Digest Proxy Authorization

gistfile1.txt

public static func proxyAuthorizationFor(host: String, port: Int, username: String, password: String, destHost: String, destPort: Int) -> [String : String]? {
        var input: InputStream?
        var output: OutputStream?
        Stream.getStreamsToHost(withName: host, port: port, inputStream: &input, outputStream: &output)
        guard let input_ = input, let output_ = output else { return nil }
        input_.open()
        output_.open()
        guard input_.streamError == nil, output_.streamError == nil else { return nil }
        let method = "CONNECT"
        let uri = "\(destHost):\(destPort)"
        let host = uri
        let queryString = "\(method) \(uri) HTTP/1.1\r\nHost: \(host)\r\n\r\n"
        let queryData = [UInt8](queryString.utf8)
        output_.write(UnsafePointer<UInt8>(queryData), maxLength: queryData.count)
        let size = 256
        let buffer = malloc(size).assumingMemoryBound(to: UInt8.self)
        defer { free(buffer) }
        var totalText = ""
        while true {
            let read = input_.read(buffer, maxLength: size)
            if read <= 0 { break }
            if read < size {
                let p = malloc(read).assumingMemoryBound(to: UInt8.self)
                defer { free(p) }
                memcpy(p, buffer, read)
                totalText += String(cString: p)
                break
            } else {
                totalText += String(cString: buffer)
            }
        }
        let prefix = "Proxy-Authenticate: Digest"
        guard let proxyAuthenticate = totalText.components(separatedBy: "\r\n").filter({$0.hasPrefix(prefix)}).first?.replacingOccurrences(of: prefix, with: "") else { return nil }
        let array = proxyAuthenticate.components(separatedBy: ",").flatMap { (raw) -> [String : String]? in
            let kv = raw.components(separatedBy: "=").flatMap({Optional($0.trimmingCharacters(in: CharacterSet.whitespacesAndNewlines).replacingOccurrences(of: "\"", with: ""))})
            guard kv.count == 2 else { return nil }
            return [kv[0] : kv[1]]
            }
        let map = array.reduce([:]) { (result, dict) -> [String : String] in
            var old = result
            for (k, v) in dict { old[k] = v }
            return old
        }
        guard let realm = map["realm"], let qop = map["qop"], let nonce = map["nonce"] else { return nil }
        let A1 = "\(username):\(realm):\(password)"
        let A2 = "\(method.uppercased()):\(uri)"
        let HA1 = A1.md5()
        var HA2 = ""
        let nc = "00000001"
        let cnonce = UUID().uuidString
        var response = ""
        if qop.contains("auth") {
            HA2 = A2.md5()
            let raw = "\(HA1):\(nonce):\(nc):\(cnonce):\(qop):\(HA2)"
            response = raw.md5()
        }
        let ret = "Digest username=\"\(username)\", realm=\"\(realm)\", nonce=\"\(nonce)\", uri=\"\(uri)\", cnonce=\"\(cnonce)\", nc=\(nc), qop=\(qop), response=\"\(response)\""
        return ["Proxy-Authenticate" : ret]
    }