I came up with this example to clarify my question
We start with a base class
/// <summary>
/// Just a silly example class
/// </summary>
class CFileStream
{
protected readonly string FilePath;
public CFileStream(string filePath)
{
FilePath = filePath;
}
public virtual void Write(string s)
{
var stream = GetStream(FilePath);
//etc
}
/// <summary>
/// Take filePath as an argument to make subclassing easier
/// </summary>
protected virtual FileStream GetStream(string filePath)
{
return new FileStream(filePath, FileMode.OpenOrCreate);
}
}
Create a subclass for it
/// <summary>
/// Building on top of CFileStream, created an encrypted version
/// </summary>
class CFileStreamEncrypted : CFileStream
{
private readonly string _key;
public CFileStreamEncrypted(string filePath, string key):base(filePath)
{
_key = key;
}
/// <summary>
/// For added complexity, let's also wrap a possible excepton
/// </summary>
public override void Write(string s)
{
try
{
base.Write(s);
}
catch (ImaginaryCryptoException ex)
{
throw new ImaginaryCustomException("bladibla", ex);
}
}
/// <summary>
/// Wrap the base stream in an imaginary crypto class
/// </summary>
protected override FileStream GetStream(string filePath)
{
return new CImaginaryCryptoStream(base.GetStream(filePath), _key);
}
}
Now we wish to create a second subclass, but one that works with the initial filewriter as well as the encrypted version.
The first one makes sense
/// <summary>
/// Building on top of CFileStream, created an auto-split version
/// </summary>
class CFileStreamSplit : CFileStream
{
public CFileStreamSplit(string filePath)
: base(filePath)
{
}
protected int Counter;
/// <summary>
/// Close stream and move to next file at the appropriate time(s)
/// </summary>
public override void Write(string s)
{
do
{
Stream stream;
if (ImaginaryBooleanMustSplit)
stream = GetStream(FilePath);
//etc
} while (ImaginaryBooleanDataLeftToWrite);
}
/// <summary>
/// Get base stream but with altered filePath
/// </summary>
protected override FileStream GetStream(string filePath)
{
return base.GetStream(GetNextpath(filePath));
}
/// <summary>
/// Ignore proper extension / file-exists etc.
/// </summary>
protected virtual string GetNextpath(string filePath)
{
return filePath + ++Counter;
}
}
The second one (below this) is completely duplicate code, except for the constructor which now also requires the encryption key.
/// <summary>
/// Build the same auto-split version but this time on top of the encrypted subclass
/// </summary>
class CFileStreamSplitEncrypted : CFileStreamEncrypted
{
public CFileStreamSplitEncrypted(string filePath, string key)
: base(filePath, key)
{
}
/*
* Note that there are no changes below this line
*/
protected int Counter;
/// <summary>
/// Close stream and move to next file at the appropriate time(s)
/// </summary>
public override void Write(string s)
{
do
{
Stream stream;
if (ImaginaryBooleanMustSplit)
stream = GetStream(FilePath);
//etc
} while (ImaginaryBooleanDataLeftToWrite);
}
/// <summary>
/// Get base stream but with altered filePath
/// </summary>
protected override FileStream GetStream(string filePath)
{
return base.GetStream(GetNextpath(filePath));
}
/// <summary>
/// Ignore proper extension / file-exists etc.
/// </summary>
protected virtual string GetNextpath(string filePath)
{
return filePath + ++Counter;
}
}
There are of course a lot of ways to reduce the amount of duplicate code here, but I have yet to find 'the best' way, if there even is such a thing. So; what is the least time-consuming, cleanest, most flexible way to get a round this issue in your opinion/experience?
For the different modifications a decent way to go may be composition over inheritance. Set up your classes to only be responsible for a single thing, taking in a base stream on constructions.
interface ICFileStream
{
void Write(string s);
FileStream GetStream(string filePath);
}
/// <summary>
/// Just a silly example class
/// </summary>
class CFileStream: ICFileStream
{
protected readonly string FilePath;
public CFileStream(string filePath)
{
FilePath = filePath;
}
public void Write(string s)
{
var stream = GetStream(FilePath);
//etc
}
/// <summary>
/// Take filePath as an argument to make subclassing easier
/// </summary>
protected FileStream GetStream(string filePath)
{
return new FileStream(filePath, FileMode.OpenOrCreate);
}
}
/// <summary>
/// Building on top of CFileStream, created an encrypted version
/// </summary>
class CFileStreamEncrypted : ICFileStream
{
private readonly string _key;
private readonly ICFileStream _stream;
public CFileStreamEncrypted(string key, ICFileStream stream)
{
_key = key;
_stream = stream;
}
/// <summary>
/// For added complexity, let's also wrap a possible excepton
/// </summary>
public void Write(string s)
{
try
{
_stream.Write(s);
}
catch (ImaginaryCryptoException ex)
{
throw new ImaginaryCustomException("bladibla", ex);
}
}
/// <summary>
/// Wrap the base stream in an imaginary crypto class
/// </summary>
protected FileStream GetStream(string filePath)
{
return new CImaginaryCryptoStream(_stream.GetStream(filePath), _key);
}
}
class CFileStreamSplit : ICFileStream
{
private readonly ICFileStream _stream;
public CFileStreamSplit(ICFileStream stream)
{
_stream = stream;
}
protected int Counter;
/// <summary>
/// Close stream and move to next file at the appropriate time(s)
/// </summary>
public void Write(string s)
{
do
{
Stream stream;
if (ImaginaryBooleanMustSplit)
stream = GetStream(FilePath);
//etc
} while (ImaginaryBooleanDataLeftToWrite);
}
/// <summary>
/// Get base stream but with altered filePath
/// </summary>
protected FileStream GetStream(string filePath)
{
return _stream.GetStream(GetNextpath(filePath));
}
/// <summary>
/// Ignore proper extension / file-exists etc.
/// </summary>
protected string GetNextpath(string filePath)
{
return filePath + ++Counter;
}
}
So when you want a splitting-crypto-filestream:
new CFileStreamSplit(new CFileStreamEncrypted("crypto-awesome-key", new CFileStream("C:\\blah...")));
This is more flexible so when you want to add LoggingCFileStream for example you don't need to add a separate class for each combination.
