Path extension and MIME type of file in swift

To fetch an extension from UTI, here is Swift 4.1 code:

import AVFoundation

extension AVFileType {
    /// Fetch and extension for a file from UTI string
    var fileExtension: String {
        if let ext = UTTypeCopyPreferredTagWithClass(self as CFString, kUTTagClassFilenameExtension)?.takeRetainedValue() {
            return ext as String
        }
        return "None"
    }
}

mov for com.apple.quicktime-movie

If anyone wants to get the MimeType from the actual URL of the file this code worked for me:

import MobileCoreServices

func mimeTypeForPath(path: String) -> String {
    let url = NSURL(fileURLWithPath: path)
    let pathExtension = url.pathExtension

    if let uti = UTTypeCreatePreferredIdentifierForTag(kUTTagClassFilenameExtension, pathExtension! as NSString, nil)?.takeRetainedValue() {
        if let mimetype = UTTypeCopyPreferredTagWithClass(uti, kUTTagClassMIMEType)?.takeRetainedValue() {
            return mimetype as String
        }
    }
    return "application/octet-stream"
}

If you need to check URL contains some Image or Audio file or Video file, here is Swift 5.1 code:

import Foundation
import MobileCoreServices

extension URL {
    func mimeType() -> String {
        let pathExtension = self.pathExtension
        if let uti = UTTypeCreatePreferredIdentifierForTag(kUTTagClassFilenameExtension, pathExtension as NSString, nil)?.takeRetainedValue() {
            if let mimetype = UTTypeCopyPreferredTagWithClass(uti, kUTTagClassMIMEType)?.takeRetainedValue() {
                return mimetype as String
            }
        }
        return "application/octet-stream"
    }
    var containsImage: Bool {
        let mimeType = self.mimeType()
        guard let uti = UTTypeCreatePreferredIdentifierForTag(kUTTagClassMIMEType, mimeType as CFString, nil)?.takeRetainedValue() else {
            return false
        }
        return UTTypeConformsTo(uti, kUTTypeImage)
    }
    var containsAudio: Bool {
        let mimeType = self.mimeType()
        guard let uti = UTTypeCreatePreferredIdentifierForTag(kUTTagClassMIMEType, mimeType as CFString, nil)?.takeRetainedValue() else {
            return false
        }
        return UTTypeConformsTo(uti, kUTTypeAudio)
    }
    var containsVideo: Bool {
        let mimeType = self.mimeType()
        guard  let uti = UTTypeCreatePreferredIdentifierForTag(kUTTagClassMIMEType, mimeType as CFString, nil)?.takeRetainedValue() else {
            return false
        }
        return UTTypeConformsTo(uti, kUTTypeMovie)
    }

}

iOS 14.0 +

Use the extensions

import UniformTypeIdentifiers

extension NSURL {
    public func mimeType() -> String {
        if let pathExt = self.pathExtension,
            let mimeType = UTType(filenameExtension: pathExt)?.preferredMIMEType {
            return mimeType
        }
        else {
            return "application/octet-stream"
        }
    }
}

extension URL {
    public func mimeType() -> String {
        if let mimeType = UTType(filenameExtension: self.pathExtension)?.preferredMIMEType {
            return mimeType
        }
        else {
            return "application/octet-stream"
        }
    }
}

extension NSString {
    public func mimeType() -> String {
        if let mimeType = UTType(filenameExtension: self.pathExtension)?.preferredMIMEType {
            return mimeType
        }
        else {
            return "application/octet-stream"
        }
    }
}

extension String {
    public func mimeType() -> String {
        return (self as NSString).mimeType()
    }
}

