C# DLL の有効期間中、Selenium サーバーのシングルトン プロセスを実行して強制終了する

StackOverflow https://stackoverflow.com/questions/2426494

質問

私は持っています Selenium テスト .DLL あれは ロード済み NUnitを使用します。

必要なコマンドを実行します Selenium Java サーバー 静かに隠れた プロセスの中で テストの実行時。

しかし、私は現在、 サーバーを起動します いつ テストが始まります そして Kill() それ いつ テスト停止.

これにより、Selenium サーバーが作成されます。 テストごとに開始/停止.


私が望んでいるのは、Selenium Server プロセスで次のことを行うことです。

  • 始める どちらかに DLLのロード/初期化 または 最初のテストが始まるとき
  • なれ Kill() の上 DLLの死 または ガベージコレクション


C# は DLL 初期化のキャッチとコードの呼び出しをサポートしていないと読みました。(私が間違っている?)

私のアイデアは、Selenium サーバーをシングルトン クラスでホストし、最初のテストの実行時に初期化することでした。その後、ガベージ コレクションに任せて、デコンストラクターを介して Dispose メソッドを呼び出します。現在、Selenium サーバーをホストする次のコードがあります。

namespace Tests.Server
{
    using System;
    using System.Diagnostics;
    using System.IO;
    using System.Security;
    using System.Windows.Forms;
    using Microsoft.Win32;

    /// <summary>
    /// A singleton class to host and control the selenium server.
    /// </summary>
    public class SeleniumServer : IDisposable
    {
        #region Fields
        /// <summary>
        /// The singleton instance
        /// </summary>
        private static volatile SeleniumServer instance;

        /// <summary>
        /// An object to perform double-check locking upon instance creation to 
        /// avoid dead-locks. 
        /// See <see href="SeleniumServer.Instance"/> for more information.
        /// </summary>
        private static object syncRoot = new Object();

        /// <summary>
        /// The current selenium server.
        /// </summary>
        private Process seleniumServer = null;

        /// <summary>
        /// A flag for the disposal of the class.
        /// </summary>
        private bool isDisposed = false;
        #endregion

        #region Constructor
        /// <summary>
        /// Initializes a new instance of the SeleniumServer class.  Starts the 
        /// Selenium Java server in a background hidden thread.
        /// </summary>
        private SeleniumServer()
        {
            // Get the java install folder.
            string javaFileLocation = this.GetJavaFileLocation();

            // Get the selenium server java executable
            string jarFileLocation = '"' + Directory.GetCurrentDirectory() + @"\SeleniumServer\selenium-server.jar""";

            // Start the selenium server
            seleniumServer = new Process();
            seleniumServer.StartInfo.FileName = javaFileLocation;
            seleniumServer.StartInfo.Arguments = " -jar " + jarFileLocation + " -browserSessionReuse -trustAllSSLCertification";
            seleniumServer.StartInfo.WorkingDirectory = jarFileLocation.Substring(0, jarFileLocation.LastIndexOf("\\"));
            seleniumServer.StartInfo.UseShellExecute = true;
            seleniumServer.StartInfo.WindowStyle = ProcessWindowStyle.Hidden;
            seleniumServer.Start();
        }
        #endregion

        #region Deconstructor
        ~SeleniumServer()
        {
            Dispose(false);
        }
        #endregion

        #region Properties
        /// <summary>
        /// A thread safe
        /// </summary>
        public static SeleniumServer Instance
        {
            get
            {
                // This approach ensures that only one instance is created and 
                // only when the instance is needed. Also, the variable is 
                // declared to be volatile to ensure that assignment to the 
                // instance variable completes before the instance variable can 
                // be accessed. Lastly, this approach uses a syncRoot instance 
                // to lock on, rather than locking on the type itself, to avoid 
                // deadlocks.
                // This double-check locking approach solves the thread 
                // concurrency problems while avoiding an exclusive lock in 
                // every call to the Instance property method. It also allows 
                // you to delay instantiation until the object is first 
                // accessed. In practice, an application rarely requires this 
                // type of implementation. In most cases, the static 
                // initialization approach is sufficient.
                if (instance == null)
                {
                    lock (syncRoot)
                    {
                        if (instance == null)
                        {
                            instance = new SeleniumServer();
                        }
                    }
                }

                return instance;
            }
        }
        #endregion

        #region Methods
        /// <summary>
        /// Stops the process.
        /// </summary>   
        protected void Dispose(bool disposing)
        {
            if (disposing)
            {
                // Code to dispose the managed resources of the class
                // Not needed right now.
            }

