react-native-firebase/lib/modules/database/Reference.js

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/**
* @flow
* Database Reference representation wrapper
*/
import Query from './Query';
import DataSnapshot from './DataSnapshot';
import OnDisconnect from './OnDisconnect';
import { getLogger } from '../../utils/log';
import { getNativeModule } from '../../utils/native';
import ReferenceBase from '../../utils/ReferenceBase';
import {
promiseOrCallback,
isFunction,
isObject,
isString,
tryJSONParse,
tryJSONStringify,
generatePushID,
} from '../../utils';
import SyncTree from '../../utils/SyncTree';
import type Database from './';
import type { DatabaseModifier, FirebaseError } from '../../types';
// track all event registrations by path
let listeners = 0;
/**
* Enum for event types
* @readonly
* @enum {String}
*/
const ReferenceEventTypes = {
value: 'value',
child_added: 'child_added',
child_removed: 'child_removed',
child_changed: 'child_changed',
child_moved: 'child_moved',
};
type DatabaseListener = {
listenerId: number,
eventName: string,
successCallback: Function,
failureCallback?: Function,
};
/**
* @typedef {String} ReferenceLocation - Path to location in the database, relative
* to the root reference. Consists of a path where segments are separated by a
* forward slash (/) and ends in a ReferenceKey - except the root location, which
* has no ReferenceKey.
*
* @example
* // root reference location: '/'
* // non-root reference: '/path/to/referenceKey'
*/
/**
* @typedef {String} ReferenceKey - Identifier for each location that is unique to that
* location, within the scope of its parent. The last part of a ReferenceLocation.
*/
/**
* Represents a specific location in your Database that can be used for
* reading or writing data.
*
* You can reference the root using firebase.database().ref() or a child location
* by calling firebase.database().ref("child/path").
*
* @link https://firebase.google.com/docs/reference/js/firebase.database.Reference
* @class Reference
* @extends ReferenceBase
*/
export default class Reference extends ReferenceBase {
_database: Database;
_promise: ?Promise<*>;
_query: Query;
_refListeners: { [listenerId: number]: DatabaseListener };
constructor(
database: Database,
path: string,
existingModifiers?: Array<DatabaseModifier>
) {
super(path);
this._promise = null;
this._refListeners = {};
this._database = database;
this._query = new Query(this, existingModifiers);
getLogger(database).debug('Created new Reference', this._getRefKey());
}
/**
* By calling `keepSynced(true)` on a location, the data for that location will
* automatically be downloaded and kept in sync, even when no listeners are
* attached for that location. Additionally, while a location is kept synced,
* it will not be evicted from the persistent disk cache.
*
* @link https://firebase.google.com/docs/reference/android/com/google/firebase/database/Query.html#keepSynced(boolean)
* @param bool
* @returns {*}
*/
keepSynced(bool: boolean): Promise<void> {
return getNativeModule(this._database).keepSynced(
this._getRefKey(),
this.path,
this._query.getModifiers(),
bool
);
}
/**
* Writes data to this Database location.
*
* @link https://firebase.google.com/docs/reference/js/firebase.database.Reference#set
* @param value
* @param onComplete
* @returns {Promise}
*/
set(value: any, onComplete?: Function): Promise<void> {
return promiseOrCallback(
getNativeModule(this._database).set(
this.path,
this._serializeAnyType(value)
),
onComplete
);
}
/**
* Sets a priority for the data at this Database location.
*
* @link https://firebase.google.com/docs/reference/js/firebase.database.Reference#setPriority
* @param priority
* @param onComplete
* @returns {Promise}
*/
setPriority(
priority: string | number | null,
onComplete?: Function
): Promise<void> {
const _priority = this._serializeAnyType(priority);
return promiseOrCallback(
getNativeModule(this._database).setPriority(this.path, _priority),
onComplete
);
}
/**
* Writes data the Database location. Like set() but also specifies the priority for that data.
*
* @link https://firebase.google.com/docs/reference/js/firebase.database.Reference#setWithPriority
* @param value
* @param priority
* @param onComplete
* @returns {Promise}
*/
setWithPriority(
value: any,
priority: string | number | null,
onComplete?: Function
): Promise<void> {
const _value = this._serializeAnyType(value);
const _priority = this._serializeAnyType(priority);
return promiseOrCallback(
getNativeModule(this._database).setWithPriority(
this.path,
_value,
_priority
),
onComplete
);
}
/**
* Writes multiple values to the Database at once.
