import new feature here: double check introduced, please try!

Author: dustturtle

RealReachability/RealReachability.h

@@ -1,6 +1,6 @@
 //
 //  RealReachability.h
-//  Version 1.1.0
+//  Version 1.1.9
 //
 //  Created by Dustturtle on 16/1/9.
 //  Copyright (c) 2016 Dustturtle. All rights reserved.
@@ -50,11 +50,26 @@ typedef NS_ENUM(NSInteger, WWANAccessType) {
     WWANType2G = 3
 };
 
+@protocol RealReachabilityDelegate <NSObject>
+@optional
+/// TODO:通过挂载一个定制的代理请求来检查网络，需要用户自己实现，我们会给出一个示例。
+/// 可以通过这种方式规避解决http可用但icmp被阻止的场景下框架判断不正确的问题。
+/// 此方法阻塞？同步返回？还是异步？如果阻塞主线程超过n秒是不行的。
+/// 当CustomAgent的doubleCheck被启用时，ping的doubleCheck将不再工作。
+/// TODO: We introduce a custom agent to check the network by making http request, that need
+/// the user to achieve this.
+/// We want to solve the issue on special case(http available but icmp prevented).
+/// NOTE: When the double check of the custom agent was used, the double check by ping will work no longer.
+- (BOOL)doubleCheckByCustomAgent;
+@end
+
 @interface RealReachability : NSObject
 
 /// Please make sure this host is available for pinging! default host:www.apple.com
 @property (nonatomic, copy) NSString *hostForPing;
 
+@property (nonatomic, copy) NSString *hostForCheck;
+
 /// Interval in minutes; default is 2.0f, suggest value from 0.3f to 60.0f;
 /// If exceeded, the value will be reset to 0.3f or 60.0f (the closer one).
 @property (nonatomic, assign) float autoCheckInterval;
@@ -71,8 +86,10 @@ typedef NS_ENUM(NSInteger, WWANAccessType) {
 /**
  *  To get real reachability we need to do async request,
  *  then we use the block blow for invoker to handle business request(need real reachability).
+ *  Now we have introduced a double check to make our result more reliable.
  *
- *  @param asyncHandler async request handler, return in 2 seconds(max limit).
+ *  @param asyncHandler async request handler, return in 5 seconds(max limit).
+ *  The limit time may be adjusted later for better experience.
  */
 - (void)reachabilityWithBlock:(void (^)(ReachabilityStatus status))asyncHandler;
 

RealReachability/RealReachability.m

@@ -35,6 +35,12 @@ @interface RealReachability()
 @property (nonatomic,strong) NSArray *typeStrings2G;
 
 @property (nonatomic, assign) ReachabilityStatus previousStatus;
+
+/// main helper
+@property (nonatomic, strong) PingHelper *pingHelper;
+
+/// for double check
+@property (nonatomic, strong) PingHelper *pingChecker;
 @end
 
 @implementation RealReachability
@@ -63,13 +69,17 @@ - (id)init
         _typeStrings4G = @[CTRadioAccessTechnologyLTE];
 
         _hostForPing = kDefaultHost;
+        _hostForCheck = kDefaultHost;
         _autoCheckInterval = kDefaultCheckInterval;
         _pingTimeout = kDefaultPingTimeout;
 
         [[NSNotificationCenter defaultCenter] addObserver:self
                                                  selector:@selector(appBecomeActive)
                                                      name:UIApplicationDidBecomeActiveNotification
                                                    object:nil];
+        
+        _pingHelper = [[PingHelper alloc] init];
+        _pingChecker = [[PingHelper alloc] init];
     }
     return self;
 }
@@ -124,16 +134,20 @@ - (void)startNotifier
 
     [GLocalConnection startNotifier];
     [[NSNotificationCenter defaultCenter] addObserver:self
-                                             selector:@selector(localConnectionChanged:)
+                                             selector:@selector(localConnectionHandler:)
                                                  name:kLocalConnectionChangedNotification
                                                object:nil];
     [[NSNotificationCenter defaultCenter] addObserver:self
-                                             selector:@selector(localConnectionInitialized:)
+                                             selector:@selector(localConnectionHandler:)
                                                  name:kLocalConnectionInitializedNotification
                                                object:nil];
 
