I'm having some trouble getting this NSTask to launch from an NSPopover view. The popover I created has several things in it. First the user selects a path using NSOpenPanel, then the user enters a username so that I can construct a path to transfer data to. Finally, there's a button that is supposed to launch the NSTask that initiates the data transfer. I had to add some extra code to make the text field work for user input. See the following link for what I followed to get the text field to work: NSStatusItem with NSPopover and NSTextField
Any reason why this wouldn't work? This code had been working when it was contained in a NSWindow.
- (IBAction)beginTransfer:(id)sender {
//Construct a string of the user selected source path.
NSString *userAccountPath = [_sourcePathTextField stringValue];
//Check that I got the expected result
NSLog (#"%#", userAccountPath);
//Create an array with the pieces I need to construct a destination account path
NSArray *strings = [NSArray arrayWithObjects:#"/Users/", [userAccountTextField stringValue], nil];
//Construct a string destination account location from the pieces
NSString *userAccountDestinationPath = [strings componentsJoinedByString:#""];
//Make sure the construction is correct
NSLog (#"%#", userAccountDestinationPath);
//Setup NSTask
NSTask *transferFiles;
transferFiles = [[NSTask alloc] init];
//Arguements for rsync
NSArray *arguements;
arguements = [NSArray arrayWithObjects:#"--paH", #"--info=progress2", #"--human-readable", #"--exclude", #"/Library/Keychains", userAccountPath, userAccountDestinationPath, nil];
//Setup output pipe
NSPipe *transferOutput = [NSPipe pipe];
[transferFiles setStandardOutput:transferOutput];
//Launch rsync with arguements from above
[transferFiles setArguments:arguements];
[transferFiles setLaunchPath:#"/usr/local/bin/rsync"];
[transferFiles launch];
NSFileHandle *fh = [transferOutput fileHandleForReading];
[fh waitForDataInBackgroundAndNotify];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(receivedData:) name:#"NSFileHandleDataAvailableNotification" object:nil];
[transferFiles waitUntilExit];
[transferFiles release];
[fh release];
}
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I've been digging for an answer for a long time but I never get to a working code.
I have a code that uses dd to generate a file. Sometimes it takes a few minutes depending on the size and I thought it would be great to have a progress bar. So far everything works and is tied up. The progress bar, however, doesn't update because I need to constantly send values to it. I found a way to get the current value, I managed to get pv to display the current data, but now I can't get the output in real time inside the application, except in the log.
So far, this is the best I got to:
// Action:
// dd if=/dev/zero bs=1048576 count=500 |pv -Wn -s <size>|of=/Users/me/Desktop/asd.img
// Be careful, it generates files of 500MB!!
NSTask * d1Task = [[NSTask alloc] init];
NSTask * pvTask = [[NSTask alloc] init];
NSTask * d2Task = [[NSTask alloc] init];
[d1Task setLaunchPath:#"/bin/dd"];
[pvTask setLaunchPath:#"/Users/me/Desktop/pv"];
[d2Task setLaunchPath:#"/bin/dd"];
// For pvTask I use something like...
// [[NSBundle mainBundle] pathForAuxiliaryExecutable: #"pv"]
// ... in the final version.
[d1Task setArguments: [NSArray arrayWithObjects:
#"if=/dev/zero"
, #"bs=1048576"
, #"count=500"
, nil]];
[pvTask setArguments:[NSArray arrayWithObjects:
#"-Wn"
, [ NSString stringWithFormat:#"-s %d", 1048576 * 500]
, nil]];
[d2Task setArguments: [NSArray arrayWithObjects:
#"of=/Users/me/Desktop/file.dmg"
, nil]];
NSPipe * pipeBetween1 = [NSPipe pipe];
[d1Task setStandardOutput: pipeBetween1];
[pvTask setStandardInput: pipeBetween1];
NSPipe * pipeBetween2 = [NSPipe pipe];
[pvTask setStandardOutput: pipeBetween2];
[d2Task setStandardInput: pipeBetween2];
// Missing code here
[d1Task launch];
[pvTask launch];
[d2Task launch];
In the missing code part, I tried several things. First I tried an observer, like this:
NSFileHandle * pvOutput = [pipeBetween2 fileHandleForReading];
[pvOutput readInBackgroundAndNotify];
[ [NSNotificationCenter defaultCenter]
addObserver:self
selector:#selector(outputData:)
name:NSFileHandleDataAvailableNotification
object:pvOutput
];
No success. I get feedback only in the beginning or the end of the execution, but still no feedbacks during it.
