C

SFTP Upload Large File in Parts

See more SFTP Examples

Demonstrates how to split a large file into N parts and then upload each part separately. This technique can be used to potentially avoid limits a SFTP server might impose on upload file size. C

#include <C_CkSFtp.h>
#include <C_CkFileAccess.h>
#include <C_CkBinData.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkSFtp sftp;
    const char *hostname;
    int port;
    const char *handle;
    const char *localFilePath;
    HCkFileAccess fac;
    int blockSize;
    int numBlocks;
    HCkBinData bd;
    int i;

    success = FALSE;

    // This example assumes the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    sftp = CkSFtp_Create();

    // Set some timeouts, in milliseconds:
    CkSFtp_putConnectTimeoutMs(sftp,5000);
    CkSFtp_putIdleTimeoutMs(sftp,10000);

    // Connect to the SSH server.  
    // The standard SSH port = 22
    // The hostname may be a hostname or IP address.
    hostname = "sftp.example.com";
    port = 22;
    success = CkSFtp_Connect(sftp,hostname,port);
    if (success != TRUE) {
        printf("%s\n",CkSFtp_lastErrorText(sftp));
        CkSFtp_Dispose(sftp);
        return;
    }

    // Authenticate with the SSH server.  Chilkat SFTP supports
    // both password-based authenication as well as public-key
    // authentication.  This example uses password authenication.
    success = CkSFtp_AuthenticatePw(sftp,"myLogin","myPassword");
    if (success != TRUE) {
        printf("%s\n",CkSFtp_lastErrorText(sftp));
        CkSFtp_Dispose(sftp);
        return;
    }

    // After authenticating, the SFTP subsystem must be initialized:
    success = CkSFtp_InitializeSftp(sftp);
    if (success != TRUE) {
        printf("%s\n",CkSFtp_lastErrorText(sftp));
        CkSFtp_Dispose(sftp);
        return;
    }

    // Open a remote file for writing on the SSH server.
    // If the file already exists, it is overwritten.
    // (Specify "createNew" instead of "createTruncate" to
    // prevent overwriting existing files.)
    handle = CkSFtp_openFile(sftp,"big.zip","writeOnly","createTruncate");
    if (CkSFtp_getLastMethodSuccess(sftp) != TRUE) {
        printf("%s\n",CkSFtp_lastErrorText(sftp));
        CkSFtp_Dispose(sftp);
        return;
    }

    // We're going to upload the local file "qa_data/zips/big.zip" (a relative local path from our current working directory)
    // to the SFTP server.
    localFilePath = "qa_data/zips/big.zip";

    // Rather than uploading in one shot, we'll read the local file in chunks
    // and upload a chunk at a time.
    fac = CkFileAccess_Create();

    success = CkFileAccess_OpenForRead(fac,localFilePath);
    if (success == FALSE) {
        CkSFtp_CloseHandle(sftp,handle);
        printf("%s\n",CkFileAccess_lastErrorText(fac));
        CkSFtp_Dispose(sftp);
        CkFileAccess_Dispose(fac);
        return;
    }

    // If we were to split the local file into 128K chunks, how many chunks (blocks) would
    // we have, including the last partial block?
    blockSize = 131072;
    numBlocks = CkFileAccess_GetNumBlocks(fac,blockSize);
    printf("Number of blocks = %d\n",numBlocks);

    bd = CkBinData_Create();
    i = 0;
    while (i < numBlocks) {
        // Read the Nth block, which gets appended to the bd.  (which means
        // we must clear the contents of bd before the next iteration)
        success = CkFileAccess_ReadBlockBd(fac,i,blockSize,bd);
        if (success == FALSE) {
            CkSFtp_CloseHandle(sftp,handle);
            printf("%s\n",CkFileAccess_lastErrorText(fac));
            CkSFtp_Dispose(sftp);
            CkFileAccess_Dispose(fac);
            CkBinData_Dispose(bd);
            return;
        }

        // Upload this block to the open remote file.
        success = CkSFtp_WriteFileBd(sftp,handle,bd);
        if (success == FALSE) {
            printf("%s\n",CkSFtp_lastErrorText(sftp));
            CkSFtp_Dispose(sftp);
            CkFileAccess_Dispose(fac);
            CkBinData_Dispose(bd);
            return;
        }

        // Clear the contents for the next iteration.
        CkBinData_Clear(bd);

        i = i + 1;
    }

    // Close the local file.
    CkFileAccess_FileClose(fac);

    // -----------------------------------------------------------------------------
    // This is important.  You must close the handle on the server.
    // Otherwise open handles will accumulate on the server until eventually a limit
    // is reached and the server will fail on a call to OpenFile.
    // -----------------------------------------------------------------------------

    // Close the remote file handle on the server.
    success = CkSFtp_CloseHandle(sftp,handle);
    if (success != TRUE) {
        printf("%s\n",CkSFtp_lastErrorText(sftp));
        CkSFtp_Dispose(sftp);
        CkFileAccess_Dispose(fac);
        CkBinData_Dispose(bd);
        return;
    }

    printf("Success.\n");


    CkSFtp_Dispose(sftp);
    CkFileAccess_Dispose(fac);
    CkBinData_Dispose(bd);

    }