Fix: improve encoder functions according to RFC

src/DNS/Client.php

@@ -226,10 +226,11 @@ private function parseRdata(string $packet, int &$offset, int $type, int $rdleng
                 while ($offset < $end) {
                     $len = ord($packet[$offset]);
                     $offset++;
-                    $txts[] = substr($packet, $offset, $len);
+                    $chunk = ($len > 0) ? substr($packet, $offset, $len) : '';
+                    $txts[] = $chunk;
                     $offset += $len;
                 }
-                return implode(' ', $txts);
+                return implode('', $txts);
             case 33: // SRV record
                 $priority = unpack('n', substr($packet, $offset, 2));
                 $weight = unpack('n', substr($packet, $offset + 2, 2));

src/DNS/Server.php

@@ -330,100 +330,155 @@ protected function resolve(array $question): array
         return $this->resolver->resolve($question);
     }
 
+    /**
+     * Encode an IPv4 address (A record) according to RFC 1035.
+     *
+     * @param string $ip
+     * @param int $ttl
+     * @return string
+     */
     protected function encodeIP(string $ip, int $ttl): string
     {
-        $result = \pack('Nn', $ttl, 4);
-
         $binaryIP = inet_pton($ip);
-        if ($binaryIP === false) {
+        if ($binaryIP === false || strlen($binaryIP) !== 4) {
             throw new \Exception("Invalid IPv4 address format: {$ip}");
         }
-
-        // Append the binary IPv4 address directly
-        $result .= $binaryIP;
-
+        $result = pack('Nn', $ttl, 4) . $binaryIP;
         return $result;
     }
 
+    /**
+     * Encode an IPv6 address (AAAA record) according to RFC 3596.
+     *
+     * @param string $ip
+     * @param int $ttl
+     * @return string
+     */
     protected function encodeIPv6(string $ip, int $ttl): string
     {
-        $result = \pack('Nn', $ttl, 16);
-
         $binaryIP = inet_pton($ip);
-        if ($binaryIP === false) {
+        if ($binaryIP === false || strlen($binaryIP) !== 16) {
             throw new \Exception("Invalid IPv6 address format: {$ip}");
         }
-
-        $result .= $binaryIP;
-
+        $result = pack('Nn', $ttl, 16) . $binaryIP;
         return $result;
     }
 
+    /**
+     * Encode a domain name (CNAME, NS, PTR) according to RFC 1035.
+     *
+     * @param string $domain
+     * @param int $ttl
+     * @return string
+     */
     protected function encodeDomain(string $domain, int $ttl): string
     {
+        $labels = explode('.', rtrim($domain, '.'));
         $result = '';
         $totalLength = 0;
-
-        foreach (\explode('.', $domain) as $label) {
-            $labelLength = \strlen($label);
-            $result .= \chr($labelLength);
-            $result .= $label;
+        foreach ($labels as $label) {
+            $labelLength = strlen($label);
+            if ($labelLength === 0) {
+                throw new \Exception("Empty label in domain: '{$domain}'");
+            }
+            if ($labelLength > 63) {
+                throw new \Exception("Label too long in domain: {$label}");
+            }
+            $result .= chr($labelLength) . $label;
             $totalLength += 1 + $labelLength;
         }
-
-        $result .= \chr(0);
+        $result .= chr(0);
         $totalLength += 1;
-
-        $result = \pack('Nn', $ttl, $totalLength) . $result;
-
+        $result = pack('Nn', $ttl, $totalLength) . $result;
         return $result;
     }
 
+    /**
+     * Encode a TXT record according to RFC 1035.
+     *
+     * @param string $text
+     * @param int $ttl
+     * @return string
+     */
     protected function encodeText(string $text, int $ttl): string
     {
-        $textLength = \strlen($text);
-        $result = \pack('Nn', $ttl, 1 + $textLength) . \chr($textLength) . $text;
-
+        $chunks = [];
+        $len = strlen($text);
+        for ($i = 0; $i < $len; $i += 255) {
+            $chunk = substr($text, $i, 255);
+            $chunks[] = chr(strlen($chunk)) . $chunk;
+        }
+        $txtData = implode('', $chunks);
+        $result = pack('Nn', $ttl, strlen($txtData)) . $txtData;
         return $result;
     }
 
