Objective-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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Objective-C

#import <CkoSFtp.h>
#import <NSString.h>
#import <CkoStringBuilder.h>

BOOL success = NO;

//  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.

CkoSFtp *sftp = [[CkoSFtp alloc] init];

//  Connect, authenticate, and initialize the SFTP subsystem.
int port = 22;
success = [sftp Connect: @"sftp.example.com" port: [NSNumber numberWithInt: port]];
if (success == NO) {
    NSLog(@"%@",sftp.LastErrorText);
    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.
NSString *password = @"mySshPassword";

success = [sftp AuthenticatePw: @"mySshLogin" password: password];
if (success == NO) {
    NSLog(@"%@",sftp.LastErrorText);
    return;
}

success = [sftp InitializeSftp];
if (success == NO) {
    NSLog(@"%@",sftp.LastErrorText);
    return;
}

NSString *handle = [sftp OpenFile: @"subdir/data.txt" access: @"readOnly" createDisp: @"openExisting"];
if (sftp.LastMethodSuccess == NO) {
    NSLog(@"%@",sftp.LastErrorText);
    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.
CkoStringBuilder *sbContent = [[CkoStringBuilder alloc] init];
int chunkSize = 4096;
BOOL reading = YES;
while (reading) {
    NSString *chunk = [sftp ReadFileText: handle numBytes: [NSNumber numberWithInt: chunkSize] charset: @"utf-8"];
    if ([sftp LastReadFailed: handle]) {
        NSLog(@"%@",sftp.LastErrorText);
        return;
    }

    [sbContent Append: chunk];
    reading = ![sftp Eof: handle];
}

success = [sftp CloseHandle: handle];
if (success == NO) {
    NSLog(@"%@",sftp.LastErrorText);
    return;
}

NSLog(@"%@",[sbContent GetAsString]);

[sftp Disconnect];