add proxying tornado server in Serve post-processor

IPython/nbconvert/postprocessors/serve.py

@@ -1,6 +1,4 b''
-"""
-Contains postprocessor for serving nbconvert output.
-"""
+"""PostProcessor for serving reveal.js HTML slideshows."""
 #-----------------------------------------------------------------------------
 #Copyright (c) 2013, the IPython Development Team.
 #
@@ -16,40 +14,94 b' Contains postprocessor for serving nbconvert output.'
 import os
 import webbrowser
 
-from BaseHTTPServer import HTTPServer
-from SimpleHTTPServer import SimpleHTTPRequestHandler
+from tornado import web, ioloop, httpserver
+from tornado.httpclient import AsyncHTTPClient
 
-from IPython.utils.traitlets import Bool
+from IPython.utils.traitlets import Bool, Unicode, Int
 
 from .base import PostProcessorBase
 
 #-----------------------------------------------------------------------------
 # Classes
 #-----------------------------------------------------------------------------
+
+class ProxyHandler(web.RequestHandler):
+    """handler the proxies requests from a local prefix to a CDN"""
+    @web.asynchronous
+    def get(self, prefix, url):
+        """proxy a request to a CDN"""
+        proxy_url = "/".join([self.settings['cdn'], url])
+        client = self.settings['client']
+        client.fetch(proxy_url, callback=self.finish_get)
+    
+    def finish_get(self, response):
+        """finish the request"""
+        # copy potentially relevant headers
+        for header in ["Content-Type", "Cache-Control", "Date", "Last-Modified", "Expires"]:
+            if header in response.headers:
+                self.set_header(header, response.headers[header])
+        self.finish(response.body)
+
 class ServePostProcessor(PostProcessorBase):
-    """Post processor designed to serve files"""
+    """Post processor designed to serve files
+    
+    Proxies reveal.js requests to a CDN if no local reveal.js is present
+    """
 
 
     open_in_browser = Bool(True, config=True,
-                           help="""Set to False to deactivate
-                           the opening of the browser""")
+        help="""Should the browser be opened automatically?"""
+    )
+    reveal_cdn = Unicode("https://cdn.jsdelivr.net/reveal.js/2.4.0", config=True,
+        help="""URL for reveal.js CDN."""
+    )
+    reveal_prefix = Unicode("reveal.js", config=True, help="URL prefix for reveal.js")
+    ip = Unicode("127.0.0.1", config=True, help="The IP address to listen on.")
+    port = Int(8000, config=True, help="port for the server to listen on.")
 
     def postprocess(self, input):
-        """
-        Simple implementation to serve the build directory.
-        """
-
+        """Serve the build directory with a webserver."""
+        dirname, filename = os.path.split(input)
+        handlers = [
+            (r"/(.+)", web.StaticFileHandler, {'path' : dirname}),
+            (r"/", web.RedirectHandler, {"url": "/%s" % filename})
+        ]
+        
+        if ('://' in self.reveal_prefix or self.reveal_prefix.startswith("//")):
+            # reveal specifically from CDN, nothing to do
+            pass
+        elif os.path.isdir(os.path.join(dirname, self.reveal_prefix)):
+            # reveal prefix exists
+            self.log.info("Serving local %s", self.reveal_prefix)
+        else:
+            self.log.info("Redirecting %s requests to %s", self.reveal_prefix, self.reveal_cdn)
+            handlers.insert(0, (r"/(%s)/(.*)" % self.reveal_prefix, ProxyHandler))
+        
+        app = web.Application(handlers,
+            cdn=self.reveal_cdn,
+            client=AsyncHTTPClient(),
+        )
+        # hook up tornado logging to our logger
+        from tornado import log
+        log.app_log = self.log
+    
+        http_server = httpserver.HTTPServer(app)
+        http_server.listen(self.port, address=self.ip)
+        url = "http://%s:%i/%s" % (self.ip, self.port, filename)
+        print("Serving your slides at %s" % url)
+        print("Use Control-C to stop this server")
+        if self.open_in_browser:
+            webbrowser.open(url, new=2)
         try:
-            dirname, filename = os.path.split(input)
-            if dirname:
-                os.chdir(dirname)
-            httpd = HTTPServer(('127.0.0.1', 8000), SimpleHTTPRequestHandler)
-            sa = httpd.socket.getsockname()
-            url = "http://" + sa[0] + ":" + str(sa[1]) + "/" + filename
-            if self.open_in_browser:
-                webbrowser.open(url, new=2)
-            print("Serving your slides on " + url)
-            print("Use Control-C to stop this server.")
-            httpd.serve_forever()
+            ioloop.IOLoop.instance().start()
         except KeyboardInterrupt:
-            print("The server is shut down.")
+            print("\nInterrupted")
+
+def main(path):
+    """allow running this module to serve the slides"""
+    server = ServePostProcessor()
+    server(path)
+    
+if __name__ == '__main__':
+    import sys
+    main(sys.argv[1])