Glad-I-Was-Here (PHP, Postgresql)

This version of the Glad-I-Was-Here guestbook App also uses PHP, but chooses Postgresql instead of Mariadb as its database.

If you have not already read through Glad-I-Was-Here (PHP, Mariadb), we recommend you do so first as we’ll only discuss things in this section that were not covered before.

To obtain the source code:

% git clone https://gitlab.com/ubos/ubos-toyapps

Go to subdirectory gladiwashere-php-postgresql.

Package lifecycle and App deployment

Like all other Apps on UBOS including Hello World, gladiwashere-php-postgresql is built with makepkg, installed with pacman and deployed with ubos-admin:

% makepkg -f
% sudo pacman -U gladiwashere-php-postgresql-*-any.pkg.tar.xz
% sudo ubos-admin createsite

Specify gladiwashere-php-postgresql as the name of the App.

Manifest JSON

Let’s examine this App’s UBOS Manifest file. It is identical to that of gladiwashere-php-mysql, with the following differences:

• It declares a different defaultcontext so you can run both the MySQL and the Postgresql version of this App at the same time on the same device with their respective default context URL, which is different from each.

• It specifies the postgresql role instead of the mysql role, to use Postgresql instead of MySQL.

• It uses Postgresql database drivers to access Postgresql from PHP.

{
  "type" : "app",

  "roles" : {
    "apache2" : {
      "defaultcontext" : "/guestbook-postgresql",
      "depends" : [
        "php",
        "php-apache",
        "php-pgsql"
      ],
      "apache2modules" : [
        "php7"
      ],
      "phpmodules" : [
        "pgsql"
      ],
      "appconfigitems" : [
        {
          "type"         : "file",
          "name"         : "index.php",
          "source"       : "web/index.php",
        },
        {
          "type"         : "file",
          "name"         : "config.php",
          "template"     : "tmpl/config.php.tmpl",
          "templatelang" : "varsubst"
        },
        {
          "type"         : "symlink",
          "name"         : "gladiwashere.php",
          "source"       : "web/gladiwashere.php"
        }
      ]
    },
    "postgresql" : {
      "appconfigitems" : [
        {
          "type"             : "database",
          "name"             : "maindb",
          "retentionpolicy"  : "keep",
          "retentionbucket"  : "maindb",
          "privileges"       : "select, insert"
        }
      ],
      "installers" : [
        {
          "name"   : "maindb",
          "type"   : "sqlscript",
          "source" : "sql/create.sql"
        }
      ]
    }
  }
}

• phpmodules lists the PHP modules that the App requires. In this case, it needs Postgresql drivers, and not MySQL drivers.

• By specifying the role postgresql instead of mysql in the lower part of the manifest file, UBOS knows that the database to be provisioned (and backed up, restored etc.) is supposed to be a Postgresql database.

• Correspondingly, in the config.php.tmpl the variables refer to Postgresql:

  <?php
  $dbName   = '${appconfig.postgresql.dbname.maindb}';
  $dbUser   = '${appconfig.postgresql.dbuser.maindb}';
  $dbPass   = '${escapeSquote( appconfig.postgresql.dbusercredential.maindb )}';
  $dbServer = '${appconfig.postgresql.dbhost.maindb}';