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--
//