*
* @link https://firebase.google.com/docs/reference/js/firebase.database.Reference#update
* @param val
* @param onComplete
* @returns {Promise}
*/
update(val: Object, onComplete?: Function): Promise<void> {
const value = this._serializeObject(val);
return promiseOrCallback(
getNativeModule(this._database).update(this.path, value),
onComplete
);
}
/**
* Removes the data at this Database location.
*
* @link https://firebase.google.com/docs/reference/js/firebase.database.Reference#remove
* @param onComplete
* @return {Promise}
*/
remove(onComplete?: Function): Promise<void> {
return promiseOrCallback(
getNativeModule(this._database).remove(this.path),
onComplete
);
}
/**
* Atomically modifies the data at this location.
*
* @link https://firebase.google.com/docs/reference/js/firebase.database.Reference#transaction
* @param transactionUpdate
* @param onComplete
* @param applyLocally
*/
transaction(
transactionUpdate: Function,
onComplete: (
error: ?Error,
committed: boolean,
snapshot: ?DataSnapshot
) => *,
applyLocally: boolean = false
) {
if (!isFunction(transactionUpdate)) {
return Promise.reject(
new Error('Missing transactionUpdate function argument.')
);
}
return new Promise((resolve, reject) => {
const onCompleteWrapper = (error, committed, snapshotData) => {
if (isFunction(onComplete)) {
if (error) {
onComplete(error, committed, null);
} else {
onComplete(null, committed, new DataSnapshot(this, snapshotData));
}
}
if (error) return reject(error);
return resolve({
committed,
snapshot: new DataSnapshot(this, snapshotData),
});
};
// start the transaction natively
this._database._transactionHandler.add(
this,
transactionUpdate,
onCompleteWrapper,
applyLocally
);
});
}
/**
*
* @param eventName
* @param successCallback
* @param cancelOrContext
* @param context
* @returns {Promise.<any>}
*/
once(
eventName: string = 'value',
successCallback: (snapshot: DataSnapshot) => void,
cancelOrContext: (error: FirebaseError) => void,
context?: Object
) {
return getNativeModule(this._database)
.once(this._getRefKey(), this.path, this._query.getModifiers(), eventName)
.then(({ snapshot }) => {
const _snapshot = new DataSnapshot(this, snapshot);
if (isFunction(successCallback)) {
if (isObject(cancelOrContext))
successCallback.bind(cancelOrContext)(_snapshot);
if (context && isObject(context))
successCallback.bind(context)(_snapshot);
successCallback(_snapshot);
}
return _snapshot;
})
.catch(error => {
if (isFunction(cancelOrContext)) return cancelOrContext(error);
throw error;
});
}
/**
*
* @param value
* @param onComplete
* @returns {*}
*/
push(value: any, onComplete?: Function): Reference | Promise<void> {
if (value === null || value === undefined) {
return new Reference(
this._database,
`${this.path}/${generatePushID(this._database._serverTimeOffset)}`
);
}
const newRef = new Reference(
this._database,
`${this.path}/${generatePushID(this._database._serverTimeOffset)}`
);
const promise = newRef.set(value);
// if callback provided then internally call the set promise with value
if (isFunction(onComplete)) {
return (
promise
2018-02-17 12:55:19 +00:00
// $FlowExpectedError: Reports that onComplete can change to null despite the null check: https://github.com/facebook/flow/issues/1655
.then(() => onComplete(null, newRef))
2018-02-17 12:55:19 +00:00
// $FlowExpectedError: Reports that onComplete can change to null despite the null check: https://github.com/facebook/flow/issues/1655
.catch(error => onComplete(error, null))
);
}
// otherwise attach promise to 'thenable' reference and return the
// new reference
newRef._setThenable(promise);
return newRef;
}
/**
* MODIFIERS
*/
/**
*
* @returns {Reference}
*/
orderByKey(): Reference {
return this.orderBy('orderByKey');
}
/**
*
* @returns {Reference}
*/
orderByPriority(): Reference {
return this.orderBy('orderByPriority');
}
/**
*
* @returns {Reference}
*/
orderByValue(): Reference {
return this.orderBy('orderByValue');
}
/**
*
* @param key
* @returns {Reference}
*/
orderByChild(key: string): Reference {
return this.orderBy('orderByChild', key);
}
/**
*
* @param name
* @param key
* @returns {Reference}
*/
orderBy(name: string, key?: string): Reference {
const newRef = new Reference(
this._database,
this.path,
this._query.getModifiers()
);
newRef._query.orderBy(name, key);
return newRef;
