如何在iPhone上设置attributesOfItemAtPath（例如修改日期/时间）

发布于 2024-11-05 15:23:42 字数 2177 浏览 9 评论 0原文

我知道我可以使用 attributesOfItemAtPath 来获取文件的修改时间/日期等等......但是有没有办法设置文件的修改日期/时间？

我问的原因是我使用 http://allseeing-i.com/ASIHTTPRequest/ （如下面）来获取文件...但是时间戳与服务器上的上次修改时间不同。我想使用 Last-Modified 标头来设置下载文件的日期/时间，以便我可以保持系统上的下载时间与服务器上的时间相同。

我的代码如下：

ASIHTTPRequest *requestFeed = [ASIHTTPRequest requestWithURL:[NSURL URLWithString:kGZipSQLURL]];
[requestFeed setNumberOfTimesToRetryOnTimeout:2];
[requestFeed setDownloadDestinationPath:librarySQLGZipPath];
[requestFeed setCachePolicy:ASIAskServerIfModifiedCachePolicy|ASIFallbackToCacheIfLoadFailsCachePolicy];
[requestFeed setCacheStoragePolicy:ASICachePermanentlyCacheStoragePolicy];
[requestFeed setSecondsToCache:60*60*24*30];
[requestFeed setDownloadCache:[ASIDownloadCache sharedCache]];
[requestFeed startSynchronous];
NSString *lastModified = [[requestFeed responseHeaders] objectForKey:@"Last-Modified"];
NSLog(@"Last Modified: %@",lastModified);

因此，字符串 lastModified 保存时间/日期戳。有没有办法确保将 librarySQLGZipPath 中的文件现在设置为 lastModified 中的日期/时间？使用当前方法，文件 librarySQLGZipPath 保存其下载时间，这对我来说是无效的。

谢谢！

Jann

稍后编辑：

因为我想很好地在此页面上放置如何执行此代码，并且仍然想感谢 Steven Kramer 的回答，我现在要编辑问题与我使用代码得到的答案：

而 NSDateFromRFC1123 是在这里找到的例程：http://blog.mro.name/2009/08/nsdateformatter-http-header/ （进行一些调整）将 Last-Modified 标头字符串更改为 NSDate 对象：

NSDictionary *attrs = [NSDictionary dictionaryWithObjectsAndKeys:[self NSDateFromRFC1123:lastModified]  ,NSFileModificationDate, nil];
NSError *errorFile;
if ([NSFileManager defaultManager] setAttributes:attrs ofItemAtPath:librarySQLGZipPath error: &errorFile])
{
NSLog(@"Set timestamp of file");
}
else {
NSLog(@"COULD NOT set timestamp of file");
}

<非常感谢史蒂文！

原文

I know I can use attributesOfItemAtPath to get modification time/date of file among other things... but is there a way to SET the modification date/time of a file?

I have looked at How to set the modification time of a file programmatically? but it does not seem to apply.

The reason I ask is I use http://allseeing-i.com/ASIHTTPRequest/ (as below) to fetch a file... however the timestamp is not kept the same as the Last-Modified time on the server. I want to use the Last-Modified header to set the date/time of the downloaded file so i can keep the downloaded time on my system the same as it is on the server.

My code follows:

ASIHTTPRequest *requestFeed = [ASIHTTPRequest requestWithURL:[NSURL URLWithString:kGZipSQLURL]];
[requestFeed setNumberOfTimesToRetryOnTimeout:2];
[requestFeed setDownloadDestinationPath:librarySQLGZipPath];
[requestFeed setCachePolicy:ASIAskServerIfModifiedCachePolicy|ASIFallbackToCacheIfLoadFailsCachePolicy];
[requestFeed setCacheStoragePolicy:ASICachePermanentlyCacheStoragePolicy];
[requestFeed setSecondsToCache:60*60*24*30];
[requestFeed setDownloadCache:[ASIDownloadCache sharedCache]];
[requestFeed startSynchronous];
NSString *lastModified = [[requestFeed responseHeaders] objectForKey:@"Last-Modified"];
NSLog(@"Last Modified: %@",lastModified);

So, the string lastModified holds the time/date stamp. Is there a way to ensure that the file at librarySQLGZipPath will now be set to the date/time in lastModified? Using the current method, the file librarySQLGZipPath holds the time it was downloaded, which to me is invalid.

Thanks!

Jann

EDIT LATER:

Because I wanted to nicely put on this page how to do the code for this and still wanted to give Steven Kramer credit for answering I am now gonna edit the question with the answer I got using code:

whereas NSDateFromRFC1123 is a routine found here: http://blog.mro.name/2009/08/nsdateformatter-http-header/ (with some adjustments) to change the Last-Modified header string into a NSDate object:

NSDictionary *attrs = [NSDictionary dictionaryWithObjectsAndKeys:[self NSDateFromRFC1123:lastModified]  ,NSFileModificationDate, nil];
NSError *errorFile;
if ([NSFileManager defaultManager] setAttributes:attrs ofItemAtPath:librarySQLGZipPath error: &errorFile])
{
NSLog(@"Set timestamp of file");
}
else {
NSLog(@"COULD NOT set timestamp of file");
}

Thanks so much Steven!

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