html - Determin if content of url has changed -

html - Determin if content of url has changed -

hello want save or content of url compare online version see if there changes. destination of url html page.

my simple approach be: store string , compare string don't think optimal way.

do have advices how accomplish in ios?

here article covers question https://devcenter.heroku.com/articles/increasing-application-performance-with-http-cache-headers article ios side https://devcenter.heroku.com/articles/ios-network-caching-http-headers

you need utilize either etag or last-modified techniques.

html ios objective-c iphone web-services