Related
I am relatively new to programming and I took it upon myself to make a simple chat application; think AIM from back in the day. This is more of a request for a code review than a list of questions. For the most part, the application works with a few minor errors which I will highlight below. Please see the code from the project: https://github.com/N8STROMO/Basic-Chat-Tcp as well as the code listed below. Questions are embedded along the way. Thanks for any help you may be able to provide!
Here is the Server Code: Server.cs
namespace Server
{
public class Server
{
// This is the port that the server will be listening on
const int PORT = 500;
// This is where the usernames and their connections will be held
readonly Dictionary<string, ServerUserConnection> userToConnections = new Dictionary<string, ServerUserConnection>();
readonly TcpListener listener;
public static void Main()
{
// Constructor for the ChatServer
Server server = new Server();
while(true)
{
Thread.Sleep(1); // Temp to keep alive
}
}
/// <summary>
/// Listens for data from clients
/// </summary>
public Server()
{
listener = TcpListener.Create(PORT);
listener.Start();
WaitForConnections();
}
/// <summary>
/// Begins an asynchronous operation to accept an incoming connection attempt
/// </summary>
private void WaitForConnections()
{
listener.BeginAcceptTcpClient(OnConnect, null);
}
/// <summary>
/// This method is executed asynchronously
/// Connects the client to the server
/// Broadcasts the user to client to be displayed on the chatform
/// Then waits for another connection to be established
/// </summary>
/// <param name="ar"></param>
void OnConnect(IAsyncResult ar)
{
//Asynchronously accepts an incoming connection attempt and creates a new TcpClient to handle remote host communication.
TcpClient client = listener.EndAcceptTcpClient(ar);
Console.WriteLine("Connected");
ReceiveUser(client);
BroadcastUserList();
WaitForConnections();
}
/// <summary>
/// Connects a user to the server and adds them to the dictionary userToConnections
/// </summary>
/// <param name="client"></param>
public void ReceiveUser(TcpClient client)
{
ServerUserConnection connection = new ServerUserConnection(this, client); // Constructor
userToConnections.Add(connection.userName, connection);
}
/// <summary>
/// For each user that is connected append the userList to include that user
/// TODO Do not need to keep a running list of users; send the user over then throw it away
/// </summary>
void BroadcastUserList()
{
string userList = "";
foreach(var connection in userToConnections)
{
userList += $"{connection.Value.userName},";
}
SendMsgToAll(MessageType.UserList, null, userList);
}
/// <summary>
/// Pushes out messages to the connected clients
/// </summary>
/// <param name="type"></param>
/// <param name="user"></param>
/// <param name="message"></param>
public void SendMsgToAll(MessageType type, ServerUserConnection user, string message)
{
Console.WriteLine($"{user?.userName}: {message}");
foreach(var connection in userToConnections)
{
Console.WriteLine($"Sending to {connection.Value.userName}");
Utils.SendInformation(type, connection.Value.stream, message);
}
}
}
}
Here is the ServerUserConnection.cs: I am having trouble understanding how the inheritance here works and what the base keyword does.
namespace Server
{
public class ServerUserConnection : UserConnection
{
readonly Server server;
/// <summary>
/// Facilitates connection
/// </summary>
/// <param name="server"></param>
/// <param name="client"></param>
public ServerUserConnection(Server server, TcpClient client) : base(client, GetUsername(client)) // Inherits from UserConnection()
{
this.server = server;
}
private static string GetUsername(TcpClient client)
{
NetworkStream stream = client.GetStream();
if(stream.CanRead)
{
// Receives infromation from the stream, determines MessageType, and returns username
string userName = Utils.ReceiveInformation(stream, client, out MessageType type);
Console.WriteLine(userName);
return userName;
}
return null;
}
/// <summary>
///
/// </summary>
/// <param name="type"></param>
/// <param name="message"></param>
protected override void OnRead(MessageType type, string message)
{
if(type != MessageType.ChatMessage)
{
return;
}
server.SendMsgToAll(MessageType.ChatMessage, this, $"{userName} {message}");
}
}
}
Here is the Client Code: Client.cs
namespace Client
{
public class ChatClient
{
private const int PORT = 500;
TcpClient client = new TcpClient();
public ChatForm chatForm;
public ClientUserConnection userConnection;
string data;
[STAThread]
public static void Main()
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
var client = new ChatClient();
var form = new ConnectForm(client);
Application.Run(form);
}
/// <summary>
/// This is called when the ConnectForm btnSubmit is pressed.
/// </summary>
/// <param name="ipAddress"></param>
/// <param name="userName"></param>
public void ConnectToServer(string ipAddress, string userName)
{
client.Connect(ipAddress, PORT);
SendUserName(userName);
}
/// <summary>
/// Sends user to the server
/// </summary>
public void SendUserName(string user)
{
userConnection = new ClientUserConnection(client, this, user);
Utils.SendInformation(MessageType.Connect, client.GetStream(), user);
}
/// <summary>
/// Sends a message to the server
/// </summary>
/// <param name="msg"></param>
public void SendMessage(string msg)
{
Utils.SendInformation(MessageType.ChatMessage, userConnection.stream, msg);
}
}
}
Here is the ClientUserConnection.cs: Is there a way to refactor or optimize this so that instead of keeping a running list of messages just send the message over and throw it away? Again, the same question about inheritance.