+    /**
+     * Encode an MX record according to RFC 1035.
+     *
+     * @param string $domain
+     * @param int $ttl
+     * @param int $priority
+     * @return string
+     */
     protected function encodeMx(string $domain, int $ttl, int $priority): string
     {
-        $result = \pack('n', $priority);
+        $labels = explode('.', rtrim($domain, '.'));
+        $result = pack('n', $priority);
         $totalLength = 2;
-
-        foreach (\explode('.', $domain) as $label) {
-            $labelLength = \strlen($label);
-            $result .= \chr($labelLength);
-            $result .= $label;
+        foreach ($labels as $label) {
+            $labelLength = strlen($label);
+            if ($labelLength > 63) {
+                throw new \Exception("Label too long in MX domain: {$label}");
+            }
+            $result .= chr($labelLength) . $label;
             $totalLength += 1 + $labelLength;
         }
-
-        $result .= \chr(0);
+        $result .= chr(0);
         $totalLength += 1;
-
-        $result = \pack('Nn', $ttl, $totalLength) . $result;
-
+        $result = pack('Nn', $ttl, $totalLength) . $result;
         return $result;
     }
 
+    /**
+     * Encode an SRV record according to RFC 2782.
+     *
+     * @param string $domain
+     * @param int $ttl
+     * @param int $priority
+     * @param int $weight
+     * @param int $port
+     * @return string
+     */
     protected function encodeSrv(string $domain, int $ttl, int $priority, int $weight, int $port): string
     {
-        $result = \pack('nnn', $priority, $weight, $port);
+        // Validate SRV parameters
+        if ($priority < 0 || $priority > 65535) {
+            throw new \Exception("SRV priority out of range: {$priority}");
+        }
+        if ($weight < 0 || $weight > 65535) {
+            throw new \Exception("SRV weight out of range: {$weight}");
+        }
+        if ($port < 0 || $port > 65535) {
+            throw new \Exception("SRV port out of range: {$port}");
+        }
+        $labels = explode('.', rtrim($domain, '.'));
+        $result = pack('nnn', $priority, $weight, $port);
         $totalLength = 6;
-
-        foreach (\explode('.', $domain) as $label) {
-            $labelLength = \strlen($label);
-            $result .= \chr($labelLength);
-            $result .= $label;
+        foreach ($labels as $label) {
+            $labelLength = strlen($label);
+            if ($labelLength === 0) {
+                throw new \Exception("Empty label in SRV domain: '{$domain}'");
+            }
+            if ($labelLength > 63) {
+                throw new \Exception("Label too long in SRV domain: {$label}");
+            }
+            $result .= chr($labelLength) . $label;
             $totalLength += 1 + $labelLength;
         }
-
-        $result .= \chr(0);
+        $result .= chr(0);
         $totalLength += 1;
-
-        $result = \pack('Nn', $ttl, $totalLength) . $result;
-
+        $result = pack('Nn', $ttl, $totalLength) . $result;
         return $result;
     }
 

src/DNS/Zone.php

@@ -178,7 +178,20 @@ public function import(string $domain, string $content): array
         $lastOwner = null;
         $logicalLines = $this->collectLogicalLines($content);
         foreach ($logicalLines as $rawLine) {
-            $line = trim($this->stripTrailingComment($rawLine));
+            // For TXT records, only strip comments at #, not at semicolons
+            $isTxt = false;
+            $peekTokens = $this->tokenize($rawLine);
+            foreach ($peekTokens as $tok) {
+                if (strtoupper($tok) === 'TXT') {
+                    $isTxt = true;
+                    break;
+                }
+            }
+            if ($isTxt) {
+                $line = trim($this->stripTrailingComment($rawLine, true));
+            } else {
+                $line = trim($this->stripTrailingComment($rawLine, false));
+            }
             if ($line === '' || $this->isComment($line)) {
                 continue;
             }
@@ -219,7 +232,14 @@ public function import(string $domain, string $content): array
             }
             $type = strtoupper($tokens[$pos++]);
             $dataParts = array_slice($tokens, $pos);
-            $data = implode(' ', $dataParts);
+            if ($type === 'TXT') {
+                $data = '';
+                foreach ($dataParts as $part) {
+                    $data .= $part;
+                }
+            } else {
+                $data = implode(' ', $dataParts);
+            }
             if ($owner !== '@' && !str_ends_with($owner, '.')) {
                 $owner .= '.' . rtrim($this->defaultOrigin, '.');
             }
@@ -265,11 +285,21 @@ public function export(string $domain, array $records): string
                 $data = "{$r->getPriority()} {$r->getRdata()}";
             } elseif ($type === 'SRV' && $r->getPriority() !== null && $r->getWeight() !== null && $r->getPort() !== null) {
                 $data = "{$r->getPriority()} {$r->getWeight()} {$r->getPort()} {$r->getRdata()}";
+            } elseif ($type === 'TXT') {
+                // Encode TXT records with double quotes and escape embedded quotes and backslashes
+                $escaped = str_replace(['\\', '"'], ['\\\\', '\\"'], $data);
+                $data = '"' . $escaped . '"';
             }
 
