Objective-C

Resolve an Absolute Remote Path with SFTP RealPath

Demonstrates the Chilkat SFtp.RealPath method, which asks the server to canonicalize a path and returns the resulting absolute remote path. The first argument is the original path and the second is an optional compose path (SFTP v5 or later); pass an empty string when no composition is needed.

Background: The server — not the client — owns the remote filesystem's layout, so path canonicalization must happen on the server. RealPath resolves ., .., and symbolic links into a single absolute path, which is the reliable way to learn the session's home directory (canonicalize .) or to turn a relative path into an absolute one before storing or displaying it. On SFTP v5 and later, the compose path can additionally join or override the original.

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Objective-C

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

BOOL success = NO;

//  Demonstrates the SFtp.RealPath method, which asks the server to canonicalize a path and
//  returns the resulting absolute remote path.  The 1st argument is the original path and the
//  2nd is an optional compose path (SFTP v5+), which may be an empty string.

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

//  Step 1: Connect the SSH transport.  Port 22 is the usual port.
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;
}

//  Step 3: Open the SFTP subsystem.  This must be done after authentication and before any
//  file or directory operations.
success = [sftp InitializeSftp];
if (success == NO) {
    NSLog(@"%@",sftp.LastErrorText);
    return;
}

//  Resolve "." to the absolute path of the session's default (home) directory.  No compose path
//  is needed, so the 2nd argument is an empty string.
NSString *homeDir = [sftp RealPath: @"." composePath: @""];
if (sftp.LastMethodSuccess == NO) {
    NSLog(@"%@",sftp.LastErrorText);
    return;
}

NSLog(@"%@%@",@"Home directory: ",homeDir);

//  Canonicalize a relative path with "..", resolving it to an absolute path.
NSString *resolved = [sftp RealPath: @"subdir/../otherdir" composePath: @""];
if (sftp.LastMethodSuccess == NO) {
    NSLog(@"%@",sftp.LastErrorText);
    return;
}

NSLog(@"%@%@",@"Resolved path: ",resolved);

[sftp Disconnect];