Objective-C
Add, Remove, Update MIME Header Fields

Demonstrates how to add, remove, or update the content of MIME header fields.
Chilkat Objective-C Downloads

Objective-C
#import <CkoMime.h>

BOOL success = NO;

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

CkoMime *mime = [[CkoMime alloc] init];

// The contents of this MIME file are shown below, 
// and is also available at https://www.chilkatsoft.com/sampleMime.txt
success = [mime LoadMimeFile: @"qa_data/mime/sampleMime.txt"];
if (success == NO) {
    NSLog(@"%@",mime.LastErrorText);
    return;
}

// The MIME used in this example has the following nested structure
// 
// multipart/alternative
//     text/plain
//     multipart/related
//         text/html
//         image/jpeg
// 

// Adding a top-level MIME header is easy.
[mime AddHeaderField: @"hello-world" value: @"Hello World!"];
// If a header field of the same name already exists, the AddHeaderField
// method adds a duplicate.
[mime AddHeaderField: @"Subject" value: @"This is the 2nd Subject header."];
NSLog(@"%@",[mime GetEntireHead]);
NSLog(@"%@",@"-");

// The top-level header now looks like this:
// 
// 	Subject: Test email.
// 	Content-Type: multipart/alternative; boundary="------------DB171738719FB06D67DEBAA0"
// 	MIME-Version: 1.0
// 	hello-world: Hello World!
// 	Subject: This is the 2nd Subject header.
// 

// The RemoveHeaderField method can remove the 1st occurrance, or all occurrences.
BOOL bAllOccurrences = YES;
// Remove all occurrences of the Subject header;
[mime RemoveHeaderField: @"Subject" bAllOccurrences: bAllOccurrences];
NSLog(@"%@",[mime GetEntireHead]);
NSLog(@"%@",@"-");

// After removing all Subject header fields, the top-level header now looks like this:
// 
// Content-Type: multipart/alternative; boundary="------------DB171738719FB06D67DEBAA0"
// MIME-Version: 1.0
// hello-world: Hello World!
// 

// The content of a header field can be updated by calling SetHeaderField.
// If the header field does not already exist, it is added.  Otherwise it is updated.
// Note: The order of header fields SHOULD never matter.
[mime SetHeaderField: @"hello-world" value: @"Goodbye World."];
NSLog(@"%@",[mime GetEntireHead]);
NSLog(@"%@",@"-");

// Now we have:
// 
// 	Content-Type: multipart/alternative; boundary="------------DB171738719FB06D67DEBAA0"
// 	MIME-Version: 1.0
// 	hello-world: Goodbye World.
// 

// To add/update/delete header fields in sub-parts, navigate to
// the sub-part and do the same..

CkoMime *mpRelated = [[CkoMime alloc] init];
[mime PartAt: [NSNumber numberWithInt: 1] subPart: mpRelated];

CkoMime *pJpg = [[CkoMime alloc] init];
[mpRelated PartAt: [NSNumber numberWithInt: 1] subPart: pJpg];

// Add a header to the image/jpeg sub-header.
[pJpg SetHeaderField: @"CustomHeader" value: @"This is the custom header value."];

// View the entire MIME..
NSLog(@"%@",[mime GetMime]);

// --------------------------------------------------------------
// --------------------------------------------------------------
// The MIME sample file loaded at the beginning of this example
// contains the following MIME:

// Subject: Test email.
// Content-Type: multipart/alternative;
// 	boundary="------------DB171738719FB06D67DEBAA0"
// MIME-Version: 1.0
// 
// --------------DB171738719FB06D67DEBAA0
// Content-Type: text/plain; charset="utf-8"; format=flowed
// Content-Transfer-Encoding: 7bit
// 
// This is a test.
// 
// --------------DB171738719FB06D67DEBAA0
// Content-Type: multipart/related;
// 	boundary="------------A940F1230E6F0105F03DB2CB"
// 
// --------------A940F1230E6F0105F03DB2CB
// Content-Type: text/html; charset="utf-8"
// Content-Transfer-Encoding: 8bit
// 
// <html><head>
// <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
//   </head>
//   <body bgcolor="#FFFFFF" text="#000000">
//     <p>This is a test.&nbsp; <img src="cid:part1.E16AE3B4.1505C436@chilkatsoft.com" height="20" width="20"></p>
//   </body>
// </html>
// 
// --------------A940F1230E6F0105F03DB2CB
// Content-Type: image/jpeg; name="starfish20.jpg"
// Content-Transfer-Encoding: base64
// Content-ID: <part1.E16AE3B4.1505C436@chilkatsoft.com>
// Content-Disposition: inline; filename="starfish20.jpg"
// 
// /9j/4AAQSkZJRgABAQEASABIAAD//gAmRmlsZSB3cml0dGVuIGJ5IEFkb2JlIFBob3Rvc2hvcD8g
// NC4w/9sAQwAQCwwODAoQDg0OEhEQExgoGhgWFhgxIyUdKDozPTw5Mzg3QEhcTkBEV0U3OFBtUVdf
// YmdoZz5NcXlwZHhcZWdj/9sAQwEREhIYFRgvGhovY0I4QmNjY2NjY2NjY2NjY2NjY2NjY2NjY2Nj
// Y2NjY2NjY2NjY2NjY2NjY2NjY2NjY2NjY2Nj/8IAEQgAFAAUAwERAAIRAQMRAf/EABcAAAMBAAAA
// AAAAAAAAAAAAAAIDBAX/xAAYAQADAQEAAAAAAAAAAAAAAAABAgMEAP/aAAwDAQACEAMQAAAB2kZY
// NNEijWKddfTmLgALWH//xAAbEAACAgMBAAAAAAAAAAAAAAABAgMRAAQSE//aAAgBAQABBQL0XqN+
// pM2aqJGMiqFFCyg7z//EABwRAAICAgMAAAAAAAAAAAAAAAERAAIQIQMSUf/aAAgBAwEBPwHqU5aq
// Axx+y1tMQl4elj//xAAcEQEAAQUBAQAAAAAAAAAAAAABEQACEBIhA1H/2gAIAQIBAT8B3Bhqy7Zc
// enyiwmGgDhiOzj//xAAdEAABAwUBAAAAAAAAAAAAAAABAAIREBIhIkFR/9oACAEBAAY/ArZyn+Cg
// xtxWuJaoCnqDuin/xAAcEAABBAMBAAAAAAAAAAAAAAABABEhYRAxQVH/2gAIAQEAAT8hkEwPUUR9
// DYfE4nxtRpIkBTsayuALIiuY/9oADAMBAAIAAwAAABDWPTsf/8QAGhEAAwADAQAAAAAAAAAAAAAA
// AAEREDFBIf/aAAgBAwEBPxC0DVPcWm+Ce4OesrkE6bjH/8QAGBEBAQEBAQAAAAAAAAAAAAAAAREA
// QRD/2gAIAQIBAT8QahMiOc8YgSrnTY3ELclHXn//xAAcEAEBAAIDAQEAAAAAAAAAAAABEQAhMUFx
// EFH/2gAIAQEAAT8Qn3igmSZSj+c4N4zapMy9IjFV98wncN2iuLFsCEbDGxQkI6RO/n//2Q==
// 
// --------------A940F1230E6F0105F03DB2CB--
// 
// --------------DB171738719FB06D67DEBAA0--
//