Creating Password Protected PDF in Objective-C

Question

I tried using the info given here

https://developer.apple.com/library/mac/#documentation/graphicsimaging/conceptual/drawingwithquartz2d/dq_pdf/dq_pdf.html#//apple_ref/doc/uid/TP30001066-CH214-TPXREF101

but it is really vague...

I also tried using this code using UIKit... the file is created.. but it is of 0 kb.. cannot write any data..

BOOL allowCopy=YES;
BOOL allowPrint=YES;
//NSString *password=@"test";

CGContextRef pdfContext; //our pdfContext

CFStringRef path;

CFURLRef url;

CGRect pageRect = CGRectMake(0, 0,500, 500);

NSString *fileName=@"Test.pdf";
// CFStringRef passwordString = (__bridge_retained CFStringRef)password;

const char *filename = [fileName UTF8String];

// Create a CFString from the filename we provide to this method when we call it
path = CFStringCreateWithCString (NULL, filename, kCFStringEncodingUTF8);

// Create a CFURL using the CFString we just defined
url = CFURLCreateWithFileSystemPath (NULL, path, kCFURLPOSIXPathStyle, 0);

CFMutableDictionaryRef myDictionary = NULL;
// This dictionary contains extra options mostly for 'signing' the PDF

myDictionary = CFDictionaryCreateMutable(NULL, 0,
                                         &kCFTypeDictionaryKeyCallBacks,
                                         &kCFTypeDictionaryValueCallBacks);

CFDictionarySetValue(myDictionary, kCGPDFContextOwnerPassword, CFSTR("user"));
CFDictionarySetValue(myDictionary, kCGPDFContextUserPassword, CFSTR("user"));

if (!allowCopy) 
    CFDictionarySetValue(myDictionary, kCGPDFContextAllowsCopying, kCFBooleanFalse);     
//kCGPDFContextAllowsCopying is set to TRUE by default

if (!allowPrint) 
    CFDictionarySetValue(myDictionary, kCGPDFContextAllowsPrinting, kCFBooleanFalse);    
//kCGPDFContextAllowsPrinting is set to TRUE by default

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); 
NSString *documentsDirectory = [paths objectAtIndex:0]; // Get documents folder
NSString *dataPath = [documentsDirectory stringByAppendingPathComponent:fileName];

if (![[NSFileManager defaultManager] fileExistsAtPath:dataPath])
    [[NSFileManager defaultManager] createFileAtPath:dataPath contents:nil attributes:nil];
// CGRect papersize= CGRectMake(0, 0, 400, 400);

pdfContext = CGPDFContextCreateWithURL (url, &pageRect, myDictionary);

// Cleanup our mess
CFRelease(myDictionary);

CFRelease(url);

//Now, this is a tricky part. We make use of a do - while loop in order to create as many pages as needed

CGContextBeginPage (pdfContext, &pageRect); //begins a new PDF page

//create layout for our page

CGRect bounds = CGRectMake(0, 0,500,500);

UIGraphicsPushContext(pdfContext); //pushing the context, as explained at the beginning of this post

CGContextSaveGState(pdfContext);

CGContextTranslateCTM(pdfContext, 0, bounds.origin.y);

CGContextScaleCTM(pdfContext, 1, -1);

CGContextTranslateCTM(pdfContext, 0, -(bounds.origin.y + bounds.size.height));

//[@"HELLO" drawInRect:CGRectMake(10,15,10,30) withFont:[UIFont fontWithName:@"Helvetica-Bold" size:40]];

//THIS IS THE NASTY PART
CGContextRestoreGState(pdfContext);

UIGraphicsPopContext();

CGContextEndPage (pdfContext); //ends the current page

// We are done with our context now, so we release it

CGContextRelease (pdfContext);

CFRelease(path);

// Create our PDF Context with the CFURL, the CGRect we provide, and the above defined dictionary

if anyone can help.. thanks..

Answer 1

Modify the listing 13-4 and add the lines below that are placed between comments:

CFDictionarySetValue(myDictionary, kCGPDFContextTitle, CFSTR("My PDF File"));
CFDictionarySetValue(myDictionary, kCGPDFContextCreator, CFSTR("My Name"));
///
CFDictionarySetValue(myDictionary, kCGPDFContextUserPassword, CFSTR("userpassword"));
CFDictionarySetValue(myDictionary, kCGPDFContextOwnerPassword, CFSTR("ownerpassword"));
///
pdfContext = CGPDFContextCreateWithURL (url, &pageRect, myDictionary); 

The supported security options are listed at the end of the article.