            // Code to dispose the un-managed resources of the class
            // TODO: Handle the exceptions
            Instance.seleniumServer.Kill();

            // All done!
            isDisposed = true;
        }

        /// <summary>
        /// Dispose of the class and stop the Selenium server process.
        /// </summary>
        public void Dispose()
        {
            Dispose(true);
            GC.SuppressFinalize(this);
        }

        /// <summary>
        /// Stops the Selenium Server.
        /// </summary>
        public void Stop()
        {
            this.Dispose();
        }

        /// <summary>
        /// Attempts to get the Java installation folder from the registry.  If 
        /// it cannot be found the default installation folder is checked before 
        /// failing.
        /// </summary>
        /// <returns>The Java executable file path.</returns>
        /// <exception cref="System.Exception">
        /// Thrown when the user does not have permission to access the 
        /// registry.
        /// </exception>
        /// <exception cref="System.ObjectDisposedException">
        /// Thrown if the registry key object is disposed of.
        /// </exception>
        /// <exception cref="System.IOException">
        /// Thrown if the registry key object is marked for deletion.
        /// </exception>
        private string GetJavaFileLocation()
        {
            string javaFileLocation = string.Empty;
            RegistryKey regKey = Registry.LocalMachine;
            RegistryKey subKey = null;
            try
            {
                // Check for Java in the native bitness
                string javaRegistryLocation = @"SOFTWARE\JavaSoft\Java Runtime Environment\";
                subKey = regKey.OpenSubKey(javaRegistryLocation);

                // Check if we are running in WOW64 and only 32 bit Java is installed.
                if (subKey == null)
                {
                    javaRegistryLocation = @"SOFTWARE\Wow6432Node\JavaSoft\Java Runtime Environment\";
                    subKey = regKey.OpenSubKey(javaRegistryLocation);
                }

                // If Java was not found in either of these location the user 
                // needs to install it.  Note that Java 32 bit is a prerequisite 
                // for the installer so should always be installed.
                if (subKey == null)
                {
                    MessageBox.Show(
                        "You must have Java installed to run the commands server. This allows browser commands to be routed to the browser window.\n\nPlease visit: http://www.java.com/ to download.",
                        "Please Install Java",
                        MessageBoxButtons.OK,
                        MessageBoxIcon.Information);

                    throw new Exception("No installation of Java was detected to run the selenium server.");
                }

                // Get all the sub keys (could be multiple versions of Java 
                // installed) and get the most recent (last one)
                string[] subKeyNames = subKey.GetSubKeyNames();
                subKey = regKey.OpenSubKey(javaRegistryLocation + subKeyNames[subKeyNames.Length - 1]);

                // Specify the java executable location
                javaFileLocation = subKey.GetValue("JavaHome").ToString() + @"\bin\java.exe";
            }
            catch (SecurityException e)
            {
                // Attempt to find the java executable at the default location.
                javaFileLocation = @"C:\Program Files\Java\jre6\bin\java.exe";
                if (!File.Exists(javaFileLocation))
                {
                    MessageBox.Show(
                        "The program did not have permission to access the registry to obtain the installation folder of Java.\n\nThe default location (" + javaFileLocation + ") of Java was used and the Java executable was not found.\n\nPlease install Java in this folder or see the help under the RegistryKey.OpenSubKey method on MSDN.",
                        "Java Executable Not Found",
                        MessageBoxButtons.OK,
                        MessageBoxIcon.Error);

