0 votes
by (200 points)

As per my understanding we use timeout to suspend any operation if it's taking time longer than usual.

Issue is: I am using following method of class VirtualTerminal, but I am able to receive data only after the timeout period has expired.

public Match Expect(Regex pattern, int maximumWaitTime);

Even I have provided timeout:60000 (60Sec) and it's returning after 60Sec, though I am receiving same data when setting timeout: 2000.

Please can any one help me in this regard.

I have used following code to calculate time difference:
DateTime t1 = DateTime.Now;
string _response = m_shell.Expect("regex:(.*)");
string _lines = m_shell.ReceivedData;
DateTime t2 = DateTime.Now;
Logger.WriteLog(String.Format(" Response Time Diff.: {0}", t2 - t1));


2 Answers

+1 vote
by (70.2k points)

At the first place I would like to clarify that the mentioned method: public Match Expect(Regex pattern, int maximumWaitTime); is a method from the VirtualTerminal class while the example you included uses a method from the VirtualShell class: public string Expect(string regexPattern).

However, the behavior of both methods is the same: Receives data until the specified pattern is found, but no longer than a timeout period.

The issue in your example is caused by "incorrect" input regex pattern. Please note, that "regex:" prefix is not wanted, just pass the pattern directly.

So, your example behaves correctly: wait until pattern "regex:(.*)" is found. Because it is not found, method returns null after the specified timeout. The m_shell.ReceivedData property contains all received data up to that time.

Also please note, that m_shell.Expect(".*") matches everything, which is also an empty string. It leads to a specific behavior: if no data are buffered, no data are received and the method returns immediately with success. You should rather use m_shell.Expect(".+") to receive at least one character (or more if available).

I would like to also point at the m_shell.Match property. The idea is as follows: The Expect method returns received data without the matched pattern. The Match property returns a data matched by the specified pattern. The ReceivedData property returns all received data. So, there is such an equality:

  • output of the Expect method concatenated with the Match property is equal to the ReceivedData property
  • C#: shell.Expect("pattern") + shell.Match == shell.ReceivedData
  • VB: shell.Expect("pattern") & shell.Match = shell.ReceivedData
by (200 points)

Yes, I was providing invalid regex.

Thanks a lot Lukas.

0 votes
by (15.2k points)

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