samples: download byte range (#1732)

* samples: download byte range * 🦉 Updates from OwlBot See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md Co-authored-by: Owl Bot <gcf-owl-bot[bot]@users.noreply.github.com>
googleapis · Dec 15, 2021 · 257f771 · 257f771
1 parent 29f91cb
commit 257f771
Show file tree

Hide file tree

Showing 5 changed files with 136 additions and 0 deletions.
diff --git a/README.md b/README.md
@@ -127,6 +127,7 @@ Samples are in the [`samples/`](https://github.com/googleapis/nodejs-storage/tre
 | Disable Default Event Based Hold | [source code](https://github.com/googleapis/nodejs-storage/blob/main/samples/disableDefaultEventBasedHold.js) | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-storage&page=editor&open_in_editor=samples/disableDefaultEventBasedHold.js,samples/README.md) |
 | Disable Requester Pays | [source code](https://github.com/googleapis/nodejs-storage/blob/main/samples/disableRequesterPays.js) | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-storage&page=editor&open_in_editor=samples/disableRequesterPays.js,samples/README.md) |
 | Disable Uniform Bucket Level Access | [source code](https://github.com/googleapis/nodejs-storage/blob/main/samples/disableUniformBucketLevelAccess.js) | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-storage&page=editor&open_in_editor=samples/disableUniformBucketLevelAccess.js,samples/README.md) |
+| Download Byte Range | [source code](https://github.com/googleapis/nodejs-storage/blob/main/samples/downloadByteRange.js) | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-storage&page=editor&open_in_editor=samples/downloadByteRange.js,samples/README.md) |
 | Download Encrypted File | [source code](https://github.com/googleapis/nodejs-storage/blob/main/samples/downloadEncryptedFile.js) | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-storage&page=editor&open_in_editor=samples/downloadEncryptedFile.js,samples/README.md) |
 | Download File | [source code](https://github.com/googleapis/nodejs-storage/blob/main/samples/downloadFile.js) | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-storage&page=editor&open_in_editor=samples/downloadFile.js,samples/README.md) |
 | Download File Using Requester Pays | [source code](https://github.com/googleapis/nodejs-storage/blob/main/samples/downloadFileUsingRequesterPays.js) | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-storage&page=editor&open_in_editor=samples/downloadFileUsingRequesterPays.js,samples/README.md) |

diff --git a/samples/README.md b/samples/README.md
@@ -45,6 +45,7 @@ objects to users via direct download.
   * [Disable Default Event Based Hold](#disable-default-event-based-hold)
   * [Disable Requester Pays](#disable-requester-pays)
   * [Disable Uniform Bucket Level Access](#disable-uniform-bucket-level-access)
+  * [Download Byte Range](#download-byte-range)
   * [Download Encrypted File](#download-encrypted-file)
   * [Download File](#download-file)
   * [Download File Using Requester Pays](#download-file-using-requester-pays)
@@ -618,6 +619,23 @@ __Usage:__
 
 
 
+### Download Byte Range
+
+View the [source code](https://github.com/googleapis/nodejs-storage/blob/main/samples/downloadByteRange.js).
+
+[![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-storage&page=editor&open_in_editor=samples/downloadByteRange.js,samples/README.md)
+
+__Usage:__
+
+
+`node samples/downloadByteRange.js`
+
+
+-----
+
+
+
+
 ### Download Encrypted File
 
 View the [source code](https://github.com/googleapis/nodejs-storage/blob/main/samples/downloadEncryptedFile.js).

