/// <summary>
/// Executes a command asynchronously
/// </summary>
/// <param name="sessionID">The ID of the session running the command</param>
/// <param name="inputCommand">The full command input</param>
/// <returns>A <see cref="CommandExecutionResponse"/> containing the results of the execution</returns>
protected async Task <CommandExecutionResponse> ExecuteCommandAsync(string sessionID, string inputCommand)
{
try
{
// Notify CommandReceived event
CommandReceived?.Invoke(this, new CommandReceivedEventArgs(inputCommand, sessionID));
// Parse Full Command, by separating what is the command from what are the arguments
var ResultingCommand = this.CommandParser.Parse(inputCommand);
// Try to assign each parameter
var methodArgumentsList = new List <object>();
// If arguments are not specified, set an empty array to it
if (ResultingCommand.Arguments == null)
{
ResultingCommand.Arguments = new ParsedCommandArgument[] { }
}
;
// Look for command
if (CommandCollectionInternal.TryGetValue(ResultingCommand.Command, out var commandInfo))
{
// Check for Help Call
if (ResultingCommand.IsHelpRequest)
{
// Display the command help
var commandHelpAttribute = commandInfo.GetCommandHelpAttribute();
if (commandHelpAttribute == null)
{
return(CommandExecutionResponse.Help(""));
}
return(CommandExecutionResponse.Help(commandHelpAttribute.Contents));
}
else
{
// Check if required parameters have been informed, if they were not, display help (if available)
// Assign Parameters
if (ResultingCommand.IsArgumentParameterSpecific)
{
// The arguments have a parameter name or a identifier, set them in sequence to be used later
var currentArgumentsDictionary = new Dictionary <string, ParsedCommandArgument>();
foreach (var r in ResultingCommand.Arguments)
{
if (currentArgumentsDictionary.ContainsKey(r.Parameter.ToLower()))
{
throw new Exception($"Parameter '{r.Parameter.ToLower()}' is repeated on the syntax");
}
currentArgumentsDictionary.Add(r.Parameter.ToLower(), r);
}
var newArgumentsList = new List <ParsedCommandArgument>();
foreach (var p in commandInfo.ParametersInfo)
{
if (currentArgumentsDictionary.TryGetValue(p.Name.ToLower(), out var parsedCommandArgument))
{
throw new Exception($"Parameter '{p.Name.ToLower()}' is not informed");
}
newArgumentsList.Add(parsedCommandArgument);
}
ResultingCommand.Arguments = newArgumentsList.ToArray();
}
// Make sure the number of arguments match the method argument number
if (ResultingCommand.Arguments.Length == commandInfo.ParametersInfo.Length)
{
for (int iArgument = 0; iArgument < ResultingCommand.Arguments.Length; iArgument++)
{
// Get Variables
var param = commandInfo.ParametersInfo[iArgument];
var argument = ResultingCommand.Arguments[iArgument];
// Try to apply parameter
try
{
if (param.ParameterType == typeof(string))
{
// A direct conversion is available
methodArgumentsList.Add(argument.Value);
}
else
{
// There is no direct conversion, try to apply the parameter using the Convert object
methodArgumentsList.Add(Convert.ChangeType(argument, param.ParameterType));
}
}
catch (Exception eAssignment)
{
// Throw an error with the invalid argument
throw new InvalidCommandArgumentsException(ResultingCommand.Command, param.Name, param.ParameterType, argument.Value, eAssignment);
}
}
}
else
{
// Number of arguments do not match, return help
var argumentException = new ArgumentException("The number of arguments needed for the command does not match the number of arguments provided");
var commandHelpAttribute = commandInfo.GetCommandHelpAttribute();
if (commandHelpAttribute == null)
{
return(CommandExecutionResponse.Help("", DefaultErrorStatus, argumentException));
}
return(CommandExecutionResponse.Help(commandHelpAttribute.Contents, DefaultErrorStatus, argumentException));
}
// Arguments are set
// Define the CommandClass where the command will be executed against
var commandObject = (object)null;
// Look for Session Information to start fetching / creating objects
if (SessionCollectionInternal.TryGetValue(sessionID, out SessionInfo sessionInfo))
{
// Session information found
// Retrieve command class info
if (CommandClassCollectionInternal.TryGetValue(commandInfo.CommandClassType, out var commandClassInfo))
{
// Check the CommandClass lifetime before trying to find the object where to run the command against
if (commandClassInfo.CommandClassAttribute.Lifetime == InstanceLifetimes.Singleton)
{
// Singleton lifetime, only one instance of the object should exist
// Make sure to lock the dictionary to force other threads to hold
lock (SingletonObjectsCollectionInternalLock)
{
// Singleton - Object should be on the SingletonObjectCollectionInternal
if (!(SingletonObjectsCollectionInternal.TryGetValue(commandInfo.CommandClassType, out commandObject)))
{
// Singleton object could not be found, then create it and add back to the collection
// Create the Command Object
commandObject = commandClassInfo.CreateInstance();
// Adds the singleton object to the collection
SingletonObjectsCollectionInternal.Add(commandInfo.CommandClassType, commandObject);
}
}
}
else if (commandClassInfo.CommandClassAttribute.Lifetime == InstanceLifetimes.Scoped)
{
// Scoped lifetime, only one instance per session should exist
// Check object on the Session Info
if (!sessionInfo.ObjectCollection.TryGetValue(commandInfo.CommandClassType, out commandObject))
{
// Create and add object to the session
lock (SessionCollectionInternalLock)
{
// Create the Command Object and add to collection
commandObject = commandClassInfo.CreateInstance();
