MDL-70760 admin: Limited length config setting validate client-side

admin/templates/setting_configtext.mustache

@@ -27,6 +27,8 @@
     * forceltr - always display as ltr
     * attributes - list of additional attributes containing name, value
     * readonly - bool
+    * data - list of arbitrary data attributes
+    * maxcharacter - maximum character
 
     Example context (json):
     {
@@ -36,12 +38,19 @@
         "size": "21",
         "forceltr": false,
         "readonly": false,
-        "attributes": [ { "name": "readonly", "value": "readonly" } ]
+        "attributes": [ { "name": "readonly", "value": "readonly" } ],
+        "data": [ { "key": "validation_max_length", "value": "10" } ],
+        "maxcharacter": false
     }
 }}
 {{!
     Setting configtext.
 }}
 <div class="form-text defaultsnext">
-    <input type="text" name="{{name}}" value="{{value}}" size="{{size}}" id="{{id}}" class="form-control {{#forceltr}}text-ltr{{/forceltr}}" {{#readonly}}disabled{{/readonly}}>
+    <input type="text" name="{{name}}" value="{{value}}" size="{{size}}" id="{{id}}" class="form-control {{#forceltr}}text-ltr{{/forceltr}}" {{#readonly}}disabled{{/readonly}} {{#data}} data-{{key}}={{#quote}}{{{value}}}{{/quote}}{{/data}}>
+    {{#data}}
+        {{#maxcharacter}}
+            <div class="form-defaultinfo text-muted d-block">{{#str}} maxcharacter, admin, {{value}} {{/str}}</div>
+        {{/maxcharacter}}
+    {{/data}}
 </div>

admin/tool/messageinbound/tests/behat/incoming_mail.feature

@@ -23,3 +23,13 @@ Feature: Incoming mail configuration
     When I navigate to "Server > Email > Incoming mail configuration" in site administration
     Then "OAuth 2 service" "select" should exist
     And I should see "Testing service" in the "OAuth 2 service" "select"
+
+  @javascript
+  Scenario: Check character limitations of mailbox name
+    When I navigate to "Server > Email > Incoming mail configuration" in site administration
+    And I set the field "Mailbox name" to "frogfrogfrogfrog"
+    Then I should see "Maximum of 15 characters"
+    And the "disabled" attribute of "form#adminsettings button[type='submit']" "css_element" should contain "true"
+    And I set the field "Mailbox name" to "frogfrogfrogfro"
+    And I should not see "Maximum of 15 characters"
+    And the "disabled" attribute of "form#adminsettings button[type='submit']" "css_element" should not be set

lang/en/admin.php

@@ -871,6 +871,7 @@
 from a STABLE branch of the Moodle code. See Moodle Docs for more details.';
 $string['maxbytes'] = 'Maximum uploaded file size';
 $string['maxconsecutiveidentchars'] = 'Consecutive identical characters';
+$string['maxcharacter'] = '{$a} character maximum';
 $string['maxsizeperdownloadcoursefile'] = 'Maximum size per file';
 $string['maxsizeperdownloadcoursefile_desc'] = 'The maximum size of each file when downloading course content. Files exceeding this size will be omitted from the download.';
 $string['maxeditingtime'] = 'Maximum time to edit posts';

lib/adminlib.php

@@ -2447,6 +2447,8 @@ class admin_setting_configtext extends admin_setting {
 
     /** @var int default field size */
     public $size;
+    /** @var array List of arbitrary data attributes */
+    protected $datavalues = [];
 
     /**
      * Config text constructor
@@ -2530,11 +2532,24 @@ public function validate($data) {
         }
     }
 
+    /**
+     * Set arbitrary data attributes for template.
+     *
+     * @param string $key Attribute key for template.
+     * @param string $value Attribute value for template.
+     */
+    public function set_data_attribute(string $key, string $value): void {
+        $this->datavalues[] = [
+            'key' => $key,
+            'value' => $value,
+        ];
+    }
+
     /**
      * Return an XHTML string for the setting
      * @return string Returns an XHTML string
      */
-    public function output_html($data, $query='') {
+    public function output_html($data, $query = '') {
         global $OUTPUT;
 
         $default = $this->get_defaultsetting();
@@ -2545,6 +2560,8 @@ public function output_html($data, $query='') {
             'value' => $data,
             'forceltr' => $this->get_force_ltr(),
             'readonly' => $this->is_readonly(),
+            'data' => $this->datavalues,
+            'maxcharacter' => array_key_exists('validation-max-length', $this->datavalues),
         ];
         $element = $OUTPUT->render_from_template('core_admin/setting_configtext', $context);
 
@@ -2578,6 +2595,7 @@ class admin_setting_configtext_with_maxlength extends admin_setting_configtext {
     public function __construct($name, $visiblename, $description, $defaultsetting, $paramtype=PARAM_RAW,
                                 $size=null, $maxlength = 0) {
         $this->maxlength = $maxlength;
+        $this->set_data_attribute('validation-max-length', $maxlength);
         parent::__construct($name, $visiblename, $description, $defaultsetting, $paramtype, $size);
     }
 
