(Objective-C) Extract Embedded Files from PDF

Demonstrates how to get information about the embedded files (if any) contained within a PDF, and shows how to extract each file.

Note: This example requires Chilkat v9.5.0.95 or greater.

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#import <CkoPdf.h>
#import <CkoJsonObject.h>
#import <CkoBinData.h>
#import <NSString.h>

// This example requires the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

CkoPdf *pdf = [[CkoPdf alloc] init];

BOOL success = [pdf LoadFile: @"qa_data/pdf/embedded_files/my_embedded_files_test.pdf"];
if (success == NO) {
    NSLog(@"%@",pdf.LastErrorText);
    return;
}

// Note: The embedded file functionality was added in Chilkat v9.5.0.95

// How many embedded files exist within the opened PDF?
int numFiles = [pdf.NumEmbeddedFiles intValue];
NSLog(@"%@%d",@"Number of embedded files: ",numFiles);

CkoJsonObject *json = [[CkoJsonObject alloc] init];
json.EmitCompact = NO;

CkoBinData *bd = [[CkoBinData alloc] init];

// Get information about each file, and extract each to the filesystem.
int i = 0;
while (i < numFiles) {

    success = [pdf GetEmbeddedFileInfo: [NSNumber numberWithInt: i] json: json];
    if (success == NO) {
        NSLog(@"%@",pdf.LastErrorText);
        return;
    }

    NSLog(@"%@",[json Emit]);

    // Get the filename from the JSON.
    NSString *filename = @"someFile.dat";

    // The filename SHOULD always be present..
    if ([json HasMember: @"filename"] == YES) {
        filename = [json StringOf: @"filename"];
    }

    // Get the file data.
    success = [pdf GetEmbeddedFileBd: [NSNumber numberWithInt: i] bd: bd];
    if (success == NO) {
        NSLog(@"%@",pdf.LastErrorText);
        return;
    }

    // Save the contents of the bd to the filename (in the current working directory) in the filesystem.
    success = [bd WriteFile: filename];
    if (success == NO) {
        NSLog(@"%@",@"Failed to write output file.");
    }

    i = i + 1;
}

// Sample output for the above code:

// Number of embedded files: 3
// {
//   "filename": "employees.json",
//   "desc": "JSON",
//   "subType": "application/json",
//   "size": 159,
//   "creationDate": "D:20230715170506-05'00'",
//   "modDate": "D:20160207153838-05'00'"
// }
// 
// {
//   "filename": "rsaPubKey.pem",
//   "desc": "RSA Public Key PEM",
//   "size": 451,
//   "creationDate": "D:20230715170546-05'00'",
//   "modDate": "D:20150724133153-05'00'"
// }
// 
// {
//   "filename": "starfish.jpg",
//   "desc": "Starfish JPG",
//   "subType": "image/jpeg",
//   "size": 6229,
//   "creationDate": "D:20230715170356-05'00'",
//   "modDate": "D:20080529103055-05'00'"
// }