public class ClientUserConnection : UserConnection
{
public readonly Client.ChatClient chatClient;
public string message = "";
public string userListText;
/// <summary>
///
/// </summary>
/// <param name="client"></param>
/// <param name="chatClient"></param>
/// <param name="userName"></param>
public ClientUserConnection(TcpClient client, Client.ChatClient chatClient, string userName) : base(client, userName) // Inherits from UserConnection()
{
this.chatClient = chatClient;
}
/// <summary>
/// When the data is reads determine what kind of message it is
/// Parse/split out the message and user; display only relevant data
/// TODO Do not need to keep a running list of messages; send the message over then throw it away
/// </summary>
/// <param name="type"></param>
/// <param name="message"></param>
protected override void OnRead(MessageType type, string message)
{
if(type == MessageType.ChatMessage)
{
int iSpace = message.IndexOf(" ");
if(iSpace < 0)
{
// if error
return;
}
string from = message.Substring(0, iSpace);
string chatMessage = message.Substring(iSpace + 1, message.Length - iSpace - 1);
this.message += $"[{from}]: {chatMessage}{Environment.NewLine}";
}
else if(type == MessageType.UserList)
{
string[] userList = message.Split(',');
string userListText = "";
for(int i = 0; i < userList.Length; i++)
{
userListText += $"{userList[i]}{Environment.NewLine}";
}
this.userListText = userListText;
}
}
}
There are also three files within a class library that are used within this project:
This is the MessageType.cs:
public enum MessageType
{
Connect, UserList, ChatMessage
}
This is the UserConnection.cs: I still need to deal with disconnecting users. If one of the chat forms is closed, it crashes the application.
public abstract class UserConnection
{
public readonly TcpClient client;
public readonly NetworkStream stream;
public readonly string userName;
byte[] data;
/// <summary>
///
/// </summary>
/// <param name="client"></param>
/// <param name="userName"></param>
public UserConnection(TcpClient client, string userName)
{
this.client = client;
this.userName = userName;
stream = client.GetStream();
data = new byte[client.ReceiveBufferSize];
WaitForData();
}
/// <summary>
///
/// </summary>
private void WaitForData()
{
Console.WriteLine("Wait");
stream.BeginRead(data, 0, data.Length, OnReadData, null);
}
/// <summary>
/// SocketException: An existing connection was forcibly closed by the remote host
/// </summary>
/// <param name="ar"></param>
void OnReadData(IAsyncResult ar)
{
Console.WriteLine("Read");
int result = stream.EndRead(ar); // TODO disconnect & error handling
Console.WriteLine("Read done");
if(result <= 0)
{
Console.WriteLine("Error reading");
return;
}
string message = Utils.ReceiveInformation(data, result, out MessageType type);
OnRead(type, message);
WaitForData();
}
/// <summary>
///
/// </summary>
/// <param name="type"></param>
/// <param name="message"></param>
protected abstract void OnRead(MessageType type, string message);
}
This is the Utils.cs: I am having trouble understanding how there are two methods called ReceiveInformation() and how they interact with each other
public class Utils
{
/// <summary>
///
/// </summary>
/// <param name="stream"></param>
/// <param name="connection"></param>
/// <param name="type"></param>
/// <returns></returns>
public static string ReceiveInformation(NetworkStream stream, TcpClient connection, out MessageType type)
{
byte[] bytes = new byte[connection.ReceiveBufferSize];
int length = stream.Read(bytes, 0, bytes.Length);
return ReceiveInformation(bytes, length, out type);
}
/// <summary>
///
/// </summary>
/// <param name="bytes"></param>
/// <param name="length"></param>
/// <param name="type"></param>
/// <returns></returns>
public static string ReceiveInformation(byte[] bytes, int length, out MessageType type)
{
string data = Encoding.ASCII.GetString(bytes, 0, length);
int iSpace = data.IndexOf(' ');
if(iSpace < 0)
{
// TODO
}
string typeString = data.Substring(0, iSpace);
type = (MessageType)Enum.Parse(typeof(MessageType), typeString);
string message = data.Substring(iSpace + 1, data.Length - iSpace - 1);
return message;
}
/// <summary>
///
/// </summary>
/// <param name="type"></param>
/// <param name="stream"></param>
/// <param name="message"></param>
public static void SendInformation(MessageType type, NetworkStream stream, string message)
{
Byte[] sendBytes = Encoding.UTF8.GetBytes($"{type} {message}");
stream.Write(sendBytes, 0, sendBytes.Length);
}
}
I am working on a proof of concept for using Unity and I am having issues with my interceptor being called. I am using policy injection.
so here is some code
setting up unity:
private void ApplyCrossCuttingConcerns(UnityContainer container)
{
container.AddNewExtension<Interception>();
container.RegisterType<IContact, Contact>(
new InterceptionBehavior<PolicyInjectionBehavior>(),
new Interceptor<InterfaceInterceptor>());
container.Configure<Interception>()
.AddPolicy("extensionPolicy")
.AddMatchingRule<TypeMatchingRule>(new InjectionConstructor(typeof(Contact).ToString()))
.AddMatchingRule<MethodSignatureMatchingRule>(new InjectionConstructor("Save",new [] {""},true))
.AddCallHandler<ExtensionHandler>(new ContainerControlledLifetimeManager(), new InjectionConstructor());
}
my contact class that inherites from BussinessObject where the method in question lives
public class Contact : BussinessObject, IContact
{...}
public abstract class BussinessObject
{
#region Local Vars
protected readonly IRepository _repository;
protected bool isNew;
#endregion Local Vars
#region Properties
/// <summary>
/// Gets or sets a value indicating whether this instance is new.
/// </summary>
/// <value>
/// <see langword="true" /> if this instance is new; otherwise, <see langword="false" />.
/// </value>
internal bool IsNew { get { return (isNew); } set { isNew = value; } }
#endregion
#region Constructors
/// <summary>
/// Initializes a new instance of the <see cref="BussinessObject"/> class.
/// </summary>
/// <param name="repository">The repository.</param>
public BussinessObject(IRepository repository)
{
if (repository.IsEmpty())
{
throw new Exception("The repository is a maditory parameter for a bussiness object");
}
_repository = repository;
}
#endregion Constructors
#region Methods
#region public
/// <summary>
/// Saves this instance.
/// </summary>
public virtual void Save()
{
Validate();
SetIdenity();
if (isNew)
{
Insert();
}
else
{
Update();
}
isNew = false;
}
/// <summary>
/// Permantlies the remove from system.
/// </summary>
/// <param name="ID">The identifier.</param>
public abstract void PermantlyRemoveFromSystem(Guid id);
#endregion public
#region Internal
/// <summary>
/// Sets the idenity.
/// </summary>
internal abstract void SetIdenity();
#endregion Internal
#region protected
/// <summary>
/// Commons the initialize.
/// </summary>
protected virtual void CommonInit()
{
isNew = false;
}
/// <summary>
/// Inserts this instance.
