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SMTP::sendCommand( string $command, string $commandstring, int|array $expect ): bool

Source
wp-includes/PHPMailer/SMTP.php:1113
Send a command to an SMTP server and check its return code.

Compatibility

WordPress
core
PHP
7.4–8.6-dev
  • 6.7.7
  • 6.8.8
  • 6.9.7
  • 7.0.4
  • 7.1.0

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

Parameters

$commandstring
The command name - not sent to the server
$commandstringstring
The actual command to send
$expectint|array
One or more expected integer success codes

Return value

bool
True on success

Performance profile

How much work a call to SMTP::sendCommand() 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
Trivial

Touches nothing outside its own arguments.

Scaling
Constant

No loop in the body: the same number of instructions runs whatever you pass in.

Instructions
13–82

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 111.

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 · 4 distinct outcomes

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

WhenInstructionsCalls it makes
always13–19->connected(), ->setError()
->connected() && $code && $command === "RSET"51–66->connected(), ->client_send(), ->get_lines(), preg_match(), ->edebug()
->connected() && $code && $command !== "RSET"54–69->connected(), ->client_send(), ->get_lines(), preg_match(), ->edebug(), ->setError()
->connected() && !$code67–82->connected(), ->client_send(), ->get_lines(), preg_match(), ->edebug(), ->setError(), ->edebug()

Across PHP versions

PHPCompiledExecutedBranchesNotes
8.6-dev11113–828
8.511113–8281 more instruction than PHP 8.4
8.411013–81823 fewer instructions than PHP 8.3
8.313313–978
8.213313–978
8.113313–9782 fewer instructions than PHP 7.4
7.413513–998

An instruction is not a fixed amount of time, so a matching count is not necessarily the same speed; what it rules out is a difference in the work itself.

Uses · 5

  • \PHPMailer\PHPMailer\SMTP::connected()
  • \PHPMailer\PHPMailer\SMTP::setError()
  • \PHPMailer\PHPMailer\SMTP::client_send()
  • \PHPMailer\PHPMailer\SMTP::get_lines()
  • \PHPMailer\PHPMailer\SMTP::edebug()

Source code

    protected function sendCommand($command, $commandstring, $expect)    {        if (!$this->connected()) {            $this->setError("Called $command without being connected");             return false;        }        //Reject line breaks in all commands        if ((strpos($commandstring, "\n") !== false) || (strpos($commandstring, "\r") !== false)) {            $this->setError("Command '$command' contained line breaks");             return false;        }        $this->client_send($commandstring . static::LE, $command);         $this->last_reply = $this->get_lines();        //Fetch SMTP code and possible error code explanation        $matches = [];        if (preg_match('/^([\d]{3})[ -](?:([\d]\\.[\d]\\.[\d]{1,2}) )?/', $this->last_reply, $matches)) {            $code = (int) $matches[1];            $code_ex = (count($matches) > 2 ? $matches[2] : null);            //Cut off error code from each response line            $detail = preg_replace(                "/{$code}[ -]" .                ($code_ex ? str_replace('.', '\\.', $code_ex) . ' ' : '') . '/m',                '',                $this->last_reply            );        } else {            //Fall back to simple parsing if regex fails            $code = (int) substr($this->last_reply, 0, 3);            $code_ex = null;            $detail = substr($this->last_reply, 4);        }         $this->edebug('SERVER -> CLIENT: ' . $this->last_reply, self::DEBUG_SERVER);         if (!in_array($code, (array) $expect, true)) {            $this->setError(                "$command command failed",                $detail,                $code,                $code_ex            );            $this->edebug(                'SMTP ERROR: ' . $this->error['error'] . ': ' . $this->last_reply,                self::DEBUG_CLIENT            );             return false;        }         //Don't clear the error store when using keepalive        if ($command !== 'RSET') {            $this->setError('');        }         return true;    }

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/SMTP.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.
Corrections
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