NEsper issue with regexp
本文关键字:regexp with issue NEsper | 更新日期: 2023-09-27 18:19:30
我已经被困在这里很长一段时间了,似乎用regex将问题归咎于不正确的NEsper行为。我写了一个简单的项目来重现这个问题,它可以从github上获得。
简而言之,NEsper允许我通过一组规则(类似SQL)来泵送消息(事件)。如果事件符合规则,NEsper将发出警报。在我的应用程序中,我需要使用正则表达式,但这似乎不起作用。
问题
我尝试了创建语句createPattern
和createEPL
的两种方法,但它们并没有触发匹配事件,但是正则表达式和输入是由.NET Regex类匹配的。如果我将匹配值("127.0.0.5")传递给该语句而不是regex("''b''d{1,3}.''d{1,3}.''d{1,3}.''b"),则事件成功触发。
输入127.0.0.5==规则失败==every(Id123=TestDummy(值regexp'''b''d{1,3}''.''d{1,3}''.''d{1,3}''.[d{1.3}''b')//我想让它过去==规则通过==every(Id123=TestDummy(值regexp"127.0.0.5")
问题
有人能帮我做一个NEsper正则表达式匹配的例子吗?或者指出我在代码中的愚蠢错误。
代码
这是我的NEsper演示包装类
public class NesperAdapter
{
public MatchEventSubscrtiber Subscriber { get; set; }
internal EPServiceProvider Engine { get; private set; }
public NesperAdapter()
{
//This call internally depend on log4net,
//will throw an error if log4net cannot be loaded
EPServiceProviderManager.PurgeDefaultProvider();
//config
var configuration = new Configuration();
configuration.AddEventType("TestDummy", typeof(TestDummy).FullName);
configuration.EngineDefaults.Threading.IsInternalTimerEnabled = false;
configuration.EngineDefaults.Logging.IsEnableExecutionDebug = false;
configuration.EngineDefaults.Logging.IsEnableTimerDebug = false;
//engine
Engine = EPServiceProviderManager.GetDefaultProvider(configuration);
Engine.EPRuntime.SendEvent(new TimerControlEvent(TimerControlEvent.ClockTypeEnum.CLOCK_EXTERNAL));
Engine.Initialize();
Engine.EPRuntime.UnmatchedEvent += OnUnmatchedEvent;
}
public void AddStatementFromRegExp(string regExp)
{
const string pattern = "any (Id123=TestDummy(Value regexp '{0}'))";
string formattedPattern = String.Format(pattern, regExp);
EPStatement statement = Engine.EPAdministrator.CreatePattern(formattedPattern);
//this is subscription
Subscriber = new MatchEventSubscrtiber();
statement.Subscriber = Subscriber;
}
internal void OnUnmatchedEvent(object sender, UnmatchedEventArgs e)
{
Console.WriteLine(@"Unmatched event");
Console.WriteLine(e.Event);
}
public void SendEvent(object someEvent)
{
Engine.EPRuntime.SendEvent(someEvent);
}
}
然后是订户和DummyType
public class MatchEventSubscrtiber
{
public bool HasEventFired { get; set; }
public MatchEventSubscrtiber()
{
HasEventFired = false;
}
public void Update(IDictionary<string, object> rows)
{
Console.WriteLine("Match event fired");
Console.WriteLine(rows);
HasEventFired = true;
}
}
public class TestDummy
{
public string Value { get; set; }
}
以及NUnit测试如果有一条注释nesper.AddStatementFromRegExp(regexp);行并取消注释//nesper.AddStatementFromRegExp(input);
行,然后测试通过。但是我需要一个正则表达式。
//Match any IP address
[TestFixture(@"'b'd{1,3}'.'d{1,3}'.'d{1,3}'.'d{1,3}'b", "127.0.0.5")]
public class WhenValidRegexpPassedAndRuleCreatedAndPropagated
{
private NesperAdapter nesper;
//Setup
public WhenValidRegexpPassedAndRuleCreatedAndPropagated(string regexp, string input)
{
//check it is valid regexp in .NET
var r = new Regex(regexp);
var match = r.Match(input);
Assert.IsTrue(match.Success, "Regexp validation failed in .NET");
//create and start engine
nesper = new NesperAdapter();
//Add a rule, this fails with a correct regexp and a matching input
//PROBLEM IS HERE
nesper.AddStatementFromRegExp(regexp);
//PROBLEM IS HERE
//This works, but it is just input self-matching
//nesper.AddStatementFromRegExp(input);
var oneEvent = new TestDummy
{
Value = input
};
nesper.SendEvent(oneEvent);
}
[Test]
public void ThenNesperFiresMatchEvent()
{
//wait till nesper process the event
Thread.Sleep(100);
//Check if subscriber has received the event
Assert.IsTrue(nesper.Subscriber.HasEventFired,
"Event didn't fire");
}
}
我调试这个问题已经有一段时间了,发现NEsper错误地处理
WHERE regexp 'foobar'
语句
所以如果我有
SELECT*FROM MyType WHERE PropertyA regexp"一些有效的regexp"
NEsper使用"一些有效的正则表达式"执行字符串格式化和验证,并从正则表达式中删除重要的(和有效的)符号。这就是我自己解决的方法。不确定这是否是推荐的方法。
文件:com.espertech.esper.epl.expression.ExprRegexpNode
原因:我认为如何构建regexp取决于用户,这不应该是框架的一部分
// Inside this method
public object Evaluate(EventBean[] eventsPerStream, bool isNewData, ExprEvaluatorContext exprEvaluatorContext){...}
// Find two occurrences of
_pattern = new Regex(String.Format("^{0}$", patternText));
// And change to
_pattern = new Regex(patternText);
文件:com.espertech.esper.epl.parse.ASTConstantHelper
原因:所有字符串都需要Unescape,但跳过regexp,因为这会阻止有效的regexp并从中删除一些有效的符号。
// Inside this method
public static Object Parse(ITree node){...}
// Find one occurrence of
case EsperEPL2GrammarParser.STRING_TYPE:
{
return StringValue.ParseString(node.Text, requireUnescape);
}
// And change to
case EsperEPL2GrammarParser.STRING_TYPE:
{
bool requireUnescape = true;
if (node.Parent != null)
{
if (!String.IsNullOrEmpty(node.Parent.Text))
{
if (node.Parent.Text == "regexp")
{
requireUnescape = false;
}
}
}
return StringValue.ParseString(node.Text, requireUnescape);
}
文件:com.espertech.esper.type.StringValue
原因:取消捕获所有字符串,但正则表达式值除外
// Inside this method
public static String ParseString(String value){...}
// Change from
public static String ParseString(String value)
{
if ((value.StartsWith("'"")) & (value.EndsWith("'"")) || (value.StartsWith("'")) & (value.EndsWith("'")))
{
if (value.Length > 1)
{
if (value.IndexOf('''') != -1)
{
return Unescape(value.Substring(1, value.Length - 2));
}
return value.Substring(1, value.Length - 2);
}
}
throw new ArgumentException("String value of '" + value + "' cannot be parsed");
}
// Change to
public static String ParseString(String value, bool requireUnescape = true)
{
if ((value.StartsWith("'"")) & (value.EndsWith("'"")) || (value.StartsWith("'")) & (value.EndsWith("'")))
{
if (value.Length > 1)
{
if (requireUnescape)
{
if (value.IndexOf('''') != -1)
{
return Unescape(value.Substring(1, value.Length - 2));
}
}
return value.Substring(1, value.Length - 2);
}
}
throw new ArgumentException("String value of '" + value + "' cannot be parsed");
}