Implement RTDB Query get

FirebaseDatabase/CHANGELOG.md

@@ -1,5 +1,6 @@
 # Unreleased
 - [added] Made emulator connection API consistent between Auth, Database, Firestore, and Functions (#5916).
+- [added] Implement RTDB Query get (#7110)
 
 # v7.0.0
 - [fixed] Disabled a deprecation warning. (#6502)

FirebaseDatabase/Sources/Api/FIRDatabaseQuery.m

@@ -581,6 +581,13 @@ - (void)keepSynced:(BOOL)keepSynced {
     });
 }
 
+- (void)getDataWithCompletionBlock:(void (^)(NSError *__nullable error,
+                                             FIRDataSnapshot *snapshot))block {
+    dispatch_async([FIRDatabaseQuery sharedQueue], ^{
+      [self.repo getValue:self withCompletionBlock:block];
+    });
+}
+
 - (void)observeSingleEventOfType:(FIRDataEventType)eventType
                        withBlock:(fbt_void_datasnapshot)block {
 

FirebaseDatabase/Sources/Api/Private/FTypedefs_Private.h

@@ -46,6 +46,8 @@ typedef BOOL (^fbt_bool_nsstring_node)(NSString *, id<FNode>);
 typedef void (^fbt_void_path_node_marray)(FPath *, id<FNode>, NSMutableArray *);
 typedef BOOL (^fbt_bool_void)(void);
 typedef void (^fbt_void_nsstring_nsstring)(NSString *str1, NSString *str2);
+typedef void (^fbt_void_nsstring_id_nsstring)(NSString *str1, id dict1,
+                                              NSString *str2);
 typedef void (^fbt_void_nsstring_nserror)(NSString *str, NSError *error);
 typedef BOOL (^fbt_bool_path)(FPath *str);
 typedef void (^fbt_void_id)(id data);

FirebaseDatabase/Sources/Constants/FConstants.h

@@ -75,6 +75,7 @@ FOUNDATION_EXPORT NSString *const kFWPAsyncServerControlMessageReset;
 
 FOUNDATION_EXPORT NSString *const kFWPRequestActionPut;
 FOUNDATION_EXPORT NSString *const kFWPRequestActionMerge;
+FOUNDATION_EXPORT NSString *const kFWPRequestActionGet;
 FOUNDATION_EXPORT NSString *const kFWPRequestActionTaggedListen;
 FOUNDATION_EXPORT NSString *const kFWPRequestActionTaggedUnlisten;
 FOUNDATION_EXPORT NSString
@@ -105,9 +106,11 @@ FOUNDATION_EXPORT NSString *const kFWPRequestStatus;
 FOUNDATION_EXPORT NSString *const kWireProtocolVersionParam;
 FOUNDATION_EXPORT NSString *const kWebsocketProtocolVersion;
 FOUNDATION_EXPORT NSString *const kWebsocketServerKillPacket;
+FOUNDATION_EXPORT NSString *const kPersistentConnOffline;
 FOUNDATION_EXPORT const int kWebsocketMaxFrameSize;
 FOUNDATION_EXPORT NSUInteger const kWebsocketKeepaliveInterval;
 FOUNDATION_EXPORT NSUInteger const kWebsocketConnectTimeout;
+FOUNDATION_EXPORT UInt64 const kPersistentConnGetConnectTimeout;
 
 FOUNDATION_EXPORT float const kPersistentConnReconnectMinDelay;
 FOUNDATION_EXPORT float const kPersistentConnReconnectMaxDelay;
@@ -145,6 +148,7 @@ FOUNDATION_EXPORT NSString *const kFInterruptReasonAuthExpired;
 FOUNDATION_EXPORT NSString *const kPayloadPriority;
 FOUNDATION_EXPORT NSString *const kPayloadValue;
 FOUNDATION_EXPORT NSString *const kPayloadMetadataPrefix;
+FOUNDATION_EXPORT NSString *const kPayloadNull;
 
