从NSData确定MIME类型? [英] Determine MIME type from NSData?

问题描述

您如何确定NSData对象的mime类型?我打算让用户从iPhone上上传视频/图片，并将该文件包装在NSData类中.

How would you determine the mime type for an NSData object? I plan to have the user to upload a video/picture from their iPhone and have that file be wrapped in a NSData class.

我想知道是否可以从NSData中分辨出哑剧类型.这个问题只有几个答案，最近的一个是2010年(4年前！).谢谢！

I was wondering if I can tell the mime type from the NSData. There are only a few answers to this question and the most recent one is from 2010 (4 years ago!). Thanks!

NSData *data; // can be an image or video
NSString *mimeType = [data getMimetype]; // how would I implement getMimeType

推荐答案

基于 ml来自类似帖子的答案，我为NSData添加了mime类型确定:

Based on ml's answer from a similar post, I've added the mime types determination for NSData:

ObjC:

+ (NSString *)mimeTypeForData:(NSData *)data {
    uint8_t c;
    [data getBytes:&c length:1];

    switch (c) {
        case 0xFF:
            return @"image/jpeg";
            break;
        case 0x89:
            return @"image/png";
            break;
        case 0x47:
            return @"image/gif";
            break;
        case 0x49:
        case 0x4D:
            return @"image/tiff";
            break;
        case 0x25:
            return @"application/pdf";
            break;
        case 0xD0:
            return @"application/vnd";
            break;
        case 0x46:
            return @"text/plain";
            break;
        default:
            return @"application/octet-stream";
    }
    return nil;
}

迅速:

static func mimeType(for data: Data) -> String {

    var b: UInt8 = 0
    data.copyBytes(to: &b, count: 1)

    switch b {
    case 0xFF:
        return "image/jpeg"
    case 0x89:
        return "image/png"
    case 0x47:
        return "image/gif"
    case 0x4D, 0x49:
        return "image/tiff"
    case 0x25:
        return "application/pdf"
    case 0xD0:
        return "application/vnd"
    case 0x46:
        return "text/plain"
    default:
        return "application/octet-stream"
    }
}

此文件仅处理主要文件类型，但您可以根据需要完成它:所有文件签名均可用这里，只需使用与我相同的模式即可.

This handle main file types only, but you can complete it to fit your needs: all the files signature are available here, just use the same pattern as I did.

PS:所有相应的哑剧类型都可以在此处使用

PS: all the corresponding mime types are available here

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