Use SQLite as default DB; added migration instructions

README.md

@@ -21,13 +21,14 @@ See the real world example at [Pantsu.cat](https://pantsu.cat/).
 
 ## Requirements
 
-Original development environment is Nginx + PHP5.5 + MySQL, but is confirmed to
+Original development environment is Nginx + PHP5.5 + SQLite, but is confirmed to
 work with Apache 2.4 and newer PHP versions. Should work with any other
-PDO-compatible database.
+PDO-compatible database.  Is known to work with MySQL, which has been the previous
+default.
 
 ## Install
 
-For the purposes of this guide, we won't cover setting up Nginx, PHP, MySQL,
+For the purposes of this guide, we won't cover setting up Nginx, PHP, or SQLite,
 Node, or NPM. So we'll just assume you already have them all running well.
 
 ### Compiling
@@ -47,6 +48,15 @@ After this, the pomf site is now compressed and set up inside `dist/`.
 
 ## Configuring
 
+We need to create the SQLite database before it may be used by pomf.
+Fortunately, this is incredibly simple.  
+
+To create it from the schema, simply run `sqlite3 /path/to/db.sq3 -init /path/to/pomf/sqlite_schema.sql`,
+obviously ensuring the paths are correct.  Using default paths, this would be
+`sqlite3 /usr/share/nginx/pomf.sq3 -init /usr/share/nginx/html/sqlite_schema.sql`.
+
+_NOTE: The **directory** where the SQLite database is stored, must be writable by the user the web server is running as_
+
 The majority of the settings are in `static/includes/settings.inc.php`.
 
 For file size configuration, open `Gruntfile.js` in an editor and modify the
@@ -62,6 +72,52 @@ A best practice is to disable executing `.php` files on the `POMF_URL` domain
 for uploaded files. This assures that a malicious user cannot execute arbitrary
 PHP code on the server.
 
+### Migrating from MySQL to SQLite
+
+Previously, we have used MySQL as the default database platform for pomf.  Generally this
+is undesirable.  
+
+MySQL is relatively complicated to administer, brings in many unneeded dependencies, and consumes
+more resources than SQLite would.  Additonally, poorly configured installations have the potential
+to pose a security risk.
+
+Fortunately, it is incredibly simple to migrate your database.  This may be done on a live server, and should require
+zero downtime.
+
+**Note: some directories that were initally in the web root, are now in static/php/.  Ensure you consider this when reading the following**
+
+*You may test this first in a subdirectory (or vhost, or equivelant) if you wish.  If you make a mistake, however, only uploading will temporarily be impacted.  None of these steps are destructive, and are easily reverted.*
+
+Make a copy of the file `static/php/includes/settings.inc.php`, and edit it, making the changes outlined below.  Note where you save it.
+```php
+define('POMF_DB_CONN', '[stuff]'); ---> define('POMF_DB_CONN', 'sqlite:/usr/share/nginx/pomf.sq3');`
+define('POMF_DB_USER', '[stuff]'); ---> define('POMF_DB_USER', null);
+define('POMF_DB_PASS', '[stuff]'); ---> define('POMF_DB_PASS', null);
+```
+
+The following script will make a dump of the MySQL database, convert it to a format acceptable for SQLite, then initialise a new SQLite database with the contents of the dump.  It will then backup your existing `settings.inc.php` file, and move the new one into place.
+```bash
+#!/bin/bash
+# ensure you change these to match your environment
+OLD_DB_USER=pomf
+OLD_DB_PASS=pass
+SETTINGS_INC_FILE='/usr/share/nginx/html/static/php/includes/settings.inc.php'
+NEW_SETTINGS_INC_FILE='/path/to/edited/file'
+# it is unlikely the following two need to be changed
+OLD_DB_NAME=pomf
+NEW_DB_PATH='/usr/share/nginx/pomf.sq3'
+
+wget -O /tmp/m2s https://github.com/dumblob/mysql2sqlite/raw/master/mysql2sqlite.sh
+mysqldump -u $OLD_DB_USER -p $OLD_DB_PASS $OLD_DB_NAME | sh /tmp/m2s | sqlite3 $NEW_DB_PATH
+rm /tmp/m2s
+echo == SQLite database has been prepared at $NEW_DB_PATH ==
+cp $SETTINGS_INC_FILE ${SETTINGS_INC_FILE}.bak
+mv $TMP_SETTINGS_INC_FILE $SETTINGS_INC_FILE
+echo == Backed up old settings.inc.file, and moved new one into place ==
+```
+
+Ensure you are able to upload files, and then, all done!  You may now uninstall, or disable. MySQL if you wish.
+
 ### Apache
 
 If you are running Apache and want to compress your output when serving files,

sqlite_schema.sql

@@ -0,0 +1,16 @@
+PRAGMA synchronous = OFF;
+PRAGMA journal_mode = MEMORY;
+BEGIN TRANSACTION;
+CREATE TABLE `files` (
+  `id` integer  NOT NULL PRIMARY KEY AUTOINCREMENT
+,  `hash` char(40) default NULL
+,  `originalname` varchar(255) default NULL
+,  `filename` varchar(30) default NULL
+,  `size` integer  default NULL
+,  `date` date default NULL
+,  `expire` date default NULL
+,  `delid` char(40) default NULL
+,  `user` integer  default '0'
+,  `dir` integer default '0'
+);
+END TRANSACTION;

static/php/includes/settings.inc.php

@@ -37,16 +37,23 @@
  * PDO_MYSQL DSN.
  * @param string POMF_DB_CONN DSN:host|unix_socket=hostname|path;dbname=database
  */
+ /* example MySQL DSN
 define('POMF_DB_CONN', 'mysql:unix_socket=/tmp/mysql.sock;dbname=pomf');
+*/
+/* NOTE: the directory, not just the file, your database is stored in must 
+   be writable by the web server user
+*/
+define('POMF_DB_CONN', 'sqlite:/usr/share/nginx/pomf.sq3');
 
 /**
  * PDO database login credentials
+ * NOTE: not necessary for SQLite; these variables are ignored if SQLite is used
  */
 
-/** @param string POMF_DB_NAME Database username */
-define('POMF_DB_USER', 'pomf');
-/** @param string POMF_DB_PASS Database password */
-define('POMF_DB_PASS', '***');
+/** @param string|null POMF_DB_NAME Database username */
+define('POMF_DB_USER', null);
+/** @param string|null POMF_DB_PASS Database password */
+define('POMF_DB_PASS', null);
 
 /**
  * File system location where to store uploaded files