Adding setCookies option to a page instance

README.md

@@ -139,6 +139,36 @@ only really makes sense if you're calling Grover directly (and not via middlewar
 Grover.new('<some URI with basic authentication', username: 'the username', password: 'super secret').to_pdf
 ```
 
+#### Adding cookies
+If you need to set cookies to your new page instance, just pass them along like this (please note that the only required properties are `name` and `value`. Check [.setCookies](https://github.com/puppeteer/puppeteer/blob/master/docs/api.md#pagesetcookiecookies) docs):
+
+```ruby
+myCookies = [
+  { name: 'sign_username', value: 'any@any.com', domain: 'mydomain' },
+  { name: '_session_id', value: '9c014df0b699d8dc08d1c472f8cc594c', domain: 'mydomain' }
+]
+Grover.new('<some URI with cookies', cookies: myCookies).to_pdf
+```
+
+If, let's say, you wanted to just forward the cookies that you got on your original request, you can do something like:
+
+```ruby
+def header_cookies
+  request.headers['Cookie'].split('; ').map do |cookie|
+    key, value = cookie.split '='
+    { name: key, value: value, domain: request.headers['Host'] }
+  end
+end
+```
+
+And give that array to Grover:
+
+```ruby
+myCookiesFromRequest = header_cookies(request)
+Grover.new('<some URI with cookies', cookies: myCookiesFromRequest).to_pdf
+```
+
+
 #### Page URL for middleware requests (or passing through raw HTML)
 If you want to have the header or footer display the page URL, Grover requires that this is passed through via the
 `display_url` option. This is because the page URL is not available in the raw HTML!

lib/grover.rb

@@ -65,6 +65,12 @@ def self.convert_function(convert_action)
               await page.authenticate({ username, password });
             }
 
+            // Setting cookies
+            const cookies = options.cookies; delete options.cookies
+            if (cookies != undefined && Array.isArray(cookies)) {
+              await page.setCookie(...cookies);
+            }
+
             // Set caching flag (if provided)
             const cache = options.cache; delete options.cache;
             if (cache != undefined) {