This middleware adds the
Strict-Transport-Security header to the response. This tells browsers, "hey, only use HTTPS for the next period of time". (See the spec for more.) Note that the header won't tell users on HTTP to switch to HTTPS, it will just tell HTTPS users to stick around. You can enforce HTTPS with the express-enforces-ssl module.
This will set the Strict Transport Security header, telling browsers to visit by HTTPS for the next 180 days:
var hsts =app// Strict-Transport-Security: max-age: 15552000; includeSubDomains
Note that the max age must be in seconds. This was different in previous versions of this module!
includeSubDomains directive is present by default. If this header is set on example.com, supported browsers will also use HTTPS on my-subdomain.example.com. You can disable this:
Chrome lets you submit your site for baked-into-Chrome HSTS by adding
preload to the header. You can add that with the following code, and then submit your site to the Chrome team at hstspreload.appspot.com.
This header will always be set because the header is ignored in insecure HTTP. If you wish to set it conditionally, you can use
This header is somewhat well-supported by browsers.