Blazor.CommandLine (a.k.a Blazor.Console)

Development:

What and why...

This is a simple console component for ASP.NET Core 3.0 Blazor Server application model. The motivation behind this simple component is to provide simple command-line interface to manage some Web API. With this component it is easy to execute some business related commands.*

Real life scenario examples;

• Clear response cache
• Export log files
• Change run-time settings
• Monitor application resources

This Blazor component is based on System.CommandLine API and reflects standart command-line features to be more reliable.

Usage

Check Demo project(BlazorConsoleDemo.csproj) for usage;

Add following extensions to services and application within Startup.cs

public void ConfigureServices(IServiceCollection services)
{
    services.AddCommandLine();
}

public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
    app.UseCommandLine(env.WebRootPath);
}

Add tag into needed view file(ex: Index.razor)

@page "/"
@using Blazor.CommandLine
@using Blazor.Components.CommandLine
@using Blazor.Components.CommandLine.Console

<h1>Hello, world!</h1>

<BlazorCommandLine @ref="console" Name="Some Demo App v1.0.0"/>

And to have fancy UI add CSS to host file, _HOST.cshtml

<link href="Blazor.CommandLine/styles.css" rel="stylesheet" />

Commands

Adding commands to Blazor.CommandLine is not complicated. First create a command class, implement it with BaseCommand . Then add the command(s) to the BlazorCommandLine's Commands as below;

Within custom command's constructor it is easy to add options to the command. Also command arguments can be enabled for the command as System.CommandLine

To implement the command's main execution just override Execute() or ExecuteAsync() method.

@page "/"
@using Blazor.CommandLine
@using Blazor.Components.CommandLine
@using Blazor.Components.CommandLine.Console

@inject IRunningCommand RunningCommand

<h1>Hello, world!</h1>

<BlazorCommandLine @ref="console" />

@code
{
    BlazorCommandLine console;

    protected override Task OnAfterRenderAsync(bool firstRender)
    {
        console.Commands.Add(new CommandExample("simple","Description of command"));
        console.Commands.Add(new LongCommand("lng","Description of long-running command"));

        return base.OnAfterRenderAsync(firstRender);
    }

    public class CommandExample : BaseCommand
    {
        public CommandExample(string name,string description):base(name,description)
        {
            base.AddOption("-t","Description of option -t");
            base.AddOption("-ar","Description of option -ar");

            base.UseArguments($"Some extra arguments for {name}");
        
        }

        public override bool Execute(DefaultStreamWriter console,string option1,string option2,string option3,string option4,List<string> arguments)
        {
            console.Write("This is output of a simple command");
            return true;
        }
    }

    public class LongCommand : BaseCommand
    {
        public LongCommand(string name, string description):base(name,description,true)
        {
            
        }

        public override async Task<bool> ExecuteAsync(DefaultStreamWriter console, string option1,string option2,string option3,string optionArgument4,List<string> arguments)
        {
            var i = 0;

            while (i < 10)
            {
                await Task.Delay(550);
                i++;
            }
            
            console.Write("This was a long running command");
            return true;
        }
    }
}

References

• Some commands might be long running tasks, Blazor.CommandLine use some features of a great component for this kind of requirement. Please also check https://github.com/h3x4d3c1m4l/Blazor.LoadingIndicator if you need a loading indicator for a Blazor app.