DataFlex

HTTPS Server Certificate Require Hostname Match

See more HTTP Examples

Demonstrates and explains the RequireHostnameMatch property. DataFlex

Use ChilkatAx-win32.pkg

Procedure Test
    Handle hoHttp
    String sHtml
    Boolean bTemp1

    // The RequireHostnameMatch property was added in Chilkat v11.0.0
    // to ensure the URL's hostname matches at least one of the server certificate SAN's (Subject Alternative Names)
    // 
    // In actuality, it is the SNI hostname that must match.  If the SNI hostname is not explicitly set,
    // then Chilkat uses the hostname from the URL as the SNI hostname.

    // Here's an example using chilkatsoft.com
    // The SSL server certificate for chilkatsoft.com has 2 Subject Alternative Names:
    // 
    // 1) DNS Name: *.chilkatsoft.com
    // 2) DNS Name: chilkatsoft.com
    // 
    // See Explaining the SNI Hostname in TLS

    Get Create (RefClass(cComChilkatHttp)) To hoHttp
    If (Not(IsComObjectCreated(hoHttp))) Begin
        Send CreateComObject of hoHttp
    End

    Set ComRequireHostnameMatch Of hoHttp To True

    // This should succeed because "www.chilkatsoft.com" matches the SAN entry "*.chilkatsoft.com"
    Get ComQuickGetStr Of hoHttp "https://www.chilkatsoft.com/helloWorld.html" To sHtml
    Get ComLastMethodSuccess Of hoHttp To bTemp1
    Showln "1) Succeeded: " bTemp1

    // At the time of writing this example, the IP address for chilkatsoft.com is 3.101.18.47
    // If we send the request using the IP address, it will fail because the IP address is does 
    // not match any of the SAN entries in the server certificate.
    Get ComQuickGetStr Of hoHttp "https://3.101.18.47/helloWorld.html" To sHtml
    Get ComLastMethodSuccess Of hoHttp To bTemp1
    Showln "2) Succeeded: " bTemp1

    // However, it will succeed if we explicitly set the SNI hostname.
    Set ComSniHostname Of hoHttp To "www.chilkatsoft.com"
    Get ComQuickGetStr Of hoHttp "https://3.101.18.47/helloWorld.html" To sHtml
    Get ComLastMethodSuccess Of hoHttp To bTemp1
    Showln "3) Succeeded: " bTemp1

    // Remove our explicit SNI hostname.
    Set ComSniHostname Of hoHttp To ""

    // Now let's try wrong.host.badssl.com
    // The SSL server certificate for badssl.com has 2 Subject Alternative Names:
    // 
    // 1) DNS Name: *.badssl.com
    // 2) DNS Name: badssl.com

    // The domain wrong.host.badssl.com will fail the RequireHostnameMatch because
    // the wildcarded domain SAN entry only extends 1 level deep.  
    Get ComQuickGetStr Of hoHttp "https://wrong.host.badssl.com/" To sHtml
    Get ComLastMethodSuccess Of hoHttp To bTemp1
    Showln "4) Succeeded: " bTemp1

    // The expected output is:
    // 1) Succeeded: True
    // 2) Succeeded: False
    // 3) Succeeded: True
    // 4) Succeeded: False


End_Procedure