Add RegExps support for Mjolnir's WordList protection

config/default.yaml

@@ -170,6 +170,15 @@ protections:
   # Configuration for the wordlist plugin, which can ban users based if they say certain
   # blocked words shortly after joining.
   wordlist:
+    # For advanced usage, regex can also be enabled. If left disabled Mjolnir will interpret words literally.
+    #
+    # For example, if enabled this 'word' would match all t.me links: (https?:\/\/)?t\.me\/(\+)?[a-zA-Z0-9_-]+
+    #
+    # See the following links for more information;
+    #  - https://www.digitalocean.com/community/tutorials/an-introduction-to-regular-expressions
+    #  - https://regexr.com/
+    enableRegExps: false
+
     # A list of case-insensitive keywords that the WordList protection will watch for from new users.
     #
     # WordList will ban users who use these words when first joining a room, so take caution when selecting them.

src/config.ts

@@ -120,6 +120,7 @@ export interface IConfig {
     };
     protections: {
         wordlist: {
+            enableRegExps: boolean;
             words: string[];
             minutesBeforeTrusting: number;
         };
@@ -228,6 +229,7 @@ const defaultConfig: IConfig = {
     },
     protections: {
         wordlist: {
+            enableRegExps: false,
             words: [],
             minutesBeforeTrusting: 20,
         },

src/protections/WordList.ts

@@ -88,15 +88,9 @@ export class WordList extends Protection {
                 }
             }
             if (!this.badWords) {
-                // See https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions#escaping
-                const escapeRegExp = (string: string) => {
-                    return string.replace(/[.*+?^${}()|[\]\\]/g, "\\$&");
-                };
-
-                // Create a mega-regex from all the tiny words.
-                const words = mjolnir.config.protections.wordlist.words
-                    .filter((word) => word.length !== 0)
-                    .map(escapeRegExp);
+                const enableRegExps = mjolnir.config.protections.wordlist.enableRegExps || false;
+                const words = mjolnir.config.protections.wordlist.words.filter((word) => word.length !== 0);
+
                 if (words.length === 0) {
                     mjolnir.managementRoomOutput.logMessage(
                         LogLevel.ERROR,
@@ -106,7 +100,19 @@ export class WordList extends Protection {
                     this.enabled = false;
                     return;
                 }
-                this.badWords = new RegExp(words.join("|"), "i");
+
+                if (enableRegExps) {
+                    this.badWords = new RegExp(words.join("|"), "i");
+                } else {
+                    // See https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions#escaping
+                    const escapeRegExp = (string: string) => {
+                        return string.replace(/[.*+?^${}()|[\]\\]/g, "\\$&");
+                    };
+
+                    // Create a mega-regex from all the tiny words.
+                    const escapedWords = words.map(escapeRegExp);
+                    this.badWords = new RegExp(escapedWords.join("|"), "i");
+                }
             }
 
             const match = this.badWords!.exec(message);