server

Documentation

Overview

Package server provides all the tools to build your own FTP server: The core library and the driver.

Index

• Constants
• type ClientContext
• type ClientHandlingDriver
• type CommandDescription
• type FileStream
• type FtpServer
  • func NewFtpServer(driver MainDriver) *FtpServer
  • func (server *FtpServer) Addr() string
  • func (server *FtpServer) Listen() error
  • func (server *FtpServer) ListenAndServe() error
  • func (server *FtpServer) Serve()
  • func (server *FtpServer) Stop()
  • func (server *FtpServer) Stopped() bool
• type MainDriver
• type PortRange
• type PublicIPResolver
• type Settings

Constants

const (
	// 100 Series - The requested action is being initiated, expect another reply before
	// proceeding with a new command.
	StatusFileStatusOK = 150 // RFC 959, 4.2.1

	// 200 Series - The requested action has been successfully completed.
	StatusOK                 = 200 // RFC 959, 4.2.1
	StatusNotImplemented     = 202 // RFC 959, 4.2.1
	StatusSystemStatus       = 211 // RFC 959, 4.2.1
	StatusDirectoryStatus    = 212 // RFC 959, 4.2.1
	StatusFileStatus         = 213 // RFC 959, 4.2.1
	StatusHelpMessage        = 214 // RFC 959, 4.2.1
	StatusSystemType         = 215 // RFC 959, 4.2.1
	StatusServiceReady       = 220 // RFC 959, 4.2.1
	StatusClosingControlConn = 221 // RFC 959, 4.2.1
	StatusClosingDataConn    = 226 // RFC 959, 4.2.1
	StatusEnteringPASV       = 227 // RFC 959, 4.2.1
	StatusEnteringEPSV       = 229 // RFC 2428, 3
	StatusUserLoggedIn       = 230 // RFC 959, 4.2.1
	StatusAuthAccepted       = 234 // RFC 2228, 3
	StatusFileOK             = 250 // RFC 959, 4.2.1
	StatusPathCreated        = 257 // RFC 959, 4.2.1

	// 300 Series - The command has been accepted, but the requested action is on hold,
	// pending receipt of further information.
	StatusUserOK            = 331 // RFC 959, 4.2.1
	StatusFileActionPending = 350 // RFC 959, 4.2.1

	// 400 Series - The command was not accepted and the requested action did not take place,
	// but the error condition is temporary and the action may be requested again.
	StatusServiceNotAvailable = 421 // RFC 959, 4.2.1
	StatusFileActionNotTaken  = 450 // RFC 959, 4.2.1

	// 500 Series - Syntax error, command unrecognized and the requested action did not take
	// place. This may include errors such as command line too long.
	StatusSyntaxErrorNotRecognised = 500 // RFC 959, 4.2.1
	StatusSyntaxErrorParameters    = 501 // RFC 959, 4.2.1
	StatusCommandNotImplemented    = 502 // RFC 959, 4.2.1
	StatusNotLoggedIn              = 530 // RFC 959, 4.2.1
	StatusActionNotTaken           = 550 // RFC 959, 4.2.1
)

Status codes as documented by: https://tools.ietf.org/html/rfc959 https://tools.ietf.org/html/rfc2428 https://tools.ietf.org/html/rfc2228

Types

type ClientContext

type ClientContext interface {
	// Path provides the path of the current connection
	Path() string

	// SetDebug activates the debugging of this connection commands
	SetDebug(debug bool)

	// Debug returns the current debugging status of this connection commands
	Debug() bool

	// Client's ID on the server
	ID() uint32

	// Client's address
	RemoteAddr() net.Addr

	// Servers's address
	LocalAddr() net.Addr
}

ClientContext is implemented on the server side to provide some access to few data around the client

type ClientHandlingDriver

type ClientHandlingDriver interface {
	// ChangeDirectory changes the current working directory
	ChangeDirectory(cc ClientContext, directory string) error

	// MakeDirectory creates a directory
	MakeDirectory(cc ClientContext, directory string) error

