问Rails 4通过https为Facebook头像提供服务

EN

<% if current_user.get_avatar_url.present? %>
                                    <img src="<%= current_user.get_avatar_url %>" width="40" height = "40" class="img-circle profile-nav"/>
                                <% else %>
                                    <img src="<%= asset_url('default-avatar.png') %>" width="40" height = "40" class="img-circle profile-nav"/>
                                <% end %>

def get_avatar_url
    ret = ''
    if self.profile.present? && self.profile.user_avatar.present?
        ret = self.profile.user_avatar.avatar.thumb.url
    end
    if ret.blank? && self.provider == 'facebook'
        ret = self.profile.avatar
    end
    ret = '/assets/default-avatar.png' if ret.blank?
    ret
end

<img src="http://graph.facebook.com/xxxxxxxxxx/picture?type=large" width="40" height="40" class="img-circle profile-nav">

Mixed Content: The page at 'https://www.example.com/#_=_' was loaded over HTTPS, but requested an insecure image 'http://graph.facebook.com/xxxxxxx/picture?type=large'. This content should also be served over HTTPS.