I also tried something like:
[pvOutput setReadabilityHandler:^(NSFileHandle *file) {
// Stuff here
}];
But there is no such method here. Maybe my XCode is outdated? (I use 4.2).
Lately I've been trying the same generic code using /sbin/ping pinging 10 times a server, but no success getting the output. How can I do this? Any documents I can read about this subject?
Thanks!
The pv tool writes the progress output to standard error, so you should establish
another pipe:
NSPipe *pvStderrPipe = [NSPipe pipe];
[pvTask setStandardError:pvStderrPipe];
NSFileHandle *pvError = [pvStderrPipe fileHandleForReading];
[pvError waitForDataInBackgroundAndNotify];
[[NSNotificationCenter defaultCenter] addObserverForName:NSFileHandleDataAvailableNotification
object:pvError queue:nil
usingBlock:^(NSNotification *note)
{
NSData *progressData = [pvError availableData];
NSString *progressStr = [[NSString alloc] initWithData:progressData encoding:NSUTF8StringEncoding];
NSLog(#"progress: %#", progressStr);
[pvError waitForDataInBackgroundAndNotify];
}];
A completely different solution might be to use the following feature of "dd":
If dd receives a SIGINFO signal,
the current input and output block counts will be written to the
standard error output in the same format as the standard completion
message.
So you could connect a pipe to stderr of "dd" and call
kill([ddTask processIdentifier], SIGINFO);
at regular intervals. Then you don't need "pv" and probably only one "dd" task.
As a learning project Im writing a simple gui for Apache stresstesting command line tool "ab". It requiers a full URL, including a filename such as index.html or simular, as one of its parameters. If a filename is not specified "ab" echos "Invalid url" and shows a lists of available flags.
I would like to catch this "error" and have tried using NSTasks standarderror output. Can´t really get it to work. Would this even classify as an error that would pipe to a standard error?
Besides validating the URL input before launching the NSTask, do you think I can prevent or rather catch this error?
My simple code:
- (void) stressTest:(NSString *)url withNumberOfRequests:(int)requests sendSimultaneously:(int)connections {
NSBundle *mainBundle = [NSBundle mainBundle];
NSString *abPath = [[mainBundle bundlePath] stringByAppendingString:#"/Contents/Resources/ab"];
NSString* requestsStr = [NSString stringWithFormat:#"%i", requests];
NSString* connectionsStr = [NSString stringWithFormat:#"%i", connections];
// Init objects for tasks and pipe
NSTask *abCmd = [NSTask new];
NSPipe *outputPipe = [NSPipe pipe];
[abCmd setLaunchPath:abPath];
[abCmd setArguments:[NSArray arrayWithObjects:#"-n", requestsStr, #"-c", connectionsStr, url, nil]];
[abCmd setStandardOutput:outputPipe];
[abCmd launch];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(readCompleted:) name:NSFileHandleReadToEndOfFileCompletionNotification object:[outputPipe fileHandleForReading]];
[[outputPipe fileHandleForReading] readToEndOfFileInBackgroundAndNotify];
}
- (void)readCompleted:(NSNotification *)notification {
NSString * tempString = [[NSString alloc] initWithData:[[notification userInfo] objectForKey:NSFileHandleNotificationDataItem] encoding:NSASCIIStringEncoding];
[resultTextOutlet setString:tempString];
[[NSNotificationCenter defaultCenter] removeObserver:self name:NSFileHandleReadToEndOfFileCompletionNotification object:[notification object]];
}
ab writes its error messages, including usage information, to standard error. You're currently only reading from standard output. To access the error messages or usage information you'll need to allocate a second NSPipe, pass it to -[NSTask setStandardError:], and then read data from it.
