wrap-resource should set basic response headers

[djpowell]

wrap-resource doesn't make an attempt to set any response headers, such as last-modified and content-length; and wrap-file-info isn't compatible with wrap-resource unless the resource came from a file on the class-path. If the resource came from a jar file, we end up without the response headers set.

I package my app as an uber-jar, so I'd like wrap-resource to support conditional gets.

It is easy enough to get the content-length and last-modified date for a resource URL, using something like the following. This works whether the resource comes from a file or a jar file (or anywhere else for that matter)

(defn last-modified-and-content-length
  [^java.net.URL res-url]
  (let [ucon (.openConnection res-url)]
    [(.getLastModified ucon) (.getContentLengthLong ucon)]))

Could we incorporate something like this into wrap-resource?

[weavejester]

This is actually one of the things that is planned for Ring 1.2.0. The new not-modified middleware will handle "304 Not Modified" responses for handlers that return a response with a "Last Modified" or "Etag" header.

The next step is to change ring.util.response/resource-response function to return a more headers, such as Last-Modified and, as you pointed out, setting the Content-Length would be a good idea as well.

[djpowell]

Here's a patch:
djpowell@89033af

• Adds Content-Length and Last-Modified to all resource-responses.
• Fixes a problem when directories paths are detected as resources.

[weavejester]

Would it be possible to open up a pull request for that? It makes keeping track of patches a little easier.

[weavejester]

This has been merged in.