}
/**
* LIMITS
*/
/**
*
* @param limit
* @returns {Reference}
*/
limitToLast(limit: number): Reference {
return this.limit('limitToLast', limit);
}
/**
*
* @param limit
* @returns {Reference}
*/
limitToFirst(limit: number): Reference {
return this.limit('limitToFirst', limit);
}
/**
*
* @param name
* @param limit
* @returns {Reference}
*/
limit(name: string, limit: number): Reference {
const newRef = new Reference(
this._database,
this.path,
this._query.getModifiers()
);
newRef._query.limit(name, limit);
return newRef;
}
/**
* FILTERS
*/
/**
*
* @param value
* @param key
* @returns {Reference}
*/
equalTo(value: any, key?: string): Reference {
return this.filter('equalTo', value, key);
}
/**
*
* @param value
* @param key
* @returns {Reference}
*/
endAt(value: any, key?: string): Reference {
return this.filter('endAt', value, key);
}
/**
*
* @param value
* @param key
* @returns {Reference}
*/
startAt(value: any, key?: string): Reference {
return this.filter('startAt', value, key);
}
/**
*
* @param name
* @param value
* @param key
* @returns {Reference}
*/
filter(name: string, value: any, key?: string): Reference {
const newRef = new Reference(
this._database,
this.path,
this._query.getModifiers()
);
newRef._query.filter(name, value, key);
return newRef;
}
/**
*
* @returns {OnDisconnect}
*/
onDisconnect(): OnDisconnect {
return new OnDisconnect(this);
}
/**
* Creates a Reference to a child of the current Reference, using a relative path.
* No validation is performed on the path to ensure it has a valid format.
* @param {String} path relative to current ref's location
* @returns {!Reference} A new Reference to the path provided, relative to the current
* Reference
* {@link https://firebase.google.com/docs/reference/js/firebase.database.Reference#child}
*/
child(path: string): Reference {
return new Reference(this._database, `${this.path}/${path}`);
}
/**
* Return the ref as a path string
* @returns {string}
*/
toString(): string {
return `${this._database.databaseUrl}/${this.path}`;
}
/**
* Returns whether another Reference represent the same location and are from the
* same instance of firebase.app.App - multiple firebase apps not currently supported.
* @param {Reference} otherRef - Other reference to compare to this one
* @return {Boolean} Whether otherReference is equal to this one
*
* {@link https://firebase.google.com/docs/reference/js/firebase.database.Reference#isEqual}
*/
isEqual(otherRef: Reference): boolean {
return (
!!otherRef &&
otherRef.constructor === Reference &&
otherRef.key === this.key &&
this._query.queryIdentifier() === otherRef._query.queryIdentifier()
);
}
/**
* GETTERS
*/
/**
* The parent location of a Reference, or null for the root Reference.
* @type {Reference}
*
* {@link https://firebase.google.com/docs/reference/js/firebase.database.Reference#parent}
*/
get parent(): Reference | null {
if (this.path === '/') return null;
return new Reference(
this._database,
this.path.substring(0, this.path.lastIndexOf('/'))
);
}
/**
* A reference to itself
* @type {!Reference}
*
* {@link https://firebase.google.com/docs/reference/js/firebase.database.Reference#ref}
*/
get ref(): Reference {
return this;
}
/**
* Reference to the root of the database: '/'
* @type {!Reference}
*
* {@link https://firebase.google.com/docs/reference/js/firebase.database.Reference#root}
*/
get root(): Reference {
return new Reference(this._database, '/');
}
/**
* Access then method of promise if set
* @return {*}
*/
then(fnResolve: any => any, fnReject: any => any) {
if (isFunction(fnResolve) && this._promise && this._promise.then) {
return this._promise.then.bind(this._promise)(
result => {
this._promise = null;
return fnResolve(result);
},
possibleErr => {
this._promise = null;
if (isFunction(fnReject)) {
return fnReject(possibleErr);
}
throw possibleErr;
}
);
}
throw new Error("Cannot read property 'then' of undefined.");
}
/**
* Access catch method of promise if set
* @return {*}
*/
catch(fnReject: any => any) {
if (isFunction(fnReject) && this._promise && this._promise.catch) {
return this._promise.catch.bind(this._promise)(possibleErr => {
this._promise = null;
return fnReject(possibleErr);
});
}
throw new Error("Cannot read property 'catch' of undefined.");
}
/**
* INTERNALS
*/
/**
* Generate a unique registration key.