Never-mind all the "why?","useless?", and "don't bother" comments. I want to compile a program inside another program using clang. I can create the NSTask and set up the arguments and it will work if the file exists, (ie. no stream), and writes to a physical file. I haven't been able to get what I would really like which is to use streams for both input and output. I know that both clang and gcc allow for compiling stdin if you use the -xc and - options but am unable to implement that feature using pipes. I am also not sure how to redirect clang's output to a file handle or stream.
Here is the code I have that compiles it and generates the correct output in outfile
task = [[NSTask alloc] init];
NSPipe* outputPipe = [[NSPipe alloc] init];
[task setStandardOutput:outputPipe ];
[task setStandardError: [task standardOutput]];
NSPipe* inPipe = [NSPipe pipe];
[task setStandardInput:inPipe];
[task setLaunchPath:#"/usr/bin/clang"];
NSString* outfile= [NSString stringWithFormat:#"%#.out",[[filename lastPathComponent] stringByDeletingPathExtension]];
//[data writeToFile:#"file.c" atomically:YES];
[task setArguments:[NSArray arrayWithObjects:filename,#"-S",#"-o",outfile,nil]];
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(getData:)
name: NSFileHandleReadCompletionNotification
object: [[task standardOutput] fileHandleForReading]];
[[[task standardOutput] fileHandleForReading] readInBackgroundAndNotify];
[task launch];
I have tried using this for the input stream:
/* on pipe creation*/
dup2([[inPipe fileHandleForReading] fileDescriptor], STDIN_FILENO);
NSFileHandle* curInputHandle = [inPipe fileHandleForWriting];
/* tried before launch and after, no output just sits */
[curInputHandle writeData:[NSData dataWithContentsOfFile:filename]];
Sometimes, I assume when the pipe closes while the NSTask still in existance the output file is created and will run. This makes me think that clang is just waiting for stdin to close. Is there a way to close the pipe when the data has been read?
For output I have tried to use NSPipe's fileHandleForWriting as the parameter of -o, That gives an error of [NSConcretePipe fileSystemRepresentation] unrecognized selector. I have tried creating a file handle with the file descriptor of stdout to the same error. I don't know of any command line argument that redirects it. I've tried using | to redirect but haven't been able to get it to work. If there is any unix magic to redirect it I can dup stdout to anywhere I want.
So is there any way to close a pipe when all the data it is read? And Redirect clangs output? If there is any other way to accomplish the same thing easier or cleaner I am open to any implementation.
Any help on these two items would be so great.
