Add very simple CAPTCHA mechanism

composer.json

@@ -1,7 +1,7 @@
 {
     "name": "fwdekker/death-notifier",
     "description": "Get notified when a famous person dies.",
-    "version": "0.19.15", "_comment_version": "Also update version in `package.json`!",
+    "version": "0.19.16", "_comment_version": "Also update version in `package.json`!",
     "type": "project",
     "license": "MIT",
     "homepage": "https://git.fwdekker.com/tools/death-notifier",

package.json

@@ -1,6 +1,6 @@
 {
     "name": "death-notifier",
-    "version": "0.19.15", "_comment_version": "Also update version in `composer.json`!",
+    "version": "0.19.16", "_comment_version": "Also update version in `composer.json`!",
     "description": "Get notified when a famous person dies.",
     "author": "Florine W. Dekker",
     "browser": "dist/bundle.js",

src/main/index.html

@@ -148,6 +148,11 @@
                             <label for="register-password-toggle">Show password</label>
                             <br /><br />
 
+                            <label for="register-captcha">Write the word "pride"</label>
+                            <input id="register-captcha" name="captcha" />
+                            <small id="register-captcha-hint" data-hint-for="register-captcha"
+                                data-hint="To prove that you are probably not a robot."></small>
+
                             <button id="register-submit">Create account</button>
                         </form>
                     </div>
@@ -349,7 +354,6 @@
                         <label for="update-password-password-new">New password</label>
                         <input id="update-password-password-new" type="password" name="password_new"
                                autocomplete="new-password" />
-                        <!-- TODO: Add password strength indicator -->
                         <small id="update-password-password-new-hint" data-hint-for="update-password-password-new"
                                data-hint="Use at least 8 characters."></small>
 

src/main/js/Main.ts

@@ -350,7 +350,8 @@ doAfterLoad(() => {
                 action: "register",
                 token: csrfToken,
                 email: $("#register-email").value,
-                password: $("#register-password").value
+                password: $("#register-password").value,
+                captcha: $("#register-captcha").value,
             },
             registerForm,
             () => {

src/main/php/com/fwdekker/deathnotifier/user/RegisterAction.php

@@ -6,6 +6,7 @@ use com\fwdekker\deathnotifier\Action;
 use com\fwdekker\deathnotifier\Config;
 use com\fwdekker\deathnotifier\mailer\Email;
 use com\fwdekker\deathnotifier\mailer\EmailQueue;
+use com\fwdekker\deathnotifier\validation\EqualsRule;
 use com\fwdekker\deathnotifier\validation\HasStringLengthRule;
 use com\fwdekker\deathnotifier\validation\InvalidTypeException;
 use com\fwdekker\deathnotifier\validation\InvalidValueException;
@@ -64,6 +65,10 @@ class RegisterAction extends Action
             "token" => [new IsValidCsrfTokenRule()],
             "email" => [new IsEmailRule()],
             "password" => [new HasStringLengthRule(UserList::MIN_PASSWORD_LENGTH, UserList::MAX_PASSWORD_LENGTH)],
+            "captcha" => [new EqualsRule(
+                "pride",
+                "Enter the word \"pride\" to prove that you are probably not a robot."
+            )],
         ]))->check($inputs);
 
         $this->user_list->transaction(function () use ($inputs) {

src/main/php/com/fwdekker/deathnotifier/validation/EqualsRule.php

@@ -0,0 +1,57 @@
+<?php
+
+namespace com\fwdekker\deathnotifier\validation;
+
+use com\fwdekker\deathnotifier\Config;
+use com\fwdekker\deathnotifier\IllegalStateError;
+
+
+/**
+ * Validates that the input equals a pre-defined string.
+ */
+class EqualsRule extends Rule
+{
+    /**
+     * @var string the string that the input should equal
+     */
+    private readonly string $expected;
+    /**
+     * @var string the message that is returned if the input is incorrect
+     */
+    private readonly string $message_if_incorrect;
+
+
+    /**
+     * Constructs a new `EqualsRule`.
+     *
+     * @param string $expected the string that the input should equal
+     * @param string $message_if_incorrect the message that is returned if the input is incorrect
+     */
+    public function __construct(string $expected, string $message_if_incorrect)
+    {
+        $this->expected = $expected;
+        $this->message_if_incorrect = $message_if_incorrect;
+    }
+
+
+    /**
+     * Validates that the input equals the CLI password.
+     *
+     * @param array<int|string, mixed> $inputs the list of inputs in which the value at {@see $key} should be checked
+     * @param string $key the key in {@see $inputs} of the input to check
+     * @return void if the checked input equals the CLI password
+     * @throws InvalidTypeException if the CLI password is a blank string, if the CLI password is at its default
+     * value, or if the checked input is not set
+     * @throws InvalidValueException if the checked input does not equal the CLI password
+     */
+    public function check(array $inputs, string $key): void
+    {
+        if (!isset($inputs[$key]))
+            throw new InvalidTypeException("Required input '$key' not set.");
+        if (!is_string($inputs[$key]))
+            throw new InvalidTypeException("Input '$key' should be string, but is " . gettype($inputs[$key]) . ".");
+
+        if ($inputs[$key] !== $this->expected)
+            throw new InvalidValueException($this->message_if_incorrect, $key);
+    }
+}

src/test/php/com/fwdekker/deathnotifier/validation/EqualsRuleTest.php

@@ -0,0 +1,25 @@
+<?php
+
+namespace com\fwdekker\deathnotifier\validation;
+
+use InvalidArgumentException;
+
+
+/**
+ * Unit tests for {@see EqualsRule}.
+ */
+class EqualsRuleTest extends RuleTest
+{
+    public function check_provider(): array
+    {
+        $type = InvalidTypeException::class;
+        $value = InvalidValueException::class;
+
+        return [
+            "exception if input is not set" => [new EqualsRule("word", "message"), null, $type, "Required input 'key' not set."],
+            "exception if input is not a string" => [new EqualsRule("word", "message"), 738, $type, "Input 'key' should be string, but is integer."],
+            "exception with custom message if input is incorrect" => [new EqualsRule("word", "message"), "incorrect", $value, "message"],
+            "no exception if input equals expected phrase" => [new EqualsRule("word", "message"), "word", null, null],
+        ];
+    }
+}