asCurlCommand.swift

extension URLRequest {
    private func quote(_ string: String) -> String {
        // handle all the regular escape sequences
        var text = string.replacingOccurrences(of: "\\", with: "\\\\")
        text = text.replacingOccurrences(of: "\"", with: "\\\"")
        text = text.replacingOccurrences(of: "\n", with: "\\\n")
        text = text.replacingOccurrences(of: "\r", with: "\\\r")
        text = text.replacingOccurrences(of: "\t", with: "\\\t")
        return "\"\(text)\""
    }
    
    public func asCurlCommand() -> String {
        guard let url = self.url else {
            return "echo 'Unable to determine url from URLRequest'"
        }
        
        var headers = ""
        for (key,val) in self.allHTTPHeaderFields ?? [:] {
            let header = "\(key): \(val)"
            headers += "-H \(quote(header)) "
        }
        
        var data = ""
        if let body = self.httpBody {
            guard let string = String(data: body, encoding: .utf8) else {
                return "echo 'Unable to represent httpBody as UTF8 string'"
            }
            data = "--data \(quote(string)) "
        }
        
        var X = ""
        if let method = self.httpMethod {
            X = "-X \(quote(method)) "
        }
        
        return "curl -v \(X)\(headers)\(data)\(quote(url.absoluteString))"
    }
}