3 - Assigning Commands

3.1 Setting up the while loop

Our application will continually ask for commands that we setup in the last section. For a console application, this is generally a while loop.

1. To determine whether or not the while loop should run, we need an addition static bool isAskedToExit = false. If the user turns this to true via the --exit command, the while loop will stop and the application will exit.
2. In each iteration of the while loop, we will need read the command from the user. In C#, we can use the Console.ReadLine API, which will prompt the user for a string entry. We can store this into string command.
3. We can add a switch statement which will parse the correct command and react to the command.
4. If the user types in --insert, we will parse out the string without the --insert command. We assume this string is the body for a new document. So we will call the .upsert command with ditto via:

string taskBody = s.Replace("--insert ", "");ditto.Store["tasks"].Upsert(new Task(taskBody, false).ToDictionary());

5. Check for a switch case for --toggle. We will parse out the string without --toggle and assume the user's input is a Task document's _id. We can then find the document by its _id and call .update
6. Check for a switch case for --delete. We will parse out the string without --delete and assume the user's input is a Task document's _id. We can then find the document by its _id and call .update
7. Finally we will add a command to look for --list, which will print out all the tasks that we've synced.

Program.cs

using System;using DittoSDK;using System.Collections.Generic;
namespace Tasks{    class Program    {        static Ditto ditto;        // 1.        static bool isAskedToExit = false;        static List<Task> tasks = new List<Task>();        static DittoLiveQuery liveQuery;        static DittoSubscription subscription;

        public static void Main(params string[] args)        {            ditto = new Ditto(DittoIdentity.OnlinePlayground("REPLACE_ME_WITH_YOUR_APP_ID", "REPLACE_ME_WITH_YOUR_PLAYGROUND_TOKEN"), path);
            /**            * Omitted for brevity            */
            subscription = ditto.Store["tasks"].Find("!isDeleted").Subscribe()
            liveQuery = ditto.Store["tasks"].Find("!isDeleted").ObserveLocal((docs, _event) => {                tasks = docs.ConvertAll(d => new Task(d));            });                        ditto.Store["tasks"].Find("isDeleted == true").Evict();
            ListCommands();
            while (!isAskedToExit)            {
                // 2.                Console.Write("\nYour command: ");                string command = Console.ReadLine();
                switch (command)                {
                    // 3. 4.                    case string s when command.StartsWith("--insert"):                        string taskBody = s.Replace("--insert ", "");                        ditto.Store["tasks"].Upsert(new Task(taskBody, false).ToDictionary());                        break;                    // 5.                    case string s when command.StartsWith("--toggle"):                        string _idToToggle = s.Replace("--toggle ", "");                        ditto.Store["tasks"]                            .FindById(new DittoDocumentId(_idToToggle))                            .Update((mutableDoc) => {                                if (mutableDoc == null) return;                                mutableDoc["isCompleted"].Set(!mutableDoc["isCompleted"].BooleanValue);                            });                        break;                    // 6.                    case string s when command.StartsWith("--delete"):                        string _idToDelete = s.Replace("--delete ", "");                        ditto.Store["tasks"]                            .FindById(new DittoDocumentId(_idToDelete))                            .Update((mutableDoc) => {                                if (mutableDoc == null) return;                                mutableDoc["isDeleted"].Set(true);                            });                        break;                    case { } when command.StartsWith("--list"):                        tasks.ForEach(task =>                        {                            Console.WriteLine(task.ToString());                        });                        break;                    // 1.                    case { } when command.StartsWith("--exit"):                        Console.WriteLine("Good bye!");                        isAskedToExit = true;                        break;                    default:                        Console.WriteLine("Unknown command");                        ListCommands();                        break;                }            }        }    }}

3.2 Final application

Our application is complete! Our Program.cs file should look like the following. Now you can run the example in your terminal, command line or right within the run command in Visual Studio.