/// </summary>
protected abstract void Insert();
/// <summary>
/// Updates this instance.
/// </summary>
protected abstract void Update();
/// <summary>
/// Validates this instance.
/// </summary>
protected abstract void Validate();
#endregion protected
#endregion
}
Now the IContact
public interface IContact : DTO.IContact
{
void Save();
void Delete();
#region Phone Number Manipulation
bool SetDefaultNumber(PhoneNumber phNum);
PhoneNumber GetDefaultNumber();
bool HasDefaultNumber();
PhoneNumber[] GetPhoneNumbers();
PhoneNumber[] GetPhoneNumbers(bool includeDeleted);
void AddPhoneNumber(PhoneNumber phToAdd);
bool RemovePhoneNumber(PhoneNumber phToRemove);
#endregion
#region Email Address Manipulation
bool SetDefaultEMailAddress(EmailAddress emAdd);
bool HasDefaultEmailAddress();
EmailAddress[] GetAllEmailAddresses();
EmailAddress[] GetAllEmailAddresses(bool includeDeleted);
EmailAddress AddEmailAddress(string addressToAdd);
EmailAddress GetDefaultEMailAddress();
#endregion
#region Snailmail Address Manipulation
bool SetDefaultAddress(SnailMailAddress ad);
SnailMailAddress GetDefaultAddress();
bool HasDefaultAddress();
SnailMailAddress[] GetAllAddresses();
SnailMailAddress[] GetAllAddresses(bool includeDeleted);
void AddAddress(SnailMailAddress adToAdd);
bool RemoveAddress(SnailMailAddress adToRemove);
#endregion
}
and finally the extensionHandler
public class ExtensionHandler : ICallHandler
{
public int Order { get; set; }
public IMethodReturn Invoke(IMethodInvocation input, GetNextHandlerDelegate getNext)
{
//going to do our work before we pass on to the next item in the pipeline
SomeFunctionality handlerFunctionality = new SomeFunctionality();
handlerFunctionality.PreformWork();
//pass on to the next item in the pipeline
var result = getNext().Invoke(input, getNext);
//we can put post processing logic in here
return result;
}
I setup a test to resolve the contact object and then set so data on it and called the save method. I have a break point at the top of the invoke method in the ExtensionHandler but I never get there. I think the issue with the way I configuring the MethodSignatureMatchingRule but I have not yet to find documentation on the net showing an example of interception being configured to a method with no parameters.
Any help would be appreaiated
so after some more experimentation I found the answer
This issue was in the matching rules
both rules where incorrect the correct code is as follows:
private void ApplyCrossCuttingConcerns(UnityContainer container)
{
container.AddNewExtension<Interception>();
container.RegisterType<IContact, Contact>(
new InterceptionBehavior<PolicyInjectionBehavior>(),
new Interceptor<InterfaceInterceptor>());
container.Configure<Interception>()
.AddPolicy("extensionPolicy")
.AddMatchingRule<TypeMatchingRule>(new InjectionConstructor(new InjectionParameter(typeof(IContact))))
.AddMatchingRule<MemberNameMatchingRule>(new InjectionConstructor(new InjectionParameter("Save")))
.AddCallHandler<ExtensionHandler>(new ContainerControlledLifetimeManager(), new InjectionConstructor());
}
I'm in face on the following problem: An application developed on Microsoft Visual Studio 2013 in .NET 4.5, needs to work in Window XP Platforms. I'm rebuild the software using .NET 4.0 and make some modifications to add compatibility, but when i click in a button the app crash and don't show a clear error message and the Trace resource don't log anything. On application start i had a little window that ask user to put your name, and this feature works fine. Anybody have any suggestion of what can i do ?
EDIT 1:
The follow code is the root of problems, this code was compiled using .NET 4.0:
SerialManager.cs
using System;
using System.Windows;
using TestSat;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.IO.Ports;
using System.Linq;
using System.Runtime.CompilerServices;
using System.Text;
using System.Threading.Tasks;
using System.Threading;
using System.Text.RegularExpressions;
using System.Diagnostics;
namespace TestSat.DataModel
{
/// <summary>
///
/// </summary>
public class SerialManager : INotifyPropertyChanged
{
#region Events
public event PropertyChangedEventHandler PropertyChanged;
/// <summary>
///
/// </summary>
/// <param name="propertyName"></param>
protected virtual void OnPropertyChanged(string propertyName)
{
PropertyChangedEventHandler handler = PropertyChanged;
if (handler != null) handler(this, new PropertyChangedEventArgs(propertyName));
}
/* [AttributeUsage(AttributeTargets.Parameter, AllowMultiple = false, Inherited = true)]
public sealed class CallerMemberNameAttribute : Attribute
{
}*/
/// <summary>
///
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="field"></param>
/// <param name="value"></param>
/// <param name="propertyName"></param>
/// <returns></returns>
protected bool SetField<T>(ref T field, T value, [CallerMemberName] string propertyName = null)
{
if (EqualityComparer<T>.Default.Equals(field, value)) return false;
field = value;
OnPropertyChanged(propertyName);
return true;
}
#endregion
#region Private Fields
private static SerialPort PortaSerial;
private ObservableCollection<String> mPorts;
private String mSelectedPort;
private int mBaudRate = 115200;
private int mDataBits = 8;
#endregion
#region Public Fields
public StringBuilder logText;
#endregion
#region Properties
/// <summary>
///
/// </summary>
public ObservableCollection<String> COMPorts
{
get { return mPorts; }
set { SetField(ref mPorts, value); }
}
/// <summary>
///
/// </summary>
public String TextoLog
{
get { return logText.ToString(); }
set
{
if (logText.Length >= logText.MaxCapacity)
{
logText.Clear();;
logText.Append(value);
}
else
{
logText.Append(value);
//MainWindow.last = value;
}
OnPropertyChanged("TextoLog");
}
}
/// <summary>
///
/// </summary>
public String SelectedPort
{
get { return mSelectedPort; }
set {SetField(ref mSelectedPort, value); }
}
#endregion
#region Construtors
/// <summary>
///
/// </summary>
public SerialManager()
{
InitComponents();
}
/// <summary>
///
/// </summary>
private void InitComponents()
{
RefreshPorts();
/*Initialize the log variable*/
logText = new StringBuilder();
/* Update selected port */
SelectedPort = COMPorts.Count > 0 ? COMPorts[0] : "";
}
#endregion
#region Public Methods
/// <summary>
///
/// </summary>
