Allow the OEM config to be provided as JSON files

Signed-off-by: Morris Jobke <hey@morrisjobke.de>

.gitignore

@@ -0,0 +1 @@
+config/*.json

README.md

@@ -1,3 +1,31 @@
 # Nextcloud Client Updater Server
 
-This is the Nextcloud client update server.
+This is the Nextcloud client update server.
+
+## Ship config of other OEMs
+
+Just create a json file in `config/` with the name of the OEM that contains the same entries as the `config.php`.
+
+If the default `config.php` doesn't hold update information for this OEM, the config is read from the JSON file.
+
+```json
+{
+  "linux": {
+    "version": "2.3.2",
+    "versionstring": "Nextcloud Client 2.3.2",
+    "web": "https://nextcloud.com/install/?pk_campaign=clientupdate#install-clients"
+  },
+  "win32": {
+    "version": "2.3.2.1",
+    "versionstring": "Nextcloud Client 2.3.2 (build 1)",
+    "downloadUrl": "https://download.nextcloud.com/desktop/releases/Windows/Nextcloud-2.3.2.1-setup.exe",
+    "web": "https://nextcloud.com/install/?pk_campaign=clientupdate#install-clients"
+  },
+  "macos": {
+    "version": "2.2.4.1",
+    "versionstring": "Nextcloud Client 2.2.4 (build 1)",
+    "downloadUrl": "https://download.nextcloud.com/desktop/releases/Mac/Updates/Nextcloud-2.2.4.1.pkg.tbz",
+    "signature": "MCwCFGC3X/fejC/y/3T2X+c8ldDk7pJGAhQoR8v6vtvvV57nIcMNePA+jNRYcw=="
+  }
+}
+```

src/Response.php

@@ -60,7 +60,25 @@ class Response {
 	 */
 	private function getUpdateVersion() : array {
 		if(!isset($this->config[$this->oem])) {
-			return [];
+			if (preg_match('/^[a-zA-Z0-9-_.]+$/', $this->oem) !== 1) {
+				return [];
+			}
+
+			if (!file_exists(__DIR__ . '/../config/' . $this->oem . '.json')) {
+				return [];
+			}
+
+			$content = file_get_contents(__DIR__ . '/../config/' . $this->oem . '.json');
+			if ($content === false) {
+				return [];
+			}
+			$data = json_decode($content, true);
+
+			if (!is_array($data)) {
+				return [];
+			}
+
+			$this->config[$this->oem] = $data;
 		}
 
 		if(!isset($this->config[$this->oem][$this->platform])) {