i have simple crawler which crawl and search page. but now i have problem how to execute and parse js link from that page. Does anyone have any idea how to parse and execute js page?
example:
要回答题为“如何在 C# 中解析和执行 JS”的问题，这里有一段封装了Windows Script Engines的代码。它支持 32 位和 64 位环境。
在您的特定情况下，这意味着根据 .JS 代码，您可能必须模拟/实现一些 HTML DOM 元素，例如“文档”、“窗口”等（使用 MyItem 类的“命名项目”功能. 这正是 Internet Explorer 所做的）。
以下是您可以使用它执行的一些示例：
1) 直接表达式求值：
Console.WriteLine(ScriptEngine.Eval("jscript", "1+2/3"));
将显示 1.66666666666667
2) 函数调用，带有可选参数：
using (ScriptEngine engine = new ScriptEngine("jscript"))
{
ParsedScript parsed = engine.Parse("function MyFunc(x){return 1+2+x}");
Console.WriteLine(parsed.CallMethod("MyFunc", 3));
}
将显示 6
3) 带有命名项和可选参数的函数调用：
using (ScriptEngine engine = new ScriptEngine("jscript"))
{
ParsedScript parsed = engine.Parse("function MyFunc(x){return 1+2+x+My.Num}");
MyItem item = new MyItem();
item.Num = 4;
engine.SetNamedItem("My", item);
Console.WriteLine(parsed.CallMethod("MyFunc", 3));
}
[ComVisible(true)] // Script engines are COM components.
public class MyItem
{
public int Num { get; set; }
}
将显示 10。
编辑：我添加了使用 CLSID 而不是脚本语言名称的可能性，因此我们可以重新使用新的快速 IE9+“脉轮”javascript 引擎，如下所示：
using (ScriptEngine engine = new ScriptEngine("{16d51579-a30b-4c8b-a276-0ff4dc41e755}"))
{
// continue with chakra now
}
这是完整的来源：
/// <summary>
/// Represents a Windows Script Engine such as JScript, VBScript, etc.
/// </summary>
public sealed class ScriptEngine : IDisposable
{
/// <summary>
/// The name of the function used for simple evaluation.
/// </summary>
public const string MethodName = "EvalMethod";
/// <summary>
/// The default scripting language name.
/// </summary>
public const string DefaultLanguage = JavaScriptLanguage;
/// <summary>
/// The JavaScript or jscript scripting language name.
/// </summary>
public const string JavaScriptLanguage = "javascript";
/// <summary>
/// The javascript or jscript scripting language name.
/// </summary>
public const string VBScriptLanguage = "vbscript";
/// <summary>
/// The chakra javascript engine CLSID. The value is {16d51579-a30b-4c8b-a276-0ff4dc41e755}.
/// </summary>
public const string ChakraClsid = "{16d51579-a30b-4c8b-a276-0ff4dc41e755}";
private IActiveScript _engine;
private IActiveScriptParse32 _parse32;
private IActiveScriptParse64 _parse64;
internal ScriptSite Site;
private Version _version;
private string _name;
[Guid("BB1A2AE1-A4F9-11cf-8F20-00805F2CD064"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
private interface IActiveScript
{
[PreserveSig]
int SetScriptSite(IActiveScriptSite pass);
[PreserveSig]
int GetScriptSite(Guid riid, out IntPtr site);
[PreserveSig]
int SetScriptState(ScriptState state);
[PreserveSig]
int GetScriptState(out ScriptState scriptState);
[PreserveSig]
int Close();
[PreserveSig]
int AddNamedItem(string name, ScriptItem flags);
[PreserveSig]
int AddTypeLib(Guid typeLib, uint major, uint minor, uint flags);
[PreserveSig]
int GetScriptDispatch(string itemName, out IntPtr dispatch);
[PreserveSig]
int GetCurrentScriptThreadID(out uint thread);
[PreserveSig]
int GetScriptThreadID(uint win32ThreadId, out uint thread);
[PreserveSig]
int GetScriptThreadState(uint thread, out ScriptThreadState state);
[PreserveSig]
int InterruptScriptThread(uint thread, out System.Runtime.InteropServices.ComTypes.EXCEPINFO exceptionInfo, uint flags);
[PreserveSig]
int Clone(out IActiveScript script);
}
[Guid("4954E0D0-FBC7-11D1-8410-006008C3FBFC"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
