Xbase++

Read Text at a String Offset from a Remote SFTP File

Demonstrates the Chilkat SFtp.ReadFileText64s method, which is like ReadFileText64 but takes the byte offset as a decimal string. The arguments are the handle, the offset string, the maximum number of bytes, and the charset.

Background: The string-offset read exists for the same reason as its write counterpart: it lets code in languages without convenient 64-bit integers still address positions in very large files by supplying the offset as text. Functionally it is identical to the int64 version.

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LOCAL nSuccess
LOCAL oSftp
LOCAL nPort
LOCAL cPassword
LOCAL cHandle
LOCAL cOffset
LOCAL nNumBytes
LOCAL cText

nSuccess := 0

//  Demonstrates the SFtp.ReadFileText64s method, which is like ReadFileText64 but takes the byte
//  offset as a decimal string.  The 1st argument is the handle, the 2nd is the offset string, the
//  3rd is the maximum number of bytes, and the 4th is the charset.

oSftp := CreateObject("Chilkat.SFtp")

//  Connect, authenticate, and initialize the SFTP subsystem.
nPort := 22
nSuccess := oSftp:Connect("sftp.example.com", nPort)
IF (nSuccess == 0)
    ? oSftp:LastErrorText
    oSftp:destroy()
    RETURN
ENDIF

//  Normally you would not hard-code the password in source.  You should instead obtain it
//  from an interactive prompt, environment variable, or a secrets vault.
cPassword := "mySshPassword"

nSuccess := oSftp:AuthenticatePw("mySshLogin", cPassword)
IF (nSuccess == 0)
    ? oSftp:LastErrorText
    oSftp:destroy()
    RETURN
ENDIF

nSuccess := oSftp:InitializeSftp()
IF (nSuccess == 0)
    ? oSftp:LastErrorText
    oSftp:destroy()
    RETURN
ENDIF

cHandle := oSftp:OpenFile("subdir/hugefile.dat", "readOnly", "openExisting")
IF (oSftp:LastMethodSuccess == 0)
    ? oSftp:LastErrorText
    oSftp:destroy()
    RETURN
ENDIF

//  Supplying the offset as a string is convenient in languages without a native 64-bit integer.
cOffset := "5000000000"
nNumBytes := 6
cText := oSftp:ReadFileText64s(cHandle, cOffset, nNumBytes, "utf-8")
IF (oSftp:LastMethodSuccess == 0)
    ? oSftp:LastErrorText
    oSftp:destroy()
    RETURN
ENDIF

? cText

nSuccess := oSftp:CloseHandle(cHandle)
IF (nSuccess == 0)
    ? oSftp:LastErrorText
    oSftp:destroy()
    RETURN
ENDIF

oSftp:Disconnect()

oSftp:destroy()