angular-localforage
Version:
Angular service & directive for https://github.com/mozilla/localForage (Offline storage, improved.)
692 lines (583 loc) • 21.7 kB
JavaScript
import createBlob from '../utils/createBlob';
import idb from '../utils/idb';
import Promise from '../utils/promise';
import executeCallback from '../utils/executeCallback';
import executeTwoCallbacks from '../utils/executeTwoCallbacks';
// Some code originally from async_storage.js in
// [Gaia](https://github.com/mozilla-b2g/gaia).
var DETECT_BLOB_SUPPORT_STORE = 'local-forage-detect-blob-support';
var supportsBlobs;
var dbContexts;
var toString = Object.prototype.toString;
// Transform a binary string to an array buffer, because otherwise
// weird stuff happens when you try to work with the binary string directly.
// It is known.
// From http://stackoverflow.com/questions/14967647/ (continues on next line)
// encode-decode-image-with-base64-breaks-image (2013-04-21)
function _binStringToArrayBuffer(bin) {
var length = bin.length;
var buf = new ArrayBuffer(length);
var arr = new Uint8Array(buf);
for (var i = 0; i < length; i++) {
arr[i] = bin.charCodeAt(i);
}
return buf;
}
//
// Blobs are not supported in all versions of IndexedDB, notably
// Chrome <37 and Android <5. In those versions, storing a blob will throw.
//
// Various other blob bugs exist in Chrome v37-42 (inclusive).
// Detecting them is expensive and confusing to users, and Chrome 37-42
// is at very low usage worldwide, so we do a hacky userAgent check instead.
//
// content-type bug: https://code.google.com/p/chromium/issues/detail?id=408120
// 404 bug: https://code.google.com/p/chromium/issues/detail?id=447916
// FileReader bug: https://code.google.com/p/chromium/issues/detail?id=447836
//
// Code borrowed from PouchDB. See:
// https://github.com/pouchdb/pouchdb/blob/9c25a23/src/adapters/idb/blobSupport.js
//
function _checkBlobSupportWithoutCaching(txn) {
return new Promise(function(resolve) {
var blob = createBlob(['']);
txn.objectStore(DETECT_BLOB_SUPPORT_STORE).put(blob, 'key');
txn.onabort = function(e) {
// If the transaction aborts now its due to not being able to
// write to the database, likely due to the disk being full
e.preventDefault();
e.stopPropagation();
resolve(false);
};
txn.oncomplete = function() {
var matchedChrome = navigator.userAgent.match(/Chrome\/(\d+)/);
var matchedEdge = navigator.userAgent.match(/Edge\//);
// MS Edge pretends to be Chrome 42:
// https://msdn.microsoft.com/en-us/library/hh869301%28v=vs.85%29.aspx
resolve(matchedEdge || !matchedChrome ||
parseInt(matchedChrome[1], 10) >= 43);
};
}).catch(function() {
return false; // error, so assume unsupported
});
}
function _checkBlobSupport(idb) {
if (typeof supportsBlobs === 'boolean') {
return Promise.resolve(supportsBlobs);
}
return _checkBlobSupportWithoutCaching(idb).then(function(value) {
supportsBlobs = value;
return supportsBlobs;
});
}
function _deferReadiness(dbInfo) {
var dbContext = dbContexts[dbInfo.name];
// Create a deferred object representing the current database operation.
var deferredOperation = {};
deferredOperation.promise = new Promise(function(resolve) {
deferredOperation.resolve = resolve;
});
// Enqueue the deferred operation.
dbContext.deferredOperations.push(deferredOperation);
// Chain its promise to the database readiness.
if (!dbContext.dbReady) {
dbContext.dbReady = deferredOperation.promise;
} else {
dbContext.dbReady = dbContext.dbReady.then(function() {
return deferredOperation.promise;
});
}
}
function _advanceReadiness(dbInfo) {
var dbContext = dbContexts[dbInfo.name];
// Dequeue a deferred operation.
var deferredOperation = dbContext.deferredOperations.pop();
// Resolve its promise (which is part of the database readiness
// chain of promises).