*
* @return {string}
*/
_getRegistrationKey(eventType: string): string {
return `$${this._database.databaseUrl}$/${
this.path
}$${this._query.queryIdentifier()}$${listeners}$${eventType}`;
}
/**
* Generate a string that uniquely identifies this
* combination of path and query modifiers
*
* @return {string}
* @private
*/
_getRefKey() {
return `$${this._database.databaseUrl}$/${
this.path
}$${this._query.queryIdentifier()}`;
}
/**
* Set the promise this 'thenable' reference relates to
* @param promise
* @private
*/
_setThenable(promise: Promise<*>) {
this._promise = promise;
}
/**
*
* @param obj
* @returns {Object}
* @private
*/
_serializeObject(obj: Object) {
if (!isObject(obj)) return obj;
// json stringify then parse it calls toString on Objects / Classes
// that support it i.e new Date() becomes a ISO string.
return tryJSONParse(tryJSONStringify(obj));
}
/**
*
* @param value
* @returns {*}
* @private
*/
_serializeAnyType(value: any) {
if (isObject(value)) {
return {
type: 'object',
value: this._serializeObject(value),
};
}
return {
type: typeof value,
value,
};
}
/**
* Register a listener for data changes at the current ref's location.
* The primary method of reading data from a Database.
*
* Listeners can be unbound using {@link off}.
*
* Event Types:
*
* - value: {@link callback}.
* - child_added: {@link callback}
* - child_removed: {@link callback}
* - child_changed: {@link callback}
* - child_moved: {@link callback}
*
* @param {ReferenceEventType} eventType - Type of event to attach a callback for.
* @param {ReferenceEventCallback} callback - Function that will be called
* when the event occurs with the new data.
* @param {cancelCallbackOrContext=} cancelCallbackOrContext - Optional callback that is called
* if the event subscription fails. {@link cancelCallbackOrContext}
* @param {*=} context - Optional object to bind the callbacks to when calling them.
* @returns {ReferenceEventCallback} callback function, unmodified (unbound), for
* convenience if you want to pass an inline function to on() and store it later for
* removing using off().
*
* {@link https://firebase.google.com/docs/reference/js/firebase.database.Reference#on}
*/
on(
eventType: string,
callback: DataSnapshot => any,
cancelCallbackOrContext?: Object => any | Object,
context?: Object
): Function {
if (!eventType) {
throw new Error(
'Query.on failed: Function called with 0 arguments. Expects at least 2.'
);
}
if (!isString(eventType) || !ReferenceEventTypes[eventType]) {
throw new Error(
`Query.on failed: First argument must be a valid string event type: "${Object.keys(
ReferenceEventTypes
).join(', ')}"`
);
}
if (!callback) {
throw new Error(
'Query.on failed: Function called with 1 argument. Expects at least 2.'
);
}
if (!isFunction(callback)) {
throw new Error(
'Query.on failed: Second argument must be a valid function.'
);
}
if (
cancelCallbackOrContext &&
!isFunction(cancelCallbackOrContext) &&
!isObject(context) &&
!isObject(cancelCallbackOrContext)
) {
throw new Error(
'Query.on failed: Function called with 3 arguments, but third optional argument `cancelCallbackOrContext` was not a function.'
);
}
if (
cancelCallbackOrContext &&
!isFunction(cancelCallbackOrContext) &&
context
) {
throw new Error(
'Query.on failed: Function called with 4 arguments, but third optional argument `cancelCallbackOrContext` was not a function.'
