Category: Common WordPress Development

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Filesystem based transient functions for WordPress

Sometimes we may have a reason to use file-based transients instead of a default DB transients.

For example, most cache plugins automatically moves transients into external cache systems such as Redis, Memcached which might be a problem. Because if for some reason redis cache is reset – then all transients get lost – which is very bad for sure.

Transients are not always data which can easily be regenerated – sometimes they contain very important temporary data and should be kept until it expires.

That’s why W3Total Cache plugin has a great feature for it – you can keep a default transient storage(DB) while using Redis or other external object caching software.

For my own codes, sometimes i use filesystem based transient which i built for myself.

Here are set and get functions:

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How to Clean POSTMETA Data of Old Orders After Switching to WooCommerce HPOS

Old Order Deletion Illustration

As of today there is no official guide for this simple need. If you have old orders more than 1000, you are right if you want to get rid of old orders – just to fasten your website.

So i decided to write my own script and apply to my web store with 30K order history.

Step1: I activated HPOS in dual-mode (aka safe mode).

Step2: 1 day passed and i disabled legacy mode and kept HPOS only

Step3: 1 more day passed and i deleted the oldest 5 orders from wp_postmeta.

Step4: Everything looked good, and i did the same for all orders.

Warning: You should take a backup before applying this code:

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Allow SFTP root access to the Linux Server – just for your own IP address

If you want to access your Linux server using SFTP and a root user, by default it can be disabled. Due to security reasons most server-providers disable that by default.

So, you can enable it yourself. But as it is not secure, you need to add some restrictions.

Such as, adding this feature only for your own static IP.

So let’s do that. Open your server’s sshd_config file by using this command.

nano /etc/ssh/sshd_config

Under the line Subsystem sftp /usr/lib/openssh/sftp-server you can paste 3 new lines.

Here is how it should look like:

Subsystem sftp  /usr/lib/openssh/sftp-server
Match Address 111.111.111.111
PasswordAuthentication yes
PermitRootLogin yes

Replace 11.111.111.111 with your own static IP address.

Then save and restart SSH by using

service ssh restart

That’s all. Now you can access to your server via SFTP, as a root user if you are connected to internet with your own static IP.

All other users will not be able to connect of course.

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Rename existing WordPress Attachments files, titles

Rename wp media object

If you change your website name, or you have to change some strings in existing imagedata of your website, we need to do the following steps:

Step 1: Fetch all attachments

Step 2: Rename all corresponding uploaded files

Step 3: update attachment data so that new files would be recognized by WP

Step 4: Update title, description data as well.

Here is a snippet which implements all 4 steps above.

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How to use Google DNS in Ubuntu/Debian permanently

Few weeks ago in one of the servers we faces strange issue: The website couldn’t send emails using remote SMTP.

First i thought it was related to SMTP port, credentials etc. – but everything was OK there. So then i tries to ping google.com and got surprised. It wasn’t worked. Simple ping didn’t work.

So it was obviously corrupted DNS issue.

First i tried the easier way, which is recommended by developers.google.com, adding Google DNS IP addresses to resolv.conf file

sudo vi /etc/resolv.conf

But it didn’t help.

So i decided to go into deeper and solving it using netplan.

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How to create downloadable PDF link that works in all mobile browsers – Chrome, Safari etc.

In some mobile browsers PDF links might not work properly.
Instead of downloading, its tab just disappears immediately after opening. And we get no downloaded PDF.

Auto-close, auto-disappear – whatever you call that – but the problem exists.

So for WordPress websites, here is how to skip this pdf-download block for mobile browsers.

We will use pseudo-page link in order to bypass that block.

I mean, instead of direct links to PDF, we will use pseudo-pdf link which doesn’t look like PDF, but actually returns PDF header and body.

Let’s say that we have a PDF ile in “wp-content/uploads/2022.pdf”.

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