#24 Support for Linux based OS

readme.md

@@ -10,6 +10,7 @@ API to easily execute PowerShell commands and scripts from Java.
 
 ## Supported platforms
 * Windows
+* Linux (with installed PowerShell)
 
 ## Example
 Call PowerShell commands or scripts like this:

src/main/java/com/github/frimtec/libraries/jpse/AbstractPowerShellExecutor.java

@@ -0,0 +1,124 @@
+package com.github.frimtec.libraries.jpse;
+
+import java.io.*;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.*;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+import static java.nio.charset.StandardCharsets.UTF_16LE;
+import static java.nio.charset.StandardCharsets.UTF_8;
+import static java.nio.file.StandardOpenOption.TRUNCATE_EXISTING;
+
+abstract class AbstractPowerShellExecutor implements PowerShellExecutor {
+
+    private static final Base64.Encoder BASE64_ENCODER = Base64.getEncoder();
+
+    private static final int INITIAL_STREAM_BUFFER_SIZE = 1000;
+    private static final String JPSE_GLOBBER_THREAD_NAME = "JPSE-Gobbler";
+
+    private final String executionCommand;
+    private final Path tempPath;
+
+    AbstractPowerShellExecutor(Path tempPath, String executionCommand) {
+        this.tempPath = tempPath;
+        this.executionCommand = executionCommand;
+        if (tempPath != null && !Files.exists(tempPath)) {
+            try {
+                Files.createDirectories(tempPath);
+            } catch (IOException e) {
+                throw new UncheckedIOException("Cannot create given temp folder: " + tempPath.toAbsolutePath(), e);
+            }
+        }
+    }
+
+    @Override
+    public ExecutionResult execute(String command) {
+        String encodedCommand = BASE64_ENCODER.encodeToString(command.getBytes(UTF_16LE));
+        return execute(createProcessBuilder(Arrays.asList(this.executionCommand, "-EncodedCommand", encodedCommand)));
+    }
+
+    @Override
+    public ExecutionResult execute(Path script, Map<String, String> arguments) {
+        List<String> commandLine = new ArrayList<>(Arrays.asList(this.executionCommand, "-File", script.toString()));
+        commandLine.addAll(arguments.entrySet()
+                .stream()
+                .flatMap(entry -> Stream.of("-" + entry.getKey(), "\"" + entry.getValue() + "\""))
+                .collect(Collectors.toList()));
+        return execute(createProcessBuilder(commandLine));
+    }
+
+    @Override
+    public ExecutionResult execute(InputStream script, Map<String, String> arguments) {
+        try {
+            String prefix = "java-power-shell-";
+            String suffix = ".ps1";
+            Path tempFile = this.tempPath != null ? Files.createTempFile(this.tempPath, prefix, suffix) : Files.createTempFile(prefix, suffix);
+            try {
+                Files.write(tempFile, readStream(script).getBytes(UTF_8), TRUNCATE_EXISTING);
+                return execute(tempFile, arguments);
+            } finally {
+                Files.deleteIfExists(tempFile);
+            }
+        } catch (IOException e) {
+            throw new UncheckedIOException("Cannot handle script", e);
+        }
+    }
+
+    @Override
+    public Optional<Version> version() {
+        try {
+            String[] versionParts = execute("'' + $PSVersionTable.PSVersion.Major + '.' +  $PSVersionTable.PSVersion.Minor").getStandardOutput().split("\\.");
+            return Optional.of(new Version(
+                    Integer.parseInt(versionParts[0]),
+                    Integer.parseInt(versionParts[1])
+            ));
+        } catch (Exception e) {
+            return Optional.empty();
+        }
+    }
+
+    protected ProcessBuilder createProcessBuilder(List<String> commandLine) {
+        return new ProcessBuilder(commandLine);
+    }
+
+    private ExecutionResult execute(ProcessBuilder processBuilder) {
+        StringWriter outputStringWriter = new StringWriter(INITIAL_STREAM_BUFFER_SIZE);
+        StringWriter errorStringWriter = new StringWriter(INITIAL_STREAM_BUFFER_SIZE);
+        PrintWriter outputBuffer = new PrintWriter(outputStringWriter);
+        PrintWriter errorBuffer = new PrintWriter(errorStringWriter);
+        try {
+            Process process = processBuilder.start();
+            StreamGobbler outputGobbler = new StreamGobbler(process.getInputStream(), outputBuffer::println);
+            StreamGobbler errorGobbler = new StreamGobbler(process.getErrorStream(), errorBuffer::println);
+            List<Thread> threads = Arrays.asList(
+                    new Thread(outputGobbler, JPSE_GLOBBER_THREAD_NAME),
+                    new Thread(errorGobbler, JPSE_GLOBBER_THREAD_NAME)
+            );
+            threads.forEach(thread -> {
+                thread.setDaemon(true);
+                thread.start();
+            });
+            for (StreamGobbler gobbler : Arrays.asList(outputGobbler, errorGobbler)) {
+                gobbler.waitTillFinished();
+            }
+            return new ExecutionResultImpl(process.waitFor(), getOutputFromWriter(outputStringWriter), getOutputFromWriter(errorStringWriter));
+        } catch (InterruptedException e) {
+            Thread.currentThread().interrupt();
+            throw new RuntimeException("Wait for process termination interrupted", e);
+        } catch (IOException e) {
+            throw new UncheckedIOException("Powershell cannot be executed", e);
+        }
+    }
+
+    private String getOutputFromWriter(StringWriter outputStringWriter) {
+        return outputStringWriter.getBuffer().toString().trim();
+    }
+
+    private String readStream(InputStream inputStream) {
+        return new BufferedReader(new InputStreamReader(inputStream, UTF_8))
+                .lines()
+                .collect(Collectors.joining("\n"));
+    }
+}

