Promisify solc-js downloader

Author: r0qs

downloadCurrentVersion.ts

@@ -3,73 +3,26 @@
 // This is used to download the correct binary version
 // as part of the prepublish step.
 
-import * as fs from 'fs';
-import { https } from 'follow-redirects';
-import MemoryStream from 'memorystream';
-import { keccak256 } from 'js-sha3';
+import downloader from './downloader';
 const pkg = require('./package.json');
 
-function getVersionList (cb) {
-  console.log('Retrieving available version list...');
-
-  const mem = new MemoryStream(null, { readable: false });
-  https.get('https://binaries.soliditylang.org/bin/list.json', function (response) {
-    if (response.statusCode !== 200) {
-      console.log('Error downloading file: ' + response.statusCode);
-      process.exit(1);
+async function download () {
+  try {
+    const list = JSON.parse(await downloader.getVersionList());
+    const wanted = pkg.version.match(/^(\d+\.\d+\.\d+)$/)[1];
+    const releaseFileName = list.releases[wanted];
+    const expectedFile = list.builds.filter(function (entry) { return entry.path === releaseFileName; })[0];
+    if (!expectedFile) {
+      throw new Error('Requested version not found. Version list is invalid or corrupted?');
     }
-    response.pipe(mem);
-    response.on('end', function () {
-      cb(mem.toString());
-    });
-  });
-}
-
-function downloadBinary (outputName, version, expectedHash) {
-  console.log('Downloading version', version);
-
-  // Remove if existing
-  if (fs.existsSync(outputName)) {
-    fs.unlinkSync(outputName);
-  }
-
-  process.on('SIGINT', function () {
-    console.log('Interrupted, removing file.');
-    fs.unlinkSync(outputName);
+    const expectedHash = expectedFile.keccak256;
+    await downloader.downloadBinary('soljson.js', releaseFileName, expectedHash);
+    process.exit();
+  } catch (err) {
+    console.log(err.message);
     process.exit(1);
-  });
-
-  const file = fs.createWriteStream(outputName, { encoding: 'binary' });
-  https.get('https://binaries.soliditylang.org/bin/' + version, function (response) {
-    if (response.statusCode !== 200) {
-      console.log('Error downloading file: ' + response.statusCode);
-      process.exit(1);
-    }
-    response.pipe(file);
-    file.on('finish', function () {
-      file.close(function () {
-        const hash = '0x' + keccak256(fs.readFileSync(outputName, { encoding: 'binary' }));
-        if (expectedHash !== hash) {
-          console.log('Hash mismatch: ' + expectedHash + ' vs ' + hash);
-          process.exit(1);
-        }
-        console.log('Done.');
-      });
-    });
-  });
+  }
 }
 
 console.log('Downloading correct solidity binary...');
-
-getVersionList(function (list) {
-  list = JSON.parse(list);
-  const wanted = pkg.version.match(/^(\d+\.\d+\.\d+)$/)[1];
-  const releaseFileName = list.releases[wanted];
-  const expectedFile = list.builds.filter(function (entry) { return entry.path === releaseFileName; })[0];
-  if (!expectedFile) {
-    console.log('Version list is invalid or corrupted?');
-    process.exit(1);
-  }
-  const expectedHash = expectedFile.keccak256;
-  downloadBinary('soljson.js', releaseFileName, expectedHash);
-});
+download();

downloader.ts

@@ -0,0 +1,64 @@
+import * as fs from 'fs';
+import { https } from 'follow-redirects';
+import MemoryStream from 'memorystream';
+import { keccak256 } from 'js-sha3';
+
+function getVersionList () {
+  console.log('Retrieving available version list...');
+
+  return new Promise<string>((resolve, reject) => {
+    const mem = new MemoryStream(null, { readable: false });
+    https.get('https://binaries.soliditylang.org/bin/list.json', function (response) {
+      if (response.statusCode !== 200) {
+        reject(new Error('Error downloading file: ' + response.statusCode));
+      }
+      response.pipe(mem);
+      response.on('end', function () {
+        resolve(mem.toString());
+      });
+    }).on('error', (err) => {
+      reject(err);
+    });
+  });
+}
+
+function downloadBinary (outputName, version, expectedHash) {
+  console.log('Downloading version', version);
+
+  return new Promise<void>((resolve, reject) => {
+    // Remove if existing
+    if (fs.existsSync(outputName)) {
+      fs.unlinkSync(outputName);
+    }
+
+    process.on('SIGINT', function () {
+      fs.unlinkSync(outputName);
+      reject(new Error('Interrupted, removing file.'));
+    });
+
+    const file = fs.createWriteStream(outputName, { encoding: 'binary' });
+    https.get('https://binaries.soliditylang.org/bin/' + version, function (response) {
+      if (response.statusCode !== 200) {
+        reject(new Error('Error downloading file: ' + response.statusCode));
+      }
+      response.pipe(file);
+      file.on('finish', function () {
+        file.close();
+        const hash = '0x' + keccak256(fs.readFileSync(outputName, { encoding: 'binary' }));
+        if (expectedHash !== hash) {
+          reject(new Error('Hash mismatch: ' + expectedHash + ' vs ' + hash));
+        } else {
+          console.log('Done.');
+          resolve();
+        }
+      });
+    }).on('error', (err) => {
+      reject(err);
+    });
+  });
+}
+
+export = {
+  getVersionList,
+  downloadBinary
+};