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SSH Client

Run commands on the server and transfer files.

Introduction​

Netuno has an SSH client integrated into its low-code framework, which allows you to connect to servers, execute commands, send and receive files, modify folders, and perform other remote operations.

It supports multiple simultaneous connections, as well as SCP and SFTP.

This, thanks to the Java and open-source implementation SSHJ, is what allows Netuno to provide these features to all scripting languages through the _ssh feature.

More about Netuno's SSH feature.

Configuration​

The first step will be to configure the SSH access data that Netuno will use to connect.

Navigate within the application you are developing to the environment configuration file. In this example, we will use the development file, located at:

  • config/_development.json

Check for SSH configuration settings. If not, add the SSH configuration parameters at the end of the configuration file (in JSON format), for example:

{
  ...
  "ssh": {
    "default": {
      "enabled": true,
      "host": "my.server.net",
      "port": 22,
      "username": "root",
      "password": "$eCr37"
    }
  },
  ...
}

After saving your changes, simply restart Netuno to apply the configuration changes. These are the default settings for the connection, as the default key name indicates.

You can add additional SSH connection configurations using other keys in the JSON.

To add additional SSH connection configurations, simply repeat the default configuration block and replace the default key with one of your choice, for example:

{
  ...
  "ssh": {
    "default": {
      "enabled": true,
      "host": "my.server.net",
      "port": 22,
      "username": "root",
      "password": "$eCr37"
    },
    "other": {
      "enabled": true,
      "host": "other.server.net",
      "port": 22,
      "username": "root",
      "password": "$eCr37"
    }
  },
  ...
}

The above configuration allows you to use the default account when coded as follows:

const ssh = _ssh.init()

To use the other configuration, simply add the configuration key as a parameter to the _ssh.init() function, as follows:

const sshOther = _ssh.init("other")

If you do not add a configuration name as a parameter, the default account configuration will be used.

Connection​

Before doing anything, you need to start the SSH connection:

ssh.connect()

Commands​

To run commands, you need to start a command session:

const sshSession = ssh.initSession()

When executing a command, an object is provided that contains the execution status and the respective output, for example:

const sshCommandResult = sshSession.exec("ls -rato")
if (sshCommandResult.ok) {
    _out.println("Successfully executed:")
    _out.println(sshCommandResult.output)
} else {
    _out.println("The command failed:")
    _out.println(sshCommandResult.error)
}

The object returned by the command is SSHExecResult.

Remember to always close the session:

sshSession.close()

SCP​

Using SCP, we can send and receive files.

To create a text file from a string and download the contents of the created file, see the example:

const sshSCP = ssh.initSCP()
// Create the text file.
sshSCP.uploadText("hello.txt", "Hello! My content here...")
// Download and print the contents of the file.
_out.println(sshSCP.downloadText("hello.txt"))
sshSCP.close()

To upload existing files in the application:

const sshSCP = ssh.initSCP()
// Sends a file that is in storage/filesystem.
sshSCP.upload("spreadsheet.xlsx", _storage.filesystem("server", "spreadsheet.xlsx").file())
// Upload a file that is in the application root.
sshSCP.upload("document.pdf", _app.file("document.pdf"))
sshSCP.close()

Para baixar (download) arquivos do servidor para a aplicação:

const sshSCP = ssh.initSCP()
// Downloads the file to storage/filesystem.
sshSCP.download("spreadsheet.xlsx", _storage.filesystem("server", "spreadsheet.xlsx").file())
// Download the file to the application root.
sshSCP.download("document.pdf", _app.file("document.pdf"))
sshSCP.close()

SFTP​

SFTP is a way to transfer and manipulate files and folders that supports the same functionality as FTP, but using SSH.

To start a new SFTP session:

const sftp = ssh.initSFTP()

Starts the [SSH SFTP](/docs/library/objects/SSH SFTP) object, which is the session client.

Create a new folder remotely:

sftp.createDirectory("path/new-folder")

Creates or replaces the remote file with the passed text content:

sftp.uploadText("path/file.txt", "My content!")

Gets the text contents of a remote file:

const contentRemoteFile = sftp.downloadText("path/file.txt"))
_out.println(contentRemoteFile)

Permanently delete a remote file:

sftp.deleteFile("path/file.txt")

Permanently delete the remote folder:

sftp.deleteDirectory("folder")

List all the contents of a folder:

for (const i of sftp.list("path/folder")) {
    if (i.directory) {
        _out.print("Directory: ")
    } else if (i.regularFile) {
        _out.print("File: ")
    } else {
        _out.print("Other: ")
    }
    _out.println(i.name)
    _out.println("<br/>")
}

Returns a list of objects of type SSHFile.

To upload existing files in the application:

// Sends a file that is in storage/filesystem.
sftp.upload("spreadsheet.xlsx", _storage.filesystem("server", "spreadsheet.xlsx").file())
// Upload a file that is in the application root.
sftp.upload("document.pdf", _app.file("document.pdf"))

To download files from the server to the application:

// Downloads the file to storage/filesystem.
sftp.download("spreadsheet.xlsx", _storage.filesystem("server", "spreadsheet.xlsx").file())
// Download the file to the application root.
sftp.download("document.pdf", _app.file("document.pdf"))

Remember to always close the SFTP session:

sftp.close()