-    GPingHelper.host = _hostForPing;
-    GPingHelper.timeout = self.pingTimeout;
+    self.pingHelper.host = _hostForPing;
+    self.pingHelper.timeout = self.pingTimeout;
+    
+    self.pingChecker.host = _hostForCheck;
+    self.pingChecker.timeout = self.pingTimeout;
+    
     [self autoCheckReachability];
 }
 
@@ -168,56 +182,31 @@ - (void)reachabilityWithBlock:(void (^)(ReachabilityStatus status))asyncHandler
         return;
     }
 
-    ReachabilityStatus status = [self currentReachabilityStatus];
     __weak __typeof(self)weakSelf = self;
-    [GPingHelper pingWithBlock:^(BOOL isSuccess)
+    [self.pingHelper pingWithBlock:^(BOOL isSuccess)
      {
          __strong __typeof(weakSelf)strongSelf = weakSelf;
-         NSDictionary *inputDic = @{kEventKeyID:@(RREventPingCallback), kEventKeyParam:@(isSuccess)};
-         NSInteger rtn = [strongSelf.engine receiveInput:inputDic];
-         if (rtn == 0) // state changed & state available, post notification.
+         if (isSuccess)
          {
-             if ([strongSelf.engine isCurrentStateAvailable])
+             // no need to post the notification because the status is not changing.
+             NSDictionary *inputDic = @{kEventKeyID:@(RREventPingCallback), kEventKeyParam:@(YES)};
+             [strongSelf.engine receiveInput:inputDic];
+            
+             if (asyncHandler != nil)
              {
-                 strongSelf.previousStatus = status;
-                 // this makes sure the change notification happens on the MAIN THREAD
-                 __weak __typeof(strongSelf)deepWeakSelf = strongSelf;
-                 dispatch_async(dispatch_get_main_queue(), ^{
-                     __strong __typeof(deepWeakSelf)deepStrongSelf = deepWeakSelf;
-                     [[NSNotificationCenter defaultCenter] postNotificationName:kRealReachabilityChangedNotification
-                                                                         object:deepStrongSelf];
-                 });
+                 ReachabilityStatus currentStatus = [strongSelf currentReachabilityStatus];
+                 asyncHandler(currentStatus);
              }
          }
-         
-         if (asyncHandler != nil)
+         else
          {
-             RRStateID currentID = strongSelf.engine.currentStateID;
-             switch (currentID)
-             {
-                 case RRStateUnReachable:
-                 {
-                     asyncHandler(RealStatusNotReachable);
-                     break;
-                 }
-                 case RRStateWIFI:
-                 {
-                     asyncHandler(RealStatusViaWiFi);
-                     break;
-                 }
-                 case RRStateWWAN:
-                 {
-                     asyncHandler(RealStatusViaWWAN);
-                     break;
-                 }
-                     
-                 default:
-                 {
-                     NSLog(@"warning! reachState uncertain! state unmatched, treat as unreachable temporary");
-                     asyncHandler(RealStatusNotReachable);
-                     break;
-                 }
-             }
+             // delay 1 seconds, then make a double check.
+             dispatch_time_t time = dispatch_time(DISPATCH_TIME_NOW, (int64_t)(1*NSEC_PER_SEC));
+             __weak __typeof(self)weakSelf = self;
+             dispatch_after(time, dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
+                 __strong __typeof(weakSelf)self = weakSelf;
+                 [self makeDoubleCheck:asyncHandler];
+             });
          }
      }];
 }
@@ -264,12 +253,22 @@ - (void)setHostForPing:(NSString *)hostForPing
     _hostForPing = nil;
     _hostForPing = [hostForPing copy];
 
-    GPingHelper.host = _hostForPing;
+    self.pingHelper.host = _hostForPing;
+}
+
+- (void)setHostForCheck:(NSString *)hostForCheck
+{
+    _hostForCheck = nil;
+    _hostForCheck = [hostForCheck copy];
+    
+    self.pingChecker.host = _hostForCheck;
 }
 
-- (void)setPingTimeout:(NSTimeInterval)pingTimeout {
+- (void)setPingTimeout:(NSTimeInterval)pingTimeout
+{
     _pingTimeout = pingTimeout;
-    GPingHelper.timeout = pingTimeout;
+    self.pingHelper.timeout = pingTimeout;
+    self.pingChecker.timeout = pingTimeout;
 }
 
 - (WWANAccessType)currentWWANtype
@@ -294,6 +293,34 @@ - (WWANAccessType)currentWWANtype
 }
 
