Add first attempt at version_check PHP script

server/version_check.php

@@ -0,0 +1,145 @@
+<?php
+
+/**
+ * Version upgrade path manager for SyncTrayzor
+ * 
+ * Clients request this with their current version, arch, and variant (portable, etc)
+ * and this gives them a version to upgrade to (if any), along with the method of
+ * ugprading to it (manual navigation to github release page, automatic silent upgrade,
+ * etc). 
+ * 
+ * $versions is a record of all of the current releases, which we might want to upgrade
+ * people to. It has the struture:
+ * [
+ *    version => [
+ *       variant => [
+ *          'url' => [
+ *             arch => 'url',
+ *             ...
+ *          ],
+ *       ],
+ *       ...
+ *       'release_notes' => release_notes,
+ *    ],
+ *    ...
+ * ]
+ *
+ * version: version string e.g. '1.2.3'
+ * variant: e.g. 'portable', 'installed'. Matched against the variant provided by the
+ *          client, or '*' can be used to specify a default.
+ * arch:    e.g. 'x86', 'x64'. Matched against the arch provided by the client, or '*'
+ *          can used to specify a default.
+ * release_notes: Release notes to display to the user.
+ * 
+ * $upgrades is a map of old_version => new_version, and specifies the formatter to
+ * use to communicate with old_version. It also allows various overrides to be
+ * specified (e.g. release notes)
+ * It has the structure:
+ * [
+ *    old_version => ['to' => new_version, 'formatter' => formatter_version, 'overrides' => [overrides]],
+ *    ...
+ * ]
+ *
+ * old_version: version being upgraded from
+ * new_version: version to upgrade ot
+ * formatter_version: formatter version to use (in $response_formatters)
+ * overrides: optional overrides, used by the formatter
+ */
+
+set_error_handler('error_handler');
+
+function error_handler($severity, $message, $filename, $lineno)
+{
+   throw new ErrorException($message, 0, $severity, $filename, $lineno);
+}
+
+function get_with_wildcard($src, $value, $default = null)
+{
+   if (isset($src[$value]))
+      return $src[$value];
+   if (isset($src['*']))
+      return $src['*'];
+   return $default;
+}
+
+$versions = [
+   '1.2.4' => [
+      '*' => [
+         'url' => ['*' => 'http://www.google.co.uk'],
+      ],
+      'release_notes' => "These\nare some release notes",
+   ],
+];
+
+$upgrades = [
+   '1.2.3' => ['to' => '1.2.4', 'formatter' => '1'],
+];
+
+$response_formatters = [
+   '1' => function($arch, $variant, $to_version, $to_version_info, $overrides)
+   {
+      $variant_info = get_with_wildcard($to_version_info, $variant);
+      $url = get_with_wildcard($variant_info['url'], $arch);
+
+      $data = [];
+      if ($url != null)
+      {
+	 $data = [
+	    'version' => $to_version,
+	    'url' => $url,
+	    'release_notes' => isset($overrides['release_notes']) ? $overrides['release_notes'] : $to_version_info['release_notes'],
+	 ];
+      }
+
+      return $data;
+   },
+];
+
+$error = null;
+$loggable_error = null;
+$data = null;
+
+try
+{
+   $version = isset($_GET['version']) ? $_GET['version'] : null;
+   $arch = isset($_GET['arch']) ? $_GET['arch'] : null;
+   $variant = isset($_GET['variant']) ? $_GET['variant'] : null;
+
+
+   if (empty($version) || empty($arch) || empty($variant))
+   {
+      $error = ['code' => 1, 'message' => 'version, arch, or variant not specified'];
+   }
+   else if (isset($upgrades[$version]))
+   {
+      $to_version = $upgrades[$version]['to'];
+      $formatter = $response_formatters[$upgrades[$version]['formatter']];
+      $overrides = isset($upgrades[$version]['overrides']) ? $upgrades[$version]['overrides'] : [];
+      $to_version_info = $versions[$to_version];
+
+      $data = $formatter($arch, $variant, $to_version, $to_version_info, $overrides);
+   }
+}
+catch (Exception $e)
+{
+   $error = ['code' => 2, 'message' => 'Unhandled error. Please try again later'];
+   $loggable_error = $e->getMessage() . "\n" . $e->getTraceAsString();
+}
+
+$rsp = [];
+if ($data != null)
+   $rsp['data'] = $data;
+if ($error != null)
+   $rsp['error'] = $error;
+
+$output = json_encode($rsp, JSON_UNESCAPED_SLASHES | JSON_FORCE_OBJECT);
+
+$date = date('c');
+$log_msg = "$date\t{$_SERVER['REMOTE_ADDR']}\t$version\t$arch\t$variant\t$output\t$loggable_error\n";
+
+$fp = fopen('log.txt', 'a+');
+flock($fp, LOCK_EX);
+fputcsv($fp, [$date, $_SERVER['REMOTE_ADDR'], $version, $arch, $variant, $output, $loggable_error]);
+fclose($fp);
+
+echo $output;