Feature/http error codes

SoftPlc/Exceptions/DbAccessException.cs

@@ -0,0 +1,102 @@
+namespace SoftPlc.Exceptions;
+
+public abstract class DbAccessException : Exception
+{
+    protected DbAccessException(string message, Exception? innerException = null) : base(message, innerException)
+    {
+    }
+
+    public abstract int StatusCode { get; }
+    public abstract string Title { get; }
+}
+
+public class InvalidDbSizeException : DbAccessException
+{
+    public InvalidDbSizeException(int size) : base($"DB size must be > 0 but was {size}.")
+    {
+        Size = size;
+    }
+
+    public int Size { get; }
+
+    public override int StatusCode => StatusCodes.Status400BadRequest;
+    public override string Title => "Invalid DB size";
+
+    public static void ThrowIfInvalid(int size)
+    {
+        if (size < 1)
+            throw new InvalidDbSizeException(size);
+    }
+}
+
+public class DbOutOfRangeException : DbAccessException
+{
+    public DbOutOfRangeException(string message, int dbNo, Exception? innerException = null) : base(message, innerException)
+    {
+        DbNo = dbNo;
+    }
+
+    public DbOutOfRangeException(int dbNo) : base($"DB number must be positive, but is {dbNo}.")
+    {
+        DbNo = dbNo;
+    }
+
+    public int DbNo { get; }
+
+    public override int StatusCode => StatusCodes.Status400BadRequest;
+    public override string Title => "DB out of range";
+
+    public static void ThrowIfInvalid(int dbNo)
+    {
+        if (dbNo < 1)
+            throw new DbOutOfRangeException(dbNo);
+    }
+}
+
+public class DbNotFoundException : DbAccessException
+{
+    public DbNotFoundException(int dbNo) : base($"DB {dbNo} not found.")
+    {
+        DbNo = dbNo;
+    }
+
+    public DbNotFoundException(string message, int dbNo, Exception? innerException = null) : base(message, innerException)
+    {
+        DbNo = dbNo;
+    }
+
+    public int DbNo { get; }
+
+    public override int StatusCode => StatusCodes.Status404NotFound;
+    public override string Title => "DB not found";
+}
+
+public class DbExistsException : DbAccessException
+{
+    public DbExistsException(int dbNo) : base($"DB {dbNo} already exists.")
+    {
+        DbNo = dbNo;
+    }
+
+    public int DbNo { get; }
+
+    public override int StatusCode => StatusCodes.Status409Conflict;
+    public override string Title => "DB already exists";
+}
+
+public class DateExceedsDbLengthException : DbAccessException
+{
+    public DateExceedsDbLengthException(int dbNo, int dbLength, int dataLength) : base($"Data with {dataLength} bytes exceeds length of DB {dbNo} of {dbLength} bytes.")
+    {
+        DbNo = dbNo;
+        DBLength = dbLength;
+        DataLength = dataLength;
+    }
+
+    public int DataLength { get; }
+    public int DBLength { get; }
+    public int DbNo { get; }
+
+    public override int StatusCode => StatusCodes.Status400BadRequest;
+    public override string Title => "Data exceeds DB length";
+}

SoftPlc/Exceptions/DbAccessExceptionHandler.cs

@@ -0,0 +1,29 @@
+using Microsoft.AspNetCore.Diagnostics;
+using Microsoft.AspNetCore.Mvc;
+
+namespace SoftPlc.Exceptions;
+
+public class DbAccessExceptionHandler : IExceptionHandler
+{
+    public async ValueTask<bool> TryHandleAsync(
+        HttpContext httpContext,
+        Exception exception,
+        CancellationToken cancellationToken)
+    {
+        if (exception is not DbAccessException dbAccessException)
+            return false;
+
+        var problemDetails =
+            new ProblemDetails
+            {
+                Status = dbAccessException.StatusCode,
+                Title = dbAccessException.Title,
+                Detail = dbAccessException.Message
+            };
+
+        httpContext.Response.StatusCode = problemDetails.Status.Value;
+
+        await httpContext.Response.WriteAsJsonAsync(problemDetails, cancellationToken);
+        return true;
+    }
+}