src/main/java/com/github/frimtec/libraries/jpse/LinuxPowerShellExecutor.java

@@ -0,0 +1,12 @@
+package com.github.frimtec.libraries.jpse;
+
+import java.nio.file.Path;
+
+class LinuxPowerShellExecutor extends AbstractPowerShellExecutor {
+
+    private static final String POWER_SHELL_CMD = "pwsh";
+
+    LinuxPowerShellExecutor(Path tempPath) {
+        super(tempPath, POWER_SHELL_CMD);
+    }
+}

src/main/java/com/github/frimtec/libraries/jpse/PowerShellExecutor.java

@@ -3,6 +3,7 @@
 import java.io.InputStream;
 import java.nio.file.Path;
 import java.util.Map;
+import java.util.Optional;
 
 /**
  * Executor for PowerShell commands and scripts.
@@ -37,8 +38,17 @@ public interface PowerShellExecutor {
      */
     ExecutionResult execute(InputStream script, Map<String, String> arguments);
 
+    /**
+     * Returns the version of the available power shell environment.
+     *
+     * @return version of the available power shell environment or empty if powershell is not available
+     * @since 1.3.0
+     */
+    Optional<Version> version();
+
     /**
      * Creates a power shell executor using the default temp path to create and execute temporary scripts.
+     *
      * @return power shell executor
      */
     static PowerShellExecutor instance() {
@@ -52,7 +62,13 @@ static PowerShellExecutor instance() {
      * @return power shell executor
      */
     static PowerShellExecutor instance(Path tempPath) {
-        String osName = System.getProperty("os.name");
-        return osName.toLowerCase().startsWith("windows") ? new WindowsPowerShellExecutor(tempPath) : new UnsupportedOsPowerShellExecutor(osName);
+        String osName = System.getProperty("os.name").toLowerCase();
+        if (osName.startsWith("win")) {
+            return new WindowsPowerShellExecutor(tempPath);
+        } else if (osName.contains("nix") || osName.contains("nux")) {
+            return new LinuxPowerShellExecutor(tempPath);
+        } else {
+            return new UnsupportedOsPowerShellExecutor(osName);
+        }
     }
 }

src/main/java/com/github/frimtec/libraries/jpse/UnsupportedOsPowerShellExecutor.java

@@ -1,28 +1,34 @@
-package com.github.frimtec.libraries.jpse;
-
-import java.io.InputStream;
-import java.nio.file.Path;
-import java.util.Map;
-
-final class UnsupportedOsPowerShellExecutor implements PowerShellExecutor {
-    private final String osName;
-
-    UnsupportedOsPowerShellExecutor(String osName) {
-        this.osName = osName;
-    }
-
-    @Override
-    public ExecutionResult execute(String command) {
-        throw new UnsupportedOperationException("Not supported on OS " + this.osName);
-    }
-
-    @Override
-    public ExecutionResult execute(Path script, Map<String, String> arguments) {
-        throw new UnsupportedOperationException("Not supported on OS " + this.osName);
-    }
-
-    @Override
-    public ExecutionResult execute(InputStream script, Map<String, String> arguments) {
-        throw new UnsupportedOperationException("Not supported on OS " + this.osName);
-    }
-}
+package com.github.frimtec.libraries.jpse;
+
+import java.io.InputStream;
+import java.nio.file.Path;
+import java.util.Map;
+import java.util.Optional;
+
+final class UnsupportedOsPowerShellExecutor implements PowerShellExecutor {
+    private final String osName;
+
+    UnsupportedOsPowerShellExecutor(String osName) {
+        this.osName = osName;
+    }
+
+    @Override
+    public ExecutionResult execute(String command) {
+        throw new UnsupportedOperationException("Not supported on OS " + this.osName);
+    }
+
+    @Override
+    public ExecutionResult execute(Path script, Map<String, String> arguments) {
+        throw new UnsupportedOperationException("Not supported on OS " + this.osName);
+    }
+
+    @Override
+    public ExecutionResult execute(InputStream script, Map<String, String> arguments) {
+        throw new UnsupportedOperationException("Not supported on OS " + this.osName);
+    }
+
+    @Override
+    public Optional<Version> version() {
+        return Optional.empty();
+    }
+}

src/main/java/com/github/frimtec/libraries/jpse/Version.java

@@ -0,0 +1,45 @@
+package com.github.frimtec.libraries.jpse;
+
+/**
+ * Power shell version.
+ *
+ * @see PowerShellExecutor#version()
+ * @since 1.3.0
+ */
+public final class Version {
+    private final int major;
+    private final int minor;
+
+    Version(int major, int minor) {
+        this.major = major;
+        this.minor = minor;
+    }
+
+    /**
+     * Major version.
+     *
+     * @return major
+     */
+    public int getMajor() {
+        return this.major;
+    }
+
+    /**
+     * Minor version.
+     *
+     * @return major
+     */
+    public int getMinor() {
+        return this.minor;
+    }
+
+    /**
+     * Version string in the format "{@code <major>.<minor>}".
+     *
+     * @return version string
+     */
+    @Override
+    public String toString() {
+        return String.format("%d.%d", this.major, this.minor);
+    }
+}