I finished writing a little program, which is able to read and write a/into a .txt file.
When I execute the program, everything is running fine except that the content of the file doesn't change permanently. I got a writeToFile and "readFile" button and the content seems to change every time I press one of them, but when I open the file manually (while testing or after shutting down the program) theres still the origin content in it.
Doesn't the "real" file content change while just using the simulator? Or is it just me making some bad mistakes?
-(IBAction)buttonPressed { //The writeToFile Method
NSString *filePath = [[NSBundle mainBundle] pathForResource:#"test" ofType:#"txt"];
NSString *writeData = enterText.text;
NSError *error;
BOOL ok = [writeData writeToFile:filePath atomically:NO encoding:NSUnicodeStringEncoding error:&error];
if (!ok)
{
NSLog(#"Error while writing file at %#/n%#",filePath,[error localizedFailureReason]);
}
testText.text =#"File saved!";
enterText.text = #"";
enterText.placeholder =#"Enter your text here";
}
testText = TextView for Output
enterText = TextField for Input
Your filePath variable is pointing to a file within the resource bundle of your app (which is not writable). What you need to do is locate the user's Documents folder, and create your file there.
Related
I am completely new to objective C and currently I am trying to advance the functionality of an already existing project.
There is a finder extension in the project which on getting clicked performs an action inside (IBAction) Share(id) sender.
Inside this action , I want to read a file from a particular location (the file contains the port number) and using that port I want to connect to the server.
But what I found was when I click on this extension , nothing happens because it tries to go and read data from the file and is not able to read anything.
I tried to debug this by printing out whatever it has read to some other file but all it printed was blank confirming that it is not able to read the data. Below is my code trying to read the port from a temporary location :
- (IBAction)privateShareAction:(id)sender {
NSFileManager *filemgr;
filemgr = [NSFileManager defaultManager];
if ([filemgr fileExistsAtPath: #"/var/folders/y3/jv117_75505fnk8htdrs0qm40000gr/T/com.aprivacy.xmlCorePort.properties" ] == YES)
{
//create file handle
NSFileHandle *file;
file = [NSFileHandle fileHandleForReadingAtPath:#"/var/folders/y3/jv117_75505fnk8htdrs0qm40000gr/T/com.aprivacy.xmlCorePort.properties"];
//read data into file in NSData format
NSData *filedata;
filedata = [file readDataToEndOfFile];
NSLog(#"fileDATA = %#", filedata);
//convert NSData to NSString
NSString *string;
string = [[NSString alloc] initWithData:filedata encoding:NSASCIIStringEncoding];
NSMutableString *directoryPath1 = [NSMutableString stringWithString: #"share1>"];
[directoryPath1 appendString: string];
NSData *dataToWrite3 = [directoryPath1 dataUsingEncoding: NSUTF8StringEncoding];
NSFileHandle* outputFile = [NSFileHandle fileHandleForWritingAtPath:#"/Users/yp/Downloads/a.txt"];
[outputFile seekToEndOfFile];
[outputFile writeData:dataToWrite3];
//convert from string to array
NSArray *lines = [string componentsSeparatedByString:#"="];
NSLog(#"arrau = %#", lines);
//take one of the string and store it in sword
NSString *sword = [lines objectAtIndex:1];
NSLog(#"port : %#", sword);
int port1=[sword intValue];
Communicator *c = [[Communicator alloc ]init];
c.host=#"http:127.0.0.1";
c.port=port1;
[c setup];
}
else
{
NSAlert *alert = [[NSAlert alloc] init];
[alert setMessageText:#"Error"];
[alert setInformativeText:#"You are not logged in.Kindly login to start performing the operations"];
[alert setAlertStyle:NSWarningAlertStyle];
[alert runModal];
}
}
The above code, on the action performed first tries to check if the file is present at the /var/folders/y3/jv117_75505fnk8htdrs0qm40000gr/T/com.aprivacy.xmlCorePort.properties location or not.