);
}
const eventRegistrationKey = this._getRegistrationKey(eventType);
const registrationCancellationKey = `${eventRegistrationKey}$cancelled`;
const _context =
cancelCallbackOrContext && !isFunction(cancelCallbackOrContext)
? cancelCallbackOrContext
: context;
const registrationObj = {
eventType,
ref: this,
path: this.path,
key: this._getRefKey(),
appName: this._database.app.name,
dbURL: this._database.databaseUrl,
eventRegistrationKey,
};
SyncTree.addRegistration({
...registrationObj,
listener: _context ? callback.bind(_context) : callback,
});
if (cancelCallbackOrContext && isFunction(cancelCallbackOrContext)) {
// cancellations have their own separate registration
// as these are one off events, and they're not guaranteed
// to occur either, only happens on failure to register on native
SyncTree.addRegistration({
ref: this,
once: true,
path: this.path,
key: this._getRefKey(),
appName: this._database.app.name,
dbURL: this._database.databaseUrl,
eventType: `${eventType}$cancelled`,
eventRegistrationKey: registrationCancellationKey,
listener: _context
? cancelCallbackOrContext.bind(_context)
: cancelCallbackOrContext,
});
}
// initialise the native listener if not already listening
getNativeModule(this._database).on({
eventType,
path: this.path,
key: this._getRefKey(),
appName: this._database.app.name,
modifiers: this._query.getModifiers(),
hasCancellationCallback: isFunction(cancelCallbackOrContext),
registration: {
eventRegistrationKey,
key: registrationObj.key,
registrationCancellationKey,
},
});
// increment number of listeners - just s short way of making
// every registration unique per .on() call
listeners += 1;
// return original unbound successCallback for
// the purposes of calling .off(eventType, callback) at a later date
return callback;
}
/**
* Detaches a callback previously attached with on().
*
* Detach a callback previously attached with on(). Note that if on() was called
* multiple times with the same eventType and callback, the callback will be called
* multiple times for each event, and off() must be called multiple times to
* remove the callback. Calling off() on a parent listener will not automatically
* remove listeners registered on child nodes, off() must also be called on any
* child listeners to remove the callback.
*
* If a callback is not specified, all callbacks for the specified eventType will be removed.
* Similarly, if no eventType or callback is specified, all callbacks for the Reference will be removed.
* @param eventType
* @param originalCallback
*/
off(eventType?: string = '', originalCallback?: () => any) {
if (!arguments.length) {
// Firebase Docs:
// if no eventType or callback is specified, all callbacks for the Reference will be removed.
return SyncTree.removeListenersForRegistrations(
SyncTree.getRegistrationsByPath(this.path)
);
}
/*
* VALIDATE ARGS
*/
if (
eventType &&
(!isString(eventType) || !ReferenceEventTypes[eventType])
) {
throw new Error(
`Query.off failed: First argument must be a valid string event type: "${Object.keys(
ReferenceEventTypes
).join(', ')}"`
);
}
if (originalCallback && !isFunction(originalCallback)) {
throw new Error(
'Query.off failed: Function called with 2 arguments, but second optional argument was not a function.'
);
}
// Firebase Docs:
// Note that if on() was called
// multiple times with the same eventType and callback, the callback will be called
// multiple times for each event, and off() must be called multiple times to
// remove the callback.
// Remove only a single registration
if (eventType && originalCallback) {
const registration = SyncTree.getOneByPathEventListener(
this.path,
eventType,
originalCallback
);
if (!registration) return [];
// remove the paired cancellation registration if any exist
SyncTree.removeListenersForRegistrations([`${registration}$cancelled`]);
// remove only the first registration to match firebase web sdk
// call multiple times to remove multiple registrations
return SyncTree.removeListenerRegistrations(originalCallback, [
registration,
]);
}
// Firebase Docs:
// If a callback is not specified, all callbacks for the specified eventType will be removed.
const registrations = SyncTree.getRegistrationsByPathEvent(
this.path,
eventType
);
SyncTree.removeListenersForRegistrations(
SyncTree.getRegistrationsByPathEvent(this.path, `${eventType}$cancelled`)
);
return SyncTree.removeListenersForRegistrations(registrations);
}
}