diff --git a/docs/api/database.md b/docs/api/database.md
index c019356..7145d71 100644
--- a/docs/api/database.md
+++ b/docs/api/database.md
@@ -36,6 +36,14 @@ firestack.database()
```
Useful for `orderByPriority` queries.
+
+Transaction Support:
+```javascript
+firestack.database()
+ .ref('posts/1234/title')
+ .transaction((title) => 'My Awesome Post');
+```
+
## Unmounted components
Listening to database updates on unmounted components will trigger a warning:
diff --git a/ios/Firestack/FirestackDatabase.h b/ios/Firestack/FirestackDatabase.h
index 77aa8f3..850a36a 100644
--- a/ios/Firestack/FirestackDatabase.h
+++ b/ios/Firestack/FirestackDatabase.h
@@ -18,6 +18,8 @@
}
@property NSMutableDictionary *dbReferences;
+@property NSMutableDictionary *transactions;
+@property dispatch_queue_t transactionQueue;
@end
diff --git a/ios/Firestack/FirestackDatabase.m b/ios/Firestack/FirestackDatabase.m
index 314500e..5cd833d 100644
--- a/ios/Firestack/FirestackDatabase.m
+++ b/ios/Firestack/FirestackDatabase.m
@@ -21,6 +21,8 @@ @interface FirestackDBReference : NSObject
@property FIRDatabaseHandle childRemovedHandler;
@property FIRDatabaseHandle childMovedHandler;
@property FIRDatabaseHandle childValueHandler;
++ (NSDictionary *) snapshotToDict:(FIRDataSnapshot *) snapshot;
+
@end
@implementation FirestackDBReference
@@ -52,7 +54,7 @@ - (void) addEventHandler:(NSString *) eventName
{
if (![self isListeningTo:eventName]) {
id withBlock = ^(FIRDataSnapshot * _Nonnull snapshot) {
- NSDictionary *props = [self snapshotToDict:snapshot];
+ NSDictionary *props = [FirestackDBReference snapshotToDict:snapshot];
[self sendJSEvent:DATABASE_DATA_EVENT
title:eventName
props: @{
@@ -142,7 +144,7 @@ - (void) removeEventHandler:(NSString *) name
[self unsetListeningOn:name];
}
-- (NSDictionary *) snapshotToDict:(FIRDataSnapshot *) snapshot
++ (NSDictionary *) snapshotToDict:(FIRDataSnapshot *) snapshot
{
NSMutableDictionary *dict = [[NSMutableDictionary alloc] init];
[dict setValue:snapshot.key forKey:@"key"];
@@ -377,6 +379,8 @@ - (id) init
self = [super init];
if (self != nil) {
_dbReferences = [[NSMutableDictionary alloc] init];
+ _transactions = [[NSMutableDictionary alloc] init];
+ _transactionQueue = dispatch_queue_create("com.fullstackreact.react-native-firestack", DISPATCH_QUEUE_CONCURRENT);
}
return self;
}
@@ -479,7 +483,85 @@ - (id) init
}
}
+RCT_EXPORT_METHOD(beginTransaction:(NSString *) path
+ withIdentifier:(NSString *) identifier
+ applyLocally:(BOOL) applyLocally
+ onComplete:(RCTResponseSenderBlock) onComplete)
+{
+ dispatch_async(_transactionQueue, ^{
+ NSMutableDictionary *transactionState = [NSMutableDictionary new];
+
+ dispatch_semaphore_t sema = dispatch_semaphore_create(0);
+ [transactionState setObject:sema forKey:@"semaphore"];
+
+ FIRDatabaseReference *ref = [self getPathRef:path];
+ [ref runTransactionBlock:^FIRTransactionResult * _Nonnull(FIRMutableData * _Nonnull currentData) {
+ dispatch_barrier_async(_transactionQueue, ^{
+ [_transactions setValue:transactionState forKey:identifier];
+ [self sendEventWithName:DATABASE_TRANSACTION_EVENT
+ body:@{
+ @"id": identifier,
+ @"originalValue": currentData.value
+ }];
+ });
+ // Wait for the event handler to call tryCommitTransaction
+ // WARNING: This wait occurs on the Firebase Worker Queue
+ // so if tryCommitTransaction fails to signal the semaphore
+ // no further blocks will be executed by Firebase until the timeout expires
+ dispatch_time_t delayTime = dispatch_time(DISPATCH_TIME_NOW, 30 * NSEC_PER_SEC);
+ BOOL timedout = dispatch_semaphore_wait(sema, delayTime) != 0;
+ BOOL abort = [transactionState valueForKey:@"abort"] || timedout;
+ id value = [transactionState valueForKey:@"value"];
+ dispatch_barrier_async(_transactionQueue, ^{
+ [_transactions removeObjectForKey:identifier];
+ });
+ if (abort) {
+ return [FIRTransactionResult abort];
+ } else {
+ currentData.value = value;
+ return [FIRTransactionResult successWithValue:currentData];
+ }
+ } andCompletionBlock:^(NSError * _Nullable databaseError, BOOL committed, FIRDataSnapshot * _Nullable snapshot) {
+ if (databaseError != nil) {
+ NSDictionary *evt = @{
+ @"errorCode": [NSNumber numberWithInt:[databaseError code]],
+ @"errorDetails": [databaseError debugDescription],
+ @"description": [databaseError description]
+ };
+ onComplete(@[evt]);
+ } else {
+ onComplete(@[[NSNull null], @{
+ @"committed": [NSNumber numberWithBool:committed],
+ @"snapshot": [FirestackDBReference snapshotToDict:snapshot],