It is not clear to me what your problem is or what you've tried. However, if you are going to read the output from a pipe on your main thread using notifications and wish to also write to a pipe one option is to write to the pipe in another thread. The code below, based on your code, does this using GCD. For simplicity in this example the binary is deposited in /tmp:
// send a simple program to clang using a GCD task
- (void)provideStdin:(NSFileHandle *)stdinHandle
{
dispatch_queue_t aQueue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
dispatch_async(aQueue, ^{
[stdinHandle writeData:[#"int main(int argc, char **argv)\n" dataUsingEncoding:NSUTF8StringEncoding]];
[stdinHandle writeData:[#"{\n" dataUsingEncoding:NSUTF8StringEncoding]];
[stdinHandle writeData:[#" write(1, \"hello\\n\", 6);\n" dataUsingEncoding:NSUTF8StringEncoding]];
[stdinHandle writeData:[#"}\n" dataUsingEncoding:NSUTF8StringEncoding]];
[stdinHandle closeFile]; // sent the code, close the file (pipe in this case)
});
}
// read the output from clang and dump to console
- (void) getData:(NSNotification *)notifcation
{
NSData *dataRead = [[notifcation userInfo] objectForKey:NSFileHandleNotificationDataItem];
NSString *textRead = [[NSString alloc] initWithData:dataRead encoding:NSUTF8StringEncoding];
NSLog(#"read %3ld: %#", (long)[textRead length], textRead);
}
// invoke clang using an NSTask, reading output via notifications
// and providing input via an async GCD task
- (void)applicationDidFinishLaunching:(NSNotification *)aNotification
{
NSTask *task = [NSTask new];
NSPipe *outputPipe = [NSPipe new];
[task setStandardOutput:outputPipe];
[task setStandardError:outputPipe];
NSFileHandle *outputHandle = [outputPipe fileHandleForReading];
NSPipe* inPipe = [NSPipe pipe];
[task setStandardInput:inPipe];
[task setLaunchPath:#"/usr/bin/clang"];
[task setArguments:[NSArray arrayWithObjects:#"-o", #"/tmp/clang.out", #"-xc",#"-",nil]];
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(getData:)
name:NSFileHandleReadCompletionNotification
object:outputHandle];
[outputHandle readInBackgroundAndNotify];
[task launch];
[self provideStdin:[inPipe fileHandleForWriting]];
}
NSTask isn't working; I think it has to do with the arguments. Here is my code:
- (IBAction)downloadFile:(id)sender {
// allocate our stuff :D
progressIndication = [[NSProgressIndicator alloc] init];
NSTask *downloader = [[NSTask alloc] init];
// set up the downloader task
[downloader setLaunchPath:#"/usr/bin/curl"];
[downloader setArguments:[NSArray arrayWithObject:[NSString stringWithFormat:#"-LO %#", downloadURL]]];
// go to the Desktop!
system("cd ~/Desktop");
// start progress indicator
[progressIndication startAnimation:self];
// download!
[downloader launch];
// stop the progress indicator, everything is done! :D
[progressIndication stopAnimation:self];
}
Thanks
You really don't need to use curl to do this; just use NSData to accomplish the task much more easily:
NSData *data = [NSData dataWithContentsOfURL:downloadURL];
[data writeToFile:[[NSString stringWithFormat:#"~/Desktop/%#", [downloadURL lastPathComponent]] stringByExpandingTildeInPath] atomically:YES];
If you insist you need to use curl for this, you're going to have to fix your code, which doesn't work for several reasons. First and foremost, your arguments are wrong. You should have the following code:
[downloader setArguments:[NSArray arrayWithObjects:#"-L", #"-O", [downloadURL absoluteString], #"-o", [NSString stringWithFormat:#"~/Desktop/%#", [downloadURL lastPathComponent]], nil];
Second, system("cd ~/Desktop") is meaningless; get rid of it.
Lastly, NSTask runs concurrently. [downloader launch] starts the operation, and your code continues. It should be:
[downloader launch];
[downloader waitUntilExit]; // block until download completes
[progressIndication stopAnimation:self];
I have an application that checks its command line parameters and stores values in persistent stores. One of those is a password that I don't want sticking around for people to see with 'ps' and friends. The approach I'm currently looking at is to, after I've stored the values I need, relaunch the process without the command line parameters. My naive approach is this, where args[0] is the path to the application:
NSTask *task = [[NSTask alloc] init];
[task setLaunchPath:[args objectAtIndex:0]];
[task launch];
[task release];
[NSApp terminate:nil];
The child is run. However, when my app is terminated the child doesn't seem to orphan but gets stuck. Am I just way off on this one?
More info: So it seems that when I call [NSApp terminate:nil] the NSTask that was launched gets stuck, but if I just exit() then it works fine. However, I'm concerned that things that are open (keychain, plist, etc.) will be in a bad state if I do that.
