Bug: fwrite(): supplied resource is not a valid stream resource

[dylanfcsr]

PHP Version

8.4

CodeIgniter4 Version

4.6.2

CodeIgniter4 Installation Method

Composer (using codeigniter4/appstarter)

Which operating systems have you tested for this bug?

Linux

Which server did you use?

apache

Database

PostgreSQL 9.6

What happened?

I upgraded from version 4.4.0 to 4.6.2 before, I did not have this error when sending email

Steps to Reproduce

// configuration de base des mails
$config['userAgent'] = 'CodeIgniter';
$config['protocol'] = 'smtp';

$config['SMTPTimeout'] = 5;
$config['wordWrap'] = TRUE;
$config['wrapChars'] = 76;
$config['mailType'] = 'html';
$config['charset'] = 'utf-8';
$config['validate'] = FALSE;
$config['priority'] = 3;
$config['CRLF'] = "\r\n";
$config['newline'] = "\r\n";
$config['BCCBatchMode'] = FALSE;
$config['BCCBatchSize'] = 200;

$config['SMTPCrypto'] = '';
$config['SMTPHost'] = '10.0.0.2';
$config['SMTPUser'] = '';
$config['SMTPPass'] = '';
$config['SMTPPort'] = 25;
$email->initialize($config);

$email->clear(true);

foreach ($file  as $key => $value) {
    $email->attach($value);
}

if ($email->send()) {
    $response['success'] = true;
    $response['messages'] = 'Le mail à bien été transmis au client';
} else {
    $response['success'] = false;
    $response['messages'] =  $email->printDebugger();
}

Expected Output

The email was sent, but I get this error every time I send an email that I didn't have before.

Anything else?

{
    "title": "TypeError",
    "type": "TypeError",
    "code": 500,
    "message": "fwrite(): supplied resource is not a valid stream resource",
    "file": "/var/www/html/planning/vendor/codeigniter4/framework/system/Email/Email.php",
    "line": 2084,
    "trace": [
        {
            "file": "/var/www/html/planning/vendor/codeigniter4/framework/system/Email/Email.php",
            "line": 2084,
            "function": "fwrite"
        },
        {
            "file": "/var/www/html/planning/vendor/codeigniter4/framework/system/Email/Email.php",
            "line": 1993,
            "function": "sendData",
            "class": "CodeIgniter\\Email\\Email",
            "type": "->"
        },
        {
            "file": "/var/www/html/planning/vendor/codeigniter4/framework/system/Email/Email.php",
            "line": 2232,
            "function": "sendCommand",
            "class": "CodeIgniter\\Email\\Email",
            "type": "->"
        },
        {
            "function": "__destruct",
            "class": "CodeIgniter\\Email\\Email",
            "type": "->"
        }
    ]
}

[michalsn]

Have you tried to increase the $config['SMTPTimeout']?

[dylanfcsr]

Yes, that doesn't change anything, and I didn't have this problem on Codeigniter 4.4.0, and the email is sent and received by the recipient

[dylanfcsr]

By modifying the email class in this way I no longer have the error, my email is sent without error but I do not know why and what is the consequence of this addition

    /**
     * @param string $data
     *
     * @return bool
     */
    protected function sendData($data)
    {
        $data .= $this->newline;

        $result = null;

        for ($written = $timestamp = 0, $length = static::strlen($data); $written < $length; $written += $result) {
           
            // ont vérifie que $this->SMTPConnect is a valid resource
            if (!is_resource($this->SMTPConnect)) {
                $this->setErrorMessage(lang('Email.SMTPNoConnect'));
                return false;
            }

            if (($result = fwrite($this->SMTPConnect, static::substr($data, $written))) === false) {
                break;
            }