             $lines[] = sprintf("%s %d %s %s %s", $owner, $ttl, $class, $type, $data);
         }
-        return implode("\n", $lines) . "\n";
+        // Remove any empty lines at the end
+        while (!empty($lines) && trim(end($lines)) === '') {
+            array_pop($lines);
+        }
+        $output = implode("\n", $lines);
+        // Guarantee only a single newline at the end
+        return rtrim($output, "\n") . "\n";
     }
 
     /**
@@ -293,7 +323,7 @@ protected function collectLogicalLines(string $content): array
         $parenDepth = 0;
         foreach ($rawLines as $rawLine) {
             // Remove trailing comments from the physical line.
-            $line = trim($this->stripTrailingComment($rawLine));
+            $line = trim($this->stripTrailingComment($rawLine, false));
             if ($line === '') {
                 continue;
             }
@@ -336,17 +366,35 @@ protected function collectLogicalLines(string $content): array
     /**
      * Remove trailing comments (anything after '#' or ';') from a line.
      */
-    protected function stripTrailingComment(string $line): string
+
+    /**
+     * Remove trailing comments (anything after '#' or ';') from a line.
+     * If $txtMode is true, only strip at #, not at semicolons.
+     */
+    protected function stripTrailingComment(string $line, bool $txtMode): string
     {
-        $hashPos = strpos($line, '#');
-        if ($hashPos !== false) {
-            $line = substr($line, 0, $hashPos);
-        }
-        $semiPos = strpos($line, ';');
-        if ($semiPos !== false) {
-            $line = substr($line, 0, $semiPos);
+        $inQuote = false;
+        $result = '';
+        for ($i = 0, $len = strlen($line); $i < $len; $i++) {
+            $c = $line[$i];
+            // Check for unescaped quote
+            if ($c === '"') {
+                $escaped = false;
+                $j = $i - 1;
+                while ($j >= 0 && $line[$j] === '\\') {
+                    $escaped = !$escaped;
+                    $j--;
+                }
+                if (!$escaped) {
+                    $inQuote = !$inQuote;
+                }
+            }
+            if (!$inQuote && ($c === '#' || (!$txtMode && $c === ';'))) {
+                break;
+            }
+            $result .= $c;
         }
-        return $line;
+        return $result;
     }
 
     protected function isComment(string $line): bool
@@ -360,22 +408,48 @@ protected function isComment(string $line): bool
      *
      * @return string[]
      */
+    /**
+     * Tokenize a line by whitespace, handling quoted strings and escapes per RFC 1035.
+     *
+     * @return string[]
+     */
     protected function tokenize(string $line): array
     {
+        // Manual tokenizer: handles quoted strings and escapes
         $tokens = [];
         $current = '';
-        $inSpace = true;
+        $inQuote = false;
+        $escape = false;
         for ($i = 0, $len = strlen($line); $i < $len; $i++) {
             $c = $line[$i];
-            if ($c === ' ' || $c === "\t") {
-                if (!$inSpace) {
+            if ($escape) {
+                $current .= $c;
+                $escape = false;
+                continue;
+            }
+            if ($c === '\\') {
+                $escape = true;
+                continue;
+            }
+            if ($inQuote) {
+                if ($c === '"') {
+                    $inQuote = false;
                     $tokens[] = $current;
                     $current = '';
+                } else {
+                    $current .= $c;
                 }
-                $inSpace = true;
             } else {
-                $current .= $c;
-                $inSpace = false;
+                if ($c === '"') {
+                    $inQuote = true;
+                } elseif ($c === ' ' || $c === "\t") {
+                    if ($current !== '') {
+                        $tokens[] = $current;
+                        $current = '';
+                    }
+                } else {
+                    $current .= $c;
+                }
             }
         }
         if ($current !== '') {

tests/DNS/ClientTest.php

@@ -105,9 +105,10 @@ public function testTXTRecords(): void
 
         $records = $this->client->query('dev2.appwrite.io', 'TXT');
 
-        $this->assertCount(2, $records);
+        $this->assertCount(3, $records);
         $this->assertEquals('key with "$\'- symbols', $records[0]->getRdata());
         $this->assertEquals('key with spaces', $records[1]->getRdata());
+        $this->assertEquals('v=DMARC1; p=none; rua=mailto:jon@snow.got; ruf=mailto:jon@snow.got; fo=1;', $records[2]->getRdata());
 
         $records = $this->client->query('dev3.appwrite.io', 'TXT');
         $this->assertCount(0, $records);