchaFieldRender';\n" .
+                "var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(gr, s);\n" .
+            "})();\n",
+            'NocaptchaField-lib'
+        );
+        if ($this->getHandleSubmitEvents()) {
+            $exemptActionsString = implode("' , '", $this->getForm()->getValidationExemptActions());
             Requirements::javascript('undefinedoffset/silverstripe-nocaptcha:javascript/NocaptchaField.js');
             Requirements::customScript(
                 "var _noCaptchaFields=_noCaptchaFields || [];_noCaptchaFields.push('".$this->ID()."');" .
                 "var _noCaptchaValidationExemptActions=_noCaptchaValidationExemptActions || [];" .
                 "_noCaptchaValidationExemptActions.push('" . $exemptActionsString . "');",
                 "NocaptchaField-" . $this->ID()
             );
+        } else {
             Requirements::customScript(
-                "(function() {\n" .
-                    "var gr = document.createElement('script'); gr.type = 'text/javascript'; gr.async = true;\n" .
-                    "gr.src = ('https:' == document.location.protocol ? 'https://www' : 'http://www') + " .
-                    "'.google.com/recaptcha/api.js?render=explicit&hl=" .
-                    Locale::getPrimaryLanguage(i18n::get_locale()) .
-                    "&onload=noCaptchaFieldRender';\n" .
-                    "var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(gr, s);\n" .
-                "})();\n",
-                'NocaptchaField-lib'
+                "var _noCaptchaFields=_noCaptchaFields || [];_noCaptchaFields.push('".$this->ID()."');",
+                "NocaptchaField-" . $this->ID()
             );
-        } else {
-            Requirements::javascript('https://www.google.com/recaptcha/api.js?render=' . urlencode($siteKey) . '&onload=noCaptchaFormRender');
+            Requirements::javascript('undefinedoffset/silverstripe-nocaptcha:javascript/NocaptchaField_noHandler_v2.js');
+        }
+    }
+
+    /**
+     * Configure any javascript and css requirements that are specific for recaptcha v3.
+     */
+    protected function configureRequirementsForV3()
+    {
+        Requirements::customCSS('.nocaptcha { display: none !important; }', self::class);
+        if ($this->getHandleSubmitEvents()) {
+            Requirements::javascript('https://www.google.com/recaptcha/api.js?render=' . urlencode($this->getSiteKey()) . '&onload=noCaptchaFormRender');
             Requirements::javascript('undefinedoffset/silverstripe-nocaptcha:javascript/NocaptchaField_v3.js');
-            Requirements::customCSS('.nocaptcha { display: none !important; }', self::class);
 
+            $form = $this->getForm();
             $helper = $form->getTemplateHelper();
             $id = $helper->generateFormID($form);
 
             Requirements::customScript(
                 "var _noCaptchaForms=_noCaptchaForms || [];_noCaptchaForms.push('". $id . "');",
                 'NocaptchaForm-' . $id
             );
+        } else {
+            Requirements::javascript('https://www.google.com/recaptcha/api.js?render=' . urlencode($this->getSiteKey()));
+            Requirements::javascript('undefinedoffset/silverstripe-nocaptcha:javascript/NocaptchaField_noHandler_v3.js');
         }
-
-        return parent::Field($properties);
     }
 
     /**
@@ -294,6 +337,28 @@ public function validate($validator) {
         return true;
     }
 
+    /**
+     * Sets whether form submit events are handled directly by this module.
+     *
+     * @param boolean $value
+     * @return NocaptchaField
+     */
+    public function setHandleSubmitEvents(bool $value)
+    {
+        $this->handleSubmitEvents = $value;
+        return $this;
+    }
+
+    /**
+     * Get whether form submit events are handled directly by this module.
+     *
+     * @return boolean
+     */
+    public function getHandleSubmitEvents(): bool
+    {
+        return $this->handleSubmitEvents;
+    }
+
     /**
      * Sets the theme for this captcha
      * @param string $value Theme to set it to, currently the api supports light and dark