diff --git a/samples/downloadByteRange.js b/samples/downloadByteRange.js
@@ -0,0 +1,81 @@
+/**
+ * Copyright 2021 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * This application demonstrates how to perform basic operations on buckets with
+ * the Google Cloud Storage API.
+ *
+ * For more information, see the README.md under /storage and the documentation
+ * at https://cloud.google.com/storage/docs.
+ */
+const path = require('path');
+const cwd = path.join(__dirname, '..');
+
+function main(
+  bucketName = 'my-bucket',
+  fileName = 'test.txt',
+  startByte = 0,
+  endByte = 20,
+  destFileName = path.join(cwd, 'downloaded.txt')
+) {
+  // [START storage_download_byte_range]
+  /**
+   * TODO(developer): Uncomment the following lines before running the sample.
+   */
+  // The ID of your GCS bucket
+  // const bucketName = 'your-unique-bucket-name';
+
+  // The ID of your GCS file
+  // const fileName = 'your-file-name';
+
+  // The starting byte at which to begin the download
+  // const startByte = 0;
+
+  // The ending byte at which to end the download
+  // const endByte = 20;
+
+  // The path to which the file should be downloaded
+  // const destFileName = '/local/path/to/file.txt';
+
+  // Imports the Google Cloud client library
+  const {Storage} = require('@google-cloud/storage');
+
+  // Creates a client
+  const storage = new Storage();
+
+  async function downloadByteRange() {
+    const options = {
+      destination: destFileName,
+      start: startByte,
+      end: endByte,
+    };
+
+    // Downloads the file from the starting byte to the ending byte specified in options
+    await storage.bucket(bucketName).file(fileName).download(options);
+
+    console.log(
+      `gs://${bucketName}/${fileName} downloaded to ${destFileName} from byte ${startByte} to byte ${endByte}.`
+    );
+  }
+
+  downloadByteRange();
+  // [END storage_download_byte_range]
+}
+process.on('unhandledRejection', err => {
+  console.error(err.message);
+  process.exitCode = 1;
+});
+main(...process.argv.slice(2));
diff --git a/samples/system-test/files.test.js b/samples/system-test/files.test.js
@@ -41,6 +41,8 @@ const kmsKeyName = process.env.GOOGLE_CLOUD_KMS_KEY_US;
 const filePath = path.join(cwd, 'resources', fileName);
 const folderPath = path.join(cwd, 'resources');
 const downloadFilePath = path.join(cwd, 'downloaded.txt');
+const startByte = 0;
+const endByte = 20;
 
 const fileContent = fs.readFileSync(filePath, 'utf-8');
 
@@ -202,6 +204,19 @@ describe('file', () => {
     fs.statSync(downloadFilePath);
   });
 
+  it('should download a file using a given byte range', () => {
+    const output = execSync(
+      `node downloadByteRange.js ${bucketName} ${fileName} ${startByte} ${endByte} ${downloadFilePath}`
+    );
+    assert.match(
+      output,
+      new RegExp(
+        `gs://${bucketName}/${fileName} downloaded to ${downloadFilePath} from byte ${startByte} to byte ${endByte}.`
+      )
+    );
+    fs.statSync(downloadFilePath);
+  });
+
   it('should move a file', async () => {
     const output = execSync(
       `node moveFile.js ${bucketName} ${fileName} ${movedFileName}`

diff --git a/system-test/storage.ts b/system-test/storage.ts
@@ -2310,6 +2310,9 @@ describe('storage', () => {
   });
 
   describe('write, read, and remove files', () => {
+    const FILE_DOWNLOAD_START_BYTE = 0;
+    const FILE_DOWNLOAD_END_BYTE = 20;
+
     before(async () => {
       function setHash(filesKey: string) {
         const file = FILES[filesKey];
@@ -2442,6 +2445,24 @@ describe('storage', () => {
       });
     });
 
+    it('should download the specified bytes of a file', done => {
+      const fileContents = fs.readFileSync(FILES.big.path);
+      bucket.upload(FILES.big.path, (err: Error | null, file?: File | null) => {
+        assert.ifError(err);
+        file!.download(
+          {start: FILE_DOWNLOAD_START_BYTE, end: FILE_DOWNLOAD_END_BYTE},
+          (err, remoteContents) => {
+            assert.ifError(err);
+            assert.strictEqual(
+              String(fileContents).slice(0, 20),
+              String(remoteContents)
+            );
+            done();
+          }
+        );
+      });
+    });
+
     it('should handle non-network errors', done => {
       const file = bucket.file('hi.jpg');
       file.download(err => {