AspNetCore.Docs/aspnetcore/includes/routeSlash.md

Routing with special characters

Routing with special characters can lead to unexpected results. For example, consider a controller with the following action method:

[HttpGet("{id?}/name")]
public async Task<ActionResult<string>> GetName(string id)
{
    var todoItem = await _context.TodoItems.FindAsync(id);

    if (todoItem == null || todoItem.Name == null)
    {
        return NotFound();
    }

    return todoItem.Name;
}

When string id contains the following encoded values, unexpected results might occur:

ASCII	Encoded
/	%2F
	+

Route parameters are not always URL decoded. This problem may be addressed in the future. For more information, see this GitHub issue;