Add download files functionality

DownloadFiles.java

@@ -0,0 +1,125 @@
+package handleSsh;
+
+import com.jcraft.jsch.*;
+import java.util.ArrayList;
+import java.io.File;
+
+
+public class DownloadFiles {
+
+    private static final String LOCAL_BASIC_PATH = "/home/rasta5man/dev/oms/downloads/";
+
+    //ADD FILES TO DOWNLOAD IN MAIN METHOD
+    private static ArrayList<String> filesToDownload = new ArrayList<>();
+
+
+
+    public static void main(String[] args) throws JSchException {
+
+        ArrayList<Server> allServers = new BuildServerArray().getAllServers();
+
+        for (Server server : allServers) {
+
+            String remoteBasicPath = "";
+            if(server.getUsername().equals("root")) { // je to LM
+                remoteBasicPath = "/root/flowserver/";
+            }
+            else {
+                remoteBasicPath = "/home/unipi/flowserver/";
+            }
+
+
+            filesToDownload.clear();
+            filesToDownload.add(remoteBasicPath + "databases/nodes.table");
+//            filesToDownload.add(remoteBasicPath + "databases/settings.table");
+
+
+            System.out.println("Connecting to server: " + server);
+            downloadFiles(server);
+        }
+    }
+
+
+    /**
+     * Establishes SFTP connection and downloads files.
+     */
+    public static void downloadFiles(Server server) throws JSchException {
+
+        JSch jsch = new JSch();
+        jsch.setKnownHosts("/home/rasta5man/.ssh/known_hosts");
+        jsch.addIdentity( "/home/rasta5man/.ssh/oms_key" );
+        Session session = null;
+        ChannelSftp sftpChannel = null;
+
+        try {
+
+            session = jsch.getSession(server.getUsername(), server.getHost(), server.getPort());
+            session.setPassword(server.getPassword());
+            //session.setConfig("StrictHostKeyChecking", "no"); // Avoids checking for new host keys (not recommended for production)
+            session.connect();
+
+            sftpChannel = (ChannelSftp) session.openChannel("sftp");
+            sftpChannel.connect();
+
+            for (String fileToDownload : filesToDownload) {
+                System.out.println("Downloading " + fileToDownload + " to " + server);
+
+                // 3. Perform the file download
+                System.out.println("Attempting to download remote file: " + fileToDownload);
+
+                String localFileName = getFileName(fileToDownload);
+                File localFile = new File(LOCAL_BASIC_PATH + localFileName + server.getHost());
+
+                // JSch's get() method downloads the remote file to the local path
+                sftpChannel.get(fileToDownload, localFile.getAbsolutePath());
+                System.out.println("\n✅ Success! File downloaded to: " + localFile.getAbsolutePath());
+            }
+
+        } catch (JSchException e) {
+            // Handle connection, authentication, or channel opening errors
+            System.err.println("\n❌ SFTP Connection Error: " + e.getMessage());
+            e.printStackTrace();
+        } catch (SftpException e) {
+            // Handle file-specific errors (e.g., file not found, permission denied)
+            System.err.println("\n❌ SFTP File Transfer Error: " + e.getMessage() + " (Error code: " + e.id + ")");
+            System.err.println("Please check if the remote file path exists and permissions are correct.");
+            e.printStackTrace();
+        } finally {
+            // 4. Clean up resources
+            if (sftpChannel != null && sftpChannel.isConnected()) {
+                sftpChannel.disconnect();
+                System.out.println("SFTP Channel disconnected.");
+            }
+            if (session != null && session.isConnected()) {
+                session.disconnect();
+                System.out.println("Session disconnected.");
+            }
+        }
+    }
+
+    /**
+     * Extracts the filename from a given file path string.
+     * It assumes a Unix-style path separator ('/'), which is standard for SFTP.
+     *
+     * @param path The full file path (e.g., "/home/george/pictures/downtown.jpg").
+     * @return The filename (e.g., "downtown.jpg"). Returns an empty string if the input is null or empty.
+     */
+    public static String getFileName(String path) {
+        if (path == null || path.isEmpty()) {
+            return "";
+        }
+        int lastSeparatorIndex = path.lastIndexOf('/');
+
+        // If the path contains a separator, return the substring after it.
+        // Otherwise, the entire path is considered the filename.
+        return (lastSeparatorIndex == -1)
+                ? path
+                : path.substring(lastSeparatorIndex + 1);
+    }
+
+}
+
+
+
+
+

README

@@ -1,6 +1,7 @@
 POUZITIE:
 
 Pocitame iba s dvomi pripadmi: bud je zariadenie LM alebo unipi, to znamena, bud je user "root" alebo "unipi".
+Dalsi predpoklad spravneho fungovania je, ze uzivatel, ktory sa pripaja na unipi zariadenie tam ma svoj ssh kluc uz nahraty.
 
 1. v "buildServerArray.java" si doplnte zariadenia, na ktore sa chcete cez ssh prihlasit: "server.put(ip, username)"
 dole v subore takisto doplnte prihlasovacie hesla pre jednotlive zariadenia: "rvoPassword.put(ip, heslo)"
@@ -9,6 +10,8 @@ tak isto nezabudnite nastavit cas medzi jednotlivymi pripajaniami na zariadenia
 3. ked chcete hromadny upload suborov, pouzite subor "UploadFiles.java". V prvom rade nastavte "BASIC_PATH" - adresar v ktorom su subory na upload.
 DOLEZITE: adresar v ktorom su subory sa musi volat na konci "flowserver" a koncit lomitkom. (moze mat predtym text, ale koniec musi byt flowserver - napr "city-flowserver/"
 Ak chcete menit ine subory na unipi alebo lm, ako flowserver, musite nastavit "directoryToUpload"
+4. ked chcete hromadny download suborov, pouzite subor "DownloadFiles.java". Nastavte "LOCAL_BASIC_PATH" - adresar, kde sa subory stiahnu.
+Dalej v metode "main" pridajte subory, ktore chcete stiahnut. Treba zadat cestu k suboru v "FLOWSERVER" adresari. 
 
 
 5.5.2025 ->