 #pragma mark -
 #pragma mark ServerValue constants

FirebaseDatabase/Sources/Constants/FConstants.m

@@ -70,6 +70,7 @@
 
 NSString *const kFWPRequestActionPut = @"p";
 NSString *const kFWPRequestActionMerge = @"m";
+NSString *const kFWPRequestActionGet = @"g";
 NSString *const kFWPRequestActionListen =
     @"l"; // {"t": "d", "d": {"r": 1, "a": "l", "b": { "p": "/" } } }
 NSString *const kFWPRequestActionUnlisten = @"u";
@@ -99,9 +100,11 @@
 NSString *const kWireProtocolVersionParam = @"v";
 NSString *const kWebsocketProtocolVersion = @"5";
 NSString *const kWebsocketServerKillPacket = @"kill";
+NSString *const kPersistentConnOffline = @"Client is offline.";
 const int kWebsocketMaxFrameSize = 16384;
 NSUInteger const kWebsocketKeepaliveInterval = 45;
 NSUInteger const kWebsocketConnectTimeout = 30;
+UInt64 const kPersistentConnGetConnectTimeout = 3 * NSEC_PER_SEC;
 
 float const kPersistentConnReconnectMinDelay = 1.0;
 float const kPersistentConnReconnectMaxDelay = 30.0;
@@ -137,6 +140,7 @@
 NSString *const kPayloadPriority = @".priority";
 NSString *const kPayloadValue = @".value";
 NSString *const kPayloadMetadataPrefix = @".";
+NSString *const kPayloadNull = @"<null>";
 
 #pragma mark -
 #pragma mark ServerValue constants

FirebaseDatabase/Sources/Core/FPersistentConnection.h

@@ -60,6 +60,9 @@
 - (void)onDisconnectCancelPath:(FPath *)path
                   withCallback:(fbt_void_nsstring_nsstring)callback;
 - (void)ackPuts;
+- (void)get:(NSString *)pathString
+      withParams:(NSDictionary *)queryWireProtocolParams
+    withCallback:(fbt_void_nsstring_id_nsstring)onComplete;
 - (void)purgeOutstandingWrites;
 
 - (void)interruptForReason:(NSString *)reason;

FirebaseDatabase/Sources/Core/FPersistentConnection.m

@@ -64,6 +64,18 @@ @implementation FOutstandingPut
 
 @end
 
+@interface FOutstandingGet : NSObject
+
+@property(nonatomic, strong) NSDictionary *request;
+@property(nonatomic, copy) fbt_void_nsstring_id_nsstring onCompleteBlock;
+@property(nonatomic) BOOL sent;
+
+@end
+
+@implementation FOutstandingGet
+
+@end
+
 typedef enum {
     ConnectionStateDisconnected,
     ConnectionStateGettingToken,
@@ -92,9 +104,11 @@ - (void)sendOnDisconnectAction:(NSString *)action
 @property(nonatomic, strong) FConnection *realtime;
 @property(nonatomic, strong) NSMutableDictionary *listens;
 @property(nonatomic, strong) NSMutableDictionary *outstandingPuts;
+@property(nonatomic, strong) NSMutableDictionary *outstandingGets;
 @property(nonatomic, strong) NSMutableArray *onDisconnectQueue;
 @property(nonatomic, strong) FRepoInfo *repoInfo;
 @property(nonatomic, strong) FAtomicNumber *putCounter;
+@property(nonatomic, strong) FAtomicNumber *getCounter;
 @property(nonatomic, strong) FAtomicNumber *requestNumber;
 @property(nonatomic, strong) NSMutableDictionary *requestCBHash;
 @property(nonatomic, strong) FIRDatabaseConfig *config;
@@ -128,8 +142,10 @@ - (id)initWithRepoInfo:(FRepoInfo *)repoInfo
 
         self.listens = [[NSMutableDictionary alloc] init];
         self.outstandingPuts = [[NSMutableDictionary alloc] init];
+        self.outstandingGets = [[NSMutableDictionary alloc] init];
         self.onDisconnectQueue = [[NSMutableArray alloc] init];
         self.putCounter = [[FAtomicNumber alloc] init];
+        self.getCounter = [[FAtomicNumber alloc] init];
         self.requestNumber = [[FAtomicNumber alloc] init];
         self.requestCBHash = [[NSMutableDictionary alloc] init];
         self.unackedListensCount = 0;
@@ -309,6 +325,9 @@ - (BOOL)canSendWrites {
     return self->connectionState == ConnectionStateConnected;
 }
 
