Objective-C

Convert a MIME Entity to multipart/alternative

Demonstrates the Chilkat Mime.ConvertToMultipartAlt method, which wraps the current entity in a new outer multipart/alternative, making the original the first child. It takes no arguments.

Note: The file paths are relative to the application's current working directory. Absolute paths may also be used. Supply the paths appropriate to your own environment.

Background: Use this to add an alternate rendering to an existing message — for example, promoting a plain-text message so an HTML version can be added alongside it. The original content becomes the first (least-preferred) alternative, and you append the richer representation after it. As with the mixed conversion, message-level headers move to the new outer entity.

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Objective-C

#import <CkoMime.h>

BOOL success = NO;

CkoMime *mime = [[CkoMime alloc] init];
success = [mime LoadMimeFile: @"qa_data/message.eml"];
if (success == NO) {
    NSLog(@"%@",mime.LastErrorText);
    return;
}

//  Wrap the current entity in a new outer multipart/alternative entity.  The original entity
//  becomes the first child, ready for an alternate representation to be added.
success = [mime ConvertToMultipartAlt];
if (success == NO) {
    NSLog(@"%@",mime.LastErrorText);
    return;
}

//  Add an alternative representation of the same content.
CkoMime *htmlPart = [[CkoMime alloc] init];
success = [htmlPart SetBodyFromHtml: @"<html><body>HTML alternative.</body></html>"];
if (success == NO) {
    NSLog(@"%@",htmlPart.LastErrorText);
    return;
}

success = [mime AppendPart: htmlPart];
if (success == NO) {
    NSLog(@"%@",mime.LastErrorText);
    return;
}

NSLog(@"%@%d",@"Number of parts: ",[mime.NumParts intValue]);