This is a tool designed to facilitate learning how web servers and the HTTP protocol work. It's designed as a companion app to the URL Demystifier.

The tool is a simple proxy to placekitten.com, but provides additional information about every incoming request to a particular /:width/:height image via a WebSocket-based logging interface at /:width/:height/log.

Quick Start

npm install
DEBUG= node app.js

Then visit http://localhost:3000/.

Environment Variables

Note: When an environment variable is described as representing a boolean value, if the variable exists with any value (even the empty string), the boolean is true; otherwise, it's false.

• DEBUG is a boolean value that indicates whether debugging is enabled.

• OMIT_HEADERS is a comma-separated list of request headers to exclude when displaying request information to end-users. Typically, this should be any headers added by a reverse proxy, such as X-Forwarded-Port.

• IP_HEADER is the name of the HTTP header that contains a comma-separated list of IP addresses from which the request originated. This is useful for reverse proxies like Heroku, which uses the X-Forwarded-For header. The last IP address in this header's value will be used as the originating IP of the request client; otherwise, the actual remote address of the client connection will be used.

Limitations

The server process is not stateless, so it can't easily scale.