This works perfectly fine , If the file is present , it shows a popup alert (which happens).
But if the file is present , it goes inside the if condition and tries to read the file where it fails .It always prints a blank string showing that nothing is being read.
So then I went and checked the entitlements in App Sandbox.
I tried to add an entitlement named com.apple.security.temporary-exception.files.absolute-path.read-only with a string value set to /var/folders/y3/jv117_75505fnk8htdrs0qm40000gr/T/com.aprivacy.xmlCorePort.properties so that it gets the permission to read the file from this location but still it doesn't solve my problem.
Could anyone please suggest how to get this file reading permission accessible in my app because the same code works completely fine in a newly created test project.
Following steps : Original client app running -login with user name and password Once logged in -it writes the port in a file At the same time ,once you are logged in with your application , if now you right click on any file in your system you will see certain extra extensions like share ,grant access etc. (This is because a finder project used to add extensions is merged with the original client) Now when I click on say share (on right clicking a file) , I want an action to be performed.The logic for action is written in (IBAction)Share (id) sender method This app used to add extensions is sandboxed because of which the permissions are restricted. So while I clicked on share , my logic was to read that file ,get the port and then connect to server using that port. I want to do everything inside action but I am unable to do so . It is not able to find the file data from /var/folder/y3/jv117_755fdlvfldsvgr/T/com.aprivacy.xmlcorePort.properties
Sandboxed apps (all in iOS) are only allowed access to specific directories. Use NSSearchPathForDirectoriesInDomainsto obtain paths to available directories.
Ex:
Objective-C:
NSArray *documentDirectoryPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) firstObject];
NSString *filePath = [documentsDirectory stringByAppendingPathComponent:fileName];
NSError *error;
BOOL status = [string writeToFile:filePath atomically:YES encoding:NSUTF8StringEncoding error:&error];
if (status == NSError) {
NSLog(#"error: %#", error)
}
Swift:
let filePath = "path/file.txt";
let documentDirectoryPath = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true).first as! String
let path = documentDirectoryPath + filePath
Note: Sandboxed paths is not consistent across clean builds.
Don't use absolute paths in sandboxed applications.
In OS X there is the NSTemporaryDirectory() function to have access to the temporary directory for this specific application in the container. Entitlements are not needed.
From the documentation
Some path-finding APIs (above the POSIX layer) refer to app-specific
locations outside of the user’s home directory. In a sandboxed app,
for example, the NSTemporaryDirectory function provides a path to a
directory that is outside of the user’s home directory but specific to
your app and within your sandbox; you have unrestricted read/write
access to it for the current user. The behavior of these path-finding
APIs is suitably adjusted for App Sandbox and no code change is
needed.
Source: App Sandbox in Depth
In the app I'm designing I have a couple text fields that each save to a .txt file when the app is closed, and then read back in when the app opens up; however, when I try to distribute the app (just exporting it as an application and dropboxing it to some friends) the people I'm sending it to don't have the file locations that I'm saving to on their computers, so the text fields don't save. Is there a way I can create the .txt files on their computers when the app downloads? or is there a better way to save when distributing than doing .txt files? Thanks.
Why not just use NSUserDefaults and store the (hopefully fairly small) text in the app's preferences database? It's guaranteed to exist and be accessible without running afoul of sandbox restrictions or nonstandard storage locations.
Beyond that, you'll need to provide more information if you want a direct answer to your question. Specifically, what is the exact path you're using and what is the exact error you're receiving? Why do you feel you need to bundle empty text files when all it takes is creating the file(s) at runtime?
I would just package the initial .txt file in your application bundle. Check if the file exists on your user's local file system. If not, read your bundle's .txt file into a string, then save that string to the user's file system in the correct place.
