include/SPTDataLoader/SPTDataLoaderRateLimiter.h

/*
 Copyright 2015-2023 Spotify AB

 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
 You may obtain a copy of the License at

     http://www.apache.org/licenses/LICENSE-2.0

 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
 */

#import <Foundation/Foundation.h>

@class SPTDataLoaderRequest;

NS_ASSUME_NONNULL_BEGIN

/**
 A rate limiter for configuring custom rates on a per service basis
 @discussion A service is defined as the scheme, host and first path component of the URL
 */
@interface SPTDataLoaderRateLimiter : NSObject

/**
 Class constructor
 @param requestsPerSecond The number of requests per second as a default to allow for a service
 */
+ (instancetype)rateLimiterWithDefaultRequestsPerSecond:(double)requestsPerSecond;

/**
 Finds the earliest time until a request can be executed
 @param request The request pending for execution
 @discussion A result of 0.0 means the request can be executed immediately
 */
- (NSTimeInterval)earliestTimeUntilRequestCanBeExecuted:(SPTDataLoaderRequest *)request;
/**
 Tells the rate limiter a request is currently being executed
 @param request The request being executed
 */
- (void)executedRequest:(SPTDataLoaderRequest *)request;
/**
 The amount of requests per second that are allowed to be executed on a URL
 @param URL The URL to check the requests per second for
 */
- (double)requestsPerSecondForURL:(NSURL *)URL;
/**
 Set the requests per second that are allowed to be executed on a URL
 @param requestsPerSecond The number of requests per second to accept
 @param URL The URL to check the requests per second for
 */
- (void)setRequestsPerSecond:(double)requestsPerSecond forURL:(NSURL *)URL;
/**
 Set the amount of time to wait until retrying for a given URL
 @param absoluteTime The time when the retry after can be realised
 @param URL The URL to set the retry after
 */
- (void)setRetryAfter:(NSTimeInterval)absoluteTime forURL:(NSURL *)URL;

@end

NS_ASSUME_NONNULL_END