HTTP GET请求的缓存不适用于iOS 6
HTTP GET请求的缓存不适用于iOS 6
提问于 2014-02-28 22:38:41
我已经编写了hello word应用程序来显示我的HTTP GET请求缓存问题。
#import "StartViewController.h"
@interface StartViewController () <NSURLConnectionDataDelegate>
@property (nonatomic, strong) NSURLConnection *connection; @end
@implementation StartViewController
- (IBAction)buttonAction:(id)sender {
NSLog(@"buttonAction");
NSURLRequest *request = [[NSURLRequest alloc] initWithURL:[NSURL URLWithString:@"http://mycoolpage.com/phones"] ];
self.connection = [[NSURLConnection alloc] initWithRequest:request delegate:self ]; }
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
NSLog(@"didReceiveResponse"); }
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
NSLog(@"didReceiveData:"); }
- (NSCachedURLResponse *)connection:(NSURLConnection *)connection willCacheResponse:(NSCachedURLResponse *)cachedResponse {
NSLog(@"willCacheResponse");
return cachedResponse; }
@endAppDelegate：
#import "AppDelegate.h"
#import "StartViewController.h"
@implementation AppDelegate
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
self.window.rootViewController = [[StartViewController alloc] init];
[self.window makeKeyAndVisible];
NSURLCache *defaultCache = [NSURLCache sharedURLCache];
NSURLCache *applicationCache = [[NSURLCache alloc] initWithMemoryCapacity:defaultCache.memoryCapacity diskCapacity:128*1024*1024 diskPath:@"MobileCache"];
[NSURLCache setSharedURLCache:applicationCache];
return YES;
}
@end当第一次发送请求时，一切正常，但第二次调用在iOS6上超时。ios 7工作没有任何问题。有从服务器发送和接收的标头：
第一个请求：
GET /phones HTTP/1.1
Host mycoolpage.com
Accept-Encoding gzip, deflate
Accept */*
Accept-Language en-us
Connection keep-alive
User-Agent CacheDemo/1.0 CFNetwork/609 Darwin/13.1.0第一个响应：
HTTP/1.1 200 OK
Cache-Control private, max-age=0
Content-Encoding gzip
Content-Type application/json; charset=UTF-8
Date Fri, 28 Feb 2014 14:28:24 GMT
ETag afcf39d75c69c694f4dfaca7f20b816b
Content-Length 28578
Connection keep-alive第二个请求：
GET /phones HTTP/1.1
Host mycoolpage.com
If-None-Match afcf39d75c69c694f4dfaca7f20b816b
Accept-Encoding gzip, deflate
Accept */*
Accept-Language en-us
Connection keep-alive
User-Agent CacheDemo/1.0 CFNetwork/609 Darwin/13.1.0第二个响应：
HTTP/1.1 304 Not Modified
Cache-Control private, max-age=0
Content-Encoding gzip
Content-length 22
Content-Type text/plain; charset=UTF-8
Date Fri, 28 Feb 2014 14:29:15 GMT
ETag afcf39d75c69c694f4dfaca7f20b816b
Connection keep-alive以下是来自控制台的日志：
2014-03-02 16:58:29.054 CacheDemo[6834:907] buttonAction
2014-03-02 16:58:29.286 CacheDemo[6834:907] response:<NSHTTPURLResponse: 0x784a2f0>
2014-03-02 16:58:29.286 CacheDemo[6834:907] didReceiveData:
2014-03-02 16:58:29.287 CacheDemo[6834:907] didReceiveData:
2014-03-02 16:58:29.351 CacheDemo[6834:907] didReceiveData:
2014-03-02 16:58:29.352 CacheDemo[6834:907] didReceiveData:
2014-03-02 16:58:29.352 CacheDemo[6834:907] didReceiveData:
2014-03-02 16:58:29.353 CacheDemo[6834:907] didReceiveData:
2014-03-02 16:58:29.353 CacheDemo[6834:907] didReceiveData:
2014-03-02 16:58:29.354 CacheDemo[6834:907] didReceiveData:
2014-03-02 16:58:29.355 CacheDemo[6834:907] didReceiveData:
2014-03-02 16:58:29.356 CacheDemo[6834:907] didReceiveData:
2014-03-02 16:58:29.356 CacheDemo[6834:907] didReceiveData:
2014-03-02 16:58:29.356 CacheDemo[6834:907] didReceiveData:
2014-03-02 16:58:29.415 CacheDemo[6834:907] didReceiveData:
2014-03-02 16:58:29.416 CacheDemo[6834:907] willCacheResponse
2014-03-02 16:58:35.095 CacheDemo[6834:907] buttonAction
// Timeout after 1 min
2014-03-02 16:59:34.754 CacheDemo[6834:907] response:<NSHTTPURLResponse: 0x766a710>
2014-03-02 16:59:34.754 CacheDemo[6834:907] didReceiveData:你知道这是怎么回事吗？
回答 1
Stack Overflow用户
发布于 2015-04-15 16:33:56
第二个响应头中的一个不同之处是状态码，它是304 Not Modified。根据Apple的说法
通常，只有在满足以下所有条件时，才会缓存响应
- 请求HTTP或HTTPS URL (或您自己支持缓存的自定义网络协议)。
- 请求成功(状态代码在200-299范围内)。
- 提供的响应来自服务器，而不是来自缓存。
- 会话配置的缓存策略允许缓存。
< NSURLRequest >H113提供的NSURLRequest对象的缓存策略(如果适用)允许缓存。
- 服务器响应中与缓存相关的标头(如果存在)允许缓存。响应大小足够小，可以合理地放入缓存中。(例如，如果提供磁盘缓存，则响应大小不得大于磁盘缓存大小的5%。)
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/22098124
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