Malformed UTF-8 characters when CertificateCheckSucceeded event is serialized to queue

[jszobody]

We are seeing an error "Unable to JSON encode payload. Error (5): Malformed UTF-8 characters, possibly incorrectly encoded." when trying to use the monitor:check-certificate command.

Did some troubleshooting, and it appears to happen when the CertificateCheckSucceeded event is dispatched here:

laravel-uptime-monitor/src/Models/Traits/SupportsCertificateCheck.php

Line 53 in 07ddc04

event(new CertificateCheckSucceeded($this, $certificate));

The certificate check is succeeding, the DB is getting updated with a valid status, but then when this success event is dispatched we get the error:

Illuminate\Queue\InvalidPayloadException Unable to JSON encode payload. Error (5): Malformed UTF-8 characters, possibly incorrectly encoded.

Here is a simple way to reproduce from tinker:

use Spatie\UptimeMonitor\Models\Monitor;
use Spatie\UptimeMonitor\Events\CertificateCheckSucceeded;
use Spatie\SslCertificate\SslCertificate;

$certificate = SslCertificate::createForHostName("www.spatie.be");
$monitor = new Monitor();

event(new CertificateCheckSucceeded($monitor, $certificate));

It seems the issue occurs when Laravel tries to serialize the SslCertificate instance for the purpose of queueing. And indeed, I can reproduce that pretty easily as well. I can't json_encode the array or serialized string of a certificate:

use Spatie\SslCertificate\SslCertificate;

$certificate = SslCertificate::createForHostName("www.spatie.be");

json_encode(serialize($certificate)); // fails
json_encode($certificate->toArray()); // fails

It seems to me that the SslCertificate class needs to base64_encode some parts of the certificate data to help with serialization and json encoding. If I dump the $certificate I definitely see what appears to be binary data in parts of the certificate data. It makes sense that this can't be directly encoded as json.

Does that seem reasonable? Should I submit a pull request to the spatie/ssl-certificate package with serialization encoding? Or is there something in my PHP config that would solve this?

I feel like I must be missing something if everyone isn't having this issue.

[jszobody]

Update: I submitted a PR to the ssl-certificate package and it was merged: spatie/ssl-certificate#190

So this issue is resolved. Though I'm still flummoxed how anyone was able to monitor SSL certificates without running into this issue. I still feel like I might be missing something. Eager to hear if anyone has thoughts.