private interface IActiveScriptProperty
{
[PreserveSig]
int GetProperty(int dwProperty, IntPtr pvarIndex, out object pvarValue);
[PreserveSig]
int SetProperty(int dwProperty, IntPtr pvarIndex, ref object pvarValue);
}
[Guid("DB01A1E3-A42B-11cf-8F20-00805F2CD064"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
private interface IActiveScriptSite
{
[PreserveSig]
int GetLCID(out int lcid);
[PreserveSig]
int GetItemInfo(string name, ScriptInfo returnMask, out IntPtr item, IntPtr typeInfo);
[PreserveSig]
int GetDocVersionString(out string version);
[PreserveSig]
int OnScriptTerminate(object result, System.Runtime.InteropServices.ComTypes.EXCEPINFO exceptionInfo);
[PreserveSig]
int OnStateChange(ScriptState scriptState);
[PreserveSig]
int OnScriptError(IActiveScriptError scriptError);
[PreserveSig]
int OnEnterScript();
[PreserveSig]
int OnLeaveScript();
}
[Guid("EAE1BA61-A4ED-11cf-8F20-00805F2CD064"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
private interface IActiveScriptError
{
[PreserveSig]
int GetExceptionInfo(out System.Runtime.InteropServices.ComTypes.EXCEPINFO exceptionInfo);
[PreserveSig]
int GetSourcePosition(out uint sourceContext, out int lineNumber, out int characterPosition);
[PreserveSig]
int GetSourceLineText(out string sourceLine);
}
[Guid("BB1A2AE2-A4F9-11cf-8F20-00805F2CD064"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
private interface IActiveScriptParse32
{
[PreserveSig]
int InitNew();
[PreserveSig]
int AddScriptlet(string defaultName, string code, string itemName, string subItemName, string eventName, string delimiter, IntPtr sourceContextCookie, uint startingLineNumber, ScriptText flags, out string name, out System.Runtime.InteropServices.ComTypes.EXCEPINFO exceptionInfo);
[PreserveSig]
int ParseScriptText(string code, string itemName, IntPtr context, string delimiter, int sourceContextCookie, uint startingLineNumber, ScriptText flags, out object result, out System.Runtime.InteropServices.ComTypes.EXCEPINFO exceptionInfo);
}
[Guid("C7EF7658-E1EE-480E-97EA-D52CB4D76D17"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
private interface IActiveScriptParse64
{
[PreserveSig]
int InitNew();
[PreserveSig]
int AddScriptlet(string defaultName, string code, string itemName, string subItemName, string eventName, string delimiter, IntPtr sourceContextCookie, uint startingLineNumber, ScriptText flags, out string name, out System.Runtime.InteropServices.ComTypes.EXCEPINFO exceptionInfo);
[PreserveSig]
int ParseScriptText(string code, string itemName, IntPtr context, string delimiter, long sourceContextCookie, uint startingLineNumber, ScriptText flags, out object result, out System.Runtime.InteropServices.ComTypes.EXCEPINFO exceptionInfo);
}
[Flags]
private enum ScriptText
{
None = 0,
//DelayExecution = 1,
//IsVisible = 2,
IsExpression = 32,
IsPersistent = 64,
//HostManageSource = 128
}
[Flags]
private enum ScriptInfo
{
//None = 0,
//IUnknown = 1,
ITypeInfo = 2
}
[Flags]
private enum ScriptItem
{
//None = 0,
IsVisible = 2,
IsSource = 4,
//GlobalMembers = 8,
//IsPersistent = 64,
//CodeOnly = 512,
//NoCode = 1024
}
private enum ScriptThreadState
{
//NotInScript = 0,
//Running = 1
}
private enum ScriptState
{
Uninitialized = 0,
Started = 1,
Connected = 2,
Disconnected = 3,
Closed = 4,
Initialized = 5
}
private const int TYPE_E_ELEMENTNOTFOUND = unchecked((int)(0x8002802B));
private const int E_NOTIMPL = -2147467263;
/// <summary>
/// Determines if a script engine with the input name exists.