+- (BOOL)canSendReads {
+    return self->connectionState == ConnectionStateConnected;
+}
 #pragma mark -
 #pragma mark FConnection delegate methods
 
@@ -707,6 +726,39 @@ - (void)sendPut:(NSNumber *)index {
             }];
 }
 
+- (void)sendGet:(NSNumber *)index {
+    NSAssert([self canSendReads],
+             @"sendGet called when not able to send reads");
+    FOutstandingGet *get = self.outstandingGets[index];
+    assert(get != nil);
+    if ([get sent]) {
+        return;
+    }
+    get.sent = YES;
+    [self sendAction:kFWPRequestActionGet
+                body:get.request
+           sensitive:NO
+            callback:^(NSDictionary *data) {
+              FOutstandingGet *currentGet = self.outstandingGets[index];
+              if (currentGet == get) {
+                  [self.outstandingGets removeObjectForKey:index];
+                  NSString *status =
+                      [data objectForKey:kFWPResponseForActionStatus];
+                  id resultData = [data objectForKey:kFWPResponseForActionData];
+                  if ([status isEqualToString:kFWPResponseForActionStatusOk]) {
+                      get.onCompleteBlock(status, resultData, nil);
+                      return;
+                  }
+                  get.onCompleteBlock(status, nil, resultData);
+              } else {
+                  FFLog(@"I-RDB034045",
+                        @"Ignoring on complete for get %@ because it was "
+                        @"already removed",
+                        index);
+              }
+            }];
+}
+
 - (void)sendUnlisten:(FPath *)path
          queryParams:(FQueryParams *)queryParams
                tagId:(NSNumber *)tagId {
@@ -759,6 +811,44 @@ - (void)putInternal:(id)data
     }
 }
 
+- (void)get:(NSString *)pathString
+      withParams:(NSDictionary *)queryWireProtocolParams
+    withCallback:(fbt_void_nsstring_id_nsstring)onComplete {
+    NSMutableDictionary *request = [NSMutableDictionary
+        dictionaryWithObjectsAndKeys:pathString, kFWPRequestPath,
+                                     queryWireProtocolParams,
+                                     kFWPRequestQueries, nil];
+    FOutstandingGet *get = [[FOutstandingGet alloc] init];
+    get.request = request;
+    get.onCompleteBlock = onComplete;
+    get.sent = NO;
+
+    NSNumber *index = [self.getCounter getAndIncrement];
+    self.outstandingGets[index] = get;
+
+    if (![self connected]) {
+        dispatch_after(
+            dispatch_time(DISPATCH_TIME_NOW, kPersistentConnGetConnectTimeout),
+            self.dispatchQueue, ^{
+              FOutstandingGet *get = self.outstandingGets[index];
+              if ([get sent]) {
+                  return;
+              }
+              get.sent = YES;
+              [self.outstandingGets removeObjectForKey:index];
+              get.onCompleteBlock(@"failed", nil, kPersistentConnOffline);
+            });
+        return;
+    }
+
+    if ([self canSendReads]) {
+        FFLog(@"I-RDB034024", @"Was connected, and added as index: %@", index);
+        [self sendGet:index];
+    } else {
+        FFLog(@"I-RDB034025", @"Was connected, and added as index: %@", index);
+    }
+}
+
 - (void)sendListen:(FOutstandingQuery *)listenSpec {
     FQuerySpec *query = listenSpec.query;
     FFLog(@"I-RDB034026", @"Listen for %@", query);
@@ -1009,6 +1099,17 @@ - (void)restoreState {
         }
     }
 
+    NSArray *getKeys = [[self.outstandingGets allKeys]
+        sortedArrayUsingSelector:@selector(compare:)];
+    for (int i = 0; i < [getKeys count]; i++) {
+        if ([self.outstandingGets objectForKey:[keys objectAtIndex:i]] != nil) {
+            FFLog(@"I-RDB034037", @"Restoring get: %d", i);
+            [self sendGet:[keys objectAtIndex:i]];
+        } else {
+            FFLog(@"I-RDB034038", @"Restoring get: skipped nil: %d", i);
+        }
+    }
+
     for (FTupleOnDisconnect *tuple in self.onDisconnectQueue) {
         [self sendOnDisconnectAction:tuple.action
                              forPath:tuple.pathString