            // See https://bugs.php.net/bug.php?id=39598 and http://php.net/manual/en/function.fwrite.php#96951
            if ($result === 0) {
                if ($timestamp === 0) {
                    $timestamp = Time::now()->getTimestamp();
                } elseif ($timestamp < (Time::now()->getTimestamp() - $this->SMTPTimeout)) {
                    $result = false;

                    break;
                }

                usleep(250000);

                continue;
            }

            $timestamp = 0;
        }

        if (! is_int($result)) {
            $this->setErrorMessage(lang('Email.SMTPDataFailure', [$data]));

            return false;
        }

        return true;
    }

    /**
     * @return string
     */
    protected function getSMTPData()
    {
        $data = '';
        
          // ont vérifie que $this->SMTPConnect is a valid resource
            if (!is_resource($this->SMTPConnect)) {
                return $data;
            }

        while ($str = fgets($this->SMTPConnect, 512)) {
            $data .= $str;

            if ($str[3] === ' ') {
                break;
            }
        }

        return $data;
    }

[michalsn]

If you call d($email->printDebugger()) after a successful send(), does any message about no connection appear?

[dylanfcsr]

After sending the email, if ($email->send()) {
$response['success'] = true;
$response['messages'] = 'The email has been successfully sent to the client';
print_r($email->printDebugger());
exit('bye');
}

string(13) "<pre> </pre>"

[michalsn]

Thank you. This is a bit of a mystery to me.

Would you mind sharing which email provider you're using? I'd like to try to recreate the issue on my end.

[michalsn]

Oh, silly me... can you please send an email with $email->send(false) to prevent clearing the debug data?

[dylanfcsr]

With true when sending mail, We use MDaemon Technologies, Ltd. reusing the email class from version 4.4.5 I don't have any errors when sending mail

[tangix]

Just got bitten by the same bug.
This spark command replicates for me:

<?php

namespace App\Commands;

use CodeIgniter\CLI\BaseCommand;

class MailDebug extends BaseCommand
{

    protected $group       = 'Demo';
    protected $name        = 'debug:email';
    protected $description = 'Sends an email';

    /**
     * @inheritDoc
     */
    public function run(array $params)
    {
        $email = service('email');
        $email->setFrom(setting('Email.fromEmail'), setting('Email.fromName') ?? '');
        $email->setTo('***@gmail.com');
        $email->setSubject('CI email debug');
        $email->setMessage('Hello World!');

        if ($email->send(false) === false) {
            log_message('error', $email->printDebugger(['headers']));
        }

        // Clear the email
        $email->clear();
    }
}

Using the same provider that works in 4.6.1 gives this error:

╰─ php spark debug:email

CodeIgniter v4.6.2 Command Line Tool - Server Time: 2025-07-29 10:54:29 UTC+02:00


Fatal error: Uncaught TypeError: fwrite(): supplied resource is not a valid stream resource in /opt/project/vendor/codeigniter4/framework/system/Email/Email.php on line 2084

TypeError: fwrite(): supplied resource is not a valid stream resource in /opt/project/vendor/codeigniter4/framework/system/Email/Email.php on line 2084

Call Stack:
    1.1076    8812168   1. CodeIgniter\Email\Email->__destruct() /opt/project/vendor/codeigniter4/framework/system/Email/Email.php:0
    1.1076    8812168   2. CodeIgniter\Email\Email->sendCommand($cmd = 'quit', $data = ???) /opt/project/vendor/codeigniter4/framework/system/Email/Email.php:2232
    1.1076    8812168   3. CodeIgniter\Email\Email->sendData($data = 'QUIT') /opt/project/vendor/codeigniter4/framework/system/Email/Email.php:1993
    1.1076    8812200   4. fwrite($stream = resource(222) of type (Unknown), $data = 'QUIT\r\n') /opt/project/vendor/codeigniter4/framework/system/Email/Email.php:2084

[michalsn]

Thank you @tangix - I was able to reproduce the issue.

@dylanfcsr thank you for reporting this. You should be able to use v4.6.1 without any problems. We'll fix this and release a new version soon.

[sanchawebo]

I had to revert back to 4.6.1 as it worked almost without any problems. With ci-shield MFA when clicking the "send me the code via mail" button an error messsage showed up to the right of the centered box. In dev (detailed as above) and prod environment (whoops).