/// </summary>
/// <param name="language">The language.</param>
/// <returns>true if the engine exists; false otherwise.</returns>
public static Version GetVersion(string language)
{
if (language == null)
throw new ArgumentNullException("language");
Type engine;
Guid clsid;
if (Guid.TryParse(language, out clsid))
{
engine = Type.GetTypeFromCLSID(clsid, false);
}
else
{
engine = Type.GetTypeFromProgID(language, false);
}
if (engine == null)
return null;
IActiveScript scriptEngine = Activator.CreateInstance(engine) as IActiveScript;
if (scriptEngine == null)
return null;
IActiveScriptProperty scriptProperty = scriptEngine as IActiveScriptProperty;
if (scriptProperty == null)
return new Version(1, 0, 0, 0);
int major = GetProperty(scriptProperty, SCRIPTPROP_MAJORVERSION, 0);
int minor = GetProperty(scriptProperty, SCRIPTPROP_MINORVERSION, 0);
int revision = GetProperty(scriptProperty, SCRIPTPROP_BUILDNUMBER, 0);
Version version = new Version(major, minor, Environment.OSVersion.Version.Build, revision);
Marshal.ReleaseComObject(scriptProperty);
Marshal.ReleaseComObject(scriptEngine);
return version;
}
private static T GetProperty<T>(IActiveScriptProperty prop, int index, T defaultValue)
{
object value;
if (prop.GetProperty(index, IntPtr.Zero, out value) != 0)
return defaultValue;
try
{
return (T)Convert.ChangeType(value, typeof(T));
}
catch
{
return defaultValue;
}
}
/// <summary>
/// Initializes a new instance of the <see cref="ScriptEngine"/> class.
/// </summary>
/// <param name="language">The scripting language. Standard Windows Script engines names are 'jscript' or 'vbscript'.</param>
public ScriptEngine(string language)
{
if (language == null)
throw new ArgumentNullException("language");
Type engine;
Guid clsid;
if (Guid.TryParse(language, out clsid))
{
engine = Type.GetTypeFromCLSID(clsid, true);
}
else
{
engine = Type.GetTypeFromProgID(language, true);
}
_engine = Activator.CreateInstance(engine) as IActiveScript;
if (_engine == null)
throw new ArgumentException(language + " is not an Windows Script Engine", "language");
Site = new ScriptSite();
_engine.SetScriptSite(Site);
// support 32-bit & 64-bit process
if (IntPtr.Size == 4)
{
_parse32 = (IActiveScriptParse32)_engine;
_parse32.InitNew();
}
else
{
_parse64 = (IActiveScriptParse64)_engine;
_parse64.InitNew();
}
}
private const int SCRIPTPROP_NAME = 0x00000000;
private const int SCRIPTPROP_MAJORVERSION = 0x00000001;
private const int SCRIPTPROP_MINORVERSION = 0x00000002;
private const int SCRIPTPROP_BUILDNUMBER = 0x00000003;
/// <summary>
/// Gets the engine version.
/// </summary>
/// <value>
/// The version.
/// </value>
public Version Version
{
get
{
if (_version == null)
{
int major = GetProperty(SCRIPTPROP_MAJORVERSION, 0);
int minor = GetProperty(SCRIPTPROP_MINORVERSION, 0);
int revision = GetProperty(SCRIPTPROP_BUILDNUMBER, 0);
_version = new Version(major, minor, Environment.OSVersion.Version.Build, revision);
}
return _version;
}
}
/// <summary>
/// Gets the engine name.
