Testing AdaptiveThumb, my mediawiki extension

Some time ago I wrote AdaptiveThumb, and mediawiki extension that allows pictures with relative sizes in mediawiki.

You can then use e.g. the following syntax:

<pic src="mindmap.jpg" width=30% align=text caption="this is a mindmap" />

You can find an example here: www.linuxintro.org/wiki/BaBE, a demo there: http://www.staerk.de/thorsten/Adaptivethumb, download and install it from https://www.mediawiki.org/wiki/Extension:AdaptiveThumb, and you can contribute and report bugs on https://github.com/tstaerk/adaptivethumb.

To test this extension, I use VMware Workstation 15 Player and install Ubuntu 20.04. This is the plan:

Product	Version
MediaWiki	1.34.2
PHP	7.3.19
WebServer	nginx 1.14.2
Database	SQLite
OS	Ubuntu 20.04
VM software	VMware Workstation 15

Issue: PHP did not work

I set up an nginx web server, but php was not working. Instead, the server tried to send me the php scripts as text files, it looked like this in the browser:

This is nonsense - I want the server to execute the php scripts, not to download it.

So, quickly went to /etc/nginx/sites-available/default and uncommented this block:

# pass PHP scripts to FastCGI server

        #

        location ~ \.php$ {

                include snippets/fastcgi-php.conf;

                # With php-fpm (or other unix sockets):

                fastcgi_pass unix:/var/run/php/php7.4-fpm.sock;

                # With php-cgi (or other tcp sockets):

                fastcgi_pass 127.0.0.1:9000;

        }

Please note that I tested this solution with Ubuntu 20 while this blog is about Debian 10. You may have to replace /var/run/php/php7.4-fpm.sock by /var/run/php7.3-fpm.sock. To find out, do an

ls /var/run/php/php7.*

Then install the server-side php code that is needed by this block:

apt-get install php-fpm

Then nginx did not start any longer:

root@ubuntu:/etc/nginx# service nginx restart

Job for nginx.service failed because the control process exited with error code.

See "systemctl status nginx.service" and "journalctl -xe" for details.

Let's find out why:

root@ubuntu:/etc/nginx# systemctl status nginx.service

● nginx.service - A high performance web server and a reverse proxy server

     Loaded: loaded (/lib/systemd/system/nginx.service; enabled; vendor preset: enabled)

     Active: failed (Result: exit-code) since Sun 2020-12-27 07:16:03 PST; 9s ago

       Docs: man:nginx(8)

    Process: 12741 ExecStartPre=/usr/sbin/nginx -t -q -g daemon on; master_process on; (code=exited, status=1/FAILURE)

Dec 27 07:16:03 ubuntu systemd[1]: Starting A high performance web server and a reverse proxy server...

Dec 27 07:16:03 ubuntu nginx[12741]: nginx: [emerg] "fastcgi_pass" directive is duplicate in /etc/nginx/sites-enabled/default:62

Dec 27 07:16:03 ubuntu nginx[12741]: nginx: configuration file /etc/nginx/nginx.conf test failed

Dec 27 07:16:03 ubuntu systemd[1]: nginx.service: Control process exited, code=exited, status=1/FAILURE

Dec 27 07:16:03 ubuntu systemd[1]: nginx.service: Failed with result 'exit-code'.

Dec 27 07:16:03 ubuntu systemd[1]: Failed to start A high performance web server and a reverse proxy server.

Looking into this, I find out that /etc/nginx/sites-enabled/default is a symbolic link to /etc/nginx/sites-available/default and both files are sourced, so it is no wonder that the fastcgi_pass directive is duplicate. So I delete the link:

root@ubuntu:/etc/nginx/sites-enabled# rm default

Now nginx starts again, but does not open port 80

copied default, removed line 62, and it worked.

Now I copy mediawiki software to /var/www/html/wiki and point the browser to localhost/wiki/index.php. It tells me it needs the php extensions mbstring and xml.

apt-get install php-mbstring

apt-get install php7.4-xml

Now mediawiki tells me it is ready for installation

Next issue: 403 Forbidden

On the next day I got the next issue - I got a 403 Forbidden when I try to access /wiki:

Solution: don't go to localhost/wiki, go to localhost/wiki/index.php

Next issue: CamelCase

Now it was time to install my extension adaptivethumb:

cd /var/www/html/wiki/extensions

wget --no-check-certificate https://github.com/tstaerk/adaptivethumb/archive/master.zip

unzip master.zip

mv adaptivethumb-master adaptivethumb

Now adding to LocalSettings.php

wfLoadExtension ( 'AdaptiveThumb ' );

makes that the whole wiki does not work any longer. You have to add 

wfLoadExtension ( 'adaptivethumb' );

instead.

But the installation guide on https://www.mediawiki.org/wiki/Extension:AdaptiveThumb says you have to use CamelCase. And this guide is auto-generated, so I renamed my github project from adaptivethumb to AdaptiveThumb

Next issue: git

Now I learned how to use git. First I created a public key:

ssh-keygen -t rsa

Then I uploaded this to github, now I could get the repository to my local machine using the command

git clone git@github.com:tstaerk/adaptivethumb.git

And I could git commit and push from there.

Next issue: debugging output

Sometimes when you debug a program, you need output like "what value has variable xyz". For this, php has the error_log functionality. It outputs your message (mostly) to a file. To find out what file, use phpinfo(). For me, phpinfo() delivered "no value" for error_log. I changed the config file and restarted php-fpm using the commands

service php7.4-fpm stop

service php7.4-fpm start

Then, phpinfo pointed to a file. Then, I could use

    error_log("test from adaptivethumb\n",3,"/tmp/errors2");

to log errors to /tmp/errors2

So I found out that $wgAllowExternalImages is false using 

    if ($wgAllowExternalImages) error_log("wgallow is true",3,"/tmp/errors2");

    else error_log("wgallow is false",3,"/tmp/errors2");

Next issue: wgAllowExternalImages

The next issue was that 

<pic src="mindmap.jpg" width=30% align=text caption="this is a mindmap" />

was not possible if $wgAllowExternalImAges was set to false, so I submitted a code change: https://github.com/tstaerk/AdaptiveThumb/commit/4d1a9a9a7bd446e3c9426eb6f14bbe0569998d4c