Fixing Curl Error 35 with WordPress API calls

I recently had an issue where a WordPress website I was building could not connect to itself for wp cron or background tasks.

This was the error:

curl: (35) error:1408F10B:SSL routines:ssl3_get_record:wrong version number

It turns out I had a faulty nginx configuation, and the server block was missing the ssl directive. The certificates worked in both Chrome and Firefox without warnings, but they weren’t doing what the needed to for curl to work.

server {
	listen 443 ssl;
	server_name www.example.com;
	
	root /var/www/example/;
        # ...
}

Adding the ssl fixed the curl issue right up.

Laravel’s Signed URLs Breaking with Nginx

Laravel includes a feature to sign URLs so that publicly accessible routes can be visited knowing the query string hasn’t been tampered with.

Laravel uses this for email verification links by default. I ran into a problem where signed URLs were always failing (throwing the 403 exception) in my production environment. The same code worked locally.

In turns out that this was a result of the way the package uses query string parameters to build the signature. My production nginx configuration was creating a different parameter signature to what Laravel was expecting. This was fine for unsigned URLs as the routing still worked, but it did mean that the ‘signed’ middleware would always fail.

The solution was just to alter my sites nginx config like this:

# Nope
try_files $uri $uri/ /index.php?q=$uri&$args;

# Yes
try_files $uri $uri/ /index.php?$query_string;

Now Laravel’s request object receives the same query parameters and the signed URL signature will match.

WordPress HTTP Error Uploading Larger Files

Sometimes WordPress shows a mysterious “HTTP Error” after attempting to upload a file. The file appears to upload with the progress sliders moving as normal, but fails at the end of the process without a descriptive error message.

There are a few possible causes of this, but if you have an Nginx server and small uploads are working while larger ones fail the problem might be Nginx’s max body size setting.

Increase Nginx’s client_max_body setting

Go to your Nginx sites-enabled directory (/etc/nginx/sites-enabled on Ubuntu systems) and update your server settings like so:

server {
   # other stuff is here too

   client_max_body_size 20M;
}

Restart Nginx.