SoftPlc/Program.cs

@@ -1,4 +1,5 @@
 using Microsoft.OpenApi.Models;
+using SoftPlc.Exceptions;
 using SoftPlc.Interfaces;
 using SoftPlc.Services;
 
@@ -28,6 +29,9 @@
         }
     });
 });
+builder.Services.AddExceptionHandler<DbAccessExceptionHandler>();
+builder.Services.AddProblemDetails();
+
 var app = builder.Build();
 
 app.UseSwagger();
@@ -44,6 +48,7 @@
 
 app.UseAuthorization();
 
+app.UseExceptionHandler();
 app.MapControllers();
 
 var plcService = app.Services.GetService<IPlcService>();

SoftPlc/Services/PlcService.cs

@@ -7,6 +7,7 @@
 using Microsoft.Extensions.Configuration;
 using System.IO;
 using Newtonsoft.Json;
+using SoftPlc.Exceptions;
 
 namespace SoftPlc.Services
 {
@@ -116,10 +117,12 @@ public IEnumerable<DatablockDescription> GetDatablocksInfo()
 		public DatablockDescription GetDatablock(int id)
 		{
 			CheckServerRunning();
-			DatablockDescription db;
-			var found = datablocks.TryGetValue(id, out db);
-			if (found) return db;
-			throw new InvalidOperationException("Datablock not found");
+            DbOutOfRangeException.ThrowIfInvalid(id);
+
+            if (datablocks.TryGetValue(id, out var db)) 
+                return db;
+			else
+			    throw new DbNotFoundException(id);
 		}
 
 		private void AddDatablock(int id, DatablockDescription datablock)
@@ -131,26 +134,37 @@ private void AddDatablock(int id, DatablockDescription datablock)
 		public void AddDatablock(int id, int size)
 		{
 			CheckServerRunning();
-			if (id < 1) throw new ArgumentException("Invalid id for datablock - id must be > 1", nameof(id));
-			if (size < 1) throw new ArgumentException("Invalid size for datablock - size must be > 1", nameof(size));
-			if (datablocks.ContainsKey(id)) throw new InvalidOperationException($"A Datablock with id = {id} already exists");
+            DbOutOfRangeException.ThrowIfInvalid(id);
+            InvalidDbSizeException.ThrowIfInvalid(size);
+
 			var db = new DatablockDescription(id, size);
-			while(!datablocks.TryAdd(id, db)){ }
+			if (!datablocks.TryAdd(id, db))
+                throw new DbExistsException(id);
+
 			server.RegisterArea(S7Server.srvAreaDB, id, ref datablocks[id].Data, datablocks[id].Data.Length);
 		}
 
 		public void UpdateDatablockData(int id, byte[] data)
 		{
-			if (data != null && data.Length > datablocks[id].Data.Length) throw new ArgumentException("Too much data as expected", nameof(data));
-			if(data != null)
-				Array.Copy(data, datablocks[id].Data, data.Length);
+            DbOutOfRangeException.ThrowIfInvalid(id);
+
+            if (!datablocks.TryGetValue(id, out var db))
+                throw new DbNotFoundException(id);
+
+			if (data.Length > db.Data.Length) 
+                throw new DateExceedsDbLengthException(id, db.Data.Length, data.Length);
+
+			Array.Copy(data, datablocks[id].Data, data.Length);
 		}
 
 		public void RemoveDatablock(int id)
 		{
-			server.UnregisterArea(S7Server.srvAreaDB, id);
-			DatablockDescription datablock;
-			while (!datablocks.TryRemove(id, out datablock)) { }
-		}
+            DbOutOfRangeException.ThrowIfInvalid(id);
+
+            if (datablocks.TryRemove(id, out _))
+                server.UnregisterArea(S7Server.srvAreaDB, id);
+            else
+                throw new DbNotFoundException(id);
+        }
 	}
 }