NSError *fileError = nil;
if ([[NSFileManager defaultManager] fileExistsAtPath:filePath]) {
//Read the file
NSString *fileContents = [[NSString alloc] initWithContentsOfFile:filePath encoding:NSUTF8StringEncoding error:&fileError];
if (fileError) {
//Handle the error
}
} else {
NSString *bundlePath = [[NSBundle mainBundle] pathForResource:#"initialFile" ofType:#"txt"];
NSString *initialFileContents = [[NSString alloc] initWithContentsOfFile:bundlePath encoding:NSUTF8StringEncoding error:&fileError];
if (!fileError) {
[initialFileContents writeToFile:filePath atomically:YES encoding:NSUTF8StringEncoding error:&fileError];
if (fileError) {
//Handle the error
}
}
}
I'm having a problem saving a string file with NSSavePanel after sandboxing the app for the Mac App Store. I set com.apple.security.files.user-selected.read-write to YES and the NSOpenPanel is working as it should.
When I try to save a new file, though, it seems that everything is working fine but then there is no saved file where it should be....
This is the code I am using to save the file:
NSSavePanel *save = [NSSavePanel savePanel];
long int result = [save runModal];
if (result == NSOKButton)
{
NSString *selectedFile = [save filename];
NSString *fileName = [[NSString alloc] initWithFormat:#"%#.dat", selectedFile];
NSString *arrayCompleto = [[NSString alloc]initWithFormat:#"bla bla bla"];
[arrayCompleto writeToFile:fileName
atomically:NO
encoding:NSUTF8StringEncoding
error:nil];
}
First of all, the -[NSSavePanel filename] selector has been deprecated. Use -[NSSavePanel URL] instead. Second, the way that the -[NSString writeToFile:atomically:encoding:error] tells you what you're doing wrong is with the error:(NSError**) argument.
You should also handle errors for file I/O in particular, because even if your code is 100% correct, there still might be errors on the user's system (insufficient privileges, etc.) and presenting the error to the user will allow them to see it failed (and have some idea why). Handling the error in code will also allow your app to recover. For instance, if you tried to read in the file below the code you pasted (after writing it to disk), but the user tried writing it to a network share they didn't have access to, your app might crash. If you know the write failed, you can proceed accordingly (perhaps prompting for a different save location).
In this case, though, I believe the following line is your problem:
NSString *fileName = [[NSString alloc] initWithFormat:#"%#.dat", selectedFile];
When your app is sandboxed, the user needs to give you permission for either a specific file or a specific directory through the open/save panels to bring them into your sandbox. What you're doing is taking the file the user gave you permission to write and saying "that's great, but I want to save a different file", which violates the sandbox. What you should do instead is set the extension in the Save Panel. The complete fixed solution would be:
NSSavePanel *save = [NSSavePanel savePanel];
[save setAllowedFileTypes:[NSArray arrayWithObject:#"dat"]];
[save setAllowsOtherFileTypes:NO];
NSInteger result = [save runModal];
if (result == NSOKButton)
{
NSString *selectedFile = [[save URL] path];
NSString *arrayCompleto = #"bla bla bla";
NSError *error = nil;
[arrayCompleto writeToFile:selectedFile
atomically:NO
encoding:NSUTF8StringEncoding
error:&error];
}
if (error) {
// This is one way to handle the error, as an example
[NSApp presentError:error];
}
If in the future something else is wrong, you can check the value of error at runtime. While debugging, set a breakpoint inside the if (error) statement to check error object's value (do a po error in Xcode's debugger). That should help you figure out what's wrong.
I have the following function written to randomly pick a file from a directory. It works totally fine when I build the project in Xcode for release with the application that automatically opens. However, if I open the application from finder, pressing the button that triggers this function will cause my program to freeze then crash. The only thing I could think of was changing the argument to contentsOfDirectoryAtPath: to not have the ./, but either version has the same exact issue.