public void RefreshPorts()
{
// Update ports
string[] pPorts = SerialPort.GetPortNames();
// Sort alphabetically
Array.Sort(pPorts);
// Sort by string length
Array.Sort(pPorts, (x, y) => x.Length.CompareTo(y.Length));
// Create collection
COMPorts = new ObservableCollection<string>(pPorts);
}
/// <summary>
///
/// </summary>
/// <param name="mSelectedPort"></param>
public void ConnectSerial(String mSelectedPort)
{
PortaSerial = new SerialPort();
PortaSerial.PortName = mSelectedPort;
PortaSerial.BaudRate = mBaudRate;
PortaSerial.Parity = Parity.None;
PortaSerial.DataBits = mDataBits;
PortaSerial.StopBits = StopBits.One;
PortaSerial.Handshake = Handshake.None;
PortaSerial.DataReceived += new SerialDataReceivedEventHandler(DataReceivedHandler);
Trace.WriteLine("DataReceived definida");
try
{
PortaSerial.Open();
}
catch (SystemException)
{
MessageBox.Show("A porta serial esta sendo usada em outra aplicação.", "Erro", MessageBoxButton.OK);
throw new SystemException();
}
}
/// <summary>
///
/// </summary>
public void DesconnectSerial()
{
if (PortaSerial.IsOpen)
{
PortaSerial.Close();
}
}
/// <summary>
///
/// </summary>
public void writeSerial(String text)
{
if (PortaSerial.IsOpen)
{
if (text.Length > 0)
{
/* char[] array = text.ToCharArray(0,text.Length);
foreach(char ch in array)
{
PortaSerial.Write(ch.ToString());
Thread.Sleep(50);
}*/
PortaSerial.WriteLine(text);
}
else
{
PortaSerial.WriteLine("");
}
}
else
{
MessageBox.Show("Porta serial não esta aberta.", "Erro", MessageBoxButton.OK);
Console.WriteLine("Porta serial não esta aberta");
}
}
/// <summary>
///
/// </summary>
public bool IsOpen()
{
return PortaSerial.IsOpen;
}
/// <summary>
///
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void DataReceivedHandler(object sender, SerialDataReceivedEventArgs e)
{
MainWindow.StartRawData = true;
SerialPort sp = (SerialPort)sender;
string indata = sp.ReadExisting();
TextoLog = indata;
/*Omited code only logical operation*/
}
#endregion
}
}
If i don't do any instance or reference to serial port the applications don't crashes. Exist a way to force this part of code compiled by .NET 3.5? Or exist another suggestion of solution for this problem?
The solution i found at http://blogs.msdn.com/b/bclteam/p/asynctargetingpackkb.asp , Issue 8. Installing the .NET 4.0 update the problems don't occured anymore.
I have a well established console application in c# 2.0 that uses plugin architecture.
As of right now, the program uses basic multi-threading that can run several instances. The threads are created and continue on until the application is stopped.
Each instance can load its own variety of plugins and configured separately.
Plugins are inherited from a base plugin. This system has been working like a charm for years.
The plugins are event driven, they all read various events to see if they are called upon, if not they return and let the next plugin read the events to see if they are called out to fire.
This system has been working for years. However, I would like to further the scope of multi-threading to allow the plugins to listen to the events in an asynchronous fashion rather than synchronous. One of the drawbacks of this setup is that once a plugin fires and does its work, it locks out the instance. When the next event is fired it has to wait for the previous work to be completed. Then it will allow the next process to take place.
What I would like it to do, is execute the plugin and not have to wait for the process to end before moving on to the next process to begin by an event.
I am stuck with .Net 2.0 for the time being, and must find a solution in that framework. I have looked at numerous examples and I can not find one that meets the criteria. One of the problems is that each plugin has its own time that it may take to process, and there is no way to count to track the percentage that the plugin is complete. The plugins will start and ends its process when it is done. Depending on the parameters of the event, and the plugin it can take any range of time to complete.
My question would be what would be the best way to handle multi-threading in this situation where plugins are executed by events. I have looked at pages such as http://msdn.microsoft.com/en-us/library/2e08f6yc(v=vs.80).aspx and I can figure out where I would be able to have an entry point in an event driven plugin architecture.
If anyone has any clue, I would appreciate it. The lack of multi-threading in this manner has been the Achilles' heel for this application for years.
Plugin base: These contain some functions that are triggered by events:
using System;
using VhaBot.Communication;
namespace VhaBot
{
/// <summary>
/// Plugin BaseClass, must be inherited by all plugins
/// </summary>
public abstract class PluginBase : MarshalByRefObject
{
private bool _locked;
private string _name;
private string _internalName;
private int _version;
private string _author;
private string[] _contributors;
private string _description;
private PluginState _defaultState;
private string[] _dependencies;
private Command[] _commands;
/// <summary>
/// Friendly display name of plugin
/// </summary>
/// <example>
/// <code>
/// this.Name = "Message of the Day";
/// </code>
/// </example>
public string Name
{
set
{
if (_locked)
{
throw new Exception();
}
_name = value;
}
get { return _name; }
}
/// <summary>
/// Internal name of the plugin
/// </summary>
/// <example>
/// <code>
/// this.InternalName = "VhMotd";
/// </code>
/// </example>
public string InternalName
{
set
{
if (_locked)
{
throw new Exception();
}
_internalName = value.ToLower();
}
get { return _internalName; }
}
/// <summary>
/// Pluigin Version
/// </summary>
/// <remarks>
/// Versions are stored as integers only. Version 1.0.0 would have a value of 100
/// </remarks>
/// <example>
/// <code>
/// this.Version = 100;
/// </code>
/// </example>
public int Version
{
set
{
if (_locked)
{
throw new Exception();
}
_version = value;
}
get { return _version; }
}
/// <summary>
/// Author of the plugin
/// </summary>
/// <example>
/// <code>
/// this.Author = "Vhab";
/// </code>
/// </example>
public string Author
{
set
{
if (_locked)
{
throw new Exception();
}
_author = value;
}
get { return _author; }
}
/// <summary>
/// List of contributors to the development of the plugin.
