PHPMailer::createHeader(): string

Compatibility

Present in every tracked release (6.7.10 to 7.1.3), and compiles on PHP 7.4 through 8.6-dev.

Return value

string

The assembled headers

Performance profile

How much work a call to PHPMailer::createHeader() 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 how much data it finds.

Instructions

77–148

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 223.

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 · 96 distinct outcomes

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

This body has more branch combinations than are worth enumerating, so the table covers the outcomes found first rather than every one that exists.

Uses · 8

• \PHPMailer\PHPMailer\PHPMailer::headerLine()
• \PHPMailer\PHPMailer\PHPMailer::rfcDate()
• \PHPMailer\PHPMailer\PHPMailer::addrFormat()
• \PHPMailer\PHPMailer\PHPMailer::addrAppend()
• \PHPMailer\PHPMailer\PHPMailer::encodeHeader()
• \PHPMailer\PHPMailer\PHPMailer::secureHeader()
• \PHPMailer\PHPMailer\PHPMailer::serverHostname()
• \PHPMailer\PHPMailer\PHPMailer::getMailMIME()

Source code

View on Trac ↗View on GitHub ↗

2665    public function createHeader()2666    {2667        $result = '';2668 2669        $result .= $this->headerLine('Date', '' === $this->MessageDate ? self::rfcDate() : $this->MessageDate);2670 2671        //The To header is created automatically by mail(), so needs to be omitted here2672        if ('mail' !== $this->Mailer) {2673            if ($this->SingleTo) {2674                foreach ($this->to as $toaddr) {2675                    $this->SingleToArray[] = $this->addrFormat($toaddr);2676                }2677            } elseif (count($this->to) > 0) {2678                $result .= $this->addrAppend('To', $this->to);2679            } elseif (count($this->cc) === 0) {2680                $result .= $this->headerLine('To', 'undisclosed-recipients:;');2681            }2682        }2683        $result .= $this->addrAppend('From', [[trim($this->From), $this->FromName]]);2684 2685        //sendmail and mail() extract Cc from the header before sending2686        if (count($this->cc) > 0) {2687            $result .= $this->addrAppend('Cc', $this->cc);2688        }2689 2690        //sendmail and mail() extract Bcc from the header before sending2691        if (2692            (2693                'sendmail' === $this->Mailer || 'qmail' === $this->Mailer || 'mail' === $this->Mailer2694            )2695            && count($this->bcc) > 02696        ) {2697            $result .= $this->addrAppend('Bcc', $this->bcc);2698        }2699 2700        if (count($this->ReplyTo) > 0) {2701            $result .= $this->addrAppend('Reply-To', $this->ReplyTo);2702        }2703 2704        //mail() sets the subject itself2705        if ('mail' !== $this->Mailer) {2706            $result .= $this->headerLine('Subject', $this->encodeHeader($this->secureHeader($this->Subject)));2707        }2708 2709        //Only allow a custom message ID if it conforms to RFC 5322 section 3.6.42710        //https://www.rfc-editor.org/rfc/rfc5322#section-3.6.42711        if (2712            '' !== $this->MessageID &&2713            preg_match(2714                '/^<((([a-z\d!#$%&\'*+\/=?^_`{|}~-]+(\.[a-z\d!#$%&\'*+\/=?^_`{|}~-]+)*)' .2715                '|("(([\x01-\x08\x0B\x0C\x0E-\x1F\x7F]|[\x21\x23-\x5B\x5D-\x7E])' .2716                '|(\\[\x01-\x09\x0B\x0C\x0E-\x7F]))*"))@(([a-z\d!#$%&\'*+\/=?^_`{|}~-]+' .2717                '(\.[a-z\d!#$%&\'*+\/=?^_`{|}~-]+)*)|(\[(([\x01-\x08\x0B\x0C\x0E-\x1F\x7F]' .2718                '|[\x21-\x5A\x5E-\x7E])|(\\[\x01-\x09\x0B\x0C\x0E-\x7F]))*\])))>$/Di',2719                $this->MessageID2720            )2721        ) {2722            $this->lastMessageID = $this->MessageID;2723        } else {2724            $this->lastMessageID = sprintf('<%s@%s>', $this->uniqueid, $this->serverHostname());2725        }2726        $result .= $this->headerLine('Message-ID', $this->lastMessageID);2727        if (null !== $this->Priority) {2728            $result .= $this->headerLine('X-Priority', $this->Priority);2729        }2730        if ('' === $this->XMailer) {2731            //Empty string for default X-Mailer header2732            $result .= $this->headerLine(2733                'X-Mailer',2734                'PHPMailer ' . self::VERSION . ' (https://github.com/PHPMailer/PHPMailer)'2735            );2736        } elseif (is_string($this->XMailer) && trim($this->XMailer) !== '') {2737            //Some string2738            $result .= $this->headerLine('X-Mailer', trim($this->XMailer));2739        } //Other values result in no X-Mailer header2740 2741        if ('' !== $this->ConfirmReadingTo) {2742            $result .= $this->headerLine('Disposition-Notification-To', '<' . $this->ConfirmReadingTo . '>');2743        }2744

Changelog

Unchanged from 6.7.10 through 7.1.3.

1. 6.7.10
2. 6.8.11
3. 6.9.10
4. 7.0.7
5. 7.1.3

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

About this page

Parsed data

Generated from the wordpress-develop 6.8.11 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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