sessionInfo.ObjectCollection.Add(commandInfo.CommandClassType, commandObject);
}
}
}
else
{
// Transient lifetime, initializes it everytime
commandObject = commandClassInfo.CreateInstance();
}
}
else
{
// Cannot find registration details for command class
throw new Exception($"Unable to find registration details for type '{commandInfo.CommandClassType.Name}'");
}
}
else
{
// Error, unable to find the session
throw new Exception($"Session {sessionID} cannot be found");
}
try
{
// Calls the Command Asynchronously
var result = await Task.Factory.StartNew <object>(() =>
{
return(commandInfo.MethodInfo.Invoke(commandObject, methodArgumentsList.ToArray()));
}
).ConfigureAwait(false);
// Depending on the type of result, throw response
if (result is CommandExecutionResponse cr)
{
return(cr);
}
else
{
// Command executed without exceptions, create a Success Response with no data
return(CommandExecutionResponse.Success(DefaultSuccessStatus, result));
}
}
catch (Exception eExecution)
{
// Throws the execution exception ahead
throw new CommandInExecutionException(ResultingCommand.Command, methodArgumentsList.ToArray(), eExecution);
}
}
}
else
{
// Command not found, throw exception
throw new CommandNotFoundException(ResultingCommand.Command);
}
}
catch (InvalidCommandArgumentsException e)
{
return(CommandExecutionResponse.Error(DefaultErrorStatus, e));
}
catch (CommandNotFoundException)
{
return(CommandExecutionResponse.NotFound(DefaultNotFoundStatus));
}
catch (Exception e)
{
return(CommandExecutionResponse.Error(DefaultErrorStatus, e));
}
}
/// <summary>
/// Register a type as a Command Class
/// </summary>
/// <param name="creationFunction">A <see cref="Func{T, TResult}"/> to define how the object is instantiated</param>
/// <remarks>The type must implement the <see cref="CommandClassAttribute"/></remarks>
/// <typeparam name="TCommandClassType">Type to be registered</typeparam>
public void RegisterCommandClass <TCommandClassType>(Func <object> creationFunction)
{
// Command Class Type
Type commandClassType = typeof(TCommandClassType);
// Check if object implement the "CommandClassAttribute"
if (!(commandClassType.GetCustomAttributes(true).Where(t => t is CommandClassAttribute)
.Select(t1 => t1)
.First() is CommandClassAttribute commandClassAttribute))
{
throw new Exception($"Class must implement the {nameof(CommandClassAttribute)}");
}
// Add registration information to the proper collection (make sure object is locked for thread-safety
lock (CommandClassCollectionInternalLock)
{
if (CommandClassCollectionInternal.ContainsKey(commandClassType))
{
// Command Class already registered
throw new Exception($"Command Class {commandClassType.Name} is already registered");
}
// Register the command class info
var commandClassInfo = new CommandClassInfo()
{
CommandClassAttribute = commandClassAttribute,
CommandClassType = commandClassType,
CreationFunction = creationFunction
};
CommandClassCollectionInternal.Add(commandClassType, commandClassInfo);
}
// Search Methods to find Commands
foreach (var method in commandClassType.GetMethods())
{
// Loop thru all CommandAttribute's tied to the method (multiple names for the same command are acceptable)
foreach (var commandAttribute in from methodAttribute
in method.GetCustomAttributes(true)
where methodAttribute is CommandAttribute
select methodAttribute as CommandAttribute)
{
// Trigger the registering command event
var registeringCommandEventArgs = new RegisteringCommandEventArgs(commandAttribute.Command);
RegisteringCommand?.Invoke(this, registeringCommandEventArgs);
// Make sure command is allowed to be registered
if (!registeringCommandEventArgs.SuppressRegistration)
{
lock (CommandCollectionInternalLock)
{
// Process Duplicated Commands
if (CommandCollectionInternal.ContainsKey(commandAttribute.Command))
{
// Call duplicated event to decide what to do
var duplicatedCommandEventArgs = new DuplicatedCommandEventArgs(commandAttribute.Command, DuplicatedCommandActions.Ignore);
RegisteringDuplicatedCommand?.Invoke(this, duplicatedCommandEventArgs);
if (duplicatedCommandEventArgs.Action == DuplicatedCommandActions.Error)
{
// ERROR: Command is duplicated
throw new Exception($"Command '{commandAttribute.Command}' is duplicated and cannot be registered");
}
else if (duplicatedCommandEventArgs.Action == DuplicatedCommandActions.Replace)
{
// Remove current command and let registration continue
CommandCollectionInternal.Remove(commandAttribute.Command);
}
else
{
// Skip to the next entry on the foreach loop
continue;
}
}
// Setup the necessary information to run a command later
var commandInfo = new CommandInfo()
{
CommandAttribute = commandAttribute,
CommandClassType = commandClassType,
MethodInfo = method,
ParametersInfo = method.GetParameters(),
};
// Initialize the ParameterInfo array into an empty array if needed
if (commandInfo.ParametersInfo == null)
{
commandInfo.ParametersInfo = new ParameterInfo[] { }
}
;
// Include Command Help Attributes on the CommandInfo
foreach (var commandHelpAttribute in from methodAttribute
in method.GetCustomAttributes(typeof(CommandHelpAttribute), true)
select methodAttribute as CommandHelpAttribute)
{
if (String.IsNullOrEmpty(commandHelpAttribute.CultureName))
{
commandInfo.CommandHelpAttributes.Add("DEFAULT", commandHelpAttribute);
}
else
{
commandInfo.CommandHelpAttributes.Add(commandHelpAttribute.CultureName, commandHelpAttribute);
}
}
// Add to the collection
CommandCollectionInternal.Add(commandAttribute.Command, commandInfo);
}
}
}
}
}