Tcl Requires Chilkat v11.0.0+

HTTPS Server Certificate Require Hostname Match

See more HTTP Examples

Demonstrates and explains the RequireHostnameMatch property. Tcl

load ./chilkat.dll

#  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

set http [new_CkHttp]

CkHttp_put_RequireHostnameMatch $http 1

#  This should succeed because "www.chilkatsoft.com" matches the SAN entry "*.chilkatsoft.com"
set html [CkHttp_quickGetStr $http "https://www.chilkatsoft.com/helloWorld.html"]
puts "1) Succeeded: [CkHttp_get_LastMethodSuccess $http]"

#  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.
set html [CkHttp_quickGetStr $http "https://3.101.18.47/helloWorld.html"]
puts "2) Succeeded: [CkHttp_get_LastMethodSuccess $http]"

#  However, it will succeed if we explicitly set the SNI hostname.
CkHttp_put_SniHostname $http "www.chilkatsoft.com"
set html [CkHttp_quickGetStr $http "https://3.101.18.47/helloWorld.html"]
puts "3) Succeeded: [CkHttp_get_LastMethodSuccess $http]"

#  Remove our explicit SNI hostname.
CkHttp_put_SniHostname $http ""

#  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.  
set html [CkHttp_quickGetStr $http "https://wrong.host.badssl.com/"]
puts "4) Succeeded: [CkHttp_get_LastMethodSuccess $http]"

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

delete_CkHttp $http