Pixel.gif server: unbreak for node.js <= 8.x

Pull #9 added support for serving via https. Great!

It also broke support for node 8.x and below (both 8 and 6 are LTS).

In v10, http.createServer() got an optional first argument of
an options object. Previous versions don't support that optional first
arg and thus ignore the second arg. This leaves them with no function
to handle requests and thus they stall all requests forever.

src/pixel-ping.coffee

@@ -123,36 +123,37 @@ process.on 'SIGUSR2', ->
 process.on 'uncaughtException', (err) ->
   console.error "Uncaught Exception: #{err}"
 
+# When a request comes in, ensure that it's looking
+# for `pixel.gif`. If it is, serve the pixel and record a hit.
+handleRequest = (req, res) ->
+  params = url.parse req.url, true
+  if params.pathname is '/pixel.gif'
+    res.writeHead 200, pixelHeaders
+    res.end pixel
+    if key = params.query?.key
+      record key, 1
+  else
+    res.writeHead 404, emptyHeaders
+    res.end ''
+  null
+
+
 # Determines the right protocol (HTTP/HTTPS) to be used on the nodejs server
 if config.sslkey && config.sslcert && config.sslca
-  protocol = https;
   protocolOptions = {
    key  : fs.readFileSync(config.sslkey),
    cert : fs.readFileSync(config.sslcert),
    ca   : fs.readFileSync(config.sslca),
   };
+  server = https.createServer(protocolOptions, handleRequest)
 else if config.sslkey && config.sslcert
-  protocol = https;
   protocolOptions = {
    key  : fs.readFileSync(config.sslkey),
    cert : fs.readFileSync(config.sslcert),
   };
+  server = https.createServer(protocolOptions, handleRequest)
 else
-  protocol = http;
-
-# Create a `Server` object. When a request comes in, ensure that it's looking
-# for `pixel.gif`. If it is, serve the pixel and record a hit.
-server = protocol.createServer protocolOptions, (req, res) ->
-  params = url.parse req.url, true
-  if params.pathname is '/pixel.gif'
-    res.writeHead 200, pixelHeaders
-    res.end pixel
-    if key = params.query?.key
-      record key, 1
-  else
-    res.writeHead 404, emptyHeaders
-    res.end ''
-  null
+  server = http.createServer(handleRequest)
 
 #### Startup
 

test/test-ping.coffee

@@ -28,7 +28,7 @@ exit = (code) ->
 
 server.listen 6999, 'localhost'
 
-ping = spawn 'node', ['bin/pixel-ping', 'test/config.json']
+ping = spawn 'node', ['bin/pixel-ping', 'test/config.json'], {stdio: 'inherit'}
 
 delay = (time, func) -> setTimeout func, time