if (deferredOperation) {
deferredOperation.resolve();
}
}
function _getConnection(dbInfo, upgradeNeeded) {
return new Promise(function(resolve, reject) {
if (dbInfo.db) {
if (upgradeNeeded) {
_deferReadiness(dbInfo);
dbInfo.db.close();
} else {
return resolve(dbInfo.db);
}
}
var dbArgs = [dbInfo.name];
if (upgradeNeeded) {
dbArgs.push(dbInfo.version);
}
var openreq = idb.open.apply(idb, dbArgs);
if (upgradeNeeded) {
openreq.onupgradeneeded = function(e) {
var db = openreq.result;
try {
db.createObjectStore(dbInfo.storeName);
if (e.oldVersion <= 1) {
// Added when support for blob shims was added
db.createObjectStore(DETECT_BLOB_SUPPORT_STORE);
}
} catch (ex) {
if (ex.name === 'ConstraintError') {
console.warn('The database "' + dbInfo.name + '"' +
' has been upgraded from version ' + e.oldVersion +
' to version ' + e.newVersion +
', but the storage "' + dbInfo.storeName + '" already exists.');
} else {
throw ex;
}
}
};
}
openreq.onerror = function() {
reject(openreq.error);
};
openreq.onsuccess = function() {
resolve(openreq.result);
_advanceReadiness(dbInfo);
};
});
}
function _getOriginalConnection(dbInfo) {
return _getConnection(dbInfo, false);
}
function _getUpgradedConnection(dbInfo) {
return _getConnection(dbInfo, true);
}
function _isUpgradeNeeded(dbInfo, defaultVersion) {
if (!dbInfo.db) {
return true;
}
var isNewStore = !dbInfo.db.objectStoreNames.contains(dbInfo.storeName);
var isDowngrade = dbInfo.version < dbInfo.db.version;
var isUpgrade = dbInfo.version > dbInfo.db.version;
if (isDowngrade) {
// If the version is not the default one
// then warn for impossible downgrade.
if (dbInfo.version !== defaultVersion) {
console.warn('The database "' + dbInfo.name + '"' +
' can\'t be downgraded from version ' + dbInfo.db.version +
' to version ' + dbInfo.version + '.');
}
// Align the versions to prevent errors.
dbInfo.version = dbInfo.db.version;
}
if (isUpgrade || isNewStore) {
// If the store is new then increment the version (if needed).
// This will trigger an "upgradeneeded" event which is required
// for creating a store.
if (isNewStore) {
var incVersion = dbInfo.db.version + 1;
if (incVersion > dbInfo.version) {
dbInfo.version = incVersion;
}
}
return true;
}
return false;
}
// encode a blob for indexeddb engines that don't support blobs
function _encodeBlob(blob) {
return new Promise(function(resolve, reject) {
var reader = new FileReader();
reader.onerror = reject;
reader.onloadend = function(e) {
var base64 = btoa(e.target.result || '');
resolve({
__local_forage_encoded_blob: true,
data: base64,
type: blob.type
});
};
reader.readAsBinaryString(blob);
});
}
// decode an encoded blob
function _decodeBlob(encodedBlob) {
var arrayBuff = _binStringToArrayBuffer(atob(encodedBlob.data));
return createBlob([arrayBuff], {type: encodedBlob.type});
}
// is this one of our fancy encoded blobs?
function _isEncodedBlob(value) {
return value && value.__local_forage_encoded_blob;
}
// Specialize the default `ready()` function by making it dependent
// on the current database operations. Thus, the driver will be actually
// ready when it's been initialized (default) *and* there are no pending
// operations on the database (initiated by some other instances).
function _fullyReady(callback) {
var self = this;
var promise = self._initReady().then(function() {
var dbContext = dbContexts[self._dbInfo.name];
if (dbContext && dbContext.dbReady) {
return dbContext.dbReady;
}
});
executeTwoCallbacks(promise, callback, callback);
return promise;
}
// Open the IndexedDB database (automatically creates one if one didn't
// previously exist), using any options set in the config.
function _initStorage(options) {
var self = this;
var dbInfo = {
db: null
};
if (options) {
for (var i in options) {
dbInfo[i] = options[i];
}
}
// Initialize a singleton container for all running localForages.
if (!dbContexts) {
dbContexts = {};
}
// Get the current context of the database;
var dbContext = dbContexts[dbInfo.name];
// ...or create a new context.
if (!dbContext) {
dbContext = {
// Running localForages sharing a database.
forages: [],
// Shared database.
db: null,
// Database readiness (promise).
dbReady: null,
// Deferred operations on the database.
deferredOperations: []
};
// Register the new context in the global container.
dbContexts[dbInfo.name] = dbContext;
}
// Register itself as a running localForage in the current context.
