在构建接受参数的控制台应用程序时,可以使用传递给Main的参数(string[] args)。
在过去,我只是简单地索引/循环该数组,并做了一些正则表达式来提取值。然而,当命令变得更加复杂时,解析就会变得非常糟糕。
我感兴趣的是:
你使用的库 你使用的模式
假设命令总是遵循常见的标准,比如这里回答的。
在构建接受参数的控制台应用程序时,可以使用传递给Main的参数(string[] args)。
在过去,我只是简单地索引/循环该数组,并做了一些正则表达式来提取值。然而,当命令变得更加复杂时,解析就会变得非常糟糕。
我感兴趣的是:
你使用的库 你使用的模式
假设命令总是遵循常见的标准,比如这里回答的。
当前回答
Genghis命令行解析器可能有点过时,但它的功能非常完整,对我来说工作得很好。
其他回答
我个人最喜欢的是Peter palota的http://www.codeproject.com/KB/recipes/plossum_commandline.aspx:
[CommandLineManager(ApplicationName="Hello World",
Copyright="Copyright (c) Peter Palotas")]
class Options
{
[CommandLineOption(Description="Displays this help text")]
public bool Help = false;
[CommandLineOption(Description = "Specifies the input file", MinOccurs=1)]
public string Name
{
get { return mName; }
set
{
if (String.IsNullOrEmpty(value))
throw new InvalidOptionValueException(
"The name must not be empty", false);
mName = value;
}
}
private string mName;
}
我强烈建议使用NDesk。选项(文档)和/或Mono。选项(相同的API,不同的名称空间)。文档中的一个例子:
bool show_help = false;
List<string> names = new List<string> ();
int repeat = 1;
var p = new OptionSet () {
{ "n|name=", "the {NAME} of someone to greet.",
v => names.Add (v) },
{ "r|repeat=",
"the number of {TIMES} to repeat the greeting.\n" +
"this must be an integer.",
(int v) => repeat = v },
{ "v", "increase debug message verbosity",
v => { if (v != null) ++verbosity; } },
{ "h|help", "show this message and exit",
v => show_help = v != null },
};
List<string> extra;
try {
extra = p.Parse (args);
}
catch (OptionException e) {
Console.Write ("greet: ");
Console.WriteLine (e.Message);
Console.WriteLine ("Try `greet --help' for more information.");
return;
}
我最近遇到了FubuCore命令行解析实现,我真的很喜欢它,原因是:
it's easy to use - although I couldn't find a documentation for it, the FubuCore solution also provides a project containing a nice set of Unit Tests that speak more about the functionality than any documentation could it has a nice object oriented design, no code repetition or other such things that I used to have in my command line parsing apps it's declarative: you basically write classes for the Commands and sets of parameters and decorate them with attributes to set various options (e.g. name, description, mandatory/optional) the library even prints a nice Usage Graph, based on these definitions
下面是一个简单的例子说明如何使用它。为了说明用法,我写了一个简单的实用程序,它有两个命令: - add(将一个对象添加到列表中-一个对象由一个名称(字符串),值(int)和一个布尔标志组成) - list(列出当前添加的所有对象)
首先,我为'add'命令写了一个Command类:
[Usage("add", "Adds an object to the list")]
[CommandDescription("Add object", Name = "add")]
public class AddCommand : FubuCommand<CommandInput>
{
public override bool Execute(CommandInput input)
{
State.Objects.Add(input); // add the new object to an in-memory collection
return true;
}
}
这个命令接受一个commandput实例作为参数,所以我下面定义它:
public class CommandInput
{
[RequiredUsage("add"), Description("The name of the object to add")]
public string ObjectName { get; set; }
[ValidUsage("add")]
[Description("The value of the object to add")]
public int ObjectValue { get; set; }
[Description("Multiply the value by -1")]
[ValidUsage("add")]
[FlagAlias("nv")]
public bool NegateValueFlag { get; set; }
}
下一个命令是'list',实现如下:
[Usage("list", "List the objects we have so far")]
[CommandDescription("List objects", Name = "list")]
public class ListCommand : FubuCommand<NullInput>
{
public override bool Execute(NullInput input)
{
State.Objects.ForEach(Console.WriteLine);
return false;
}
}
'list'命令不带参数,所以我定义了一个NullInput类:
public class NullInput { }
现在剩下的就是在Main()方法中把它连接起来,就像这样:
static void Main(string[] args)
{
var factory = new CommandFactory();
factory.RegisterCommands(typeof(Program).Assembly);
var executor = new CommandExecutor(factory);
