Add glue for dbconfig-common configuration

dist/debian/.gitignore

@@ -6,6 +6,8 @@
 !copyright
 !lintian-overrides
 !rules
+!config.php
+!dbconfig-common.php
 
 !source/
 source/*

dist/debian/arsse.install

@@ -8,10 +8,11 @@ UPGRADING usr/share/arsse/
 README.md usr/share/arsse/
 arsse.php usr/share/arsse/
 
-dist/debian/bin/arsse usr/bin/
+config.defaults.php            etc/arsse/
 manual                         usr/share/doc/arsse/
 dist/man/*                     usr/share/man/
 dist/nginx                     etc/arsse/
 dist/apache                    etc/arsse/
-dist/config.php       etc/arsse
-config.defaults.php   etc/arsse/
+dist/debian/config.php         etc/arsse/
+dist/debian/dbconfig-cmmon.php usr/share/arsse/
+dist/debian/bin/arsse          usr/bin/

dist/debian/config.php

@@ -0,0 +1,15 @@
+<?php
+/***
+    Please refer to config.defaults.php or the manual at /usr/share/doc/arsse/
+    for possible configuration parameters.
+
+    The last line includes database auto-configuration information which
+    Debian may have created during installation; any database-related 
+    configuration defined in this file will override anything defined in the 
+    included file.
+***/
+
+return [
+    'dbAutoUpdate' => true,
+]
++ (@include "/usr/share/arsse/dbconfig-common.php");

dist/debian/dbconfig-common.php

@@ -0,0 +1,44 @@
+<?php
+
+# This script transforms Debian's dbconfig-common's PHP-format include files
+# into a form usable by The Arsse. This is necessary because The Arsse
+# supports defining configuration parameters for all supported database types
+# at once, using separate keys for the different types
+
+$dbconfpath = "/var/lib/arsse/dbconfig.inc"; // path defined in postinst script
+
+if (file_exists($dbconfpath)) {
+    require_once "/var/lib/arsse/dbconfig.inc";
+    $dbtype = $dbtype ?? "";
+    // the returned configuration depends on the $dbtype
+    if ($dbtype === "sqlite3") {
+        $conf = ['dbDriver' => "sqlite3"];
+        if (strlen((string) $basepath) && strlen((string) $dbname)) {
+            $conf['dbSQLite3File'] = "$basepath/$dbname";
+        }
+    } elseif ($dbtype === "pgsql") {
+        $conf = [
+            'dbDriver' => "postgresql",
+            'dbPostgreSQLHost' => $dbserver ?? "",
+            'dbPostgreSQLUser' => $dbuser ?? "arsse",
+            'dbPostgreSQLPass' => $dbpass ?? "",
+            'dbPostgreSQLPort' => $dbport ?? 5432,
+            'dbPostgreSQLDb'   => $dbname ?? "arsse",
+        ];
+    } elseif ($dbtype === "mysql") {
+        $conf = [
+            'dbDriver' => "mysql",
+            'dbMySQLHost' => $dbserver ?? "",
+            'dbMySQLUser' => $dbuser ?? "arsse",
+            'dbMySQLPass' => $dbpass ?? "",
+            'dbMySQLPort' => $dbport ?? 3306,
+            'dbMySQLDb'   => $dbname ?? "arsse",
+        ];
+    } else {
+        throw new \Exception("Debian dbconfig-common configuration file $dbconfpath is invalid");
+    }
+    return $conf;
+} else {
+    // if not configuration file exists simply return an empty array
+    return [];
+}