	// ListFiles lists the files of a directory
	ListFiles(cc ClientContext) ([]os.FileInfo, error)

	// OpenFile opens a file in 3 possible modes: read, write, appending write (use appropriate flags)
	OpenFile(cc ClientContext, path string, flag int) (FileStream, error)

	// DeleteFile deletes a file or a directory
	DeleteFile(cc ClientContext, path string) error

	// GetFileInfo gets some info around a file or a directory
	GetFileInfo(cc ClientContext, path string) (os.FileInfo, error)

	// RenameFile renames a file or a directory
	RenameFile(cc ClientContext, from, to string) error

	// CanAllocate gives the approval to allocate some data
	CanAllocate(cc ClientContext, size int) (bool, error)

	// ChmodFile changes the attributes of the file
	ChmodFile(cc ClientContext, path string, mode os.FileMode) error
}

ClientHandlingDriver handles the file system access logic

type CommandDescription

type CommandDescription struct {
	Open bool                       // Open to clients without auth
	Fn   func(*clientHandler) error // Function to handle it
}

CommandDescription defines which function should be used and if it should be open to anyone or only logged in users

type FileStream

type FileStream interface {
	io.Writer
	io.Reader
	io.Closer
	io.Seeker
}

FileStream is a read or write closeable stream

type FtpServer

type FtpServer struct {
	*logrus.Entry // Logrus Logger
	// contains filtered or unexported fields
}

FtpServer is where everything is stored We want to keep it as simple as possible

func NewFtpServer

func NewFtpServer(driver MainDriver) *FtpServer

NewFtpServer creates a new FtpServer instance

func (*FtpServer) Addr

func (server *FtpServer) Addr() string

Addr shows the listening address

func (*FtpServer) Listen

func (server *FtpServer) Listen() error

Listen starts the listening It's not a blocking call

func (*FtpServer) ListenAndServe

func (server *FtpServer) ListenAndServe() error

ListenAndServe simply chains the Listen and Serve method calls

func (*FtpServer) Serve

func (server *FtpServer) Serve()

Serve accepts and process any new client coming

func (*FtpServer) Stop

func (server *FtpServer) Stop()

Stop closes the listener

func (*FtpServer) Stopped

func (server *FtpServer) Stopped() bool

Stopped returns true of the server has been stopped

type MainDriver

type MainDriver interface {
	// GetSettings returns some general settings around the server setup
	GetSettings() (*Settings, error)

	// WelcomeUser is called to send the very first welcome message
	WelcomeUser(cc ClientContext) (string, error)

	// UserLeft is called when the user disconnects, even if he never authenticated
	UserLeft(cc ClientContext)

	// AuthUser authenticates the user and selects an handling driver
	AuthUser(cc ClientContext, user, pass string) (ClientHandlingDriver, error)

	// GetTLSConfig returns a TLS Certificate to use
	// The certificate could frequently change if we use something like "let's encrypt"
	GetTLSConfig() (*tls.Config, error)
}

MainDriver handles the authentication and ClientHandlingDriver selection

type PortRange

type PortRange struct {
	Start int // Range start
	End   int // Range end
}

PortRange is a range of ports

type PublicIPResolver

type PublicIPResolver func(ClientContext) (string, error)

PublicIPResolver takes a ClientContext for a connection and returns the public IP to use in the response to the PASV command, or an error if a public IP cannot be determined.

type Settings

type Settings struct {
	Listener                  net.Listener     // Allow providing an already initialized listener. Mutually exclusive with ListenAddr
	ListenAddr                string           // Listening address
	PublicHost                string           // Public IP to expose (only an IP address is accepted at this stage)
	PublicIPResolver          PublicIPResolver // Optional function that can perform a public ip lookup for the given CientContext.
	DataPortRange             *PortRange       // Port Range for data connections. Random one will be used if not specified
	DisableMLSD               bool             // Disable MLSD support
	DisableMLST               bool             // Disable MLST support
	NonStandardActiveDataPort bool             // Allow to use a non-standard active data port
	IdleTimeout               int              // Maximum inactivity time before disconnecting (#58)
}

Settings defines all the server settings