# File lib/rack/etag.rb, line 22 def call(env) status, headers, body = @app.call(env) if etag_status?(status) && etag_body?(body) && !skip_caching?(headers) digest, body = digest_body(body) headers['ETag'] = %("#{digest}") if digest end unless headers['Cache-Control'] headers['Cache-Control'] = (digest ? @cache_control : @no_cache_control) || [] end [status, headers, body] end