PHPMailer::DKIM_Add( string $headers_line, string $subject, string $body ): string

Compatibility

Present in every tracked release (6.7.7 to 7.1.0), and compiles on PHP 7.4 through 8.6-dev.

Parameters

$headers_linestring

Header lines

$subjectstring

Subject

$bodystring

Body

Return value

string

Performance profile

How much work a call to PHPMailer::DKIM_Add() does, and what it touches: the algorithmic scaling, the Zend instruction count per call across PHP versions, the hooks it hands control to, and the core code that calls it. Measured from the compiled opcodes, not a stopwatch, so every number is identical on any machine running the same PHP version, and every function in core is ranked by cost.

Cost class

Light

Touches nothing outside its own arguments.

Scaling

Scales with input

The body loops, so the work grows with what you pass in.

Instructions

115–138

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 273.

Plugin surface

None

Nothing here hands control to plugin code.

Called by

0

Nothing in core calls this; the cost is only what you spend yourself.

What one call costs · 1 distinct outcome

One number would be a lie: the work depends on which branch runs. These are every distinct cost PHPMailer::DKIM_Add() can have, taken from its control-flow graph on PHP 8.5.

Uses · 6

• stripos()
• \PHPMailer\PHPMailer\PHPMailer::DKIM_QP()
• \PHPMailer\PHPMailer\PHPMailer::DKIM_BodyC()
• \PHPMailer\PHPMailer\PHPMailer::DKIM_HeaderC()
• \PHPMailer\PHPMailer\PHPMailer::DKIM_Sign()
• static::normalizeBreaks()

Source code

View on Trac ↗View on GitHub ↗

5324    public function DKIM_Add($headers_line, $subject, $body)5325    {5326        $DKIMsignatureType = 'rsa-sha256'; //Signature & hash algorithms5327        $DKIMcanonicalization = 'relaxed/simple'; //Canonicalization methods of header & body5328        $DKIMquery = 'dns/txt'; //Query method5329        $DKIMtime = time();5330        //Always sign these headers without being asked5331        //Recommended list from https://www.rfc-editor.org/rfc/rfc6376#section-5.4.15332        $autoSignHeaders = [5333            'from',5334            'to',5335            'cc',5336            'date',5337            'subject',5338            'reply-to',5339            'message-id',5340            'content-type',5341            'mime-version',5342            'x-mailer',5343        ];5344        if (stripos($headers_line, 'Subject') === false) {5345            $headers_line .= 'Subject: ' . $subject . static::$LE;5346        }5347        $headerLines = explode(static::$LE, $headers_line);5348        $currentHeaderLabel = '';5349        $currentHeaderValue = '';5350        $parsedHeaders = [];5351        $headerLineIndex = 0;5352        $headerLineCount = count($headerLines);5353        foreach ($headerLines as $headerLine) {5354            $matches = [];5355            if (preg_match('/^([^ \t]*?)(?::[ \t]*)(.*)$/', $headerLine, $matches)) {5356                if ($currentHeaderLabel !== '') {5357                    //We were previously in another header; This is the start of a new header, so save the previous one5358                    $parsedHeaders[] = ['label' => $currentHeaderLabel, 'value' => $currentHeaderValue];5359                }5360                $currentHeaderLabel = $matches[1];5361                $currentHeaderValue = $matches[2];5362            } elseif (preg_match('/^[ \t]+(.*)$/', $headerLine, $matches)) {5363                //This is a folded continuation of the current header, so unfold it5364                $currentHeaderValue .= ' ' . $matches[1];5365            }5366            ++$headerLineIndex;5367            if ($headerLineIndex >= $headerLineCount) {5368                //This was the last line, so finish off this header5369                $parsedHeaders[] = ['label' => $currentHeaderLabel, 'value' => $currentHeaderValue];5370            }5371        }5372        $copiedHeaders = [];5373        $headersToSignKeys = [];5374        $headersToSign = [];5375        foreach ($parsedHeaders as $header) {5376            //Is this header one that must be included in the DKIM signature?5377            if (in_array(strtolower($header['label']), $autoSignHeaders, true)) {5378                $headersToSignKeys[] = $header['label'];5379                $headersToSign[] = $header['label'] . ': ' . $header['value'];5380                if ($this->DKIM_copyHeaderFields) {5381                    $copiedHeaders[] = $header['label'] . ':' . //Note no space after this, as per RFC5382                        str_replace('|', '=7C', $this->DKIM_QP($header['value']));5383                }5384                continue;5385            }5386            //Is this an extra custom header we've been asked to sign?5387            if (in_array($header['label'], $this->DKIM_extraHeaders, true)) {5388                //Find its value in custom headers5389                foreach ($this->CustomHeader as $customHeader) {5390                    if ($customHeader[0] === $header['label']) {5391                        $headersToSignKeys[] = $header['label'];5392                        $headersToSign[] = $header['label'] . ': ' . $header['value'];5393                        if ($this->DKIM_copyHeaderFields) {5394                            $copiedHeaders[] = $header['label'] . ':' . //Note no space after this, as per RFC5395                                str_replace('|', '=7C', $this->DKIM_QP($header['value']));5396                        }5397                        //Skip straight to the next header5398                        continue 2;5399                    }5400                }5401            }5402        }5403        $copiedHeaderFields = '';

Changelog

Unchanged from 6.7.7 through 7.1.0.

1. 6.7.7
2. 6.8.8
3. 6.9.7
4. 7.0.4
5. 7.1.0

Signature, return type and hooks compared across 5 parsed releases.

About this page

Parsed data

Generated from the wordpress-develop 7.1.0 tag, from src/wp-includes/PHPMailer/PHPMailer.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.

Corrections

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