@@ -2604,6 +2622,20 @@ public function validate($data) {
             return $parentvalidation;
         }
     }
+
+    /**
+     * Return an XHTML string for the setting.
+     *
+     * @param string $data data.
+     * @param string $query query statement.
+     * @return string Returns an XHTML string
+     */
+    public function output_html($data, $query = ''): string {
+        global $PAGE;
+        $PAGE->requires->js_call_amd('core_form/configtext_maxlength', 'init');
+
+        return parent::output_html($data, $query);
+    }
 }
 
 /**

lib/form/amd/src/configtext_maxlength.js

@@ -0,0 +1,121 @@
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * Validation for configtext_maxlength.
+ *
+ * @module     core_form/configtext-maxlength
+ * @copyright  2021 The Open University
+ */
+import {get_string as getString} from 'core/str';
+import Templates from 'core/templates';
+import Notification from 'core/notification';
+import {prefetchStrings, prefetchTemplates} from 'core/prefetch';
+
+let registered = false;
+
+/**
+ * Initialisation function.
+ */
+export const init = () => {
+    if (registered) {
+        return;
+    }
+    prefetchStrings('core', [
+        'maximumchars',
+    ]);
+
+    prefetchTemplates([
+        'core_form/setting_validation_failure',
+    ]);
+
+    registered = true;
+
+    document.addEventListener('input', e => {
+        const maxLengthField = e.target.closest('[data-validation-max-length]');
+        if (!maxLengthField) {
+            return;
+        }
+
+        if (maxLengthField.value.length > maxLengthField.dataset.validationMaxLength) {
+            // Disable the form for this field.
+            maxLengthField.form.addEventListener('submit', submissionCheck);
+            // Display an error.
+            getString('maximumchars', 'core', maxLengthField.dataset.validationMaxLength)
+                .then(errorMessage => {
+                    return Templates.renderForPromise('core_form/setting_validation_failure', {
+                        fieldid: maxLengthField.id,
+                        message: errorMessage,
+                    });
+                })
+                .then(errorTemplate => {
+                    if (!maxLengthField.dataset.validationFailureId) {
+                        const formWrapper = maxLengthField.closest('.form-text');
+                        Templates.prependNodeContents(formWrapper, errorTemplate.html, errorTemplate.js);
+                        maxLengthField.dataset.validationFailureId = `maxlength_error_${maxLengthField.id}`;
+                        // Disable submit button when the message is displayed.
+                        updateSubmitButton();
+                    }
+                    return;
+                })
+                .then(() => {
+                    maxLengthField.setAttribute('aria-invalid', true);
+                    const errorField = document.getElementById(maxLengthField.dataset.validationFailureId);
+                    if (errorField) {
+                        errorField.setAttribute('aria-describedby', maxLengthField.id);
+                    }
+                    return;
+                })
+                .catch(Notification.exception);
+        } else {
+            // Remove the old message.
+            const validationMessage = document.getElementById(maxLengthField.dataset.validationFailureId);
+            if (validationMessage) {
+                validationMessage.parentElement.remove();
+                delete maxLengthField.dataset.validationFailureId;
+                maxLengthField.removeAttribute('aria-invalid');
+                // Enable submit button when the message was removed.
+                updateSubmitButton();
+            }
+        }
+    });
+};
+
+/**
+ * Handle form submission.
+ *
+ * @param {Event} e The event.
+ */
+const submissionCheck = e => {
+    const maxLengthFields = e.target.querySelectorAll('[data-validation-max-length]');
+    const maxLengthFieldsArray = Array.from(maxLengthFields);
+    maxLengthFieldsArray.some(maxLengthField => {
+        // Focus on the first validation failure.
+        if (maxLengthField.value.length > maxLengthField.dataset.validationMaxLength) {
+            e.preventDefault();
+            maxLengthField.focus();
+            return true;
+        }
+        return false;
+    });
+};
+
+/**
+ * Update submit button.
+ */
+const updateSubmitButton = () => {
+    const shouldDisable = document.querySelector('form#adminsettings .error');
+    document.querySelector('form#adminsettings button[type="submit"]').disabled = !!shouldDisable;
+};

lib/form/templates/setting_validation_failure.mustache

@@ -0,0 +1,36 @@
+{{!
+    This file is part of Moodle - http://moodle.org/
+
+    Moodle is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    Moodle is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+}}
+{{!
+    @template core_form/setting_validation_failure
+    Error displayed when field fails validation (longer than max length).
+
+    Context variables required for this template:
+    * fieldid - element field id
+    * message - error message
+
+    Example context (json):
+    {
+        "fieldid": "test0",
+        "message": "test message"
+    }
+}}
+{{!
+    Setting error template for configtext_maxlength.
+}}
+<div>
+    <span class="error" id="maxlength_error_{{fieldid}}">{{message}}</span>
+</div>