C#: CommandLineParser How to parse URL?

Question

I am working on a C# project which basically works on commands to perform certain operations. It uses CommandLineParser library to parse all these commands and respective argument.

As per the new business requirement, I need to parse an URL which contains verb and parameters.

Is there any built-in/easy way to parse URL in CommandLineParser library, that will avoid writing custom logic which I explained in below approach?

---

Here is my approach to solve this challenge:

Covert URL to command, then using CommandLine parser assign values to option properties.

e.g.

URL:

https://localhost:9000/Open?appId=123&appName=paint&uId=511a3434-37e0-4600-ab09-65728ac4d8fe

Implementation:

• Custom logic to covert url to command

  open -appId 123 -name paint -uid 511a3434-37e0-4600-ab09-65728ac4d8fe
  

• Then pass it to parser.ParseArguments

• Here is the class structure

  [Verb("open", HelpText = "Open an application")]
  public class OpenOptions
  {
      [Option("id", "appId", Required = false, HelpText = "Application Id")]
      public int ApplicationId{ get; set; }
      [Option("name", "appName", Required = false, HelpText = "Application Name")]
      public string ApplicationName{ get; set; }
      [Option("uId", "userId", Required = true, HelpText = "User Id")]
      public Guid UserId{ get; set; }
  }
  

Answer 1

There is no out-of-the-box solution. Normally HttpUtility class (ref Get URL parameters from a string in .NET) can do the trick.

Here is the first approach:

var url = "https://localhost:9000/Open?appId=123&appName=paint&uId=511a3434-37e0-4600-ab09-65728ac4d8fe";
Uri uri = new Uri(url);
var @params = HttpUtility.ParseQueryString(uri.Query);
string? appId = @params.Get("appId");
Console.WriteLine(appId);

Will return 123, and so on with your other parameters.

The returned value will be a string type. You can eventually use Guid.TryParse to parse your Guid object and int.TryParse for an int value.

Answer 2

CommandLineParser is not made for parsing Uri's. But using the Uri class and Linq, this is quite easy:

using System;
using System.Collections.Generic;
using System.Linq;

public class Program
{
    public static void Main()
    {
        var (verb, query) = ParseUri("https://localhost:9000/Open/appId=123&appName=paint&uId=511a3434-37e0-4600-ab09-65728ac4d8fe");

        var appId = query["appId"];
        var appName = query["appName"];
        var uId = query["uId"];

        Console.WriteLine($"verb='{verb}'");
        Console.WriteLine($"appId='{appId}', appName='{appName}', uId='{uId}'");
    }

    static (string verb, Dictionary<string, string> args) ParseUri(string strUri)
    {
        var uri = new Uri(strUri);

        // get the verb
        var verb = uri.Segments[1].TrimEnd('/');

        // get the query part as dictionary
        var args = uri.Segments[2].Split('&')
            .Select(s => s.Split('=')).ToDictionary(d => d[0], d => d[1]);

        return (verb, args);    
    }

}

First parsing happens by instantiating an Uri allowing to use the Segments property. Then split the query by using & and finally create a dictionary by using = to split the key/value pair.

Because query is a Dictionary, you can simply access individual query parameters like:

var appId = query["appId"];
var appName = query["appName"];
var uId = query["uId"];

Console.WriteLine($"verb='{verb}'");
Console.WriteLine($"appId='{appId}', appName='{appName}', uId='{uId}'");

which prints:

verb='Open'
appId='123', appName='paint', uId='511a3434-37e0-4600-ab09-65728ac4d8fe'

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Note: In LinqPad, you can use query.Dump(verb); to visualize the result:

Answer 3

var link = "https://localhost:9000/Open?appId=123&appName=paint&uId=511a3434-37e0-4600-ab09-65728ac4d8fe";

var uri = new Uri(link);
var command = uri.LocalPath.TrimStart('/').ToLower();
var query = HttpUtility.ParseQueryString(uri.Query);

var sb = new StringBuilder($"{command} ");
foreach(string key in query)
{
    sb.Append($"-{key} {query.Get(key)} ");
}

var commandWithArgs = sb.ToString();