本頁面由 Cloud Translation API 翻譯而成。

在網路上建立 Cloud Storage 參考資料

您的檔案儲存在 Cloud Storage 值區。如同本機硬碟上的檔案系統，或是 Firebase Realtime Database 中的資料。建立檔案參照後，應用程式就能取得檔案存取權。這些參考資料可用來上傳/下載資料、取得或更新中繼資料，或是刪除檔案。參照可以指向特定檔案或更高層級資源階層

如果您已使用 Firebase Realtime Database，則這些路徑應該不過，檔案資料會儲存在 Cloud Storage，不在 Realtime Database 中。

可建立參照

如要上傳或下載檔案、刪除檔案，或取得或更新中繼資料，您必須建立要操作檔案的參照。參考資料可視為指向雲端檔案的指標參考檔案為而且數量不限多項作業

如要建立參照，請使用 getStorage()，然後呼叫 ref() 並將服務做為引數。這個參照指向 Cloud Storage 值區的根目錄。

Web

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

// Get a reference to the storage service, which is used to create references in your storage bucket
const storage = getStorage();

// Create a storage reference from our storage service
const storageRef = ref(storage);storage_create_ref.js

Web

// Get a reference to the storage service, which is used to create references in your storage bucket
var storage = firebase.storage();

// Create a storage reference from our storage service
var storageRef = storage.ref();create-reference.js

您可以建立對樹狀圖中下方位置的參照表示 'images/space.jpg'，方法是在這個路徑中，做為第二個引數傳入正在呼叫 ref()。

Web

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

const storage = getStorage();

// Create a child reference
const imagesRef = ref(storage, 'images');
// imagesRef now points to 'images'

// Child references can also take paths delimited by '/'
const spaceRef = ref(storage, 'images/space.jpg');
// spaceRef now points to "images/space.jpg"
// imagesRef still points to "images"storage_create_ref_child.js

Web

// Create a child reference
var imagesRef = storageRef.child('images');
// imagesRef now points to 'images'

// Child references can also take paths delimited by '/'
var spaceRef = storageRef.child('images/space.jpg');
// spaceRef now points to "images/space.jpg"
// imagesRef still points to "images"create-reference.js

使用參考資料進行導覽

您也可以使用 parent 和 root 屬性前往檔案階層parent 會向上導覽一個層級 root 則會一直導覽到頂端。

Web

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

const storage = getStorage();
const spaceRef = ref(storage, 'images/space.jpg');

// Parent allows us to move to the parent of a reference
const imagesRef = spaceRef.parent;
// imagesRef now points to 'images'

// Root allows us to move all the way back to the top of our bucket
const rootRef = spaceRef.root;
// rootRef now points to the rootstorage_navigate_ref.js

Web

// Parent allows us to move to the parent of a reference
var imagesRef = spaceRef.parent;
// imagesRef now points to 'images'

// Root allows us to move all the way back to the top of our bucket
var rootRef = spaceRef.root;
// rootRef now points to the rootcreate-reference.js

child()、parent 和 root 可以多次鏈結，例如每個物件都會傳回一個參照例外狀況是 root 的 parent，為 null。

Web

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

const storage = getStorage();
const spaceRef = ref(storage, 'images/space.jpg');

// References can be chained together multiple times
const earthRef = ref(spaceRef.parent, 'earth.jpg');
// earthRef points to 'images/earth.jpg'

// nullRef is null, since the parent of root is null
const nullRef = spaceRef.root.parent;storage_navigate_ref_chain.js

Web

// References can be chained together multiple times
var earthRef = spaceRef.parent.child('earth.jpg');
// earthRef points to 'images/earth.jpg'

// nullRef is null, since the parent of root is null
var nullRef = spaceRef.root.parent;create-reference.js

參照屬性

你可以檢查參照，進一步瞭解指標指向的檔案方法是使用 fullPath、name 和 bucket 屬性。這些屬性取得檔案的完整路徑、檔案名稱以及檔案儲存的值區

Web

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

const storage = getStorage();
const spaceRef = ref(storage, 'images/space.jpg');

// Reference's path is: 'images/space.jpg'
// This is analogous to a file path on disk
spaceRef.fullPath;

// Reference's name is the last segment of the full path: 'space.jpg'
// This is analogous to the file name
spaceRef.name;

// Reference's bucket is the name of the storage bucket where files are stored
spaceRef.bucket;storage_ref_properties.js

Web

// Reference's path is: 'images/space.jpg'
// This is analogous to a file path on disk
spaceRef.fullPath;

// Reference's name is the last segment of the full path: 'space.jpg'
// This is analogous to the file name
spaceRef.name;

// Reference's bucket is the name of the storage bucket where files are stored
spaceRef.bucket;create-reference.js

參考檔案的限制

參照路徑和名稱可包含任何有效的 Unicode 字元序列，但有以下限制：

使用 UTF-8 編碼時，reference.fullPath 的總長度必須介於 1 到 1024 個位元組之間。
不得使用回車或換行字元。
請避免使用 #、[、]、* 或 ?，因為這些工具無法與其他工具 (例如 Firebase Realtime Database 或 gsutil) 搭配使用。

完整範例

Web

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

const storage = getStorage();

// Points to the root reference
const storageRef = ref(storage);

// Points to 'images'
const imagesRef = ref(storageRef, 'images');

// Points to 'images/space.jpg'
// Note that you can use variables to create child values
const fileName = 'space.jpg';
const spaceRef = ref(imagesRef, fileName);

// File path is 'images/space.jpg'
const path = spaceRef.fullPath;

// File name is 'space.jpg'
const name = spaceRef.name;

// Points to 'images'
const imagesRefAgain = spaceRef.parent;storage_ref_full_example.js

Web

// Points to the root reference
var storageRef = firebase.storage().ref();

// Points to 'images'
var imagesRef = storageRef.child('images');

// Points to 'images/space.jpg'
// Note that you can use variables to create child values
var fileName = 'space.jpg';
var spaceRef = imagesRef.child(fileName);

// File path is 'images/space.jpg'
var path = spaceRef.fullPath;

// File name is 'space.jpg'
var name = spaceRef.name;

// Points to 'images'
var imagesRef = spaceRef.parent;create-reference.js

接下來，我們將說明如何上傳檔案至 Cloud Storage。