executor.Execute(args);
}
程序按预期工作,在任何命令无效的情况下打印正确用法的提示:
------------------------
Available commands:
------------------------
add -> Add object
list -> List objects
------------------------
下面是'add'命令的用法示例:
Usages for 'add' (Add object)
add <objectname> [-nv]
-------------------------------------------------
Arguments
-------------------------------------------------
objectname -> The name of the object to add
objectvalue -> The value of the object to add
-------------------------------------------------
-------------------------------------
Flags
-------------------------------------
[-nv] -> Multiply the value by -1
-------------------------------------
看看http://github.com/mono/mono/tree/master/mcs/class/Mono.Options/
这是我基于Novell Options类编写的处理程序。
它针对的是执行while (input !="exit")样式循环的控制台应用程序,例如一个交互式控制台,例如FTP控制台。
使用示例:
static void Main(string[] args)
{
// Setup
CommandHandler handler = new CommandHandler();
CommandOptions options = new CommandOptions();
// Add some commands. Use the v syntax for passing arguments
options.Add("show", handler.Show)
.Add("connect", v => handler.Connect(v))
.Add("dir", handler.Dir);
// Read lines
System.Console.Write(">");
string input = System.Console.ReadLine();
while (input != "quit" && input != "exit")
{
if (input == "cls" || input == "clear")
{
System.Console.Clear();
}
else
{
if (!string.IsNullOrEmpty(input))
{
if (options.Parse(input))
{
System.Console.WriteLine(handler.OutputMessage);
}
else
{
System.Console.WriteLine("I didn't understand that command");
}
}
}
System.Console.Write(">");
input = System.Console.ReadLine();
}
}
来源是:
/// <summary>
/// A class for parsing commands inside a tool. Based on Novell Options class (http://www.ndesk.org/Options).
/// </summary>
public class CommandOptions
{
private Dictionary<string, Action<string[]>> _actions;
private Dictionary<string, Action> _actionsNoParams;
/// <summary>
/// Initializes a new instance of the <see cref="CommandOptions"/> class.
/// </summary>
public CommandOptions()
{
_actions = new Dictionary<string, Action<string[]>>();
_actionsNoParams = new Dictionary<string, Action>();
}
/// <summary>
/// Adds a command option and an action to perform when the command is found.
/// </summary>
/// <param name="name">The name of the command.</param>
/// <param name="action">An action delegate</param>
/// <returns>The current CommandOptions instance.</returns>
public CommandOptions Add(string name, Action action)
{
_actionsNoParams.Add(name, action);
return this;
}
/// <summary>
/// Adds a command option and an action (with parameter) to perform when the command is found.
/// </summary>
/// <param name="name">The name of the command.</param>
/// <param name="action">An action delegate that has one parameter - string[] args.</param>
/// <returns>The current CommandOptions instance.</returns>
public CommandOptions Add(string name, Action<string[]> action)
{
_actions.Add(name, action);
return this;
}
/// <summary>
/// Parses the text command and calls any actions associated with the command.
/// </summary>
/// <param name="command">The text command, e.g "show databases"</param>
public bool Parse(string command)
{
if (command.IndexOf(" ") == -1)
{
// No params
foreach (string key in _actionsNoParams.Keys)
{
if (command == key)
{
_actionsNoParams[key].Invoke();
return true;
}
}
}
else
{
// Params
foreach (string key in _actions.Keys)
{
if (command.StartsWith(key) && command.Length > key.Length)
{
string options = command.Substring(key.Length);
options = options.Trim();
string[] parts = options.Split(' ');
_actions[key].Invoke(parts);
return true;
}
}
}
return false;
}
}