Xbase++

Detect End-of-File on a Remote SFTP File

Demonstrates the Chilkat SFtp.Eof method, which returns whether the most recent read for a handle received the SFTP end-of-file status. The only argument is the handle. This example reads until Eof is true.

Background: The timing here is worth understanding: reading exactly through the final byte does not immediately set EOF. The next read succeeds, returns zero bytes, sets the status to SSH_FX_EOF, and only then does Eof report true. That is why the loop tests Eof after each read rather than assuming a short read means the end — a short read can also just be the server returning less than requested.

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LOCAL nSuccess
LOCAL oSftp
LOCAL nPort
LOCAL cPassword
LOCAL cHandle
LOCAL oSbContent
LOCAL nChunkSize
LOCAL nReading
LOCAL cChunk

nSuccess := 0

//  Demonstrates the SFtp.Eof method, which returns whether the most recent read for a handle
//  received the SFTP end-of-file status.  The only argument is the handle.

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/data.txt", "readOnly", "openExisting")
IF (oSftp:LastMethodSuccess == 0)
    ? oSftp:LastErrorText
    oSftp:destroy()
    RETURN
ENDIF

//  Read until Eof reports the end of the file.  Note that reading exactly through the final byte
//  does not set EOF; the next read returns zero bytes and then Eof becomes true.
oSbContent := CreateObject("Chilkat.StringBuilder")
nChunkSize := 4096
nReading := 1
DO WHILE nReading
    cChunk := oSftp:ReadFileText(cHandle, nChunkSize, "utf-8")
    IF (oSftp:LastReadFailed(cHandle))
        ? oSftp:LastErrorText
        oSftp:destroy()
        oSbContent:destroy()
        RETURN
    ENDIF

    oSbContent:Append(cChunk)
    nReading := .NOT. oSftp:Eof(cHandle)
ENDDO

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

? oSbContent:GetAsString()

oSftp:Disconnect()

oSftp:destroy()
oSbContent:destroy()