                    throw new Exception("The program did not have permission to access the registry to obtain the installation folder of Java.", e);
                }
            }
            catch (UnauthorizedAccessException e)
            {
                // Attempt to find the java executable at the default location.
                javaFileLocation = @"C:\Program Files\Java\jre6\bin\java.exe";
                if (!File.Exists(javaFileLocation))
                {
                    MessageBox.Show(
                        "The user does not have the necessary registry rights to obtain the installation folder of Java.\n\nThe default location (" + javaFileLocation + ") of Java was used and the Java executable was not found.\n\nPlease install Java in this folder or see the help under the RegistryKey.OpenSubKey method on MSDN.",
                        "Java Executable Not Found",
                        MessageBoxButtons.OK,
                        MessageBoxIcon.Error);

                    throw new Exception("The user does not have the necessary registry rights to obtain the installation folder of Java.", e);
                }
            }
            catch (ObjectDisposedException e)
            {
                // This hopefully shouldn't happen so ask the user to report it.
                MessageBox.Show(
                    "The Java registry object was closed, resulting in the Java server not being started.  Please report this error.",
                    "Error",
                    MessageBoxButtons.OK,
                    MessageBoxIcon.Error);
                throw new ObjectDisposedException("The Java registry object was closed.  Please report this error.", e);
            }
            catch (IOException e)
            {
                // This hopefully shouldn't happen so ask the user to report it.
                MessageBox.Show(
                    "The Java registry object was marked for deletion, resulting in the Java server not being started.  Please report this error.",
                    "Error",
                    MessageBoxButtons.OK,
                    MessageBoxIcon.Error);
                throw new ObjectDisposedException("The Java registry object was marked for deletion.  Please report this error.", e);
            }

            return javaFileLocation;
        }
        #endregion
    }
}

私の質問は次のとおりです。

  1. これは、DLL の存続期間中プロセスをホストする賢明な方法ですか?
  2. コードからこのクラスを設定するにはどうすればよいですか?静的/グローバルにする必要がありますか?シングルトンを使用する良い例を知っていますか?
  3. DLL のアンロード時にガベージ コレクションによってこのシングルトンが破棄されますか?
  4. NUnit は離散的なタイムポイントでのみ DLL 内のテストを実行するため、DLL が継続的にアクティブではない場合でも、プロセスを DLL の子プロセスとしてホストできますか?
役に立ちましたか?

解決

それをマネージドます:

// <copyright file="SeleniumServer.cs" company="Your Company">
// Copyright (c) 2010 All Right Reserved
// </copyright>
// <summary>
// Provides a singleton class for hosting and running the selenium server.
// </summary>

namespace YourCompany.Tests.Server
{
    using System;
    using System.Diagnostics;
    using System.IO;
    using System.Security;
    using System.Windows.Forms;
    using Microsoft.Win32;

    /// <summary>
    /// A singleton class to host and control the selenium server.
    /// </summary>
    public sealed class SeleniumServer : IDisposable
    {
        #region Fields
        /// <summary>
        /// The singleton instance
        /// </summary>
        private static volatile SeleniumServer instance;

        /// <summary>
        /// An object to perform double-check locking upon instance creation to 
        /// avoid dead-locks. 
        /// See <see href="SeleniumServer.Instance"/> for more information.
        /// </summary>
        private static object syncRoot = new object();

        /// <summary>
        /// The current selenium server.
        /// </summary>
        private Process seleniumServer = null;

        /// <summary>
        /// A flag for the disposal of the class.
        /// </summary>
        private bool isDisposed = false;
        #endregion

        #region Constructor
        /// <summary>
        /// Prevents a default instance of the SeleniumServer class from being created.  Starts the Selenium Java server in a background hidden thread.
        /// </summary>
        private SeleniumServer()
        {
            // Get the java install folder.
            string javaFileLocation = this.GetJavaFileLocation();

            // Get the selenium server java executable
            string jarFileLocation = '"' + Directory.GetCurrentDirectory() + @"\SeleniumServer\selenium-server.jar""";

