缓存2

#import <Foundation/Foundation.h>



typedef NS_ENUM(NSInteger, WACachePolicy) {
    WAURLRequestReturnCacheDataElseLoad,//有缓存就用缓存，没有缓存就重新请求
    WAURLRequestReturnLocalAndRemoteCacheData,//先返回本地数据，然后返回网络数据
    WAURLRequestReloadIgnoringLocalAndRemoteCacheData //直接请求网络数据
};

@interface WARequest : NSObject

+ (void)requestWithUrl:(NSString *)url params:(NSDictionary *)params cachePolicy:(WACachePolicy)cachePolicy cacheTime:(NSInteger)cacheTime completeBlock:(void(^)(NSDictionary *result))completeBlock;

@end

//
//  WARequest.m
//  test
//
//  Created by yfxiari on 2018/2/5.
//  Copyright © 2018年 xxx. All rights reserved.
//

#import "WARequest.h"
#import <CommonCrypto/CommonCrypto.h>

@implementation WARequest

/**
 缓存类型：
 1.本地有缓存，加载本地缓存，如果没过期，不用加载最新的数据；如果过期了，则请求最新的数据，并缓存。
 2.本地有缓存先加载本地缓存，然后请求网络数据，再更新缓存
 3.不加载缓存，直接请求网络数据。
 */

/**
 策略2其实还是有问题的，因为如果回调了两遍，如果是分页的话，第二页就有问题了，因为加载第二页数据会重复加载。
 所以：如果是预加载缓存缓存还是写在页面基类中比较好，网络封装缓存应使用只加载缓存或只请求网络数据两者策略。
 
 但是：如果缓存用的是数据库，用id和size来分页，则就可以使用网络封装来实现预加载功能。
 
 */

+ (void)requestWithUrl:(NSString *)url params:(NSDictionary *)params cachePolicy:(WACachePolicy)cachePolicy cacheTime:(NSInteger)cacheTime completeBlock:(void(^)(NSDictionary *result))completeBlock {
    [self clearCache];
    // 用混存数据
    if (cachePolicy == WAURLRequestReturnCacheDataElseLoad) {
        NSDictionary *dict = [self getCacheUrl:url params:params cacheTime:cacheTime];
        BOOL valid = [self checkCacheUrl:url params:params cacheTime:cacheTime];
        if (dict) {
            completeBlock(dict);
            if (valid) {
                return;
            }
        }
    }
    
    if (cachePolicy == WAURLRequestReturnLocalAndRemoteCacheData) {
        NSDictionary *dict = [self getCacheUrl:url params:params cacheTime:cacheTime];
        if (dict) {
            completeBlock(dict);
        }
    }
    
    NSString *allUrl = [self urlStringWithUrl:url params:params];
    
    // 请求去了
    NSDictionary *headers = @{ @"Cache-Control": @"no-cache",
                               @"Postman-Token": @"0f97d71d-a97a-be5b-15d8-7276d645eb26" };
    
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:allUrl]
                                                           cachePolicy:NSURLRequestUseProtocolCachePolicy
                                                       timeoutInterval:10.0];
    [request setHTTPMethod:@"GET"];
    [request setAllHTTPHeaderFields:headers];
    
    NSURLSession *session = [NSURLSession sharedSession];
    NSURLSessionDataTask *dataTask = [session dataTaskWithRequest:request
                                                completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
                                                    if (error) {
                                                    } else {
                                                        NSDictionary *result = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableLeaves error:nil];
                                                        if (result) {
                                                            completeBlock(result);
                                                            if (cachePolicy != WAURLRequestReloadIgnoringLocalAndRemoteCacheData) {
                                                                [self cacheUrl:url params:params data:result];
                                                            }
                                                        }
                                                    }
                                                }];
    [dataTask resume];
    
}

+ (void)cacheUrl:(NSString *)url params:(NSDictionary *)params data:(NSDictionary *)dict {
    
    NSString *file = [self filePathWithUrl:url params:params];
    BOOL writed = [dict writeToFile:file atomically:YES];
    NSString *log = writed ? @"写入成功":@"写入失败";
    NSLog(@"%@", log);
}