/// </summary>
/// <value>
/// The name.
/// </value>
public string Name
{
get
{
if (_name == null)
{
_name = GetProperty(SCRIPTPROP_NAME, string.Empty);
}
return _name;
}
}
/// <summary>
/// Gets a script engine property.
/// </summary>
/// <typeparam name="T">The expected property type.</typeparam>
/// <param name="index">The property index.</param>
/// <param name="defaultValue">The default value if not found.</param>
/// <returns>The value of the property or the default value.</returns>
public T GetProperty<T>(int index, T defaultValue)
{
object value;
if (!TryGetProperty(index, out value))
return defaultValue;
try
{
return (T)Convert.ChangeType(value, typeof(T));
}
catch
{
return defaultValue;
}
}
/// <summary>
/// Gets a script engine property.
/// </summary>
/// <param name="index">The property index.</param>
/// <param name="value">The value.</param>
/// <returns>true if the property was successfully got; false otherwise.</returns>
public bool TryGetProperty(int index, out object value)
{
value = null;
IActiveScriptProperty property = _engine as IActiveScriptProperty;
if (property == null)
return false;
return property.GetProperty(index, IntPtr.Zero, out value) == 0;
}
/// <summary>
/// Sets a script engine property.
/// </summary>
/// <param name="index">The property index.</param>
/// <param name="value">The value.</param>
/// <returns>true if the property was successfully set; false otherwise.</returns>
public bool SetProperty(int index, object value)
{
IActiveScriptProperty property = _engine as IActiveScriptProperty;
if (property == null)
return false;
return property.SetProperty(index, IntPtr.Zero, ref value) == 0;
}
/// <summary>
/// Adds the name of a root-level item to the scripting engine's name space.
/// </summary>
/// <param name="name">The name. May not be null.</param>
/// <param name="value">The value. It must be a ComVisible object.</param>
public void SetNamedItem(string name, object value)
{
if (name == null)
throw new ArgumentNullException("name");
_engine.AddNamedItem(name, ScriptItem.IsVisible | ScriptItem.IsSource);
Site.NamedItems[name] = value;
}
internal class ScriptSite : IActiveScriptSite
{
internal ScriptException LastException;
internal Dictionary<string, object> NamedItems = new Dictionary<string, object>();
int IActiveScriptSite.GetLCID(out int lcid)
{
lcid = Thread.CurrentThread.CurrentCulture.LCID;
return 0;
}
int IActiveScriptSite.GetItemInfo(string name, ScriptInfo returnMask, out IntPtr item, IntPtr typeInfo)
{
item = IntPtr.Zero;
if ((returnMask & ScriptInfo.ITypeInfo) == ScriptInfo.ITypeInfo)
return E_NOTIMPL;
object value;
if (!NamedItems.TryGetValue(name, out value))
return TYPE_E_ELEMENTNOTFOUND;
item = Marshal.GetIUnknownForObject(value);
return 0;
}
int IActiveScriptSite.GetDocVersionString(out string version)
{
version = null;
return 0;
}
int IActiveScriptSite.OnScriptTerminate(object result, System.Runtime.InteropServices.ComTypes.EXCEPINFO exceptionInfo)
{
return 0;
}
int IActiveScriptSite.OnStateChange(ScriptState scriptState)
{
return 0;
}
int IActiveScriptSite.OnScriptError(IActiveScriptError scriptError)
{
string sourceLine = null;
try
{
scriptError.GetSourceLineText(out sourceLine);
}
catch
{
// happens sometimes...