            // Start the selenium server
            this.seleniumServer = new Process();
            this.seleniumServer.StartInfo.FileName = javaFileLocation;
            this.seleniumServer.StartInfo.Arguments = " -jar " + jarFileLocation + " -browserSessionReuse -trustAllSSLCertificates";
            this.seleniumServer.StartInfo.WorkingDirectory = jarFileLocation.Substring(0, jarFileLocation.LastIndexOf("\\"));
            this.seleniumServer.StartInfo.UseShellExecute = true;
            this.seleniumServer.StartInfo.WindowStyle = ProcessWindowStyle.Hidden;
            this.seleniumServer.Start();

            // The class is no long disposed
            this.isDisposed = false;
        }
        #endregion

        #region Deconstructor
        /// <summary>
        /// Finalizes an instance of the SeleniumServer class.
        /// </summary>
        ~SeleniumServer()
        {
            this.Dispose(false);
        }
        #endregion

        #region Properties
        /// <summary>
        /// Gets a thread safe instance of the Selenium Server class.
        /// </summary>
        public static SeleniumServer Instance
        {
            get
            {
                // This approach ensures that only one instance is created and 
                // only when the instance is needed. Also, the variable is 
                // declared to be volatile to ensure that assignment to the 
                // instance variable completes before the instance variable can 
                // be accessed. Lastly, this approach uses a syncRoot instance 
                // to lock on, rather than locking on the type itself, to avoid 
                // deadlocks.
                // This double-check locking approach solves the thread 
                // concurrency problems while avoiding an exclusive lock in 
                // every call to the Instance property method. It also allows 
                // you to delay instantiation until the object is first 
                // accessed. In practice, an application rarely requires this 
                // type of implementation. In most cases, the static 
                // initialization approach is sufficient.
                if (instance == null)
                {
                    lock (syncRoot)
                    {
                        if (instance == null)
                        {
                            instance = new SeleniumServer();
                        }
                    }
                }

                return instance;
            }
        }
        #endregion

        #region Methods
        /// <summary>
        /// Dispose of the class and stop the Selenium server process.
        /// </summary>
        public void Dispose()
        {
            this.Dispose(true);
            GC.SuppressFinalize(this);
        }

        /// <summary>
        /// Stops the process.
        /// </summary>
        /// <param name="disposing">
        /// True if managed resources need to be disposed
        /// </param>
        private void Dispose(bool disposing)
        {
            if (!this.isDisposed)
            {
                if (disposing)
                {         
                    // If this class is expanded:
                    // Code to dispose the managed resources of the class
                }

                // Kill the server
                if (this.seleniumServer != null)
                {
                    try
                    {
                        this.seleniumServer.Kill();
                        this.seleniumServer = null;
                    }
                    catch (Exception)
                    {
                        MessageBox.Show(
                            "The Selenium Java Server could not be stopped, please start Task Manager and killed \"java.exe\"",
                            "Failed to Stop Jave Server",
                            MessageBoxButtons.OK,
                            MessageBoxIcon.Error);
                    }
                }
            }

            // All done!
            this.isDisposed = true;
        }

        /// <summary>
        /// Attempts to get the Java installation folder from the registry.  If 
        /// it cannot be found the default installation folder is checked before 
        /// failing.
        /// </summary>
        /// <returns>The Java executable file path.</returns>
        /// <exception cref="System.Exception">
        /// Thrown when the user does not have permission to access the 
        /// registry.
        /// </exception>
        /// <exception cref="System.ObjectDisposedException">
        /// Thrown if the registry key object is disposed of.
        /// </exception>
        /// <exception cref="System.IOException">
        /// Thrown if the registry key object is marked for deletion.
        /// </exception>
        private string GetJavaFileLocation()
        {
            string javaFileLocation = string.Empty;
            RegistryKey regKey = Registry.LocalMachine;
            RegistryKey subKey = null;
            try
            {
                // Check for Java in the native bitness
                string javaRegistryLocation = @"SOFTWARE\JavaSoft\Java Runtime Environment\";
                subKey = regKey.OpenSubKey(javaRegistryLocation);

