The FireLogger protocol lets you log messages in an HTTP response that get encoded and delivered in headers, separately from the response body. So, no matter what you're serving up (eg. HTML, CSS, JS, images), you can send log messages along with it.
This is a quick and dirty bit of middleware for express/connect that lets you send FireLogger messages in node.js servers. It was the product of an hour's hacking and is very light on features or tests. But, someone might find it handy.
example.js for a demo.
See the FireLogger protocol for more under-the-hood details. The gist is:
- Log message objects are bundled up in an array
- That array is encoded as JSON string in UTF-8
- That JSON string is encoded with Base64
- That Base64 string is carved up into lines
- Those lines are stuffed into HTTP headers
- Those HTTP headers are sent along with the response
- The FireLogger addon unpacks all the above and delivers the messages
Here's a peek behind the scenes:
% node example.js &  11181 % curl -sD - 'http://localhost:9001/'; echo HTTP/1.1 200 OK X-Powered-By: Express Content-Type: text/html; charset=utf-8 Content-Length: 13 Connection: keep-alive Hello, world. % curl -sD - -H 'X-FireLogger: 1.2' 'http://localhost:9001/' HTTP/1.1 200 OK X-Powered-By: Express Content-Type: text/html; charset=utf-8 Content-Length: 14 FireLogger-9667348-0: eyJsb2dzIjpbeyJsZXZlbCI6ImRlYnVnIiwibWVzc2FnZSI6IkRlYnVnIG1lc3NhZ2UiLCJ0aW1 FireLogger-9667348-1: lIjoiMTI6NTE6MjEgR01ULTA1MDAgKEVTVCkiLCJ0aW1lc3RhbXAiOjEzMzEzMTU0ODE1MzUwMD FireLogger-9667348-2: B9LHsibGV2ZWwiOiJ3YXJuaW5nIiwibWVzc2FnZSI6Ildhcm5pbmcgbWVzc2FnZSIsInRpbWUiO FireLogger-9667348-3: iIxMjo1MToyMSBHTVQtMDUwMCAoRVNUKSIsInRpbWVzdGFtcCI6MTMzMTMxNTQ4MTUzNjAwMH0s FireLogger-9667348-4: eyJuYW1lIjoibG9nZ2VyX25hbWUiLCJsZXZlbCI6ImluZm8iLCJtZXNzYWdlIjoiSW5mb3JtYXR FireLogger-9667348-5: pdmUgbWVzc2FnZSIsInRpbWUiOiIxMjo1MToyMSBHTVQtMDUwMCAoRVNUKSIsInRpbWVzdGFtcC FireLogger-9667348-6: I6MTMzMTMxNTQ4MTUzNjAwMH0seyJuYW1lIjoic29tZV9tb2R1bGUiLCJsaW5lbm8iOjEyMzQsI FireLogger-9667348-7: nBhdGhuYW1lIjoibW9kdWxlL215ZmlsZS5qcyIsImxldmVsIjoiZXJyb3IiLCJtZXNzYWdlIjoi FireLogger-9667348-8: U29tZXRoaW5nIHdlbnQgd3JvbmchIiwidGltZSI6IjEyOjUxOjIxIEdNVC0wNTAwIChFU1QpIiw FireLogger-9667348-9: idGltZXN0YW1wIjoxMzMxMzE1NDgxNTM2MDAwfSx7Im5hbWUiOiJteWxvZ2dlciIsImxldmVsIj FireLogger-9667348-10: oiY3JpdGljYWwiLCJtZXNzYWdlIjoiVGhpcyBpcyB0aGUgbG9uZyBmb3JtIiwidGltZSI6IjEyO FireLogger-9667348-11: jUxOjIxIEdNVC0wNTAwIChFU1QpIiwidGltZXN0YW1wIjoxMzMxMzE1NDgxNTM2MDAwfV19 Connection: keep-alive Hello, world.
MIT license, I guess?
I don't really care. Take the code, fork it, do what you want. Don't blame me if it starts a fire. Say nice things about me, if you like.