}
uint sourceContext;
int lineNumber;
int characterPosition;
scriptError.GetSourcePosition(out sourceContext, out lineNumber, out characterPosition);
lineNumber++;
characterPosition++;
System.Runtime.InteropServices.ComTypes.EXCEPINFO exceptionInfo;
scriptError.GetExceptionInfo(out exceptionInfo);
string message;
if (!string.IsNullOrEmpty(sourceLine))
{
message = "Script exception: {1}. Error number {0} (0x{0:X8}): {2} at line {3}, column {4}. Source line: '{5}'.";
}
else
{
message = "Script exception: {1}. Error number {0} (0x{0:X8}): {2} at line {3}, column {4}.";
}
LastException = new ScriptException(string.Format(message, exceptionInfo.scode, exceptionInfo.bstrSource, exceptionInfo.bstrDescription, lineNumber, characterPosition, sourceLine));
LastException.Column = characterPosition;
LastException.Description = exceptionInfo.bstrDescription;
LastException.Line = lineNumber;
LastException.Number = exceptionInfo.scode;
LastException.Text = sourceLine;
return 0;
}
int IActiveScriptSite.OnEnterScript()
{
LastException = null;
return 0;
}
int IActiveScriptSite.OnLeaveScript()
{
return 0;
}
}
/// <summary>
/// Evaluates an expression using the specified language.
/// </summary>
/// <param name="language">The language.</param>
/// <param name="expression">The expression. May not be null.</param>
/// <returns>The result of the evaluation.</returns>
public static object Eval(string language, string expression)
{
return Eval(language, expression, null);
}
/// <summary>
/// Evaluates an expression using the specified language, with an optional array of named items.
/// </summary>
/// <param name="language">The language.</param>
/// <param name="expression">The expression. May not be null.</param>
/// <param name="namedItems">The named items array.</param>
/// <returns>The result of the evaluation.</returns>
public static object Eval(string language, string expression, params KeyValuePair<string, object>[] namedItems)
{
if (language == null)
throw new ArgumentNullException("language");
if (expression == null)
throw new ArgumentNullException("expression");
using (ScriptEngine engine = new ScriptEngine(language))
{
if (namedItems != null)
{
foreach (KeyValuePair<string, object> kvp in namedItems)
{
engine.SetNamedItem(kvp.Key, kvp.Value);
}
}
return engine.Eval(expression);
}
}
/// <summary>
/// Evaluates an expression.
/// </summary>
/// <param name="expression">The expression. May not be null.</param>
/// <returns>The result of the evaluation.</returns>
public object Eval(string expression)
{
if (expression == null)
throw new ArgumentNullException("expression");
return Parse(expression, true);
}
/// <summary>
/// Parses the specified text and returns an object that can be used for evaluation.
/// </summary>
/// <param name="text">The text to parse.</param>
/// <returns>An instance of the ParsedScript class.</returns>
public ParsedScript Parse(string text)
{
if (text == null)
throw new ArgumentNullException("text");
return (ParsedScript)Parse(text, false);
}
private object Parse(string text, bool expression)
{
const string varName = "x___";
object result;
_engine.SetScriptState(ScriptState.Connected);
ScriptText flags = ScriptText.None;
if (expression)
{
flags |= ScriptText.IsExpression;
}
try
{
// immediate expression computation seems to work only for 64-bit
// so hack something for 32-bit...
System.Runtime.InteropServices.ComTypes.EXCEPINFO exceptionInfo;
if (_parse32 != null)
{
if (expression)
{
// should work for jscript & vbscript at least...
text = varName + "=" + text;
}
_parse32.ParseScriptText(text, null, IntPtr.Zero, null, 0, 0, flags, out result, out exceptionInfo);
}
else
{
_parse64.ParseScriptText(text, null, IntPtr.Zero, null, 0, 0, flags, out result, out exceptionInfo);
}
}
catch
{
if (Site.LastException != null)
throw Site.LastException;
throw;
}
IntPtr dispatch;
if (expression)
{
// continue our 32-bit hack...
if (_parse32 != null)
{
_engine.GetScriptDispatch(null, out dispatch);
object dp = Marshal.GetObjectForIUnknown(dispatch);
try
{
return dp.GetType().InvokeMember(varName, BindingFlags.GetProperty, null, dp, null);
}
catch
{
if (Site.LastException != null)
throw Site.LastException;
throw;
}
}
return result;
}
_engine.GetScriptDispatch(null, out dispatch);
ParsedScript parsed = new ParsedScript(this, dispatch);
return parsed;
}
/// <summary>
/// Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.