/// </summary>
/// <example>
/// <code>
/// this.Contributors = new string[] { "Iriche", "Kilmanagh" };
/// </code>
/// </example>
public string[] Contributors
{
set
{
if (_locked)
{
throw new Exception();
}
_contributors = value;
}
get
{
if (_contributors != null)
{
return _contributors;
}
return new string[0];
}
}
/// <summary>
/// Description of the plugin
/// </summary>
/// <example>
/// <code>
/// this.Description = "Provides an interface to the user to view who is online and/or on the private channel.";
/// </code>
/// </example>
public string Description
{
set
{
if (_locked)
{
throw new Exception();
}
_description = value;
}
get { return _description; }
}
/// <summary>
/// The default <see cref="VhaBot.PluginState" /> of the plugin
/// </summary>
/// <example>
/// <code>
/// this.DefaultState = PluginState.Installed;
/// </code>
/// </example>
/// <seealso cref="VhaBot.PluginState" />
public PluginState DefaultState
{
set
{
if (_locked)
{
throw new Exception();
}
_defaultState = value;
}
get { return _defaultState; }
}
/// <summary>
/// List of other plugins that a plugin is dependent on to function
/// </summary>
/// <remarks>
/// Plugins are referred to using their internal names. See <see cref="VhaBot.PluginBase.InternalName" />
/// </remarks>
/// <example>
/// <code>
/// this.Dependencies = new string[] { "vhItems" };
/// </code>
/// </example>
public string[] Dependencies
{
set
{
if (_locked)
{
throw new Exception();
}
_dependencies = value;
}
get
{
if (_dependencies != null)
{
return _dependencies;
}
return new string[0];
}
}
public Command[] Commands
{
set
{
if (_locked)
{
throw new Exception();
}
_commands = value;
}
get
{
if (_commands != null)
{
return _commands;
}
return new Command[0];
}
}
internal void Init()
{
_locked = true;
}
/// <summary>
/// A plugin has loaded in response to <see cref="VhaBot.ShellModules.Plugins.Load" />
/// </summary>
/// <param name="bot"></param>
/// ///
/// <remarks>Code inside this method will be executed when a plugin is loading</remarks>
public virtual void OnLoad(BotShell bot)
{
}
/// <summary>
/// A plugin has unloaded in response to <see cref="VhaBot.ShellModules.Plugins.Unload" />
/// </summary>
/// <param name="bot"></param>
/// <remarks>Code inside this method will be executed when a plugin is unloading</remarks>
public virtual void OnUnload(BotShell bot)
{
}
/// <summary>
/// A plugin has installed in response to <see cref="VhaBot.ShellModules.Plugins.Install" />
/// </summary>
/// <param name="bot"></param>
public virtual void OnInstall(BotShell bot)
{
}
/// <summary>
/// A plugin as been uninstalled in response to <see cref="VhaBot.ShellModules.Plugins.Uninstall" />
/// </summary>
/// <param name="bot"></param>
public virtual void OnUninstall(BotShell bot)
{
}
/// <summary>
/// A plugin has been upgraded (Unused)
/// </summary>
/// <param name="bot"></param>
/// <param name="version"></param>
/// <remarks>This function is not active</remarks>
public virtual void OnUpgrade(BotShell bot, Int32 version)
{
}
/// <summary>
/// Response to a command
/// </summary>
/// <param name="bot"></param>
/// <param name="e"></param>
public virtual void OnCommand(BotShell bot, CommandArgs e)
{
}
/// <summary>
/// Response to an unauthorized command
/// </summary>
/// <param name="bot"></param>
/// <param name="e"></param>
public virtual void OnUnauthorizedCommand(BotShell bot, CommandArgs e)
{
}
/// <summary>
/// Response to a command help query <see cref="VhaBot.ShellModules.Commands.GetHelp." />
/// </summary>
/// <param name="bot"></param>
/// <param name="command"></param>
/// <returns></returns>
/// <remarks>Code inside this method will be executed when help is requested</remarks>
public virtual string OnHelp(BotShell bot, string command)
{
return null;
}
/// <summary>
/// Response to a custom configuration
/// </summary>
/// <param name="bot"></param>
/// <param name="key"></param>
/// <returns></returns>
public virtual string OnCustomConfiguration(BotShell bot, string key)
{
return null;
}
/// <summary>
/// Response to a plugin message
/// </summary>
/// <param name="bot"></param>
/// <param name="message"></param>
public virtual void OnPluginMessage(BotShell bot, PluginMessage message)
{
}
/// <summary>
/// Response to a bot message
/// </summary>
/// <param name="bot"></param>
/// <param name="message"></param>
public virtual void OnBotMessage(BotShell bot, BotMessage message)
{
}
/// <summary>
/// Returns display name of bot and current version
/// </summary>
/// <returns></returns>
public override string ToString()
{
return Name + " v" + Version;
}
/// <summary>
/// There is no information to document this command
/// </summary>
/// <param name="bot"></param>
/// <param name="args"></param>
public void FireOnCommand(BotShell bot, CommandArgs args)
{
try
{
if (args.Authorized)
OnCommand(bot, args);
else
OnUnauthorizedCommand(bot, args);
}
catch (Exception ex)
{
CommandArgs e = args;
var window = new RichTextWindow(bot);
window.AppendTitle("Error Report");
window.AppendHighlight("Error: ");
window.AppendNormal(ex.Message);
window.AppendLinkEnd();
window.AppendLineBreak();
window.AppendHighlight("Source: ");
window.AppendNormal(ex.Source);
window.AppendLinkEnd();
window.AppendLineBreak();
window.AppendHighlight("Target Site: ");
window.AppendNormal(ex.TargetSite.ToString());
window.AppendLinkEnd();
