Download binary on npm postinstall hook

.npm/bin/index.js

@@ -18,12 +18,10 @@ function spawnCommand(binaryExecutable) {
     });
 }
 
-if (process.platform === 'darwin') {
-    spawnCommand('lefthook-mac');
-} else if (process.platform === 'linux') {
-    spawnCommand('lefthook-linux');
+if (process.platform === 'darwin' || process.platform === 'linux') {
+    spawnCommand('lefthook');
 } else if (process.platform === 'win32') {
-    spawnCommand('lefthook-win.exe');
+    spawnCommand('lefthook.exe');
 } else {
     console.log("Unsupported OS");
     process.exit(1);

.npm/postinstall.js

@@ -1,23 +1,129 @@
 require("process");
 const { spawn } = require("child_process");
-const { join } = require("path");
+const { createWriteStream, mkdirSync, unlink } = require("fs");
+const { createGunzip } = require("zlib");
+const { get } = require("https");
+const { join, resolve } = require("path");
+
+const { version } = require("./package.json");
+
+const binaryName = "lefthook";
+const packageDir = process.env.INIT_CWD || resolve(".");
+
+function closeAndRemoveFile(file) {
+  file.on("close", () => {
+    unlink(file);
+  });
+  file.close();
+}
+
+function resolveDownloadPath(os, version, arch) {
+  let archStr;
+  let osStr;
+
+  if (os === "darwin") {
+    osStr = "MacOS";
+  } else if (os === "linux") {
+    osStr = "Linux";
+  } else if (os === "win32") {
+    if (arch === "ia32" || arch === "x86") {
+      console.error("Lefthook is only supported on Windows with 64bit architecture.");
+      process.exit(0);
+    }
+    osStr = "Windows";
+  }
+
+  if (arch === "x64") {
+    archStr = "x86_64";
+  } else if (arch === "ia32" || arch === "x86") {
+    archStr = "i386";
+  } else {
+    console.error(`Unable to resolve architecture (${arch}), only supported architectures are: 'ia32', 'x86', and 'x64'`);
+    process.exit(0);
+  }
+
+  return `https://github.com/Arkweid/lefthook/releases/download/v${version}/lefthook_${version}_${osStr}_${archStr}.gz`;
+}
+
+function downloadBinary(os, callback) {
+  // construct single binary file path
+  const binaryDir = join(packageDir, "node_modules", "@arkweid", "lefthook", "bin");
+  const binaryPath = join(binaryDir, `${binaryName}${os === "win32" ? ".exe" : ""}`);
+
+  // create directory if not existing, yet
+  try {
+    mkdirSync(binaryDir);
+  } catch (err) {
+    if (err.code !== 'EEXIST') {
+      console.error(err.message);
+      process.exit(0);
+    }
+  }
+
+  // create write stream as file with the constructed binaryPath, set it
+  // up to close as soon as no more data is expected
+  const file = createWriteStream(binaryPath, { mode: 0o755 });
+  file.on("finish", () => {
+    file.close();
+  });
+  file.on("close", () => {
+    callback(binaryPath);
+  });
+
+  // start download of binary file, set it up to remove the file if an
+  // error occurs
+  const downloadPath = resolveDownloadPath(os, version, process.arch);
+  const download = get(downloadPath, downloadResponse => {
+    // handle github binary redirect
+    if (downloadResponse.statusCode === 302) {
+      const redirectDownloadPath = downloadResponse.headers.location;
+
+      const redirectDownload = get(redirectDownloadPath, redirectDownloadResponse => {
+        if (redirectDownloadResponse.statusCode === 200) {
+          const gzip = createGunzip();
+          redirectDownloadResponse.pipe(gzip).pipe(file);
+        } else {
+          console.error("Unable to download lefthook binary file from redirect");
+        }
+      });
+
+      redirectDownload.on("error", err => {
+        console.error("Unable to download lefthook binary file");
+        console.error(err.message);
+        closeAndRemoveFile(file);
+      });
+    } else if (downloadResponse.statusCode === 200) {
+      downloadResponse.pipe(file);
+      downloadResponse.on("close", () => {
+        callback(binaryPath);
+      });
+    } else {
+      console.error("Unable to download lefthook binary file: Unhandled response", downloadResponse.statusCode);
+    }
+  });
+  download.on("error", err => {
+    console.error("Unable to download lefthook binary file");
+    console.error(err.message);
+    closeAndRemoveFile(file);
+  });
+}
+
+function installGitHooks(binaryPath) {
+  console.log("Installing git hooks");
+  spawn(binaryPath, ["install", "-f"], { stdio: [process.stdin, process.stdout, process.stderr] });
+}
 
 const isCI = process.env.CI;
 if (!isCI) {
   process.chdir(process.env.INIT_CWD);
 
-  if (process.platform === 'darwin') {
-    binary = 'lefthook-mac';
-  } else if (process.platform === 'linux') {
-      binary = 'lefthook-linux';
-  } else if (process.platform === 'win32') {
-      binary = 'lefthook-win.exe';
-  } else {
+  if (!["darwin", "linux", "win32"].includes(process.platform)) {
     console.log("Unsupported OS");
     process.exit(0);
   }
 
-  binpath = join(process.cwd(), 'node_modules', '@arkweid', 'lefthook', 'bin', binary);
-
-  result = spawn(binpath, ["install", "-f"], { stdio: [process.stdin, process.stdout, process.stderr] });
+  console.log("Downloading `lefthook` binary");
+  downloadBinary(process.platform, installGitHooks);
+} else {
+  console.log("Skipping downloading of `lefthook` binary due to CI environment.");
 }