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92 lines
3.9 KiB
92 lines
3.9 KiB
4 years ago
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//
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// CachedResponseHandler.swift
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//
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// Copyright (c) 2019 Alamofire Software Foundation (http://alamofire.org/)
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to deal
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// in the Software without restriction, including without limitation the rights
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// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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// copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in
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// all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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// THE SOFTWARE.
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//
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import Foundation
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/// A type that handles whether the data task should store the HTTP response in the cache.
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public protocol CachedResponseHandler {
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/// Determines whether the HTTP response should be stored in the cache.
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///
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/// The `completion` closure should be passed one of three possible options:
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///
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/// 1. The cached response provided by the server (this is the most common use case).
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/// 2. A modified version of the cached response (you may want to modify it in some way before caching).
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/// 3. A `nil` value to prevent the cached response from being stored in the cache.
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///
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/// - Parameters:
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/// - task: The data task whose request resulted in the cached response.
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/// - response: The cached response to potentially store in the cache.
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/// - completion: The closure to execute containing cached response, a modified response, or `nil`.
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func dataTask(_ task: URLSessionDataTask,
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willCacheResponse response: CachedURLResponse,
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completion: @escaping (CachedURLResponse?) -> Void)
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}
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// MARK: -
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/// `ResponseCacher` is a convenience `CachedResponseHandler` making it easy to cache, not cache, or modify a cached
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/// response.
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public struct ResponseCacher {
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/// Defines the behavior of the `ResponseCacher` type.
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public enum Behavior {
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/// Stores the cached response in the cache.
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case cache
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/// Prevents the cached response from being stored in the cache.
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case doNotCache
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/// Modifies the cached response before storing it in the cache.
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case modify((URLSessionDataTask, CachedURLResponse) -> CachedURLResponse?)
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}
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/// Returns a `ResponseCacher` with a follow `Behavior`.
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public static let cache = ResponseCacher(behavior: .cache)
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/// Returns a `ResponseCacher` with a do not follow `Behavior`.
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public static let doNotCache = ResponseCacher(behavior: .doNotCache)
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/// The `Behavior` of the `ResponseCacher`.
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public let behavior: Behavior
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/// Creates a `ResponseCacher` instance from the `Behavior`.
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///
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/// - Parameter behavior: The `Behavior`.
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public init(behavior: Behavior) {
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self.behavior = behavior
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}
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}
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extension ResponseCacher: CachedResponseHandler {
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public func dataTask(_ task: URLSessionDataTask,
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willCacheResponse response: CachedURLResponse,
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completion: @escaping (CachedURLResponse?) -> Void) {
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switch behavior {
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case .cache:
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completion(response)
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case .doNotCache:
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completion(nil)
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case let .modify(closure):
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let response = closure(task, response)
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completion(response)
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}
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}
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}
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