window.AppendLineBreak();
window.AppendHighlight("Stack Trace:");
window.AppendLineBreak();
window.AppendNormal(ex.StackTrace);
window.AppendLinkEnd();
window.AppendLineBreak();
bot.SendReply(e,
"There has been an error while executing this command »» " +
window.ToString("More Information"));
BotShell.Output("[Plugin Execution Error] " + ex);
}
}
}
}
Events Class:
namespace VhaBot.ShellModules
{
/// <summary>
/// VhaBot Events
/// </summary>
public class Events
{
public event BotStateChangedHandler BotStateChangedEvent;
public event ChannelJoinEventHandler ChannelJoinEvent;
public event UserJoinChannelHandler UserJoinChannelEvent;
public event UserLeaveChannelHandler UserLeaveChannelEvent;
public event UserLogonHandler UserLogonEvent;
public event UserLogoffHandler UserLogoffEvent;
public event PrivateMessageHandler PrivateMessageEvent;
public event PrivateChannelMessageHandler PrivateChannelMessageEvent;
public event ChannelMessageHandler ChannelMessageEvent;
public event MemberAddedHandler MemberAddedEvent;
public event MemberRemovedHandler MemberRemovedEvent;
public event MemberUpdatedHandler MemberUpdatedEvent;
public event AltAddedHandler AltAddedEvent;
public event AltRemovedHandler AltRemovedEvent;
/// <summary>
/// A message was sent to the IRC channel in response to a <see cref="VhaBot.BotShell.SendIrcMessage" /> request
/// </summary>
public event IrcMessageHandler IrcMessageEvent;
public event ConfigurationChangedHandler ConfigurationChangedEvent;
internal void OnBotStateChanged(BotShell bot, BotStateChangedArgs e)
{
if (BotStateChangedEvent != null)
try
{
BotStateChangedEvent(bot, e);
}
catch
{
}
}
internal void OnChannelJoin(BotShell bot, ChannelJoinEventArgs e)
{
if (ChannelJoinEvent != null)
try
{
ChannelJoinEvent(bot, e);
}
catch
{
}
}
internal void OnUserJoinChannel(BotShell bot, UserJoinChannelArgs e)
{
if (UserJoinChannelEvent != null)
try
{
UserJoinChannelEvent(bot, e);
}
catch
{
}
}
internal void OnUserLeaveChannel(BotShell bot, UserLeaveChannelArgs e)
{
if (UserLeaveChannelEvent != null)
try
{
UserLeaveChannelEvent(bot, e);
}
catch
{
}
}
internal void OnUserLogon(BotShell bot, UserLogonArgs e)
{
if (UserLogonEvent != null)
try
{
UserLogonEvent(bot, e);
}
catch
{
}
}
internal void OnUserLogoff(BotShell bot, UserLogoffArgs e)
{
if (UserLogoffEvent != null)
try
{
UserLogoffEvent(bot, e);
}
catch
{
}
}
internal void OnPrivateMessage(BotShell bot, PrivateMessageArgs e)
{
if (PrivateMessageEvent != null)
try
{
PrivateMessageEvent(bot, e);
}
catch
{
}
}
internal void OnPrivateChannelMessage(BotShell bot, PrivateChannelMessageArgs e)
{
if (PrivateChannelMessageEvent != null)
try
{
PrivateChannelMessageEvent(bot, e);
}
catch
{
}
}
internal void OnChannelMessage(BotShell bot, ChannelMessageArgs e)
{
if (ChannelMessageEvent != null)
try
{
ChannelMessageEvent(bot, e);
}
catch
{
}
}
internal void OnMemberAdded(BotShell bot, MemberAddedArgs e)
{
if (MemberAddedEvent != null)
try
{
MemberAddedEvent(bot, e);
}
catch
{
}
}
internal void OnMemberRemoved(BotShell bot, MemberRemovedArgs e)
{
if (MemberRemovedEvent != null)
try
{
MemberRemovedEvent(bot, e);
}
catch
{
}
}
internal void OnMemberUpdated(BotShell bot, MemberUpdatedArgs e)
{
if (MemberUpdatedEvent != null)
try
{
MemberUpdatedEvent(bot, e);
}
catch
{
}
}
internal void OnAltAdded(BotShell bot, AltAddedArgs e)
{
if (AltAddedEvent != null)
try
{
AltAddedEvent(bot, e);
}
catch
{
}
}
internal void OnAltRemoved(BotShell bot, AltRemovedArgs e)
{
if (AltRemovedEvent != null)
try
{
AltRemovedEvent(bot, e);
}
catch
{
}
}
internal void OnConfigurationChanged(BotShell bot, ConfigurationChangedArgs e)
{
if (ConfigurationChangedEvent != null)
try
{
ConfigurationChangedEvent(bot, e);
}
catch
{
}
}
internal void OnIrcMessage(BotShell bot, IrcMessageArgs e)
{
if (IrcMessageEvent != null)
{
IrcMessageEvent(bot, e);
}
try
{
}
catch
{
}
}
}
}
I've got little to go on as your description of the system is a bit vague but I'll give it a shot.
From your description it seems you have some plugin, say
interface IPlugin {
PluginResult ReadAndExecuteEvents(Events e);
// Added asynchronous methods.
IAsyncResult BeginReadAndExecuteEvents(Events e, AsyncCallback cb, Object state);
PluginResult EndReadAndExecuteEvents(IAsyncResult result);
}
with
class PluginResult
{
public Boolean Stop;
// etc.
}
also you don't seem to be using .NET events, but rather some sort of Event class/enumeration.
Your old code seems to be something like:
foreach (var eventList in ReadEvents())
foreach (var plugin in pluginList)
if (plugin.ReadAndExecuteEvents(eventList).Stop)
break;
You can make this asynchronous doing something like:
foreach (var eventList in ReadEvents())
{
// It seems this is what you want, only one event processed at a time by an "instance"? So block here until unlocked.
LockProcess();
var pluginIndex = 0;
AsyncCallback handleResult = null;
handleResult = delegate(IAsyncResult result)
{
if (pluginList[pluginIndex].EndReadAndExecuteEvents(result).Stop)
goto STOP;
pluginIndex += 1;
if (pluginIndex == pluginList.Count)
goto STOP;
Events e = (Events)result.AsyncState;
pluginList[pluginIndex].BeginReadAndExecuteEvents(e, handleResult, e);
return;
STOP:
UnlockProcess();
};
pluginList[0].BeginReadAndExecuteEvents(eventList, handleResult, eventList);
}
So in .NET 2 style you could add some BeginXxx method and in its AsyncCallback do your stuff.
