ring-middleware

This project is adapted from tailrecursion's ring-proxy middleware, and is meant for use with the Trapperkeeper Jetty9 Webservice.

Usage

To use ring-middleware, add this project as a dependency in your leiningen project file:

wrap-proxy

This project provides a wrap-proxy function with the following signature:

(wrap-proxy [handler proxied-path remote-uri-base & [http-opts]])

This function returns a ring handler that, when given a URL with a certain prefix, proxies the request to a remote URL specified by the remote-uri-base argument.

The arguments are as follows:

• handler: A ring-handler that will be used if the provided url does not begin with the proxied-path prefix
• proxied-path: The URL prefix of all requests that are to be proxied. This can be either a string or a regular expression pattern. Note that, when this is a regular expression, the entire request URI will be appended to remote-uri-base when the URI is being rewritten, whereas if this argument is a string, the proxied-path will not be included.
• remote-uri-base: The base URL that you want to proxy requests with the proxied-path prefix to
• http-opts: An optional list of options for an http client. This is used by the handler returned by wrap-proxy when it makes a proxied request to a remote URI. For a list of available options, please see the options defined for clj-http-client.

For example, the following:

(wrap-proxy handler "/hello-world" "http://localhost:9000/hello")

would return a ring handler that proxies all requests with URL prefix "/hello-world" to http://localhost:9000/hello.

The following:

(wrap-proxy handler #"^/hello-world" "http://localhost:9000/hello")

would return a ring handler that proxies all requests with a URL path matching the regex #^/hello-world" to http://localhost:9000/hello/[url-path].

Proxy Redirect Support

By default, all proxy requests using wrap-proxy will follow any redirects, including on POST and PUT requests. To allow redirects but restrict their use on POST and PUT requests, set the :force-redirects option to false in the http-opts map. To disable redirect following on proxy requests, set the :follow-redirects option to false in the http-opts map. Please not that if proxy redirect following is disabled, you may have to disable it on the client making the proxy request as well if the location returned by the redirect is relative.

SSL Support

wrap-proxy supports SSL. To add SSL support, you can set SSL options in the http-opts map as you would in a request made with clj-http-client. Simply set the :ssl-cert, :ssl-key, and :ssl-ca-cert options in the http-opts map to be paths to your .pem files.

wrap-with-certificate-cn

This middleware adds a :ssl-client-cn key to the request map if a :ssl-client-cert is present. If no client certificate is present, the key's value is set to nil. This makes for easier certificate whitelisting (using the cert whitelisting function from pl/kitchensink)

wrap-add-cache-headers

A utility middleware with the following signature:

(wrap-add-cache-headers [handler])

This middleware adds cache-control headers ("private, max-age=0, no-cache") to GET and PUT requests if they are handled by the handler.

wrap-add-x-frame-options-deny

A utility middleware with the following signature:

(wrap-add-x-frame-options-deny [handler])

This middleware adds X-Frame-Options: DENY headers to requests if they are handled by the handler.