How to Add Attachments to your PDFs with Foxit PDF SDK (Objective-C)

With Foxit PDF SDK, attachments refer to documents rather than file attachment annotations. This allows whole files to be embedded in a document, much like email attachments. PDF SDK provides application APIs to access functions such as loading attachments, getting attachments, inserting/removing attachments, and accessing properties of attachments.

Example:

How to export the embedded attachment file from a PDF and save it as a single file

#include "FSPDFObjC.h"
...
FSAttachments *attachments = [[FSAttachments alloc] initWithDoc:doc nametree:[[FSPDFNameTree alloc] init]];
int count = [attachments getCount];
for (int i = 0; i < count; i++) {
    NSString *key = [attachments getKey:i];
    FSFileSpec *file_spec = [attachments getEmbeddedFile:key];
    if (![file_spec isEmpty]) {
        NSString *name = [file_spec getFileName];
        if ([file_spec isEmbedded]) {
            NSString *exFilePath = [[NSString alloc] initWithFormat:@"%@%@", output_directory, name];
            bool bExportStatus = [file_spec exportToFile:exFilePath];
        }
    }
}

How to remove all the attachments of a PDF

#include "FSPDFObjC.h"
...
// Assuming FSPDFDoc doc has been loaded.
FSAttachments *attachments = [[FSAttachments alloc] initWithDoc:doc nametree:[[FSPDFNameTree alloc] init]];
[attachments removeAllEmbeddedFiles];      
...