 #pragma mark - inner methods
+- (void)makeDoubleCheck:(void (^)(ReachabilityStatus status))asyncHandler
+{
+    __weak __typeof(self)weakSelf = self;
+    [self.pingChecker pingWithBlock:^(BOOL isSuccess) {
+        __strong __typeof(weakSelf)strongSelf = weakSelf;
+        
+        NSDictionary *inputDic = @{kEventKeyID:@(RREventPingCallback), kEventKeyParam:@(isSuccess)};
+        [strongSelf.engine receiveInput:inputDic];
+        
+        if (!isSuccess)
+        {
+            // Only fail make the change; then we post the fail notification.
+            __weak __typeof(strongSelf)deepWeakSelf = strongSelf;
+            dispatch_async(dispatch_get_main_queue(), ^{
+                __strong __typeof(deepWeakSelf)deepStrongSelf = deepWeakSelf;
+                [[NSNotificationCenter defaultCenter] postNotificationName:kRealReachabilityChangedNotification
+                                                                    object:deepStrongSelf];
+            });
+        }
+        
+        if (asyncHandler != nil)
+        {
+            ReachabilityStatus currentStatus = [strongSelf currentReachabilityStatus];
+            asyncHandler(currentStatus);
+        }
+    }];
+}
+
 - (NSString *)paramValueFromStatus:(LocalConnectionStatus)status
 {
     switch (status)
@@ -368,11 +395,11 @@ - (WWANAccessType)accessTypeForString:(NSString *)accessString
 }
 
 #pragma mark - Notification observer
-- (void)localConnectionChanged:(NSNotification *)notification
+- (void)localConnectionHandler:(NSNotification *)notification
 {
     LocalConnection *lc = (LocalConnection *)notification.object;
     LocalConnectionStatus lcStatus = [lc currentLocalConnectionStatus];
-    //NSLog(@"currentLocalConnectionStatus:%@",@(lcStatus));
+    //NSLog(@"currentLocalConnectionStatus:%@, receive notification:%@",@(lcStatus), notification.name);
     ReachabilityStatus status = [self currentReachabilityStatus];
 
     NSDictionary *inputDic = @{kEventKeyID:@(RREventLocalConnectionCallback), kEventKeyParam:[self paramValueFromStatus:lcStatus]};
@@ -383,10 +410,14 @@ - (void)localConnectionChanged:(NSNotification *)notification
         if ([self.engine isCurrentStateAvailable])
         {
             self.previousStatus = status;
-            // already in main thread.
-            [[NSNotificationCenter defaultCenter] postNotificationName:kRealReachabilityChangedNotification
-                                                                object:self];
 
+            // already in main thread.
+            if ([notification.name isEqualToString:kLocalConnectionChangedNotification])
+            {
+                [[NSNotificationCenter defaultCenter] postNotificationName:kRealReachabilityChangedNotification
+                                                                    object:self];
+            }
+    
             if (lcStatus != LC_UnReachable)
             {
                 // To make sure your reachability is "Real".
@@ -396,22 +427,5 @@ - (void)localConnectionChanged:(NSNotification *)notification
     }
 }
 
-- (void)localConnectionInitialized:(NSNotification *)notification
-{
-    LocalConnection *lc = (LocalConnection *)notification.object;
-    LocalConnectionStatus lcStatus = [lc currentLocalConnectionStatus];
-    NSLog(@"localConnectionInitializedStatus:%@",@(lcStatus));
-    
-    NSDictionary *inputDic = @{kEventKeyID:@(RREventLocalConnectionCallback), kEventKeyParam:[self paramValueFromStatus:lcStatus]};
-    NSInteger rtn = [self.engine receiveInput:inputDic];
-    
-    // Initialized state, ping once to check the reachability(if local status reachable).
-    if ((rtn == 0) && [self.engine isCurrentStateAvailable] && (lcStatus != LC_UnReachable))
-    {
-        // To make sure your reachability is "Real".
-        [self reachabilityWithBlock:nil];
-    }
-}
-
 @end
 

testRealReachability/AppDelegate.m

@@ -18,6 +18,8 @@ @implementation AppDelegate
 
 - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
     // Override point for customization after application launch.
+    GLobalRealReachability.hostForPing = @"www.baidu.com";
+    GLobalRealReachability.hostForCheck = @"www.apple.com";
     [GLobalRealReachability startNotifier];
     return YES;
 }