And note that lots of example code out there is about some watchdog-like process that restarts a separate process when needed. I'm trying to restart the current process that's already running from within that same process.
There are plenty of examples on the web, but this one (also below) looks like it has all the code you need. There are more detailed explanations out there, as well.
// gcc -Wall -arch i386 -arch ppc -mmacosx-version-min=10.4 -Os -framework AppKit -o relaunch relaunch.m
#import <AppKit/AppKit.h>
#interface TerminationListener : NSObject
{
const char *executablePath;
pid_t parentProcessId;
}
- (void) relaunch;
#end
#implementation TerminationListener
- (id) initWithExecutablePath:(const char *)execPath parentProcessId:(pid_t)ppid
{
self = [super init];
if (self != nil) {
executablePath = execPath;
parentProcessId = ppid;
// This adds the input source required by the run loop
[[[NSWorkspace sharedWorkspace] notificationCenter] addObserver:self selector:#selector(applicationDidTerminate:) name:NSWorkspaceDidTerminateApplicationNotification object:nil];
if (getppid() == 1) {
// ppid is launchd (1) => parent terminated already
[self relaunch];
}
}
return self;
}
- (void) applicationDidTerminate:(NSNotification *)notification
{
if (parentProcessId == [[[notification userInfo] valueForKey:#"NSApplicationProcessIdentifier"] intValue]) {
// parent just terminated
[self relaunch];
}
}
- (void) relaunch
{
[[NSWorkspace sharedWorkspace] launchApplication:[NSString stringWithUTF8String:executablePath]];
exit(0);
}
#end
int main (int argc, const char * argv[])
{
if (argc != 3) return EXIT_FAILURE;
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
[[[TerminationListener alloc] initWithExecutablePath:argv[1] parentProcessId:atoi(argv[2])] autorelease];
[[NSApplication sharedApplication] run];
[pool release];
return EXIT_SUCCESS;
}
I know its a bit late to answer but this answer may help others. Here is a cool trick that can help you.
By using the terminal command, just open your application as a new instance and terminate the current instance.
This is how it is done:
....
NSString* path = [[NSBundle mainBundle] bundlePath];
NSString* cmd = [NSString stringWithFormat:#"open -n %#", path];
[self runCommand:cmd];
exit(0);
}
/// temrinal function
-(NSString*)runCommand:(NSString*)commandToRun;
{
NSTask *task;
task = [[NSTask alloc] init];
[task setLaunchPath: #"/bin/sh"];
NSArray *arguments = [NSArray arrayWithObjects:
#"-c" ,
[NSString stringWithFormat:#"%#", commandToRun],
nil];
NSLog(#"run command: %#",commandToRun);
[task setArguments: arguments];
NSPipe *pipe;
pipe = [NSPipe pipe];
[task setStandardOutput: pipe];
NSFileHandle *file;
file = [pipe fileHandleForReading];
[task launch];
NSData *data;
data = [file readDataToEndOfFile];
NSString *output;
output = [[NSString alloc] initWithData: data encoding: NSUTF8StringEncoding];
return output;
}
Create an external process that launches yours when it terminates. Then terminate. Launching Cocoa programs with NSTask doesn't work quite right.
For anyone who still wants to use NSTask to relaunch,I found one possible way: Please DO NOT set NSPipe of the NSTask,because the NSTask will terminate the app itself,once the app terminated,the NSTask that started might get stuck there.
At least for me,after I removed the NSPipe settings,my app relaunch successfully.
The following is what I do:
1. Write a command line tool which has 3 parameters: app bundle id,app full path,please note that in this command line you need to terminate the app and wait for a while to make sure it is really terminated before launch the new one,I keep checking app.isTerminated and sleep(1) if it's not terminated.
Launch the Command line tool in app using NSTask,and set the parameters accorddingly,Don't use NSPipe,simply create NSTask and launch
The app relaunches now