RFC Compliant URL Matching

Implemented https://gist.github.com/dperini/729294 in C++

This makes URL Validation / Matching RFC compliant.

src/messages/messagebuilder.cpp

@@ -44,8 +44,41 @@ void MessageBuilder::appendTimestamp(const QTime &time)
 
 QString MessageBuilder::matchLink(const QString &string)
 {
-    static QRegularExpression linkRegex("[[:ascii:]]*\\.[a-zA-Z]+\\/?[[:ascii:]]*");
+    const QString urlRegExp = "^"
-    static QRegularExpression httpRegex("\\bhttps?://");
+    // protocol identifier
+    "(?:(?:https?|ftp)://)"
+    // user:pass authentication
+    "(?:\\S+(?::\\S*)?@)?"
+    "(?:"
+    // IP address exclusion
+    // private & local networks
+    "(?!(?:10|127)(?:\\.\\d{1,3}){3})"
+    "(?!(?:169\\.254|192\\.168)(?:\\.\\d{1,3}){2})"
+    "(?!172\\.(?:1[6-9]|2\\d|3[0-1])(?:\\.\\d{1,3}){2})"
+    // IP address dotted notation octets
+    // excludes loopback network 0.0.0.0
+    // excludes reserved space >= 224.0.0.0
+    // excludes network & broacast addresses
+    // (first & last IP address of each class)
+    "(?:[1-9]\\d?|1\\d\\d|2[01]\\d|22[0-3])"
+    "(?:\\.(?:1?\\d{1,2}|2[0-4]\\d|25[0-5])){2}"
+    "(?:\\.(?:[1-9]\\d?|1\\d\\d|2[0-4]\\d|25[0-4]))"
+    "|"
+    // host name
+    "(?:(?:[a-z\\x{00a1}-\\x{ffff}0-9]-*)*[a-z\\x{00a1}-\\x{ffff0}-9]+)"
+    // domain name
+    "(?:\\.(?:[a-z\\x{00a1}-\\x{ffff0}-9]-*)*[a-z\\x{00a1}-\\x{ffff0}-9]+)*"
+    // TLD identifier
+    "(?:\\.(?:[a-z\\x{00a1}-\\x{ffff}]{2,}))"
+    "\\.?"
+    ")"
+    // port number
+    "(?::\\d{2,5})?"
+    // resource path
+    "(?:[/?#]\\S*)?"
+    "$";
+
+    static QRegularExpression linkRegex(urlRegExp, QRegularExpression::CaseInsensitiveOption);
 
     auto match = linkRegex.match(string);
 
@@ -55,10 +88,6 @@ QString MessageBuilder::matchLink(const QString &string)
 
     QString captured = match.captured();
 
-    if (!captured.contains(httpRegex)) {
-        captured.insert(0, "http://");
-    }
-
     return captured;
 }