Check PHP version and display error message

.gitignore

@@ -2,3 +2,4 @@ out/
 node_modules/
 vendor/
 composer.lock
+typings/

package.json

@@ -50,6 +50,7 @@
     "vscode": "^0.11.17"
   },
   "dependencies": {
+    "semver": "^5.3.0",
     "vscode-languageclient": "^2.4.2-next.13"
   }
 }

src/extension.ts

@@ -1,16 +1,39 @@
 'use strict';
 
 import * as path from 'path';
-import { spawn } from 'child_process';
-import { ExtensionContext } from 'vscode';
-import { LanguageClient, LanguageClientOptions } from 'vscode-languageclient';
+import { spawn, execFile, ChildProcess } from 'child_process';
+import * as vscode from 'vscode';
+import { LanguageClient, LanguageClientOptions, StreamInfo } from 'vscode-languageclient';
+import * as semver from 'semver';
 
-export function activate(context: ExtensionContext) {
+export function activate(context: vscode.ExtensionContext) {
 
+    // Check if PHP is available and version is ^7.0.0
+    execFile('php', ['--version'], (err: NodeJS.ErrnoException, stdout: Buffer, stderr: Buffer) => {
+
+        if (err) {
+            if (err.code === 'ENOENT') {
+                vscode.window.showErrorMessage('PHP executable not found. You need PHP 7 installed and in your PATH');
+            } else {
+                vscode.window.showErrorMessage('Error spawning PHP: ' + err.message);
+                console.error(err);
+            }
+            return;
+        }
+
+        let version = stdout.toString().match(/^PHP ([^\s]+)/)[1];
+        // Convert PHP prerelease format like 7.0.0rc1 to 7.0.0-rc1
+        if (!/^\d+.\d+.\d+$/.test(version)) {
+            version = version.replace(/(\d+.\d+.\d+)/, '$1-');
+        }
+        if (!semver.satisfies(version, '^7.0.0')) {
+            vscode.window.showErrorMessage('The language server needs at least PHP 7 installed and in your PATH. Version found: ' + version);
+            return;
+        }
+
+        const serverOptions = (): Promise<ChildProcess | StreamInfo> => {
             // The server is implemented in PHP
             const serverPath = context.asAbsolutePath(path.join('vendor', 'felixfbecker', 'language-server', 'bin', 'php-language-server.php'));
-
-    const serverOptions = () => {
             const childProcess = spawn('php', [serverPath]);
             childProcess.stderr.on('data', (chunk: Buffer) => {
                 console.error(chunk + '');
@@ -39,4 +62,5 @@ export function activate(context: ExtensionContext) {
         // Push the disposable to the context's subscriptions so that the
         // client can be deactivated on extension deactivation
         context.subscriptions.push(disposable);
+    });
 }

tsconfig.json

@@ -5,6 +5,7 @@
 		"moduleResolution": "node",
 		"outDir": "out",
 		"noLib": true,
+    "noImplicitAny": true,
 		"sourceMap": true,
     "rootDir": "src"
 	},

typings.json

@@ -0,0 +1,5 @@
+{
+  "dependencies": {
+    "semver": "registry:npm/semver#5.0.0+20160723033700"
+  }
+}