dbContext.forages.push(self);
// Replace the default `ready()` function with the specialized one.
if (!self._initReady) {
self._initReady = self.ready;
self.ready = _fullyReady;
}
// Create an array of initialization states of the related localForages.
var initPromises = [];
function ignoreErrors() {
// Don't handle errors here,
// just makes sure related localForages aren't pending.
return Promise.resolve();
}
for (var j = 0; j < dbContext.forages.length; j++) {
var forage = dbContext.forages[j];
if (forage !== self) { // Don't wait for itself...
initPromises.push(forage._initReady().catch(ignoreErrors));
}
}
// Take a snapshot of the related localForages.
var forages = dbContext.forages.slice(0);
// Initialize the connection process only when
// all the related localForages aren't pending.
return Promise.all(initPromises).then(function() {
dbInfo.db = dbContext.db;
// Get the connection or open a new one without upgrade.
return _getOriginalConnection(dbInfo);
}).then(function(db) {
dbInfo.db = db;
if (_isUpgradeNeeded(dbInfo, self._defaultConfig.version)) {
// Reopen the database for upgrading.
return _getUpgradedConnection(dbInfo);
}
return db;
}).then(function(db) {
dbInfo.db = dbContext.db = db;
self._dbInfo = dbInfo;
// Share the final connection amongst related localForages.
for (var k = 0; k < forages.length; k++) {
var forage = forages[k];
if (forage !== self) { // Self is already up-to-date.
forage._dbInfo.db = dbInfo.db;
forage._dbInfo.version = dbInfo.version;
}
}
});
}
function getItem(key, callback) {
var self = this;
// Cast the key to a string, as that's all we can set as a key.
if (typeof key !== 'string') {
console.warn(key +
' used as a key, but it is not a string.');
key = String(key);
}
var promise = new Promise(function(resolve, reject) {
self.ready().then(function() {
var dbInfo = self._dbInfo;
var store = dbInfo.db.transaction(dbInfo.storeName, 'readonly')
.objectStore(dbInfo.storeName);
var req = store.get(key);
req.onsuccess = function() {
var value = req.result;
if (value === undefined) {
value = null;
}
if (_isEncodedBlob(value)) {
value = _decodeBlob(value);
}
resolve(value);
};
req.onerror = function() {
reject(req.error);
};
}).catch(reject);
});
executeCallback(promise, callback);
return promise;
}
// Iterate over all items stored in database.
function iterate(iterator, callback) {
var self = this;
var promise = new Promise(function(resolve, reject) {
self.ready().then(function() {
var dbInfo = self._dbInfo;
var store = dbInfo.db.transaction(dbInfo.storeName, 'readonly')
.objectStore(dbInfo.storeName);
var req = store.openCursor();
var iterationNumber = 1;
req.onsuccess = function() {
var cursor = req.result;
if (cursor) {
var value = cursor.value;
if (_isEncodedBlob(value)) {
value = _decodeBlob(value);
}
var result = iterator(value, cursor.key,
iterationNumber++);
if (result !== void(0)) {
resolve(result);
} else {
cursor.continue();
}
} else {
resolve();
}
};
req.onerror = function() {
reject(req.error);
};
}).catch(reject);
});
executeCallback(promise, callback);
return promise;
}
function setItem(key, value, callback) {
var self = this;
// Cast the key to a string, as that's all we can set as a key.
if (typeof key !== 'string') {
console.warn(key +
' used as a key, but it is not a string.');
key = String(key);
}
var promise = new Promise(function(resolve, reject) {
var dbInfo;
self.ready().then(function() {
dbInfo = self._dbInfo;
if (toString.call(value) === '[object Blob]') {
return _checkBlobSupport(dbInfo.db).then(function(blobSupport) {
if (blobSupport) {
return value;
}
return _encodeBlob(value);
});
}
return value;
}).then(function(value) {
var transaction = dbInfo.db.transaction(dbInfo.storeName, 'readwrite');
var store = transaction.objectStore(dbInfo.storeName);
// The reason we don't _save_ null is because IE 10 does
// not support saving the `null` type in IndexedDB. How
// ironic, given the bug below!
