Objective-C

Extract Linked Domains from an HTML Email

Demonstrates the Chilkat Email.LinkedDomains method, which extracts the domain names from the hyperlinks in an HTML email. Lowercase domains are appended to a StringTable without creating duplicates. This example sets an HTML body with several links and lists the distinct domains.

Background: The set of domains a message links to is a strong signal for spam and phishing analysis — legitimate mail usually points at a few expected domains, while abusive mail often hides links to many unrelated or look-alike hosts. LinkedDomains gives you that de-duplicated list directly. Note it only parses the links; it does not fetch them, so no network request is made.

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Objective-C

#import <CkoEmail.h>
#import <CkoStringTable.h>

BOOL success = NO;

//  Demonstrates the LinkedDomains method, which extracts the domain names from the
//  hyperlinks in an HTML email.  Lowercase domains are appended to a StringTable without
//  creating duplicates.

CkoEmail *email = [[CkoEmail alloc] init];
email.Subject = @"LinkedDomains example";

//  An HTML body containing several hyperlinks.
[email SetHtmlBody: @"<html><body>Visit <a href=\"https://www.example.com/page\">Example</a>, <a href=\"http://sales.contoso.com\">Contoso</a>, and <a href=\"https://www.example.com/other\">Example again</a>.</body></html>"];

//  Extract the linked domains into a StringTable.
CkoStringTable *domains = [[CkoStringTable alloc] init];

success = [email LinkedDomains: domains];
if (success == NO) {
    NSLog(@"%@",email.LastErrorText);
    return true;
}

int n = [domains.Count intValue];
int i;
for (i = 0; i <= n - 1; i++) {
    NSLog(@"%@",[domains StringAt: [NSNumber numberWithInt: i]]);
}