static string Execute(ConsoleCommand command)
{
// Validate the class name and command name:
// +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
string badCommandMessage = string.Format(""
+ "Unrecognized command \'{0}.{1}\'. "
+ "Please type a valid command.",
command.LibraryClassName, command.Name);
// Validate the command name:
if (!_commandLibraries.ContainsKey(command.LibraryClassName))
{
return(badCommandMessage);
}
var methodDictionary = _commandLibraries[command.LibraryClassName];
if (!methodDictionary.ContainsKey(command.Name))
{
return(badCommandMessage);
}
// Make sure the correct number of required arguments are provided:
// +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
var methodParameterValueList = new List <object>();
IEnumerable <ParameterInfo> paramInfoList = methodDictionary[command.Name].ToList();
// Validate proper # of required arguments provided. Some may be optional:
var requiredParams = paramInfoList.Where(p => p.IsOptional == false);
var optionalParams = paramInfoList.Where(p => p.IsOptional);
int requiredCount = requiredParams.Count();
int optionalCount = optionalParams.Count();
int providedCount = command.Arguments.Count();
if (requiredCount > providedCount)
{
return(string.Format(
"Missing required argument. {0} required, {1} optional, {2} provided",
requiredCount, optionalCount, providedCount));
}
// Make sure all arguments are coerced to the proper type, and that there is a
// value for every method parameter. The InvokeMember method fails if the number
// of arguments provided does not match the number of parameters in the
// method signature, even if some are optional:
// +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
if (paramInfoList.Count() > 0)
{
// Populate the list with default values:
foreach (var param in paramInfoList)
{
// This will either add a null object reference if the param is required
// by the method, or will set a default value for optional parameters. in
// any case, there will be a value or null for each method argument
// in the method signature:
methodParameterValueList.Add(param.DefaultValue);
}
// Now walk through all the arguments passed from the console and assign
// accordingly. Any optional arguments not provided have already been set to
// the default specified by the method signature:
for (int i = 0; i < command.Arguments.Count(); i++)
{
var methodParam = paramInfoList.ElementAt(i);
var typeRequired = methodParam.ParameterType;
object value = null;
try
{
// Coming from the Console, all of our arguments are passed in as
// strings. Coerce to the type to match the method parameter:
value = CoerceArgument(typeRequired, command.Arguments.ElementAt(i));
methodParameterValueList.RemoveAt(i);
methodParameterValueList.Insert(i, value);
}
catch (ArgumentException ex)
{
string argumentName = methodParam.Name;
string argumentTypeName = typeRequired.Name;
string message =
string.Format(""
+ "The value passed for argument '{0}' cannot be parsed to type '{1}': " + ex,
argumentName, argumentTypeName);
throw new ArgumentException(message);
}
}
}
// Set up to invoke the method using reflection:
// +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Assembly current = typeof(Program).Assembly;
// Need the full Namespace for this:
Type commandLibraryClass =
current.GetType(_commandNamespace + "." + command.LibraryClassName);
object[] inputArgs = null;
if (methodParameterValueList.Count > 0)
{
inputArgs = methodParameterValueList.ToArray();
}
var typeInfo = commandLibraryClass;
// This will throw if the number of arguments provided does not match the number
// required by the method signature, even if some are optional:
try
{
var result = typeInfo.InvokeMember(
command.Name,
BindingFlags.InvokeMethod | BindingFlags.Static | BindingFlags.Public,
null, null, inputArgs);
return(result.ToString());
}
catch (TargetInvocationException ex)
{
throw ex.InnerException;
}
}
public static void Run()
{
System.Console.Title = typeof(Program).Name;
// Any static classes containing commands for use from the
// console are located in the Commands namespace. Load
// references to each type in that namespace via reflection:
_commandLibraries = new Dictionary <string, Dictionary <string,
IEnumerable <ParameterInfo> > >();
// Use reflection to load all of the classes in the Commands namespace:
var q = from t in Assembly.GetExecutingAssembly().GetTypes()
where t.IsClass && t.Namespace == _commandNamespace
select t;
var commandClasses = q.ToList();
foreach (var commandClass in commandClasses)
{
// Load the method info from each class into a dictionary:
var methods = commandClass.GetMethods(BindingFlags.Static | BindingFlags.Public);
var methodDictionary = new Dictionary <string, IEnumerable <ParameterInfo> >();
foreach (var method in methods)
{
string commandName = method.Name;
methodDictionary.Add(commandName, method.GetParameters());
}
// Add the dictionary of methods for the current class into a dictionary of command classes:
_commandLibraries.Add(commandClass.Name, methodDictionary);
}
//Open log file to store history of command line usage
FileStream writeToHistory;
StreamWriter writer = null;
while (true)
{
var consoleInput = ReadFromConsole();
if (string.IsNullOrWhiteSpace(consoleInput))
{
continue;
}
try
{
// Create a ConsoleCommand instance:
var cmd = new ConsoleCommand(consoleInput);
writeToHistory = new FileStream("./history.txt", FileMode.Append, FileAccess.Write);
writer = new StreamWriter(writeToHistory);
writer.WriteLine(consoleInput);
writer.Close();
// Execute the command:
string result = Execute(cmd);
// Write out the result:
WriteToConsole(result);
}
catch (Exception ex)
{
// OOPS! Something went wrong - Write out the problem:
WriteToConsole(ex.Message);
}
}
}