Looking at Console tells me that my program exited abnormally with a Floating Point Exception, but I have no idea what's causing it. Is there something jumping out to you guys that I'm not seeing? I only started learning/using objective-C and cocoa about a week ago, so this is all fairly new to me.
Thanks for taking a look at this...
- (NSMutableString*)setFilePathRandom{
NSArray* files;
NSFileManager* fileManager;
fileManager = [[NSFileManager alloc] init];
files = [fileManager contentsOfDirectoryAtPath:#"./Random Trippy Pics" error:NULL];
NSString* directoryPath = (NSMutableString*)[fileManager currentDirectoryPath];
NSString* fileName;
do{
fileName = [files objectAtIndex:(arc4random()%[files count])];
}while([fileName isEqualToString:#".DS_Store"]);
filePath = [NSString stringWithFormat:#"%#/Random Trippy Pics/%#",directoryPath,fileName];
[fileManager release];
return filePath;
}
When an OS X application is run from Xcode, its current directory is the path to the build folder. When run "normally", the current directory is /. So your program is looking for a directory at /Random Trippy Pics, which almost certainly doesn't exist. Where is that directory normally?
Edit:
You could get the directory in which the application is currently stored with this bit of code:
NSString *currentStoragePath = [[[NSBundle mainBundle] bundlePath] stringByDeletingLastPathComponent];
However, if the Random Trippy Pics directory is required by the application, you should store it in a known location -- preferably the application's Resource directory. Then you can get the contents with:
NSArray *files = [[NSBundle mainBundle] pathsForResourceOfType:nil inDirectory:#"Random Trippy Pics"];
I'm using a text file to save the changes made by a user on a list (the reason that I'm doing this is so that I can upload the text file to a PC later on, and from there insert it into an Excel spreadsheet). I have 3 data structures: A NSMutableArray of keys, and a NSMutableDictionary who's key values are MSMutableArrays of NSStrings.
I iterate through these data structures and compile a file string that looks much like this:
(Key);(value)\t(value)\t(value):\n(Key);(value).. .so on.
SO, onto the actual question: When I attempt to save it, it fails. I'm 99% sure this is because of the file path that I'm using, but I wanted backup to check this out. Code follows:
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask, YES);
NSString *filePath = [paths objectAtIndex:0];
NSString *fileString = [NSString stringWithString:[self toFileString]];
if(![fileString writeToFile:filePath atomically:YES encoding:NSUTF8StringEncoding error:NULL]){
NSLog(#"File save failed");
} else {
// do stuff
}
(Code above is re-copied, since the actual code is on a different computer. It compiles, so ignore spelling errors?)
I tried using NSError, but I got bogged down in documentation and figured I might as well ask SO while trying to figure out how to properly use NSError (might be a little bit of an idiot, sorry).
99% sure it's the NSArray *paths line that's tripping it up, but I don't know how else to get the documents directory.
Edit: Problem solved, and one final question: If I save it to the App's document directory, where can I go after I close the app to see if it saved properly? If it works like I think it does, isn't it sandboxed in with the app's installation on the simulator? (i.e. no way of checking it)
NSLog() that filePath string. I think you're trying to write to the directory itself, not to a file.
Try this instead:
filePath = [[paths objectAtIndex:0]stringByAppendingPathComponent:#"myfile.txt"];
What is the file name you want to save? The method
NSArray *paths = NSSearchPathForDirectoriesInDomains(...);
NSString *filePath = [paths objectAtIndex:0];
...
if(![fileString writeToFile:filePath ...
means you are saving the string into a file path which has the same name as a folder. This will of course fail. Please give it a name, e.g.
NSString* fileName = [filePath stringByAppendingPathComponent:#"file.txt"];
if(![fileString writeToFile:fileName ...
and try again.
BTW, to use NSError:
NSError* theError = nil;
if(![fileString writeToFile:fileName ... error:&theError]) {
// ^^^^^^^^^
NSLog(#"Failed with reason %#", theError);
// theError is autoreleased.
}