如何在Mac上以编程方式访问文件信息? [英] How to access file info programmatically on Mac?

问题描述

我的新Mac(优胜美地)上有一堆音频文件.当我右键单击任何文件并执行获取信息"时，它会在更多信息"标签下为我提供有关该歌曲的详细信息，例如

I have a bunch of audio files on my new Mac (Yosemite). When I right click on any file and do "Get Info", it gives me nice detailed info about that song under "More Info" tag, e.g.

我需要编写一个可以列出的程序，对于目录中的所有歌曲，类似这样:

I need to write a program where I can list, something like this for all songs in a directory:

Album, Title, Year Recorded
.
.
.

问题:

我不知道该怎么做.我对Mac和Objective-C/Swift完全陌生(Objective-C或Swift是我想用来编写此程序的方式，我想是吗?)

Problem:

I have no idea how to do this. I am totally new to Mac and Objective-C/Swift (Objective-C or Swift is what I will have to use to write this program I guess??)

是否有一个API，可以通过编程方式访问此文件信息?还有其他我可以用来编写此类程序的语言吗?我已经知道的东西，例如Java，Python等?

Is there an API where I can access this file info programmatically? And is there any other language which I can use to write this sort of program? Something which I already know, like Java, Python, etc.?

由于我仍在寻找起点，因此到目前为止，我没有任何代码可以显示到目前为止我已经尝试过的内容".任何指针将不胜感激.

I don't have any code as of now to show 'What I have tried so far', since I am still searching for the starting point. Any pointers would be much appreciated.

推荐答案

您已经注意到，mdls命令可以提供此元数据.您不应该尝试解析它.相反，您可以使用与其建立相同的API.

As you've noticed, the mdls command can provide this metadata. You should not try to parse that. Instead, you can use the same APIs that it is built on.

您需要获取感兴趣的文件的NSURL.然后，您可以获取其元数据属性的字典，如下所示:

You need to obtain an NSURL for a file of interest. Then, you can obtain a dictionary of its metadata attributes like so:

MDItemRef item = MDItemCreateWithURL(NULL, (__bridge CFURLRef)url);
NSArray* names = @[ (__bridge NSString*)kMDItemAlbum, /* ... */ ];
NSDictionary* dictionary = CFBridgingRelease(MDItemCopyAttributes(item, (__bridge CFArrayRef)names));
CFRelease(item);

现在，dictionary包含所需的属性.

Now, dictionary contains the desired attributes.

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