Merge pull request #2017 from ably/fix/2009-fallbacks-in-custom-env

[ECO-5190] Fallbacks in custom environment
ably · Feb 10, 2025 · 022fee0 · 022fee0
2 parents 11f6787 + e58e13a
commit 022fee0
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Showing 4 changed files with 237 additions and 49 deletions.
diff --git a/Source/ARTDefault.m b/Source/ARTDefault.m
@@ -28,7 +28,7 @@ + (NSArray*)fallbackHostsWithEnvironment:(NSString *)environment {
     NSArray<NSString *> * fallbacks = @[@"a", @"b", @"c", @"d", @"e"];
     NSString *prefix = @"";
     NSString *suffix = @"";
-    if (environment && ![[environment stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]] isEqualToString:@""] && ![environment isEqualToString:ARTDefaultProduction]) {
+    if (environment && ![environment isEqualToString:@""] && ![environment isEqualToString:ARTDefaultProduction]) {
         prefix = [NSString stringWithFormat:@"%@-", environment];
         suffix = @"-fallback";
     }

diff --git a/Source/ARTRealtime.m b/Source/ARTRealtime.m
@@ -15,6 +15,7 @@
 #import "ARTMessage.h"
 #import "ARTClientOptions.h"
 #import "ARTClientOptions+TestConfiguration.h"
+#import "ARTClientOptions+Private.h"
 #import "ARTTestClientOptions.h"
 #import "ARTChannelOptions.h"
 #import "ARTPresenceMessage.h"
@@ -1499,13 +1500,31 @@ - (BOOL)reconnectWithFallback {
     }
 }
 
-- (BOOL)shouldRetryWithFallback:(ARTRealtimeTransportError *)error {
-    if (
-        (error.type == ARTRealtimeTransportErrorTypeBadResponse && error.badResponseCode >= 500 && error.badResponseCode <= 504) ||
-        error.type == ARTRealtimeTransportErrorTypeHostUnreachable ||
-        error.type == ARTRealtimeTransportErrorTypeTimeout
-        ) {
-        return YES;
+- (BOOL)shouldRetryWithFallbackForError:(ARTRealtimeTransportError *)error options:(ARTClientOptions *)options {
+    if ((error.type == ARTRealtimeTransportErrorTypeBadResponse && error.badResponseCode >= 500 && error.badResponseCode <= 504) ||
+         error.type == ARTRealtimeTransportErrorTypeHostUnreachable || error.type == ARTRealtimeTransportErrorTypeTimeout) {
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wdeprecated-declarations"
+        // RTN17b3
+        if (options.fallbackHostsUseDefault) {
+            return YES;
+        }
+#pragma clang diagnostic pop
+
+        // RTN17b1
+        if (!(options.hasCustomRealtimeHost || options.hasCustomPort || options.hasCustomTlsPort)) {
+            return YES;
+        }
+
+        // RTN17b2
+        if (options.fallbackHosts) {
+            return YES;
+        }
+
+        // RSC15g2
+        if (options.hasEnvironmentDifferentThanProduction) {
+            return YES;
+        }
     }
     return NO;
 }
@@ -1648,28 +1667,25 @@ - (void)realtimeTransportFailed:(id<ARTRealtimeTransport>)transport withError:(A
 
     ARTLogDebug(self.logger, @"R:%p realtime transport failed: %@", self, transportError);
 
-    if ([self shouldRetryWithFallback:transportError]) {
+    ARTErrorInfo *const errorInfo = [ARTErrorInfo createFromNSError:transportError.error];
+    ARTConnectionStateChangeParams *const params = [[ARTConnectionStateChangeParams alloc] initWithErrorInfo:errorInfo];
+
+    ARTClientOptions *const clientOptions = [self getClientOptions];
+
+    if ([self shouldRetryWithFallbackForError:transportError options:clientOptions]) {
         ARTLogDebug(self.logger, @"R:%p host is down; can retry with fallback host", self);
-        if (!_fallbacks && [transportError.url.host isEqualToString:[ARTDefault realtimeHost]]) {
-            ARTClientOptions *const clientOptions = [self getClientOptions];
+        if (!_fallbacks) {
             NSArray *hosts = [ARTFallbackHosts hostsFromOptions:clientOptions];
-            self->_fallbacks = [[ARTFallback alloc] initWithFallbackHosts:hosts shuffleArray:clientOptions.testOptions.shuffleArray];
-            if (self->_fallbacks != nil) {
-                [self reconnectWithFallback];
-            } else {
-                ARTErrorInfo *const errorInfo = [ARTErrorInfo createFromNSError:transportError.error];
-                ARTConnectionStateChangeParams *const params = [[ARTConnectionStateChangeParams alloc] initWithErrorInfo:errorInfo];
-                [self performTransitionToState:ARTRealtimeFailed withParams:params];
-            }
-            return;
-        } else if (_fallbacks && [self reconnectWithFallback]) {
-            return;
+            _fallbacks = [[ARTFallback alloc] initWithFallbackHosts:hosts shuffleArray:clientOptions.testOptions.shuffleArray];
+        }
+        if (_fallbacks) {
+            [self reconnectWithFallback];
+        } else {
+            [self performTransitionToState:ARTRealtimeFailed withParams:params];
         }
+    } else {
+        [self performTransitionToDisconnectedOrSuspendedWithParams:params];
     }
-
-    ARTErrorInfo *const errorInfo = [ARTErrorInfo createFromNSError:transportError.error];
-    ARTConnectionStateChangeParams *const params = [[ARTConnectionStateChangeParams alloc] initWithErrorInfo:errorInfo];
-    [self performTransitionToDisconnectedOrSuspendedWithParams:params];
 }
 
 - (void)realtimeTransportNeverConnected:(id<ARTRealtimeTransport>)transport {

diff --git a/Source/include/Ably/ARTClientOptions.h b/Source/include/Ably/ARTClientOptions.h
@@ -37,7 +37,7 @@ NS_ASSUME_NONNULL_BEGIN
 /**
  * Enables a [custom environment](https://ably.com/docs/platform-customization) to be used with the Ably service.
  */
-@property (readwrite, nonatomic) NSString *environment;
+@property (readwrite, nonatomic, nullable) NSString *environment;
 
 /**
  * When `false`, the client will use an insecure connection. The default is `true`, meaning a TLS connection will be used to connect to Ably.