// See: https://github.com/mozilla/localForage/issues/161
if (value === null) {
value = undefined;
}
transaction.oncomplete = function() {
// Cast to undefined so the value passed to
// callback/promise is the same as what one would get out
// of `getItem()` later. This leads to some weirdness
// (setItem('foo', undefined) will return `null`), but
// it's not my fault localStorage is our baseline and that
// it's weird.
if (value === undefined) {
value = null;
}
resolve(value);
};
transaction.onabort = transaction.onerror = function() {
var err = req.error ? req.error : req.transaction.error;
reject(err);
};
var req = store.put(value, key);
}).catch(reject);
});
executeCallback(promise, callback);
return promise;
}
function removeItem(key, callback) {
var self = this;
// Cast the key to a string, as that's all we can set as a key.
if (typeof key !== 'string') {
console.warn(key +
' used as a key, but it is not a string.');
key = String(key);
}
var promise = new Promise(function(resolve, reject) {
self.ready().then(function() {
var dbInfo = self._dbInfo;
var transaction = dbInfo.db.transaction(dbInfo.storeName, 'readwrite');
var store = transaction.objectStore(dbInfo.storeName);
// We use a Grunt task to make this safe for IE and some
// versions of Android (including those used by Cordova).
// Normally IE won't like `.delete()` and will insist on
// using `['delete']()`, but we have a build step that
// fixes this for us now.
var req = store.delete(key);
transaction.oncomplete = function() {
resolve();
};
transaction.onerror = function() {
reject(req.error);
};
// The request will be also be aborted if we've exceeded our storage
// space.
transaction.onabort = function() {
var err = req.error ? req.error : req.transaction.error;
reject(err);
};
}).catch(reject);
});
executeCallback(promise, callback);
return promise;
}
function clear(callback) {
var self = this;
var promise = new Promise(function(resolve, reject) {
self.ready().then(function() {
var dbInfo = self._dbInfo;
var transaction = dbInfo.db.transaction(dbInfo.storeName, 'readwrite');
var store = transaction.objectStore(dbInfo.storeName);
var req = store.clear();
transaction.oncomplete = function() {
resolve();
};
transaction.onabort = transaction.onerror = function() {
var err = req.error ? req.error : req.transaction.error;
reject(err);
};
}).catch(reject);
});
executeCallback(promise, callback);
return promise;
}
function length(callback) {
var self = this;
var promise = new Promise(function(resolve, reject) {
self.ready().then(function() {
var dbInfo = self._dbInfo;
var store = dbInfo.db.transaction(dbInfo.storeName, 'readonly')
.objectStore(dbInfo.storeName);
var req = store.count();
req.onsuccess = function() {
resolve(req.result);
};
req.onerror = function() {
reject(req.error);
};
}).catch(reject);
});
executeCallback(promise, callback);
return promise;
}
function key(n, callback) {
var self = this;
var promise = new Promise(function(resolve, reject) {
if (n < 0) {
resolve(null);
return;
}
self.ready().then(function() {
var dbInfo = self._dbInfo;
var store = dbInfo.db.transaction(dbInfo.storeName, 'readonly')
.objectStore(dbInfo.storeName);
var advanced = false;
var req = store.openCursor();
req.onsuccess = function() {
var cursor = req.result;
if (!cursor) {
// this means there weren't enough keys
resolve(null);
return;
}
if (n === 0) {
// We have the first key, return it if that's what they
// wanted.
resolve(cursor.key);
} else {
if (!advanced) {
// Otherwise, ask the cursor to skip ahead n
// records.
advanced = true;
cursor.advance(n);
} else {
// When we get here, we've got the nth key.
resolve(cursor.key);
}
}
};
req.onerror = function() {
reject(req.error);
};
}).catch(reject);
});
executeCallback(promise, callback);
return promise;
}
function keys(callback) {
var self = this;
var promise = new Promise(function(resolve, reject) {
self.ready().then(function() {
var dbInfo = self._dbInfo;
var store = dbInfo.db.transaction(dbInfo.storeName, 'readonly')
.objectStore(dbInfo.storeName);
var req = store.openCursor();
var keys = [];
req.onsuccess = function() {
var cursor = req.result;
if (!cursor) {
resolve(keys);
return;
}
keys.push(cursor.key);
cursor.continue();
};
req.onerror = function() {
reject(req.error);
};
}).catch(reject);
});
executeCallback(promise, callback);
return promise;
}
var asyncStorage = {
_driver: 'asyncStorage',
_initStorage: _initStorage,
iterate: iterate,
getItem: getItem,
setItem: setItem,
removeItem: removeItem,
clear: clear,
length: length,
key: key,
keys: keys
};
export default asyncStorage;