Of course it is up to the actual plugin to do its multithreading/asynchronisity, say if it writes a file by using BeginWrite to a FileStream etc.
I have conveniently ignored exception handling here.
So, to make your whole application use this asynchronisity you can put this code in a BeginRunEvents method, say, following the same "APM" pattern. You can then schedule this to the threadpool if you wish.
If this is not at all what you are looking for please provide some more code examples/info.
I am trying to figure out the best practices when loggin exceptions.
So far, I am logging every time I catch an exception. But when a lower lever class catches an exception (say, from the database layer), and wraps it in our own application exception - should I also log the original exception there, or should I just let the upper lever class log all the details?
And what about locations where my lower level class decides to throw an exception because of bad input parameters? Should it log the exception there also, or, once again, just let the catching code log it?
Mainly you should avoid logging it in both a lower-level catch and a higher-level catch, as this bloats the log with redundant information (not to mention takes up additional IO resources to write to the log).
If you are looking for general best practice information on exception handling, this link is handy.
You can get away with logging only once at the very top level of your app, as long as your logging code (a) logs the stack trace of an exception, and (b) logs the entire chain of inner exceptions as well.
The Microsoft Exception Handling Application Block takes care of both of those things for you. I guess other logging frameworks would do the same.
In my winform's applications i created some Observer for logging. Observer has subscribers, which can write log somewhere, or process it.
It's look:
public static class LoggingObserver
{
/// <summary>
/// Last getted log message
/// </summary>
public static string LastLog;
/// <summary>
/// Last getted exception
/// </summary>
public static Exception LastException;
/// <summary>
/// List of log's processors
/// </summary>
public static List<BaseLogging> loggings = new List<BaseLogging>();
/// <summary>
/// Get Exception and send for log's processors
/// </summary>
/// <param name="ex">Exception with message</param>
public static void AddLogs(Exception ex)
{
LastException = ex;
LastLog = string.Empty;
foreach (BaseLogging logs in loggings)
{
logs.AddLogs(ex);
}
}
/// <summary>
/// Get message log for log's processors
/// </summary>
/// <param name="str">Message log</param>
public static void AddLogs(string str)
{
LastException = null;
LastLog = str;
foreach (BaseLogging logs in loggings)
{
logs.AddLogs(str);
}
}
/// <summary>
/// Close all processors
/// </summary>
public static void Close()
{
foreach (BaseLogging logs in loggings)
{
logs.Close();
}
}
}
Subscriber's abstract class:
public abstract class BaseLogging
{
/// <summary>
/// Culture (using for date)
/// </summary>
public CultureInfo culture;
/// <summary>
/// Constructor
/// </summary>
/// <param name="culture">Culture</param>
public BaseLogging(CultureInfo culture)
{
this.culture = culture;
}
/// <summary>
/// Add log in log system
/// </summary>
/// <param name="str">message of log</param>
public virtual void AddLogs(string str)
{
DateTime dt = DateTime.Now;
string dts = Convert.ToString(dt, culture.DateTimeFormat);
WriteLine(String.Format("{0} : {1}", dts, str));
}
/// <summary>
/// Add log in log system
/// </summary>
/// <param name="ex">Exception</param>
public virtual void AddLogs(Exception ex)
{
DateTime dt = DateTime.Now;
string dts = Convert.ToString(dt, culture.DateTimeFormat);
WriteException(ex);
}
/// <summary>
/// Write string on log system processor
/// </summary>
/// <param name="str">logs message</param>
protected abstract void WriteLine(string str);
/// <summary>
/// Write string on log system processor
/// </summary>
/// <param name="ex">Exception</param>
protected abstract void WriteException(Exception ex);
/// <summary>
/// Close log system (file, stream, etc...)
/// </summary>
public abstract void Close();
}
And implementation for logging to file:
/// <summary>
/// Logger processor, which write log to some stream
/// </summary>
public class LoggingStream : BaseLogging
{
private Stream stream;
/// <summary>
/// Constructor.
/// </summary>
/// <param name="stream">Initialized stream</param>
/// <param name="culture">Culture of log system</param>
public LoggingStream (Stream stream, CultureInfo culture)
: base(culture)
{
this.stream = stream;
}
/// <summary>
/// Write message log to stream
/// </summary>
/// <param name="str">Message log</param>
protected override void WriteLine(string str)
{
try
{
byte[] bytes;
bytes = Encoding.ASCII.GetBytes(str + "\n");
stream.Write(bytes, 0, bytes.Length);
stream.Flush();
}
catch { }
}
/// <summary>
/// Write Exception to stream
/// </summary>
/// <param name="ex">Log's Exception</param>
protected override void WriteException(Exception ex)
{
DateTime dt = DateTime.Now;
string dts = Convert.ToString(dt, culture.DateTimeFormat);
string message = String.Format("{0} : Exception : {1}", dts, ex.Message);
if (ex.InnerException != null)
{
message = "Error : " + AddInnerEx(ex.InnerException, message);
}
WriteLine(message);
}
/// <summary>
/// Closing stream
/// </summary>
public override void Close()
{
stream.Close();
}
private string AddInnerEx(Exception exception, string message)
{
message += "\nInner Exception : " + exception.Message;
if (exception.InnerException != null)
{
message = AddInnerEx(exception.InnerException, message);
}
return message;
}
}
Using:
//initialization
FileStream FS = new FileStream(LogFilePath, FileMode.Create);
LoggingObserver.loggings.Add(new LoggingStream(FS, Thread.CurrentThread.CurrentCulture));
//write exception
catch (Exception ex) {
LoggingObserver.AddLog(new Exception ("Exception message", ex));
}
//write log
LoggingObserver.AddLog("Just a log");
log where you catch, If you're wrapping then you should. If the lower wrapper doesn't then you have a reason (for debugability) to do so. However don't swallow the exception unless you know its benign or you can handle it.
I'd suggest
try{
.
.
.
} catch(Exception ex){
... log ....
throw;
}
if you need to log and pass the exception on.