Program.cs

using System;using DittoSDK;using System.Collections.Generic;
namespace Tasks{    class Program    {        static Ditto ditto;        static bool isAskedToExit = false;        static List<Task> tasks = new List<Task>();        static DittoLiveQuery liveQuery;        static DittoSubscription subscription;

        public static void Main(params string[] args)        {            ditto = new Ditto(DittoIdentity.OnlinePlayground("REPLACE_ME_WITH_YOUR_APP_ID", "REPLACE_ME_WITH_YOUR_PLAYGROUND_TOKEN"), path);
            try            {                DittoTransportConfig transportConfig = new DittoTransportConfig();
                // Enable Local Area Network Connections                transportConfig.EnableAllPeerToPeer();
                // Listen for incoming connections on port 4000                transportConfig.Listen.Tcp.Enabled = true;                transportConfig.Listen.Tcp.InterfaceIp = "0.0.0.0";                transportConfig.Listen.Tcp.Port = 4000;
                // Connect explicitly to a remote device on                 transportConfig.Connect.TcpServers.Add("135.1.5.5:12345");                // you can add as many TcpServers as you would like.                transportConfig.Connect.TcpServers.Add("185.1.5.5:12345");
                ditto.TransportConfig = transportConfig;
                ditto.StartSync();            }            catch (DittoException ex)            {                Console.WriteLine("There was an error starting Ditto.");                Console.WriteLine("Here's the following error");                Console.WriteLine(ex.ToString());                Console.WriteLine("Ditto cannot start sync but don't worry.");                Console.WriteLine("Ditto will still work as a local database.");            }
            Console.WriteLine("Welcome to Ditto's Task App");
            subscription = ditto.Store["tasks"].Find("!isDeleted").Subscribe();
            liveQuery = ditto.Store["tasks"].Find("!isDeleted").ObserveLocal((docs, _event) => {                tasks = docs.ConvertAll(document => new Task(document));            });
            ditto.Store["tasks"].Find("isDeleted == true").Evict();
            ListCommands();
            while (!isAskedToExit)            {                                Console.Write("\nYour command: ");                string command = Console.ReadLine();
                switch (command)                {                                        case string s when command.StartsWith("--insert"):                        string taskBody = s.Replace("--insert ", "");                        ditto.Store["tasks"].Upsert(new Task(taskBody, false).ToDictionary());                        break;                    case string s when command.StartsWith("--toggle"):                        string _idToToggle = s.Replace("--toggle ", "");                        ditto.Store["tasks"]                            .FindById(new DittoDocumentId(_idToToggle))                            .Update((mutableDoc) => {                                if (mutableDoc == null) return;                                mutableDoc["isCompleted"].Set(!mutableDoc["isCompleted"].BooleanValue);                            });                        break;                    case string s when command.StartsWith("--delete"):                        string _idToDelete = s.Replace("--delete ", "");                        ditto.Store["tasks"]                            .FindById(new DittoDocumentId(_idToDelete))                            .Update((mutableDoc) => {                                if (mutableDoc == null) return;                                mutableDoc["isDeleted"].Set(true);                            });                        break;                    case { } when command.StartsWith("--list"):                        tasks.ForEach(task =>                        {                            Console.WriteLine(task.ToString());                        });                        break;                    case { } when command.StartsWith("--exit"):                        Console.WriteLine("Good bye!");                        isAskedToExit = true;                        break;                    default:                        Console.WriteLine("Unknown command");                        ListCommands();                        break;                }            }        }
        public static void ListCommands()        {            Console.WriteLine("************* Commands *************");            Console.WriteLine("--insert my new task");            Console.WriteLine("   Inserts a task");            Console.WriteLine("   Example: \"--insert Get Milk\"");            Console.WriteLine("--toggle myTaskTd");            Console.WriteLine("   Toggles the isComplete property to the opposite value");            Console.WriteLine("   Example: \"--toggle 1234abc\"");            Console.WriteLine("--delete myTaskTd");            Console.WriteLine("   Deletes a task");            Console.WriteLine("   Example: \"--delete 1234abc\"");            Console.WriteLine("--list");            Console.WriteLine("   List the current tasks");            Console.WriteLine("--exit");            Console.WriteLine("   Exits the program");            Console.WriteLine("************* Commands *************");        }    }}