text: //
  //  KSReachability.h
  //
  //  Created by Karl Stenerud on 5/5/12.
  //
  //  Copyright (c) 2012 Karl Stenerud. All rights reserved.
  //
  // Permission is hereby granted, free of charge, to any person obtaining a copy
  // of this software and associated documentation files (the "Software"), to deal
  // in the Software without restriction, including without limitation the rights
  // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  // copies of the Software, and to permit persons to whom the Software is
  // furnished to do so, subject to the following conditions:
  //
  // The above copyright notice and this permission notice shall remain in place
  // in this source code.
  //
  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  // THE SOFTWARE.
  //
  
  #import <Foundation/Foundation.h>
  #import <SystemConfiguration/SystemConfiguration.h>
  
  
  /** This is the notification name used in the Apple reachability example. */
  #define kDefaultNetworkReachabilityChangedNotification @"kNetworkReachabilityChangedNotification"
  
  
  /** Monitors network connectivity.
   *
   * Note: Upon construction, this object will fetch its initial reachability
   * state in the background. This means that the reachability status will ALWAYS
   * be "unreachable" until some time after object construction. If you want
   * the true reachability state before the current code block ends, you can call
   * updateFlags. Note, however, that it will probably block.
   *
   * You can elect to be notified via blocks (onReachabilityChanged),
   * notifications (notificationName), or KVO (flags, reachable, and WWANOnly).
   *
   * All notification methods are disabled by default.
   */
  @interface KSReachability : NSObject
  
  #pragma mark Constructors
  
  /** Reachability to a specific host.
   *
   * @param hostname The name or IP address of the host to monitor. If nil or
   *                 empty string, check reachability to the internet in general.
   */
  + (KSReachability*) reachabilityToHost:(NSString*) hostname;
  
  /** Reachability to the local (wired or wifi) network.
   */
  + (KSReachability*) reachabilityToLocalNetwork;
  
  
  #pragma mark General Information
  
  /** The host we are monitoring reachability to, if any. */
  @property(nonatomic,readonly,retain) NSString* hostname;
  
  
  #pragma mark Notifications and Callbacks
  
  /** If non-nil, called whenever reachability flags change.
   * Block will be invoked on the main thread.
   */
  @property(nonatomic,readwrite,copy) void(^onReachabilityChanged)(KSReachability* reachability);
  
  /** The notification to send when reachability changes (nil = don't send).
   * Default = nil
   */
  @property(nonatomic,readwrite,retain) NSString* notificationName;
  
  
  #pragma mark KVO Compliant Status Properties
  
  /** The current reachability flags. */
  @property(nonatomic,readonly,assign) SCNetworkReachabilityFlags flags;
  
  /** Whether the host is reachable or not. */
  @property(nonatomic,readonly,assign) BOOL reachable;
  
  /* If YES, the host is only reachable by WWAN (iOS only). */
  @property(nonatomic,readonly,assign) BOOL WWANOnly;
  
  
  #pragma mark Utility
  
  /** Force updating of the reachability flags.
   * This method will potentially block.
   *
   * @return YES if the flags were successfully updated.
   */
  - (BOOL) updateFlags;
  
  @end
  
  
  
  /** A one-time operation to perform as soon as a host is deemed reachable.
   * The operation will only be performed once, regardless of how many times a
   * host becomes reachable.
   */
  @interface KSReachableOperation: NSObject
  
  /** Constructor.
   *
   * @param hostname The name or IP address of the host to monitor. If nil or
   *                 empty string, check reachability to the internet in general.
   *                 If hostname is a URL string, it will use the host portion.
   *
   * @param allowWWAN If NO, a WWAN-only connection is not enough to trigger
   *                  this operation.
   *
   * @param block The block to invoke when the host becomes reachable.
   *              Block will be invoked on the main thread.
   */
  + (KSReachableOperation*) operationWithHost:(NSString*) hostname
                                    allowWWAN:(BOOL) allowWWAN
                                        block:(void(^)()) block;
  
  /** Constructor.
   *
   * @param hostname The name or IP address of the host to monitor. If nil or
   *                 empty string, check reachability to the internet in general.
   *                 If hostname is a URL string, it will use the host portion.
   *
   * @param allowWWAN If NO, a WWAN-only connection is not enough to trigger
   *                  this operation.
   *
   * @param block The block to invoke when the host becomes reachable.
   *              Block will be invoked on the main thread.
   */
  - (id) initWithHost:(NSString*) hostname
            allowWWAN:(BOOL) allowWWAN
                block:(void(^)()) block;
  
  @end
  