Re: HttpCore NIO: "Status Code May Not Be Negative"

> Chas Williams wrote:
>
>> Hi all,
>>
>>     I'm having an issue with a long-running piece of web-crawling software
>> built using the HttpCore NIO extensions. Whenever the IOReactor encounters
>> an http server that (incorrectly) returns a negative status code, the
>> entire
>> IOReactor shuts down.
>>
>>     I've tried overriding the default exception handler, which seems to
>> have no effect.
>>
>> Here's the exception (from the IOReactor's audit log):
>>
>> java.lang.IllegalArgumentException: Status code may not be negative.
>>        at
>> org.apache.http.message.BasicStatusLine.<init>(BasicStatusLine.java:74)
>>        at
>>
>> org.apache.http.message.BasicLineParser.createStatusLine(BasicLineParser.java:453)
>>        at
>>
>> org.apache.http.message.BasicLineParser.parseStatusLine(BasicLineParser.java:431)
>>        at
>>
>> org.apache.http.impl.nio.codecs.HttpResponseParser.createMessage(HttpResponseParser.java:75)
>>        at
>>
>> org.apache.http.impl.nio.codecs.AbstractMessageParser.parseHeadLine(AbstractMessageParser.java:147)
>>        at
>>
>> org.apache.http.impl.nio.codecs.AbstractMessageParser.parse(AbstractMessageParser.java:196)
>>        at
>>
>> org.apache.http.impl.nio.DefaultNHttpClientConnection.consumeInput(DefaultNHttpClientConnection.java:160)
>>        at
>>
>> org.apache.http.impl.nio.DefaultClientIOEventDispatch.inputReady(DefaultClientIOEventDispatch.java:146)
>>        at
>>
>> org.apache.http.impl.nio.reactor.BaseIOReactor.readable(BaseIOReactor.java:153)
>>        at
>>
>> org.apache.http.impl.nio.reactor.AbstractIOReactor.processEvent(AbstractIOReactor.java:314)
>>        at
>>
>> org.apache.http.impl.nio.reactor.AbstractIOReactor.processEvents(AbstractIOReactor.java:294)
>>        at
>>
>> org.apache.http.impl.nio.reactor.AbstractIOReactor.execute(AbstractIOReactor.java:256)
>>        at
>>
>> org.apache.http.impl.nio.reactor.BaseIOReactor.execute(BaseIOReactor.java:96)
>>        at
>>
>> org.apache.http.impl.nio.reactor.AbstractMultiworkerIOReactor$Worker.run(AbstractMultiworkerIOReactor.java:556)
>>        at java.lang.Thread.run(Thread.java:619)
>>
>>
>> I used the setExceptionHandler() method to override the default exception
>> handler for my ConnectingIOReactor object, here's my implementation:
>>
>>
>> ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------
>>
>> public class MyIOReactorExceptionHandler implements
>> IOReactorExceptionHandler
>> {
>>
>>    public boolean handle(IOException arg0)
>>    {
>>        System.err.println("MyIOReactorExceptionHandler encountered
>> IOException: " + arg0);
>>        return true;
>>    }
>>
>>    public boolean handle(RuntimeException arg0)
>>    {
>>        System.err.println("MyIOReactorExceptionHandler encountered
>> RuntimeException: " + arg0);
>>
>>        //Ignore this one
>>        if (arg0 instanceof IllegalArgumentException &&
>> arg0.getMessage().contains("Status code may not be negative."))
>>        {
>>            System.err.println("...ignoring recoverable error: " +
>> arg0.getMessage());
>>            return false;
>>        }
>>
>>        System.err.println("Signaling unrecoverable error...");
>>
>>        return true;
>>    }
>>
>> }
>>
>>
> Chas,
>
> It is the other way around. The handler should return true if it is safe to
> ignore the exception and continue execution of the I/O reactor and if the
> I/O reactor must re-throw RuntimeException and terminate.
>
> ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------
>>
>> Looking my program logs, it seems like the handle(RuntimeException) method
>> is called, and "ignoring recoverable error: ..." is printed, but the
>> IOReactor still shuts down.
>>
>> What am I missing here? Is there a better way to recover from this error
>> without shutting down the IOReactor?
>>
>>
> A better solution to this problem would be a custom message parser.
>
> Hope this helps
>
> Oleg
>
>
>  Thanks,
>>
>> Chas
>>
>>
>
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