+ (NSString *)filePathWithUrl:(NSString *)url params:(NSDictionary *)params {
    
    NSString *cache_path = [self cachePath];
    NSString *fileString = [self urlStringWithUrl:url params:params];
    NSString *file = [self getMd5WithString:fileString];
    NSString *path = [cache_path stringByAppendingPathComponent:file];
    return path;
}

+ (NSDictionary *)getCacheUrl:(NSString *)url params:(NSDictionary *)params cacheTime:(NSInteger)cacheTime{
    
    NSString *file = [self filePathWithUrl:url params:params];
    return [NSDictionary dictionaryWithContentsOfFile:file];
    
    return @{};
}

// 是否过期
+ (BOOL)checkCacheUrl:(NSString *)url params:(NSDictionary *)params cacheTime:(NSInteger)cacheTime {
    
    NSString *file = [self filePathWithUrl:url params:params];
    
    NSDictionary *attr = [[NSFileManager defaultManager] attributesOfItemAtPath:file error:nil];
    NSDate *modifiedDate = [attr objectForKey:NSFileModificationDate];
    NSTimeInterval time = [[NSDate date] timeIntervalSinceDate:modifiedDate];
    if (time > cacheTime) {
        return NO;
    }
    return YES;
}


+ (NSString *)cachePath {
    NSString *path = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) lastObject];
    return path;
}

+ (NSString *)urlStringWithUrl:(NSString *)url params:(NSDictionary *)params {
    NSArray *sortArray = [params.allKeys sortedArrayUsingComparator:^NSComparisonResult(id  _Nonnull obj1, id  _Nonnull obj2) {
        return [obj1 compare:obj2];
    }];
    
    NSString *paramsString = @"";
    
    for (NSString *key in sortArray) {
        NSString *valueString = [NSString stringWithFormat:@"%@=%@&", key, params[key]];
        paramsString = [paramsString stringByAppendingString:valueString];
    }
    NSString *allUrl = url;
    if ([allUrl containsString:@"?"]) {
        allUrl =[allUrl stringByAppendingString:paramsString];
    }else {
        allUrl = [allUrl stringByAppendingString:@"?"
         ];
        allUrl =[allUrl stringByAppendingString:paramsString];
    }
    
    NSLog(@"%@", allUrl);
    return allUrl;
}

+ (NSString *)urlKeyMd5StringWithUrl:(NSString *)url {
    return [self getMd5WithString:url];
}



+ (NSString *)getMd5WithString:(NSString *)string {
    const char *data = [string UTF8String];
    //2: 初始化一个字符串数组,用来存放MD5加密后的数据
    unsigned char resultArray[CC_MD5_DIGEST_LENGTH];
    CC_MD5(data, (CC_LONG) strlen(data), resultArray);
    //4: 初始化一个保存结果的字符串
    NSMutableString *resultString = [NSMutableString string];
    //5: 从保存结果的数组中,取出值赋给字符串
    for (int i = 0; i < CC_MD5_DIGEST_LENGTH; i++) {
        [resultString appendFormat:@"%02X", resultArray[i]];
    }
    //6: 返回结果
    return resultString;
    
}



+ (void)clearCache {
    // 判断缓存大小
    // 删除过期缓存
    [self clearExpiredFile];
}


// 获取文件大小
- (float) folderSizeAtPath:(NSString *)folderPath{
    
    NSFileManager * manager = [NSFileManager defaultManager];
    if (![manager fileExistsAtPath :folderPath]) return 0 ;
    NSEnumerator *childFilesEnumerator = [[manager subpathsAtPath :folderPath] objectEnumerator];
    NSString * fileName;
    long long folderSize = 0 ;
    while ((fileName = [childFilesEnumerator nextObject]) != nil ){
        //获取文件全路径
        NSString * fileAbsolutePath = [folderPath stringByAppendingPathComponent :fileName];
        folderSize += [self fileSizeAtPath:fileAbsolutePath];
    }
    
    return folderSize/( 1024.0 * 1024.0);
    
}
- (long long)fileSizeAtPath:(NSString *)filePath{
    NSFileManager * manager = [NSFileManager defaultManager];
    if ([manager fileExistsAtPath :filePath]){
        return [[manager attributesOfItemAtPath :filePath error : nil] fileSize];
    }
    return 0;
}

/**
 *  清空过期的日志
 */
+ (void)clearExpiredFile{
}


@end