/// </summary>
public void Dispose()
{
if (_parse32 != null)
{
Marshal.ReleaseComObject(_parse32);
_parse32 = null;
}
if (_parse64 != null)
{
Marshal.ReleaseComObject(_parse64);
_parse64 = null;
}
if (_engine != null)
{
Marshal.ReleaseComObject(_engine);
_engine = null;
}
}
}
public sealed class ParsedScript : IDisposable
{
private object _dispatch;
private readonly ScriptEngine _engine;
internal ParsedScript(ScriptEngine engine, IntPtr dispatch)
{
_engine = engine;
_dispatch = Marshal.GetObjectForIUnknown(dispatch);
}
public object CallMethod(string methodName, params object[] arguments)
{
if (_dispatch == null)
throw new InvalidOperationException();
if (methodName == null)
throw new ArgumentNullException("methodName");
try
{
return _dispatch.GetType().InvokeMember(methodName, BindingFlags.InvokeMethod, null, _dispatch, arguments);
}
catch
{
if (_engine.Site.LastException != null)
throw _engine.Site.LastException;
throw;
}
}
void IDisposable.Dispose()
{
if (_dispatch != null)
{
Marshal.ReleaseComObject(_dispatch);
_dispatch = null;
}
}
}
[Serializable]
public class ScriptException : Exception
{
public ScriptException()
: base("Script Exception")
{
}
public ScriptException(string message)
: base(message)
{
}
public ScriptException(Exception innerException)
: base(null, innerException)
{
}
public ScriptException(string message, Exception innerException)
: base(message, innerException)
{
}
protected ScriptException(SerializationInfo info, StreamingContext context)
: base(info, context)
{
}
public string Description { get; internal set; }
public int Line { get; internal set; }
public int Column { get; internal set; }
public int Number { get; internal set; }
public string Text { get; internal set; }
}
也许不是您正在寻找的答案，但这个问题是 3 年前发布的。今天有替代选择。
另请参阅： 将 JavaScript 引擎嵌入 .NET
现在，您可以为您的项目使用“JavaScript Engine Switcher”NuGet 包。选择最适合您的环境的一种。
例如，v8 将要求确保在您的服务器上安装了某些二进制文件，而 Jint NuGet 包为您包装了所有内容（也就是“正常工作”）。
Jint 已移至 GitHub，可在此处获取： https ://github.com/sebastienros/jint
要执行您的问题所针对的那种功能，您可能需要在脚本引擎中启用对 .NET 程序集的访问并将其用于 AJAX 调用。其他配置选项可能会提供更多功能。
可能有点晚（问题发布四年后），但您可以使用原生 C# 编写的侏罗纪 JavaScript 引擎。这是 100% 用托管 C# 编写的，甚至可以在 Mono 上运行，这意味着您可以将脚本需求隔离为平台独立。如果您喜欢 Mono 并使用 GTK+ 作为应用程序的 GUI 前端，那么您就有了适用于 Windows、Linux 和 OS X 的解决方案——更不用说 WP、iOS 和 Android。
该项目可以在这里找到： https ://jurassic.codeplex.com/
要完全做到这一点，您需要模拟整个浏览器模型 - 永远不会发生。
由于您声明“我的页面”，因此这里通常的技巧是执行以下操作：
<a id="foo" href="crawlableRoute">text</a>
并且（稍后）将 javascript 附加到click返回false的，抑制原始链接。您的爬虫通过 导航crawlableRoute。例如（使用 jQuery）：
$(function() {
$('#foo').click(function() {
// do stuff;
return false; // suppress navigation
});
});
这样你就不需要处理js了。