/* * Copyright (c) 2017 Apple Inc. All Rights Reserved. * * @APPLE_LICENSE_HEADER_START@ * * This file contains Original Code and/or Modifications of Original Code * as defined in and that are subject to the Apple Public Source License * Version 2.0 (the 'License'). You may not use this file except in * compliance with the License. Please obtain a copy of the License at * http://www.opensource.apple.com/apsl/ and read it before using this * file. * * The Original Code and all software distributed under the License are * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. * Please see the License for the specific language governing rights and * limitations under the License. * * @APPLE_LICENSE_HEADER_END@ */ #import <Foundation/Foundation.h> NS_ASSUME_NONNULL_BEGIN @interface RateLimiter : NSObject <NSSecureCoding> @property (readonly, nonatomic) NSDictionary* config; @property (readonly, nonatomic) NSUInteger stateSize; @property (readonly, nonatomic, nullable) NSString* assetType; typedef NS_ENUM(NSInteger, RateLimiterBadness) { RateLimiterBadnessClear = 0, // everything is fine, process right now RateLimiterBadnessCongested, RateLimiterBadnessSeverelyCongested, RateLimiterBadnessGridlocked, RateLimiterBadnessOverloaded, // everything is on fire, go away }; - (instancetype _Nullable)initWithConfig:(NSDictionary*)config; - (instancetype _Nullable)initWithPlistFromURL:(NSURL*)url; - (instancetype _Nullable)initWithAssetType:(NSString*)type; // Not implemented yet - (instancetype _Nullable)initWithCoder:(NSCoder*)coder; - (instancetype _Nullable)init NS_UNAVAILABLE; /*! * @brief Find out whether objects may be processed or must wait. * @param obj The object being judged. * @param time Current time. * @param limitTime Assigned okay-to-process time. Nil when object may be processed immediately. * @return RateLimiterBadness enum value indicating current congestion situation, or to signal * * judge:at: will set the limitTime object to nil in case of 0 badness. For badnesses 1-4 the time object will indicate when it is okay to send the entry. * At badness 5 judge:at: has determined there is too much activity so the caller should hold off altogether. The limitTime object will indicate when * this overloaded state will end. */ - (NSInteger)judge:(id)obj at:(NSDate*)time limitTime:(NSDate* _Nonnull __autoreleasing* _Nonnull)limitTime; - (void)reset; - (NSString*)diagnostics; + (BOOL)supportsSecureCoding; // TODO: // implement config loading from MobileAsset @end NS_ASSUME_NONNULL_END /* Annotated example plist <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"> <plist version="1.0"> <dict> <key>general</key> <dict> <!-- Total item limit --> <key>maxStateSize</key> <integer>250</integer> <!-- Throw away items after this many seconds --> <key>maxItemAge</key> <integer>3600</integer> <!-- Ignore everybody for this many seconds --> <key>overloadDuration</key> <integer>1800</integer> <!-- Printable string for logs --> <key>name</key> <string>CKKS</string> <!-- Load config stored in this MobileAsset (ignored if inited with config or plist directly) --> <key>MAType</key> <string></string> </dict> <!-- Each property you want to ratelimit on must have its own group dictionary --> <key>groups</key> <array> <dict> <!-- The first group must be for the global bucket. It behaves identically otherwise --> <key>property</key> <string>global</string> <key>capacity</key> <integer>20</integer> <key>rate</key> <integer>30</integer> <key>badness</key> <integer>1</integer> </dict> <dict> <!-- Your object must respond to this selector that takes no arguments by returning an NSString * --> <key>property</key> <string>UUID</string> <!-- Buckets of this type hold at most this many tokens --> <key>capacity</key> <integer>3</integer> <!-- Tokens replenish at 1 every this many seconds --> <key>rate</key> <integer>600</integer> <!-- Max of all empty bucket badnesses is returned to caller. See RateLimiterBadness enum --> <key>badness</key> <integer>3</integer> </dict> </array> </dict> </plist> */