Objective-C

Get a Header Attribute of an Attached Message

Demonstrates the Chilkat Email.GetAttachedMessageAttr method, which returns a header-field attribute value for the Nth attached (embedded) email. The first argument is the zero-based attached-message index, the second is the header field name, and the third is the attribute name. This example attaches an email and reads the filename attribute of its Content-Disposition header.

Background: MIME header fields can carry named attributes (parameters) after the main value — for example Content-Disposition: attachment; filename="report.eml", where filename is an attribute. Rather than parsing the raw header yourself, this method extracts a single named attribute from a chosen header of a specific embedded message, which is convenient when a message forwards other emails as nested message/rfc822 parts.

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Objective-C

#import <CkoEmail.h>
#import <NSString.h>

BOOL success = NO;

//  Demonstrates the GetAttachedMessageAttr method, which returns a header-field attribute
//  value for the Nth attached (embedded) email.  The first argument is the zero-based
//  attached-message index, the second is the header field name, and the third is the attribute name.

//  Build an inner email to attach.
CkoEmail *innerEmail = [[CkoEmail alloc] init];
innerEmail.Subject = @"Embedded message";
innerEmail.From = @"alice@example.com";
[innerEmail AddTo: @"Bob" emailAddress: @"bob@example.com"];

//  Attach it to an outer email as a message/rfc822 part.
CkoEmail *email = [[CkoEmail alloc] init];
email.Subject = @"Has an attached message";
success = [email AttachEmail: innerEmail];
if (success == NO) {
    NSLog(@"%@",email.LastErrorText);
    return true;
}

//  Get the "filename" attribute of the "Content-Disposition" header of the first
//  attached message (index 0).
NSString *fname = [email GetAttachedMessageAttr: [NSNumber numberWithInt: 0] fieldName: @"Content-Disposition" attrName: @"filename"];
NSLog(@"%@%@",@"Attached message filename attribute: ",fname);