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Fix encoding TXT records as length-prefixed character-strings #130

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Merged
samuelwilliams merged 1 commit into from
Aug 18, 2026
Merged

Fix encoding TXT records as length-prefixed character-strings #130

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18 changes: 15 additions & 3 deletions lib/Rdata/TXT.php
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Original file line number Diff line number Diff line change
Expand Up @@ -60,14 +60,26 @@ public function toText(): string

public function toWire(): string
{
return $this->text ?? '';
$wire = '';
foreach (str_split($this->text ?? '', 255) as $chunk) {
$wire .= chr(strlen($chunk)).$chunk;
}

return '' === $wire ? "\x00" : $wire;
}

public function fromWire(string $rdata, int &$offset = 0, ?int $rdLength = null): void
{
$rdLength = $rdLength ?? strlen($rdata);
$this->setText(substr($rdata, $offset, $rdLength));
$offset += $rdLength;
$end = $offset + $rdLength;
$text = '';
while ($offset < $end) {
$length = ord($rdata[$offset]);
++$offset;
$text .= substr($rdata, $offset, $length);
$offset += $length;
}
$this->setText($text, true);
}

public function fromText(string $text): void
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11 changes: 6 additions & 5 deletions tests/Rdata/SpfTest.php
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Expand Up @@ -42,15 +42,16 @@ public function testToText(): void

public function testWire(): void
{
$wireFormat = chr(49).'v=spf1 ip4:192.0.2.0/24 ip4:198.51.100.123 a -all';
$offset = 1;
$rdLength = 49;
$text = 'v=spf1 ip4:192.0.2.0/24 ip4:198.51.100.123 a -all';
$wireFormat = chr(strlen($text)).$text;

$spf = new SPF();
$spf->setText('v=spf1 ip4:192.0.2.0/24 ip4:198.51.100.123 a -all');
$spf->setText($text);
$this->assertEquals($wireFormat, $spf->toWire());

$offset = 0;
$fromWire = new SPF();
$fromWire->fromWire($wireFormat, $offset, $rdLength);
$fromWire->fromWire($wireFormat, $offset, strlen($wireFormat));
$this->assertEquals($spf, $fromWire);
}

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39 changes: 34 additions & 5 deletions tests/Rdata/TxtTest.php
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Expand Up @@ -76,15 +76,44 @@ public function testFromTxt(string $text, string $expectation): void
$this->assertEquals($expectation, $txt->getText());
}

public function testWire(): void
public function testWire1(): void
{
$expectation = 'This is some text. It\'s a nice piece of text.';
$text = 'This is some text. It\'s a nice piece of text.';
$txt = new TXT();
$txt->setText($expectation);
$txt->setText($text);

$this->assertEquals(chr(strlen($text)).$text, $txt->toWire());

$this->assertEquals($expectation, $txt->toWire());
$fromWire = new TXT();
$fromWire->fromWire($expectation);
$fromWire->fromWire($txt->toWire());
$this->assertEquals($txt, $fromWire);
}

public function testWire2(): void
{
$text = str_repeat('a', 255).str_repeat('b', 100);
$txt = new TXT();
$txt->setText($text);

$this->assertEquals(
chr(255).str_repeat('a', 255).chr(100).str_repeat('b', 100),
$txt->toWire()
);

$fromWire = new TXT();
$fromWire->fromWire($txt->toWire());
$this->assertEquals($text, $fromWire->getText());
}

public function testWire3(): void
{
$txt = new TXT();
$txt->setText('');

$this->assertEquals("\x00", $txt->toWire());

$fromWire = new TXT();
$fromWire->fromWire($txt->toWire());
$this->assertEquals('', $fromWire->getText());
}
}
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