pdfprops.m

#import <Foundation/Foundation.h>
#import <Quartz/Quartz.h>

// prints a short hint about how to use the utility
void printUsage (void) {
	printf("\npdfprops - Tool to modify PDF metadata\n\n");
	printf("Usage: pdfprops [-file PDF file path] [arguments]\n\n");
	printf("Arguments:\n");
	printf("\t[-author 'Max Frisch']\n");
	printf("\t[-title 'Homo faber']\n");
	printf("\t[-subject 'Whatever']\n");
	printf("\t[-creator 'A wonderful Mac application']\n");
	printf("\t[-keywords 'Literature,Fiction,Book']\n\n");
	printf("Example: pdfprops -file '/Users/steve/Desktop/test.pdf' -author 'Steve Jobs' -keywords 'iPhone,Mac,iPod'\n\n");
}

// workhorse routine
int main (int argc, const char * argv[]) {
    NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
	
	// checking the given command line arguments
	NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];
	NSString *filePath = [userDefaults stringForKey:@"file"];
	if (filePath == NULL) {
		printf("ERROR: Missing PDF file path\n");
		printUsage();
		return 1;
	}
	NSString *author = [userDefaults stringForKey:@"author"];
	NSString *title = [userDefaults stringForKey:@"title"];
	NSString *subject = [userDefaults stringForKey:@"subject"];
	NSString *creator = [userDefaults stringForKey:@"creator"];
	NSString *keywordsString = [userDefaults stringForKey:@"keywords"];
	NSArray *keywords;
	if (!keywordsString == nil) {
		keywords = [keywordsString componentsSeparatedByString:@","];
	}
	
	// does the given file path exist?
	NSFileManager *fileManager = [NSFileManager defaultManager];
	BOOL isDir;
	if (! [fileManager fileExistsAtPath:filePath isDirectory:&isDir]) {
		printf("ERROR: The given file path does not exist\n%s\n", [filePath UTF8String]);
		return 1;
	} else {
		if (isDir) {
			printf("ERROR: The given file path points to a directory\n%s\n", [filePath UTF8String]);
			return 1;
		}
	}
	
	// loading the PDF document
	NSURL *fileURL = [NSURL fileURLWithPath:filePath];
	PDFDocument *pdfDoc = [[PDFDocument alloc] initWithURL:fileURL];
	if (pdfDoc == NULL) {
		printf("ERROR: The file does not seem to be a PDF document\n%s\n", [filePath UTF8String]);
		return 1;
	}

	// modifying the PDF document attributes
	NSMutableDictionary *pdfProps = [[NSMutableDictionary alloc] initWithCapacity:1];
	[pdfProps addEntriesFromDictionary:[pdfDoc documentAttributes]];
	if (!author == nil) {
		[pdfProps setValue:author forKey:@"Author"];
	}
	if (!title == nil) {
		[pdfProps setValue:title forKey:@"Title"];
	}
	if (!subject == nil) {
		[pdfProps setValue:subject forKey:@"Subject"];
	}
	if (!creator == nil) {
		[pdfProps setValue:creator forKey:@"Creator"];
	}
	if (!keywordsString == nil) {
		[pdfProps setValue:keywords forKey:@"Keywords"];
	}
	[pdfDoc setDocumentAttributes:pdfProps];
	
	// writing the PDF out
	BOOL pdfWriteSuccess = [pdfDoc writeToFile:filePath];
	if (! pdfWriteSuccess) {
		printf("ERROR: Could not write to file\n%s\n", [filePath UTF8String]);
		return 1;
	}
	
	// cleaning up
	[pdfProps release];
	[pdfDoc release];
    [pool release];
    return 0;
}