I have Apache Tomcat running in my local machine currently.
When I try this with telnet:
telnet localhost 8080
Trying ::1...
Connected to localhost.
Escape character is '^]'.
GET /beer/
I will get a response that looks something like:
<!DOCTYPE html>
<html lang="en">
<head>
<title>Beer Expert!</title>
<meta charset="utf-8">
</head>
<body>
etc, etc..
My first question is: Where is all the HTTP Response Headers such as HTTP/1.1 200 OK etc?
Also when I try my telnet query as follows:
telnet localhost 8080
Trying ::1...
Connected to localhost.
Escape character is '^]'.
GET /beer/ HTTP/1.1
I will get:
HTTP/1.1 400 Bad Request
Server: Apache-Coyote/1.1
Transfer-Encoding: chunked
Date: Tue, 19 Jan 2016 12:15:23 GMT
Connection: close
0
Connection closed by foreign host.
Why do I see the HTTP Response headers now? And why am I getting a Bad Request response?
With just stating GET /beer/ you're not stating which protocol version you'd like. I'm not sure what tomcat defaults to, but my recommendation is to state the protocol version that you like.
With HTTP/1.0 you should be in a protocol which is easier to type on telnet. As soon as you go to HTTP/1.0, you'll have more request headers that you can send - e.g.
GET /beer/ HTTP/1.0
Host: www.example.com
will reveal that virtual host's content, in case you have many different hosts on one server.
I'm only using HTTP/1.0 (over 1.1) when I'm telnetting into a webserver - for such a long time that I can't remember if HTTP/1.1 was hard or impossible to type, or if it was just the example that I found when I started doing so. There might be mandatory headers, or information for, e.g. encoding etc, that are missing and make yours a bad request. If HTTP/1.0 is enough for you: run with it. Otherwise let us know what else you need.