Once you've copied a website, how do you download only new and changed files? The WebCopy UI isn't clear in this regard, so here's a few tips.
First, in order to copy only the changes to a website, the website itself needs to support the
ETag headers, and you need to set up your project in a specific way.
- The Save link information in project option should be set (General)
- The Empty website folder before copy option should not be set (Copy)
- The Always download latest version option should not be set (Advanced)
This combination of settings should ensure that WebCopy only copies new and changed files. However, if the website doesn't return a "Not Modified" response code, WebCopy has no way of knowing if the file is unchanged or not, and will proceed with the re-downloading the file.