angular-localforage
Version:
Angular service & directive for https://github.com/mozilla/localForage (Offline storage, improved.)
352 lines (300 loc) • 11.6 kB
JavaScript
import serializer from '../utils/serializer';
import Promise from '../utils/promise';
import executeCallback from '../utils/executeCallback';
/*
* Includes code from:
*
* base64-arraybuffer
* https://github.com/niklasvh/base64-arraybuffer
*
* Copyright (c) 2012 Niklas von Hertzen
* Licensed under the MIT license.
*/
// Open the WebSQL 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] = typeof(options[i]) !== 'string' ?
options[i].toString() : options[i];
}
}
var dbInfoPromise = new Promise(function(resolve, reject) {
// Open the database; the openDatabase API will automatically
// create it for us if it doesn't exist.
try {
dbInfo.db = openDatabase(dbInfo.name, String(dbInfo.version),
dbInfo.description, dbInfo.size);
} catch (e) {
return reject(e);
}
// Create our key/value table if it doesn't exist.
dbInfo.db.transaction(function(t) {
t.executeSql('CREATE TABLE IF NOT EXISTS ' + dbInfo.storeName +
' (id INTEGER PRIMARY KEY, key unique, value)', [],
function() {
self._dbInfo = dbInfo;
resolve();
}, function(t, error) {
reject(error);
});
});
});
dbInfo.serializer = serializer;
return dbInfoPromise;
}
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;
dbInfo.db.transaction(function(t) {
t.executeSql('SELECT * FROM ' + dbInfo.storeName +
' WHERE key = ? LIMIT 1', [key],
function(t, results) {
var result = results.rows.length ?
results.rows.item(0).value : null;
// Check to see if this is serialized content we need to
// unpack.
if (result) {
result = dbInfo.serializer.deserialize(result);
}
resolve(result);
}, function(t, error) {
reject(error);
});
});
}).catch(reject);
});
executeCallback(promise, callback);
return promise;
}
function iterate(iterator, callback) {
var self = this;
var promise = new Promise(function(resolve, reject) {
self.ready().then(function() {
var dbInfo = self._dbInfo;
dbInfo.db.transaction(function(t) {
t.executeSql('SELECT * FROM ' + dbInfo.storeName, [],
function(t, results) {
var rows = results.rows;
var length = rows.length;
for (var i = 0; i < length; i++) {
var item = rows.item(i);
var result = item.value;
// Check to see if this is serialized content
// we need to unpack.
if (result) {
result = dbInfo.serializer.deserialize(result);
}
result = iterator(result, item.key, i + 1);
// void(0) prevents problems with redefinition
// of `undefined`.
if (result !== void(0)) {
resolve(result);
return;
}
}
resolve();
}, function(t, error) {
reject(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) {
self.ready().then(function() {
// The localStorage API doesn't return undefined values in an
// "expected" way, so undefined is always cast to null in all
// drivers. See: https://github.com/mozilla/localForage/pull/42
if (value === undefined) {
value = null;
}
// Save the original value to pass to the callback.
var originalValue = value;
var dbInfo = self._dbInfo;
dbInfo.serializer.serialize(value, function(value, error) {
if (error) {
reject(error);
} else {
dbInfo.db.transaction(function(t) {
t.executeSql('INSERT OR REPLACE INTO ' +
dbInfo.storeName +
' (key, value) VALUES (?, ?)',
[key, value], function() {
resolve(originalValue);
}, function(t, error) {
reject(error);
});
}, function(sqlError) {
// The transaction failed; check
// to see if it's a quota error.
if (sqlError.code === sqlError.QUOTA_ERR) {
// We reject the callback outright for now, but
// it's worth trying to re-run the transaction.
// Even if the user accepts the prompt to use
// more storage on Safari, this error will
// be called.
//
// TODO: Try to re-run the transaction.
reject(sqlError);
}
});
}
});
}).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;
dbInfo.db.transaction(function(t) {
t.executeSql('DELETE FROM ' + dbInfo.storeName +
' WHERE key = ?', [key],
function() {
resolve();
}, function(t, error) {
reject(error);
});
});
}).catch(reject);
});
executeCallback(promise, callback);
return promise;
}
// Deletes every item in the table.
// TODO: Find out if this resets the AUTO_INCREMENT number.
function clear(callback) {
var self = this;
var promise = new Promise(function(resolve, reject) {
self.ready().then(function() {
var dbInfo = self._dbInfo;
dbInfo.db.transaction(function(t) {
t.executeSql('DELETE FROM ' + dbInfo.storeName, [],
function() {
resolve();
}, function(t, error) {
reject(error);
});
});
}).catch(reject);
});
executeCallback(promise, callback);
return promise;
}
// Does a simple `COUNT(key)` to get the number of items stored in
// localForage.
function length(callback) {
var self = this;
var promise = new Promise(function(resolve, reject) {
self.ready().then(function() {
var dbInfo = self._dbInfo;
dbInfo.db.transaction(function(t) {
// Ahhh, SQL makes this one soooooo easy.
t.executeSql('SELECT COUNT(key) as c FROM ' +
dbInfo.storeName, [], function(t, results) {
var result = results.rows.item(0).c;
resolve(result);
}, function(t, error) {
reject(error);
});
});
}).catch(reject);
});
executeCallback(promise, callback);
return promise;
}
// Return the key located at key index X; essentially gets the key from a
// `WHERE id = ?`. This is the most efficient way I can think to implement
// this rarely-used (in my experience) part of the API, but it can seem
// inconsistent, because we do `INSERT OR REPLACE INTO` on `setItem()`, so
// the ID of each key will change every time it's updated. Perhaps a stored
// procedure for the `setItem()` SQL would solve this problem?
// TODO: Don't change ID on `setItem()`.
function key(n, callback) {
var self = this;
var promise = new Promise(function(resolve, reject) {
self.ready().then(function() {
var dbInfo = self._dbInfo;
dbInfo.db.transaction(function(t) {
t.executeSql('SELECT key FROM ' + dbInfo.storeName +
' WHERE id = ? LIMIT 1', [n + 1],
function(t, results) {
var result = results.rows.length ?
results.rows.item(0).key : null;
resolve(result);
}, function(t, error) {
reject(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;
dbInfo.db.transaction(function(t) {
t.executeSql('SELECT key FROM ' + dbInfo.storeName, [],
function(t, results) {
var keys = [];
for (var i = 0; i < results.rows.length; i++) {
keys.push(results.rows.item(i).key);
}
resolve(keys);
}, function(t, error) {
reject(error);
});
});
}).catch(reject);
});
executeCallback(promise, callback);
return promise;
}
var webSQLStorage = {
_driver: 'webSQLStorage',
_initStorage: _initStorage,
iterate: iterate,
getItem: getItem,
setItem: setItem,
removeItem: removeItem,
clear: clear,
length: length,
key: key,
keys: keys
};
export default webSQLStorage;