BETaskHelper helps you run NSTask interactively. Specifically you can:
- receive output of the task line-by-line
- send strings such as passwords to the task
We use BETaskHelper in our apps Archiver and MainMenu.
This example uses the openssl
command to encrypt a file.
In the header file implement the BETaskHelperDelegate
protocol:
#import "BETaskHelper.h"
@interface FileEncrypter : NSObject <BETaskHelperDelegate> {
BETaskHelper *taskHelper;
}
// Sets up and runs the find task (you can call the method anything you like)
-(void) run;
@end
Note that we keep the task helper as an instance variable because the task runs asynchronously.
In the implementation file use the BETaskHelper
delegate methods to capture the output of the openssl
command and send the password when requested:
#import "FileEncrypter.h"
@implementation FileEncrypter
-(void) run {
// Setup task
NSTask *task = [[[NSTask alloc] init] autorelease]; // BETaskHelper will retain it for us
[task setLaunchPath:@"/usr/bin/openssl"];
NSString *inputPath = [NSHomeDirectory() stringByAppendingPathComponent:@"Report.txt"];
NSString *outputPath = [NSHomeDirectory() stringByAppendingPathComponent:@"Report.enc"];
[task setArguments:[NSArray arrayWithObjects:@"enc", @"-aes-256-cbc", @"-salt", @"-in", inputPath, @"-out", outputPath, nil]];
// Hook up task with helper
taskHelper = [[BETaskHelper alloc] initWithDelegate:self forTask:task];
// Launch task -- must happen via task helper!
[taskHelper launchTask];
}
#pragma mark BETaskHelper delegate methods
-(void) task:(NSTask *)task hasOutputAvailable:(NSString *)outputLine {
// Log all output
NSLog(@"%@", outputLine);
// Send password if requested (will be called twice for verification)
if ([outputLine rangeOfString:@" password:"].location != NSNotFound) {
// Most commands require newline character to signal end of input
[taskHelper sendInput:@"YouWillNeverGuess\n"];
}
}
-(void) task:(NSTask *)task hasCompletedWithStatus:(int) status {
NSString *message = (status == 0) ? @"Success!" : @"Failed!";
NSLog(@"%@", message);
}
@end
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