Parsing JSON values from media file metadata on OSX - json

Question

This is my very first attempt at Swift 3 and Xcode 8.3.3. I'm trying to parse a JSON metadata extracted from a file through the command-line application Exiftool.
let task = Process()
let filePath = url.path
let etPath = "/usr/local/bin/exiftool"
task.launchPath = etPath
task.arguments = ["-a", "-g1", "-json", filePath]
let pipe = Pipe()
task.standardOutput = pipe
task.launch()
// Get the data
let data = pipe.fileHandleForReading.readDataToEndOfFile()
let output = NSString(data: data, encoding: String.Encoding.utf8.rawValue)
let mydata = output?.data(using: String.Encoding.utf8.rawValue)!
do {
let myJson = try JSONSerialization.jsonObject(with: mydata!, options: []) as AnyObject
if let XMPdc = myJson["XMP-dc"] as AnyObject? {
if let creator = XMPdc["Creator"] as! NSArray? {
print(creator)
}
}
} catch let error as NSError {
print(error)
}
The first part of the script works well, allowing me to get the JSON data into the variable myJson. If I print that variable out, I obtain this:
(
{
Composite = {
ImageSize = 100x100;
Megapixels = "0.01";
};
ExifIFD = {
ColorSpace = Uncalibrated;
ExifImageHeight = 100;
ExifImageWidth = 100;
};
ExifTool = {
ExifToolVersion = "10.61";
};
File = {
ExifByteOrder = "Little-endian (Intel, II)";
FileType = TIFF;
FileTypeExtension = tif;
MIMEType = "image/tiff";
};
"ICC-header" = {
CMMFlags = "Not Embedded, Independent";
ColorSpaceData = "RGB ";
ConnectionSpaceIlluminant = "0.9642 1 0.82487";
DeviceAttributes = "Reflective, Glossy, Positive, Color";
DeviceManufacturer = KODA;
DeviceModel = ROMM;
PrimaryPlatform = "Microsoft Corporation";
ProfileCMMType = KCMS;
ProfileClass = "Display Device Profile";
ProfileConnectionSpace = "XYZ ";
ProfileCreator = KODA;
ProfileDateTime = "1998:12:01 18:58:21";
ProfileFileSignature = acsp;
ProfileID = 0;
ProfileVersion = "2.1.0";
RenderingIntent = "Media-Relative Colorimetric";
};
"ICC_Profile" = {
BlueMatrixColumn = "0.03134 9e-05 0.82491";
BlueTRC = "(Binary data 14 bytes, use -b option to extract)";
DeviceMfgDesc = KODAK;
DeviceModelDesc = "Reference Output Medium Metric(ROMM) ";
GreenMatrixColumn = "0.13519 0.71188 0";
GreenTRC = "(Binary data 14 bytes, use -b option to extract)";
MakeAndModel = "(Binary data 40 bytes, use -b option to extract)";
MediaWhitePoint = "0.9642 1 0.82489";
ProfileCopyright = "Copyright (c) Eastman Kodak Company, 1999, all rights reserved.";
ProfileDescription = "ProPhoto RGB";
RedMatrixColumn = "0.79767 0.28804 0";
RedTRC = "(Binary data 14 bytes, use -b option to extract)";
};
IFD0 = {
Artist = Autore;
BitsPerSample = "16 16 16";
Compression = LZW;
ImageDescription = "Creator: Test ; Date: 1900";
ImageHeight = 100;
ImageWidth = 100;
ModifyDate = "2017:08:10 10:58:42";
Orientation = "Horizontal (normal)";
PhotometricInterpretation = RGB;
PlanarConfiguration = Chunky;
ResolutionUnit = inches;
RowsPerStrip = 100;
SamplesPerPixel = 3;
Software = "Adobe Photoshop CC 2015 (Macintosh)";
StripByteCounts = 1037;
StripOffsets = 11450;
SubfileType = "Full-resolution Image";
XResolution = 300;
YCbCrPositioning = "Co-sited";
YResolution = 300;
};
Photoshop = {
DisplayedUnitsX = inches;
DisplayedUnitsY = inches;
GlobalAltitude = 30;
GlobalAngle = 90;
HasRealMergedData = Yes;
IPTCDigest = 00000000000000000000000000000000;
PhotoshopThumbnail = "(Binary data 557 bytes, use -b option to extract)";
PixelAspectRatio = 1;
PrintPosition = "0 0";
PrintScale = 1;
PrintStyle = Centered;
ReaderName = "Adobe Photoshop CC 2015";
SlicesGroupName = "";
"URL_List" = (
);
WriterName = "Adobe Photoshop";
XResolution = 300;
YResolution = 300;
};
"XMP-dc" = {
Creator = Autore;
Description = "Creator: Test ; Date: 1900";
Format = "image/tiff";
Publisher = "-";
Rights = "-";
Subject = "-";
Title = tite;
};
"XMP-pdf" = {
Producer = "-";
};
"XMP-photoshop" = {
ColorMode = RGB;
ICCProfileName = "ProPhoto RGB";
};
"XMP-x" = {
XMPToolkit = "Image::ExifTool 10.53";
};
"XMP-xmp" = {
CreateDate = 1900;
CreatorTool = "Adobe Photoshop CC 2015 (Macintosh)";
MetadataDate = "2017:08:10 10:58:42-04:00";
ModifyDate = "2017:08:10 10:58:42-04:00";
ThumbnailFormat = "-";
ThumbnailImage = "(Binary data 48 bytes, use -b option to extract)";
};
"XMP-xmpRights" = {
Marked = 1;
};
}
)
However, I don't understand how to correctly parse the data in order to store a specific value, let's say the value that corresponds to the object { "XMP-dc" = {Creator = Autore } }, within my variable creator.
What am I doing wrong?

Answer 1

Try to downcast your json and xmp-dc to the dictionary
let myJson = try JSONSerialization.jsonObject(with: mydata!, options: []) as? [String: Any]
if let XMPdc = myJson?["XMP-dc"] as? [String: Any?] {
//print that dictionary to be sure that al is correct
print(XMPdc)
//I'm not sure that the value Creator is an Array, honestly I don't understand what is the type of that object, but anyway, few fixes for your code
if let creator = XMPdc["Creator"] as? NSArray {
print(creator)
}
}
Again, I'm not sure about the type of the variable Creator, but at least you will know this when you will make print(XMPdc), then you can change the downcast for the creator to the String or whatever.
Let me know if you need something