FirebaseDatabase/Sources/Core/FRepo.h

@@ -17,6 +17,7 @@
 #import "FirebaseDatabase/Sources/Core/FPersistentConnection.h"
 #import "FirebaseDatabase/Sources/Core/FRepoInfo.h"
 #import "FirebaseDatabase/Sources/Public/FirebaseDatabase/FIRDataEventType.h"
+#import "FirebaseDatabase/Sources/Public/FirebaseDatabase/FIRDatabaseQuery.h"
 #import "FirebaseDatabase/Sources/Utilities/Tuples/FTupleUserCallback.h"
 #import <Foundation/Foundation.h>
 
@@ -45,6 +46,11 @@
     withCallback:(fbt_void_nserror_ref)callback;
 - (void)purgeOutstandingWrites;
 
+- (void)getValue:(FIRDatabaseQuery *)query
+    withCompletionBlock:
+        (void (^_Nonnull)(NSError *__nullable error,
+                          FIRDataSnapshot *__nullable snapshot))block;
+
 - (void)addEventRegistration:(id<FEventRegistration>)eventRegistration
                     forQuery:(FQuerySpec *)query;
 - (void)removeEventRegistration:(id<FEventRegistration>)eventRegistration

FirebaseDatabase/Sources/Core/FRepo.m

@@ -513,6 +513,57 @@ - (void)purgeOutstandingWrites {
     [self.connection purgeOutstandingWrites];
 }
 
+- (void)getValue:(FIRDatabaseQuery *)query
+    withCompletionBlock:
+        (void (^_Nonnull)(NSError *__nullable error,
+                          FIRDataSnapshot *__nullable snapshot))block {
+    FQuerySpec *querySpec = [query querySpec];
+    [self.persistenceManager setQueryActive:querySpec];
+    [self.connection
+                 get:[query.path toString]
+          withParams:querySpec.params.wireProtocolParams
+        withCallback:^(NSString *status, id data, NSString *errorReason) {
+          id<FNode> node;
+          if (![status isEqualToString:kFWPResponseForActionStatusOk]) {
+              FFLog(@"I-RDB038024",
+                    @"getValue for query %@ falling back to cache",
+                    [querySpec.path toString]);
+              node = [self.serverSyncTree
+                  calcCompleteEventCacheAtPath:querySpec.path
+                               excludeWriteIds:@[]];
+              if ([node isEmpty]) {
+                  FFWarn(@"I-RDB038025", @"getValue for query at %@ failed: %@",
+                         [querySpec.path toString], status);
+                  NSDictionary *errorDict = @{
+                      NSLocalizedFailureReasonErrorKey : errorReason,
+                      NSLocalizedDescriptionKey : [NSString
+                          stringWithFormat:
+                              @"Unable to get latest value for query %@, "
+                              @"client offline and cache is empty",
+                              querySpec]
+                  };
+                  block([NSError errorWithDomain:kFirebaseCoreErrorDomain
+                                            code:1
+                                        userInfo:errorDict],
+                        nil);
+                  return;
+              }
+          } else {
+              node = [FSnapshotUtilities nodeFrom:data];
+          }
+          [self.eventRaiser
+              raiseEvents:[self.serverSyncTree
+                              applyServerOverwriteAtPath:[query path]
+                                                 newData:node]];
+          block(nil, [[FIRDataSnapshot alloc]
+                         initWithRef:query.ref
+                         indexedNode:[FIndexedNode
+                                         indexedNodeWithNode:node
+                                                       index:querySpec.index]]);
+          [self.persistenceManager setQueryInactive:querySpec];
+        }];
+}
+
 - (void)addEventRegistration:(id<FEventRegistration>)eventRegistration
                     forQuery:(FQuerySpec *)query {
     NSArray *events = nil;

FirebaseDatabase/Sources/Public/FirebaseDatabase/FIRDatabaseQuery.h

@@ -131,6 +131,10 @@ NS_SWIFT_NAME(DatabaseQuery)
                       withCancelBlock:
                           (nullable void (^)(NSError *error))cancelBlock;
 
+- (void)getDataWithCompletionBlock:
+    (void (^_Nonnull)(NSError *__nullable error,
+                      FIRDataSnapshot *snapshot))block;
+
 /**
  * This is equivalent to observeEventType:withBlock:, except the block is
  * immediately canceled after the initial data is returned.