                // Check if we are running in WOW64 and only 32 bit Java is installed.
                if (subKey == null)
                {
                    javaRegistryLocation = @"SOFTWARE\Wow6432Node\JavaSoft\Java Runtime Environment\";
                    subKey = regKey.OpenSubKey(javaRegistryLocation);
                }

                // If Java was not found in either of these location the user 
                // needs to install it.  Note that Java 32 bit is a prerequisite 
                // for the installer so should always be installed.
                if (subKey == null)
                {
                    MessageBox.Show(
                        "You must have Java installed to run the commands server. This allows browser commands to be routed to the browser window.\n\nPlease visit: http://www.java.com/ to download.",
                        "Please Install Java",
                        MessageBoxButtons.OK,
                        MessageBoxIcon.Information);

                    throw new Exception("No installation of Java was detected to run the selenium server.");
                }

                // Get all the sub keys (could be multiple versions of Java 
                // installed) and get the most recent (last one)
                string[] subKeyNames = subKey.GetSubKeyNames();
                subKey = regKey.OpenSubKey(javaRegistryLocation + subKeyNames[subKeyNames.Length - 1]);

                // Specify the java executable location
                javaFileLocation = subKey.GetValue("JavaHome").ToString() + @"\bin\java.exe";
            }
            catch (SecurityException e)
            {
                // Attempt to find the java executable at the default location.
                javaFileLocation = @"C:\Program Files\Java\jre6\bin\java.exe";
                if (!File.Exists(javaFileLocation))
                {
                    MessageBox.Show(
                        "The program did not have permission to access the registry to obtain the installation folder of Java.\n\nThe default location (" + javaFileLocation + ") of Java was used and the Java executable was not found.\n\nPlease install Java in this folder or see the help under the RegistryKey.OpenSubKey method on MSDN.",
                        "Java Executable Not Found",
                        MessageBoxButtons.OK,
                        MessageBoxIcon.Error);

                    throw new Exception("The program did not have permission to access the registry to obtain the installation folder of Java.", e);
                }
            }
            catch (UnauthorizedAccessException e)
            {
                // Attempt to find the java executable at the default location.
                javaFileLocation = @"C:\Program Files\Java\jre6\bin\java.exe";
                if (!File.Exists(javaFileLocation))
                {
                    MessageBox.Show(
                        "The user does not have the necessary registry rights to obtain the installation folder of Java.\n\nThe default location (" + javaFileLocation + ") of Java was used and the Java executable was not found.\n\nPlease install Java in this folder or see the help under the RegistryKey.OpenSubKey method on MSDN.",
                        "Java Executable Not Found",
                        MessageBoxButtons.OK,
                        MessageBoxIcon.Error);

                    throw new Exception("The user does not have the necessary registry rights to obtain the installation folder of Java.", e);
                }
            }
            catch (ObjectDisposedException e)
            {
                // This hopefully shouldn't happen so ask the user to report it.
                MessageBox.Show(
                    "The Java registry object was closed, resulting in the Java server not being started.  Please report this error.",
                    "Error",
                    MessageBoxButtons.OK,
                    MessageBoxIcon.Error);
                throw new ObjectDisposedException("The Java registry object was closed.  Please report this error.", e);
            }
            catch (IOException e)
            {
                // This hopefully shouldn't happen so ask the user to report it.
                MessageBox.Show(
                    "The Java registry object was marked for deletion, resulting in the Java server not being started.  Please report this error.",
                    "Error",
                    MessageBoxButtons.OK,
                    MessageBoxIcon.Error);
                throw new ObjectDisposedException("The Java registry object was marked for deletion.  Please report this error.", e);
            }

            return javaFileLocation;
        }
        #endregion
    }
}

ちょうど行います:

SeleniumServer seleniumServer = SeleniumServer.Instance;

セットアップの開始時にサーバを起動します。

私は誰もがこの問題を検索した場合に投稿しようと思いました。

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