add checksum validation

src/lib/download-manager.js

@@ -3,6 +3,7 @@ const fs = require('fs-extra');
 const path = require('path');
 const fetch = require('node-fetch');
 const UI = require('./ui');
+const crypto = require('crypto');
 
 class DownloadManager {
 	/**
@@ -45,10 +46,11 @@ class DownloadManager {
 		}
 	}
 
-	async _downloadFile(fileUrl, outputFileName) {
+	async _downloadFile(fileUrl, outputFileName, expectedChecksum) {
 		const tempFilePath = path.join(this._tempDir, outputFileName);
 		const finalFilePath = path.join(this._downloadDir, outputFileName);
 		const baseUrl = this.channel.url;
+		const progressBar = this.ui.createProgressBar();
 		const url = `${baseUrl}/${fileUrl}`;
 		// TODO (hmontero): Implement cache for downloaded files
 		const cachedFile = await this.getCachedFile(outputFileName);
@@ -61,7 +63,7 @@ class DownloadManager {
 			let downloadedBytes = 0;
 			if (fs.existsSync(tempFilePath)) {
 				downloadedBytes = fs.statSync(tempFilePath).size;
-				this.ui.write(`Resuming download from byte ${downloadedBytes}`);
+				this.ui.write(`Resuming download file: ${outputFileName}`);
 			}
 
 			const headers = downloadedBytes > 0 ? { Range: `bytes=${downloadedBytes}-` } : {};
@@ -70,20 +72,42 @@ class DownloadManager {
 			if (!response.ok && response.status !== 206) {
 				throw new Error(`Unexpected response status: ${response.status}`);
 			}
-
+			const totalBytes = parseInt(response.headers.get('content-length') || '0', 10);
+			if (progressBar && totalBytes) {
+				progressBar.start(totalBytes, downloadedBytes, { description: `Downloading ${outputFileName} ...` });
+			}
 			const writer = fs.createWriteStream(tempFilePath, { flags: 'a' });
 			await new Promise((resolve, reject) => {
+				const hash = crypto.createHash('sha256');
+				response.body.on('data', (chunk) => {
+					downloadedBytes += chunk.length;
+					hash.update(chunk);
+					if (progressBar) {
+						progressBar.increment(chunk.length);
+					}
+				});
 				response.body.pipe(writer);
 				response.body.on('error', reject);
-				writer.on('finish', resolve);
+				writer.on('finish', async () => {
+					const fileChecksum = hash.digest('hex');
+					if (expectedChecksum && fileChecksum !== expectedChecksum) {
+						// if we don't remove the file, the next time we try to download it, it will be resumed
+						await fs.remove(tempFilePath);
+						return reject(new Error(`Checksum validation failed for ${outputFileName}`));
+					}
+					resolve();
+				});
 			});
-
 			// Move temp file to final location
 			fs.renameSync(tempFilePath, finalFilePath);
 			this.ui.write(`Download completed: ${finalFilePath}`);
 		} catch (error) {
 			this.ui.error(`Error downloading file from ${url}: ${error.message}`);
 			throw error;
+		} finally {
+			if (progressBar) {
+				progressBar.stop();
+			}
 		}
 	}
 

src/lib/download-manager.test.js

@@ -100,6 +100,7 @@ describe('DownloadManager', () => {
 			ui = sinon.createStubInstance(UI, {
 				write: sinon.stub(),
 				error: sinon.stub(),
+				createProgressBar: sinon.stub(),
 			});
 			downloadManager = new DownloadManager(channel, ui);
 		});
@@ -176,6 +177,44 @@ describe('DownloadManager', () => {
 				expect(error.message).to.include('Unexpected response status: 500');
 			}
 		});
+
+		it('throws an error if checksum does not match', async () => {
+			const fileUrl = 'file.txt';
+			const outputFileName = 'file.txt';
+			const fileContent = 'This is a test file.';
+
+			// Mock the HTTP response
+			nock(channel.url)
+				.get(`/${fileUrl}`)
+				.reply(200, fileContent);
+
+			try {
+				await downloadManager._downloadFile(fileUrl, outputFileName, 'invalidchecksum');
+				throw new Error('Expected method to throw.');
+			} catch (error) {
+				expect(error.message).to.include('Checksum validation failed for file.txt');
+				const tempPath = path.join(downloadManager.tempDir, outputFileName);
+				expect(fs.existsSync(tempPath)).to.be.false;
+			}
+		});
+		it('validates checksum and save the file', async () => {
+			const fileUrl = 'file.txt';
+			const outputFileName = 'file.txt';
+			const fileContent = 'This is a test file.';
+			const checksum = 'f29bc64a9d3732b4b9035125fdb3285f5b6455778edca72414671e0ca3b2e0de';
+
+			// Mock the HTTP response
+			nock(channel.url)
+				.get(`/${fileUrl}`)
+				.reply(200, fileContent);
+
+			await downloadManager._downloadFile(fileUrl, outputFileName, checksum);
+
+			const finalFilePath = path.join(downloadManager.downloadDir, outputFileName);
+			expect(fs.existsSync(finalFilePath)).to.be.true;
+			const content = fs.readFileSync(finalFilePath, 'utf8');
+			expect(content).to.equal(fileContent);
+		});
 	});
 
 });