Below iOS 14

MimeType.swift

import Foundation

internal let DEFAULT_MIME_TYPE = "application/octet-stream"

internal let mimeTypes = [
    "html": "text/html",
    "htm": "text/html",
    "shtml": "text/html",
    "css": "text/css",
    "xml": "text/xml",
    "gif": "image/gif",
    "jpeg": "image/jpeg",
    "jpg": "image/jpeg",
    "js": "application/javascript",
    "atom": "application/atom+xml",
    "rss": "application/rss+xml",
    "mml": "text/mathml",
    "txt": "text/plain",
    "jad": "text/vnd.sun.j2me.app-descriptor",
    "wml": "text/vnd.wap.wml",
    "htc": "text/x-component",
    "png": "image/png",
    "tif": "image/tiff",
    "tiff": "image/tiff",
    "wbmp": "image/vnd.wap.wbmp",
    "ico": "image/x-icon",
    "jng": "image/x-jng",
    "bmp": "image/x-ms-bmp",
    "svg": "image/svg+xml",
    "svgz": "image/svg+xml",
    "webp": "image/webp",
    "woff": "application/font-woff",
    "jar": "application/java-archive",
    "war": "application/java-archive",
    "ear": "application/java-archive",
    "json": "application/json",
    "hqx": "application/mac-binhex40",
    "doc": "application/msword",
    "pdf": "application/pdf",
    "ps": "application/postscript",
    "eps": "application/postscript",
    "ai": "application/postscript",
    "rtf": "application/rtf",
    "m3u8": "application/vnd.apple.mpegurl",
    "xls": "application/vnd.ms-excel",
    "eot": "application/vnd.ms-fontobject",
    "ppt": "application/vnd.ms-powerpoint",
    "wmlc": "application/vnd.wap.wmlc",
    "kml": "application/vnd.google-earth.kml+xml",
    "kmz": "application/vnd.google-earth.kmz",
    "7z": "application/x-7z-compressed",
    "cco": "application/x-cocoa",
    "jardiff": "application/x-java-archive-diff",
    "jnlp": "application/x-java-jnlp-file",
    "run": "application/x-makeself",
    "pl": "application/x-perl",
    "pm": "application/x-perl",
    "prc": "application/x-pilot",
    "pdb": "application/x-pilot",
    "rar": "application/x-rar-compressed",
    "rpm": "application/x-redhat-package-manager",
    "sea": "application/x-sea",
    "swf": "application/x-shockwave-flash",
    "sit": "application/x-stuffit",
    "tcl": "application/x-tcl",
    "tk": "application/x-tcl",
    "der": "application/x-x509-ca-cert",
    "pem": "application/x-x509-ca-cert",
    "crt": "application/x-x509-ca-cert",
    "xpi": "application/x-xpinstall",
    "xhtml": "application/xhtml+xml",
    "xspf": "application/xspf+xml",
    "zip": "application/zip",
    "epub": "application/epub+zip",
    "docx": "application/vnd.openxmlformats-officedocument.wordprocessingml.document",
    "xlsx": "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet",
    "pptx": "application/vnd.openxmlformats-officedocument.presentationml.presentation",
    "mid": "audio/midi",
    "midi": "audio/midi",
    "kar": "audio/midi",
    "mp3": "audio/mpeg",
    "ogg": "audio/ogg",
    "m4a": "audio/x-m4a",
    "ra": "audio/x-realaudio",
    "3gpp": "video/3gpp",
    "3gp": "video/3gpp",
    "ts": "video/mp2t",
    "mp4": "video/mp4",
    "mpeg": "video/mpeg",
    "mpg": "video/mpeg",
    "mov": "video/quicktime",
    "webm": "video/webm",
    "flv": "video/x-flv",
    "m4v": "video/x-m4v",
    "mng": "video/x-mng",
    "asx": "video/x-ms-asf",
    "asf": "video/x-ms-asf",
    "wmv": "video/x-ms-wmv",
    "avi": "video/x-msvideo"
]

internal func MimeType(ext: String?) -> String {
    return mimeTypes[ext?.lowercased() ?? "" ] ?? DEFAULT_MIME_TYPE
}

extension NSURL {
    public func mimeType() -> String {
        return MimeType(ext: self.pathExtension)
    }
}

extension URL {
    public func mimeType() -> String {
        return MimeType(ext: self.pathExtension)
    }
}

extension NSString {
    public func mimeType() -> String {
        return MimeType(ext: self.pathExtension)
    }
}

extension String {
    public func mimeType() -> String {
        return (self as NSString).mimeType()
    }
}

How to use

let string = "https://homepages.cae.wisc.edu/~ece533/images/boat.png"

let mimeType = string.mimeType()

Workes with NSURL, URL, NSString, String

Reference 1

Reference 2