C++

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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C++

#include <CkSFtp.h>
#include <CkStringBuilder.h>

void ChilkatSample(void)
    {
    bool success = false;

    //  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.

    CkSFtp sftp;

    //  Connect, authenticate, and initialize the SFTP subsystem.
    int port = 22;
    success = sftp.Connect("sftp.example.com",port);
    if (success == false) {
        std::cout << sftp.lastErrorText() << "\r\n";
        return;
    }

    //  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.
    const char *password = "mySshPassword";

    success = sftp.AuthenticatePw("mySshLogin",password);
    if (success == false) {
        std::cout << sftp.lastErrorText() << "\r\n";
        return;
    }

    success = sftp.InitializeSftp();
    if (success == false) {
        std::cout << sftp.lastErrorText() << "\r\n";
        return;
    }

    const char *handle = sftp.openFile("subdir/data.txt","readOnly","openExisting");
    if (sftp.get_LastMethodSuccess() == false) {
        std::cout << sftp.lastErrorText() << "\r\n";
        return;
    }

    //  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.
    CkStringBuilder sbContent;
    int chunkSize = 4096;
    bool reading = true;
    while (reading) {
        const char *chunk = sftp.readFileText(handle,chunkSize,"utf-8");
        if (sftp.LastReadFailed(handle)) {
            std::cout << sftp.lastErrorText() << "\r\n";
            return;
        }

        sbContent.Append(chunk);
        reading = !sftp.Eof(handle);
    }

    success = sftp.CloseHandle(handle);
    if (success == false) {
        std::cout << sftp.lastErrorText() << "\r\n";
        return;
    }

    std::cout << sbContent.getAsString() << "\r\n";

    sftp.Disconnect();
    }