如何在objective-c中读取MIME类型的文件
问题描述：
我有兴趣检测iPhone应用程序文档目录中文件的MIME类型。通过文档搜索没有提供任何答案。
I am interested in detecting the MIME-type for a file in the documents directory of my iPhone application. A search through the docs did not provide any answers.
答
这有点hacky，但它应该工作，不知道当然，因为我只是猜测它
It's a bit hacky, but it should work, don't know for sure because I'm just guessing at it
有两种选择：
- 如果您只需要MIME类型，请使用timeoutInterval：NSURLRequest。
- 如果您还想要数据，则应使用注释掉的NSURLRequest。
确保在线程中执行请求，因为它是同步的。
Make sure to perform the request in a thread though, since it's synchronous.
NSString* filePath = [[NSBundle mainBundle] pathForResource:@"imagename" ofType:@"jpg"];
NSString* fullPath = [filePath stringByExpandingTildeInPath];
NSURL* fileUrl = [NSURL fileURLWithPath:fullPath];
//NSURLRequest* fileUrlRequest = [[NSURLRequest alloc] initWithURL:fileUrl];
NSURLRequest* fileUrlRequest = [[NSURLRequest alloc] initWithURL:fileUrl cachePolicy:NSURLCacheStorageNotAllowed timeoutInterval:.1];
NSError* error = nil;
NSURLResponse* response = nil;
NSData* fileData = [NSURLConnection sendSynchronousRequest:fileUrlRequest returningResponse:&response error:&error];
fileData; // Ignore this if you're using the timeoutInterval
// request, since the data will be truncated.
NSString* mimeType = [response MIMEType];
[fileUrlRequest release];