--- /dev/null
+require 'rack/file'
+
+module Rack
+ class File #:nodoc:
+ alias :to_path :path
+ end
+
+ # = Sendfile
+ #
+ # The Sendfile middleware intercepts responses whose body is being
+ # served from a file and replaces it with a server specific X-Sendfile
+ # header. The web server is then responsible for writing the file contents
+ # to the client. This can dramatically reduce the amount of work required
+ # by the Ruby backend and takes advantage of the web servers optimized file
+ # delivery code.
+ #
+ # In order to take advantage of this middleware, the response body must
+ # respond to +to_path+ and the request must include an X-Sendfile-Type
+ # header. Rack::File and other components implement +to_path+ so there's
+ # rarely anything you need to do in your application. The X-Sendfile-Type
+ # header is typically set in your web servers configuration. The following
+ # sections attempt to document
+ #
+ # === Nginx
+ #
+ # Nginx supports the X-Accel-Redirect header. This is similar to X-Sendfile
+ # but requires parts of the filesystem to be mapped into a private URL
+ # hierarachy.
+ #
+ # The following example shows the Nginx configuration required to create
+ # a private "/files/" area, enable X-Accel-Redirect, and pass the special
+ # X-Sendfile-Type and X-Accel-Mapping headers to the backend:
+ #
+ # location /files/ {
+ # internal;
+ # alias /var/www/;
+ # }
+ #
+ # location / {
+ # proxy_redirect false;
+ #
+ # proxy_set_header Host $host;
+ # proxy_set_header X-Real-IP $remote_addr;
+ # proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+ #
+ # proxy_set_header X-Sendfile-Type X-Accel-Redirect
+ # proxy_set_header X-Accel-Mapping /files/=/var/www/;
+ #
+ # proxy_pass http://127.0.0.1:8080/;
+ # }
+ #
+ # Note that the X-Sendfile-Type header must be set exactly as shown above. The
+ # X-Accel-Mapping header should specify the name of the private URL pattern,
+ # followed by an equals sign (=), followed by the location on the file system
+ # that it maps to. The middleware performs a simple substitution on the
+ # resulting path.
+ #
+ # See Also: http://wiki.codemongers.com/NginxXSendfile
+ #
+ # === lighttpd
+ #
+ # Lighttpd has supported some variation of the X-Sendfile header for some
+ # time, although only recent version support X-Sendfile in a reverse proxy
+ # configuration.
+ #
+ # $HTTP["host"] == "example.com" {
+ # proxy-core.protocol = "http"
+ # proxy-core.balancer = "round-robin"
+ # proxy-core.backends = (
+ # "127.0.0.1:8000",
+ # "127.0.0.1:8001",
+ # ...
+ # )
+ #
+ # proxy-core.allow-x-sendfile = "enable"
+ # proxy-core.rewrite-request = (
+ # "X-Sendfile-Type" => (".*" => "X-Sendfile")
+ # )
+ # }
+ #
+ # See Also: http://redmine.lighttpd.net/wiki/lighttpd/Docs:ModProxyCore
+ #
+ # === Apache
+ #
+ # X-Sendfile is supported under Apache 2.x using a separate module:
+ #
+ # http://tn123.ath.cx/mod_xsendfile/
+ #
+ # Once the module is compiled and installed, you can enable it using
+ # XSendFile config directive:
+ #
+ # RequestHeader Set X-Sendfile-Type X-Sendfile
+ # ProxyPassReverse / http://localhost:8001/
+ # XSendFile on
+
+ class Sendfile
+ F = ::File
+
+ def initialize(app, variation=nil)
+ @app = app
+ @variation = variation
+ end
+
+ def call(env)
+ status, headers, body = @app.call(env)
+ if body.respond_to?(:to_path)
+ case type = variation(env)
+ when 'X-Accel-Redirect'
+ path = F.expand_path(body.to_path)
+ if url = map_accel_path(env, path)
+ headers[type] = url
+ body = []
+ else
+ env['rack.errors'] << "X-Accel-Mapping header missing"
+ end
+ when 'X-Sendfile', 'X-Lighttpd-Send-File'
+ path = F.expand_path(body.to_path)
+ headers[type] = path
+ body = []
+ when '', nil
+ else
+ env['rack.errors'] << "Unknown x-sendfile variation: '#{variation}'.\n"
+ end
+ end
+ [status, headers, body]
+ end
+
+ private
+ def variation(env)
+ @variation ||
+ env['sendfile.type'] ||
+ env['HTTP_X_SENDFILE_TYPE']
+ end
+
+ def map_accel_path(env, file)
+ if mapping = env['HTTP_X_ACCEL_MAPPING']
+ internal, external = mapping.split('=', 2).map{ |p| p.strip }
+ file.sub(/^#{internal}/i, external)
+ end
+ end
+ end
+end
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