PHPMailer::createHeader(): string

Compatibility

Present in every tracked release (6.7.7 to 7.1.0), 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

78–152

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 · 192 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::sanitiseDate()
• \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 ↗

2850    public function createHeader()2851    {2852        $result = '';2853 2854        $result .= $this->headerLine(2855            'Date',2856            self::sanitiseDate($this->MessageDate)2857        );2858 2859        //The To header is created automatically by mail(), so needs to be omitted here2860        if ('mail' !== $this->Mailer) {2861            if ($this->SingleTo) {2862                foreach ($this->to as $toaddr) {2863                    $this->SingleToArray[] = $this->addrFormat($toaddr);2864                }2865            } elseif (count($this->to) > 0) {2866                $result .= $this->addrAppend('To', $this->to);2867            } elseif (count($this->cc) === 0) {2868                $result .= $this->headerLine('To', 'undisclosed-recipients:;');2869            }2870        }2871        $result .= $this->addrAppend('From', [[trim($this->From), $this->FromName]]);2872 2873        //sendmail and mail() extract Cc from the header before sending2874        if (count($this->cc) > 0) {2875            $result .= $this->addrAppend('Cc', $this->cc);2876        }2877 2878        //sendmail and mail() extract Bcc from the header before sending2879        if (2880            (2881                'sendmail' === $this->Mailer || 'qmail' === $this->Mailer || 'mail' === $this->Mailer2882            )2883            && count($this->bcc) > 02884        ) {2885            $result .= $this->addrAppend('Bcc', $this->bcc);2886        }2887 2888        if (count($this->ReplyTo) > 0) {2889            $result .= $this->addrAppend('Reply-To', $this->ReplyTo);2890        }2891 2892        //mail() sets the subject itself2893        if ('mail' !== $this->Mailer) {2894            $result .= $this->headerLine('Subject', $this->encodeHeader($this->secureHeader($this->Subject)));2895        }2896 2897        //Only allow a custom message ID if it conforms to RFC 5322 section 3.6.42898        //https://www.rfc-editor.org/rfc/rfc5322#section-3.6.42899        if (2900            '' !== $this->MessageID &&2901            preg_match(2902                '/^<((([a-z\d!#$%&\'*+\/=?^_`{|}~-]+(\.[a-z\d!#$%&\'*+\/=?^_`{|}~-]+)*)' .2903                '|("(([\x01-\x08\x0B\x0C\x0E-\x1F\x7F]|[\x21\x23-\x5B\x5D-\x7E])' .2904                '|(\\[\x01-\x09\x0B\x0C\x0E-\x7F]))*"))@(([a-z\d!#$%&\'*+\/=?^_`{|}~-]+' .2905                '(\.[a-z\d!#$%&\'*+\/=?^_`{|}~-]+)*)|(\[(([\x01-\x08\x0B\x0C\x0E-\x1F\x7F]' .2906                '|[\x21-\x5A\x5E-\x7E])|(\\[\x01-\x09\x0B\x0C\x0E-\x7F]))*\])))>$/Di',2907                $this->MessageID2908            )2909        ) {2910            $this->lastMessageID = $this->MessageID;2911        } else {2912            $this->lastMessageID = sprintf('<%s@%s>', $this->uniqueid, $this->serverHostname());2913        }2914        $result .= $this->headerLine('Message-ID', $this->lastMessageID);2915        if (null !== $this->Priority) {2916            $result .= $this->headerLine('X-Priority', $this->Priority);2917        }2918        if ('' === $this->XMailer) {2919            //Empty string for default X-Mailer header2920            $result .= $this->headerLine(2921                'X-Mailer',2922                'PHPMailer ' . self::VERSION . ' (https://github.com/PHPMailer/PHPMailer)'2923            );2924        } elseif (is_string($this->XMailer) && trim($this->XMailer) !== '') {2925            //Some string2926            $result .= $this->headerLine('X-Mailer', $this->secureHeader(trim($this->XMailer)));2927        } //Other values result in no X-Mailer header2928 2929        if ('' !== $this->ConfirmReadingTo) {

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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