create schema on first use. fixes #9

Author: restena-sw

README.md

@@ -48,29 +48,16 @@ Then you need to copy config-templates/module_webauthn.php to your config direct
 Using storage
 -------------
 
-You first need to setup the database. 
+The database schema sets itself up on first use automatically. The schema can be
+found in the sources at src/WebAuthN/Store/Database.php (__construct).
 
-Here is the initialization SQL script:
+If you want to trim down permissions for the database user, here is the minimal
+set of required permissions:
 
 ```sql
-CREATE TABLE credentials (
-    creation_date TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
-    user_id VARCHAR(80) NOT NULL,
-    credentialId VARCHAR(500) NOT NULL,
-    credential MEDIUMBLOB NOT NULL,
-    algo INT DEFAULT NULL,
-    signCounter INT NOT NULL,
-    friendlyName VARCHAR(100) DEFAULT "Unnamed Token",
-    UNIQUE (user_id,credentialId)
-);
 
 GRANT SELECT,INSERT,UPDATE,DELETE ON ...credentials TO '...dbuser'@'1.2.3.4' IDENTIFIED BY '...dbpass';
 
-CREATE TABLE userstatus (
-    user_id VARCHAR(80) NOT NULL,
-    fido2Status ENUM("FIDO2Disabled","FIDO2Enabled") NOT NULL DEFAULT "FIDO2Disabled",
-    UNIQUE (user_id)
-);
 
 GRANT SELECT ON ...userstatus TO '...dbuser'@'1.2.3.4' IDENTIFIED BY '...dbpass';
 ```

src/WebAuthn/Store/Database.php

@@ -54,6 +54,22 @@ public function __construct(array $config)
         parent::__construct($config);
         $this->config = $config;
         $this->db = \SimpleSAML\Database::getInstance(Configuration::loadFromArray($config));
+        $this->db->write("SET sql_notes = 0"); // ignore the warning "already exists"
+        $this->db->write("CREATE TABLE IF NOT EXISTS credentials (
+            creation_date TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
+            user_id VARCHAR(80) NOT NULL,
+            credentialId VARCHAR(500) NOT NULL,
+            credential MEDIUMBLOB NOT NULL,
+            algo INT DEFAULT NULL,
+            signCounter INT NOT NULL,
+            friendlyName VARCHAR(100) DEFAULT 'Unnamed Token',
+            UNIQUE (user_id,credentialId)
+            );");
+        $this->db->write("CREATE TABLE IF NOT EXISTS userstatus (
+            user_id VARCHAR(80) NOT NULL,
+            fido2Status ENUM('FIDO2Disabled','FIDO2Enabled') NOT NULL DEFAULT 'FIDO2Disabled',
+            UNIQUE (user_id)
+            );");
     }
 
     /**