本頁面由 Cloud Translation API 翻譯而成。

使用 Cloud Storage 網頁版下載檔案

Cloud Storage for Firebase 可讓您輕鬆快速地下載從 Cloud Storage 由 Firebase 提供並管理的值區

可建立參照

如要下載檔案，請先建立 Cloud Storage 參考資料加入要下載的檔案

您可以在 Cloud Storage 值區，或者您也可以從現有 gs:// 或 https:// 網址；參照 Cloud Storage 中的物件。

Web

import { getStorage, ref } from "firebase/storage";

// Create a reference with an initial file path and name
const storage = getStorage();
const pathReference = ref(storage, 'images/stars.jpg');

// Create a reference from a Google Cloud Storage URI
const gsReference = ref(storage, 'gs://bucket/images/stars.jpg');

// Create a reference from an HTTPS URL
// Note that in the URL, characters are URL escaped!
const httpsReference = ref(storage, 'https://firebasestorage.googleapis.com/b/bucket/o/images%20stars.jpg');  storage_download_create_ref.js

Web

// Create a reference with an initial file path and name
var storage = firebase.storage();
var pathReference = storage.ref('images/stars.jpg');

// Create a reference from a Google Cloud Storage URI
var gsReference = storage.refFromURL('gs://bucket/images/stars.jpg');

// Create a reference from an HTTPS URL
// Note that in the URL, characters are URL escaped!
var httpsReference = storage.refFromURL('https://firebasestorage.googleapis.com/b/bucket/o/images%20stars.jpg');  download-files.js

透過網址下載資料

您可以呼叫 Cloud Storage 參考資料的 getDownloadURL() 方法。

Web

import { getStorage, ref, getDownloadURL } from "firebase/storage";

const storage = getStorage();
getDownloadURL(ref(storage, 'images/stars.jpg'))
  .then((url) => {
    // `url` is the download URL for 'images/stars.jpg'

    // This can be downloaded directly:
    const xhr = new XMLHttpRequest();
    xhr.responseType = 'blob';
    xhr.onload = (event) => {
      const blob = xhr.response;
    };
    xhr.open('GET', url);
    xhr.send();

    // Or inserted into an <img> element
    const img = document.getElementById('myimg');
    img.setAttribute('src', url);
  })
  .catch((error) => {
    // Handle any errors
  });storage_download_via_url.js

Web

storageRef.child('images/stars.jpg').getDownloadURL()
  .then((url) => {
    // `url` is the download URL for 'images/stars.jpg'

    // This can be downloaded directly:
    var xhr = new XMLHttpRequest();
    xhr.responseType = 'blob';
    xhr.onload = (event) => {
      var blob = xhr.response;
    };
    xhr.open('GET', url);
    xhr.send();

    // Or inserted into an <img> element
    var img = document.getElementById('myimg');
    img.setAttribute('src', url);
  })
  .catch((error) => {
    // Handle any errors
  });download-files.js

直接從 SDK 下載資料

從 9.5 以上版本開始，SDK 可為直接使用下載：

使用這些函式，可以略過從網址下載的過程，並改為傳回資料這樣一來，您就能透過 Firebase 安全性規則。

CORS 設定

如要在瀏覽器中直接下載資料，您必須設定用於跨源存取 (CORS) 的 Cloud Storage 值區。都可以使用 gsutil 指令列工具，您可以從這裡安裝。

如果不想設定任何網域限制 (最常見的情況)，請將這個 JSON 複製到名為 cors.json 的檔案：

[
  {
    "origin": ["*"],
    "method": ["GET"],
    "maxAgeSeconds": 3600
  }
]

執行「gsutil cors set cors.json gs://<your-cloud-storage-bucket>」進行部署這些限制。

詳情請參閱 Google Cloud Storage 說明文件。

處理錯誤

下載時可能會發生錯誤的原因有很多，包括檔案不存在，或使用者沒有存取所需檔案的權限。如要進一步瞭解錯誤，請前往處理錯誤一節。

完整範例

下面是含有錯誤處理的下載完整範例：

Web

import { getStorage, ref, getDownloadURL } from "firebase/storage";

// Create a reference to the file we want to download
const storage = getStorage();
const starsRef = ref(storage, 'images/stars.jpg');

// Get the download URL
getDownloadURL(starsRef)
  .then((url) => {
    // Insert url into an <img> tag to "download"
  })
  .catch((error) => {
    // A full list of error codes is available at
    // https://firebase.google.com/docs/storage/web/handle-errors
    switch (error.code) {
      case 'storage/object-not-found':
        // File doesn't exist
        break;
      case 'storage/unauthorized':
        // User doesn't have permission to access the object
        break;
      case 'storage/canceled':
        // User canceled the upload
        break;

      // ...

      case 'storage/unknown':
        // Unknown error occurred, inspect the server response
        break;
    }
  });storage_download_full_example.js

Web

// Create a reference to the file we want to download
var starsRef = storageRef.child('images/stars.jpg');

// Get the download URL
starsRef.getDownloadURL()
.then((url) => {
  // Insert url into an <img> tag to "download"
})
.catch((error) => {
  // A full list of error codes is available at
  // https://firebase.google.com/docs/storage/web/handle-errors
  switch (error.code) {
    case 'storage/object-not-found':
      // File doesn't exist
      break;
    case 'storage/unauthorized':
      // User doesn't have permission to access the object
      break;
    case 'storage/canceled':
      // User canceled the upload
      break;

    // ...

    case 'storage/unknown':
      // Unknown error occurred, inspect the server response
      break;
  }
});download-files.js

您也可以取得或更新中繼資料儲存在 Cloud Storage 中的檔案