+ @"status": @"success",
+ @"method": @"transaction"
+ }]);
+ }
+ } withLocalEvents:applyLocally];
+ });
+}
+RCT_EXPORT_METHOD(tryCommitTransaction:(NSString *) identifier
+ withData:(NSDictionary *) data
+ orAbort:(BOOL) abort)
+{
+ __block NSMutableDictionary *transactionState;
+ dispatch_sync(_transactionQueue, ^{
+ transactionState = [_transactions objectForKey: identifier];
+ });
+ if (!transactionState) {
+ NSLog(@"tryCommitTransaction for unknown ID %@", identifier);
+ return;
+ }
+ dispatch_semaphore_t sema = [transactionState valueForKey:@"semaphore"];
+ if (abort) {
+ [transactionState setValue:@true forKey:@"abort"];
+ } else {
+ id newValue = [data valueForKey:@"value"];
+ [transactionState setValue:newValue forKey:@"value"];
+ }
+ dispatch_semaphore_signal(sema);
+}
RCT_EXPORT_METHOD(on:(NSString *) path
modifiersString:(NSString *) modifiersString
@@ -634,7 +716,7 @@ - (NSString *) getDBListenerKey:(NSString *) path
// Not sure how to get away from this... yet
- (NSArray<NSString *> *)supportedEvents {
- return @[DATABASE_DATA_EVENT, DATABASE_ERROR_EVENT];
+ return @[DATABASE_DATA_EVENT, DATABASE_ERROR_EVENT, DATABASE_TRANSACTION_EVENT];
}
diff --git a/ios/Firestack/FirestackEvents.h b/ios/Firestack/FirestackEvents.h
index fd6b01d..68ead8b 100644
--- a/ios/Firestack/FirestackEvents.h
+++ b/ios/Firestack/FirestackEvents.h
@@ -29,6 +29,7 @@ static NSString *const DEBUG_EVENT = @"debug";
// Database
static NSString *const DATABASE_DATA_EVENT = @"database_event";
static NSString *const DATABASE_ERROR_EVENT = @"database_error";
+static NSString *const DATABASE_TRANSACTION_EVENT = @"database_transaction_update";
static NSString *const DATABASE_VALUE_EVENT = @"value";
static NSString *const DATABASE_CHILD_ADDED_EVENT = @"child_added";
diff --git a/lib/modules/database/index.js b/lib/modules/database/index.js
index e117648..f3eecdd 100644
--- a/lib/modules/database/index.js
+++ b/lib/modules/database/index.js
@@ -19,7 +19,10 @@ export default class Database extends Base {
constructor(firestack: Object, options: Object = {}) {
super(firestack, options);
this.subscriptions = {};
+
+ this.transactions = {};
this.errorSubscriptions = {};
+
this.serverTimeOffset = 0;
this.persistenceEnabled = false;
this.namespace = 'firestack:database';
@@ -34,6 +37,11 @@ export default class Database extends Base {
err => this._handleDatabaseError(err)
);
+ this.transactionListener = FirestackDatabaseEvt.addListener(
+ 'database_transaction_update',
+ event => this._handleDatabaseTransaction(event)
+ );
+
this.offsetRef = this.ref('.info/serverTimeOffset');
this.offsetRef.on('value', (snapshot) => {
@@ -164,6 +172,34 @@ export default class Database extends Base {
FirestackDatabase.goOffline();
}
+ addTransaction(path, updateCallback, applyLocally) {
+ let id = this._generateTransactionID();
+ this.transactions[id] = updateCallback;
+ return promisify('beginTransaction', FirestackDatabase)(path, id, applyLocally || false)
+ .then((v) => {delete this.transactions[id]; return v;},
+ (e) => {delete this.transactions[id]; throw e;});
+ }
+
+ _generateTransactionID() {
+ // 10 char random alphanumeric
+ return Math.random().toString(36).substr(2, 10);
+ }
+
+ _handleDatabaseTransaction(event) {
+ const {id, originalValue} = event;
+ let newValue;
+ try {
+ const updateCallback = this.transactions[id];
+ newValue = updateCallback(originalValue);
+ } finally {
+ let abort = false;
+ if (newValue === undefined) {
+ abort = true;
+ }
+ FirestackDatabase.tryCommitTransaction(id, {value: newValue}, abort);
+ }
+ }
+
/**
* INTERNALS
*/
diff --git a/lib/modules/database/reference.js b/lib/modules/database/reference.js
index e74b5aa..adc6952 100644
--- a/lib/modules/database/reference.js
+++ b/lib/modules/database/reference.js
@@ -137,6 +137,19 @@ export default class Reference extends ReferenceBase {
return this.db.off(path, modifiersString, eventName, origCB);
}
+ transaction(transactionUpdate, onComplete, applyLocally) {
+ const path = this._dbPath();
+ return this.db.addTransaction(path, transactionUpdate, applyLocally)
+ .then((({ snapshot, committed }) => {return {snapshot: new Snapshot(this, snapshot), committed}}).bind(this))
+ .then(({ snapshot, committed }) => {
+ if (isFunction(onComplete)) onComplete(null, snapshot);
+ return {snapshot, committed};
+ }).catch((e) => {
+ if (isFunction(onComplete)) return onComplete(e, null);
+ throw e;
+ });
+ }
+
/**
* MODIFIERS
*/