Objective-C
Send HTML Email with External CSS as Related Item

Demonstrates how to compose an HTML email with an external CSS file included as a related item and referenced by CID (Content-ID).
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Objective-C
#import <CkoMailMan.h>
#import <CkoEmail.h>
#import <CkoStringBuilder.h>
#import <NSString.h>

BOOL success = NO;

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

// The mailman object is used for sending and receiving email.
CkoMailMan *mailman = [[CkoMailMan alloc] init];

// Use your SMTP server hostname.  This example uses office365, but it could be any SMTP server..
mailman.SmtpHost = @"outlook.office365.com";
mailman.SmtpPort = [NSNumber numberWithInt:587];
mailman.StartTLS = YES;

// Set the SMTP login/password
mailman.SmtpUsername = @"OFFICE365-SMTP-LOGIN";
mailman.SmtpPassword = @"OFFICE365-SMTP-PASSWORD";

// Create a new email object
CkoEmail *email = [[CkoEmail alloc] init];
email.Subject = @"HTML Email with embedded CSS";
email.From = @"Chilkat Support <my-office365-user@mydomain.com>";
[email AddTo: @"Chilkat Support" emailAddress: @"support@chilkatsoft.com"];

CkoStringBuilder *sbCss = [[CkoStringBuilder alloc] init];
BOOL bCrlf = YES;
[sbCss AppendLine: @"body {" crlf: bCrlf];
[sbCss AppendLine: @"    background-color: powderblue;" crlf: bCrlf];
[sbCss AppendLine: @"}" crlf: bCrlf];
[sbCss AppendLine: @"h1 {" crlf: bCrlf];
[sbCss AppendLine: @"    color: blue;" crlf: bCrlf];
[sbCss AppendLine: @"}" crlf: bCrlf];
[sbCss AppendLine: @"p {" crlf: bCrlf];
[sbCss AppendLine: @"    color: red;" crlf: bCrlf];
[sbCss AppendLine: @"}" crlf: bCrlf];

// It's possible to add a CSS file directly by calling AddRelatedFile.
// This example will add the CSS from a string.
NSString *filenameInHtml = @"styles.css";
NSString *contentIdCss = [email AddRelatedString: filenameInHtml str: [sbCss GetAsString] charset: @"utf-8"];
if (email.LastMethodSuccess != YES) {
    NSLog(@"%@",email.LastErrorText);
    return;
}

// The src attribute for the image tag is set to the contentIdCss:
CkoStringBuilder *sbHtml = [[CkoStringBuilder alloc] init];
[sbHtml AppendLine: @"<!DOCTYPE html>" crlf: bCrlf];
[sbHtml AppendLine: @"<html>" crlf: bCrlf];
[sbHtml AppendLine: @"<head>" crlf: bCrlf];
[sbHtml AppendLine: @"  <link rel=\"stylesheet\" href=\"cid:CONTENT_ID_CSS\">" crlf: bCrlf];
[sbHtml AppendLine: @"</head>" crlf: bCrlf];
[sbHtml AppendLine: @"<body>" crlf: bCrlf];
[sbHtml AppendLine: @"" crlf: bCrlf];
[sbHtml AppendLine: @"<h1>This is a heading</h1>" crlf: bCrlf];
[sbHtml AppendLine: @"<p>This is a paragraph.</p>" crlf: bCrlf];
[sbHtml AppendLine: @"" crlf: bCrlf];
[sbHtml AppendLine: @"</body>" crlf: bCrlf];
[sbHtml AppendLine: @"</html>" crlf: bCrlf];

int numReplacements = [[sbHtml Replace: @"CONTENT_ID_CSS" replacement: contentIdCss] intValue];

[email SetHtmlBody: [sbHtml GetAsString]];

success = [mailman SendEmail: email];
if (success != YES) {
    NSLog(@"%@",mailman.LastErrorText);
}
else {
    NSLog(@"%@",@"Mail Sent!");
}