Update README.md

README.md

@@ -12,20 +12,80 @@ Learn more about Project Gemini [here](https://gopher.commons.host/gopher://zaib
 - A built-in static file server with support for gemini directory files.
 - Lightweight, single-file framework with zero dependencies.
 - Supports concurrent connections using an asynchronous event loop.
-- Extendable - loosely implements the [WSGI](https://en.wikipedia.org/wiki/Web_Server_Gateway_Interface) server/application pattern.
+- Extendable - loosely implements the [WSGI](https://en.wikipedia.org/wiki/Web_Server_Gateway_Interface)
+  server/application pattern.
 
 ## Installation
 
-Requires Python 3.7+ and OpenSSL. The latest release of Jetforce can be downloaded from [PyPI](https://pypi.org/project/Jetforce/):
+Requires Python 3.7+ and OpenSSL.
 
-```bash
+The latest release can be installed from [PyPI](https://pypi.org/project/Jetforce/)
+
+```
 $ pip install jetforce
 ```
 
-Or, you can download the repository and run the script directly:
+Or, clone the repository and run the script directly
 
-```bash
+```
 $ git clone https://github.com/michael-lazar/jetforce
 $ cd jetforce
 $ ./jetforce.py
 ```
+
+## Usage
+
+Use the ``--help`` flag to view command-line options:
+
+
+```
+$ jetforce --help
+usage: jetforce [-h] [--host HOST] [--port PORT] [--tls-certfile FILE]
+                [--tls-keyfile FILE] [--hostname HOSTNAME] [--dir DIR]
+                [--index-file INDEX_FILE]
+
+An Experimental Gemini Protocol Server
+
+optional arguments:
+  -h, --help            show this help message and exit
+  --host HOST           Address to bind server to (default: 127.0.0.1)
+  --port PORT           Port to bind server to (default: 1965)
+  --tls-certfile FILE   TLS certificate file (default: None)
+  --tls-keyfile FILE    TLS private key file (default: None)
+  --hostname HOSTNAME   Server hostname (default: localhost)
+  --dir DIR             Path on the filesystem to serve (default: /var/gemini)
+  --index-file INDEX_FILE
+                        The gemini directory index file [i.e. index.html]
+                        (default: index.gmi)
+
+If the TLS cert/keyfile is not provided, a self-signed certificate will
+automatically be generated and saved to your temporary file directory.
+```
+
+### TLS Certificates
+
+The gemini specification *requires* that all connections be sent over TLS.
+Before you deploy jetforce, you should either generate your own self-signed
+certificate, or obtain one from a Certificate Authority like
+[Let's Encrypt](https://letsencrypt.org).
+
+In order to make local development easier, if you do not specify the certificate
+arguments, jetforce will automatically generate a temporary ad-hoc TLS certificate
+to use. Here's the OpenSSL command that jetforce runs internally:
+
+
+```
+$ openssl req -newkey rsa:2048 -nodes -keyout {hostname}.key \
+    -nodes -x509 -out {hostname}.crt -subj "/CN={hostname}"
+```
+
+### Hostname
+
+Because the gemini protocol sends the *whole* URL in the request, it's necessary
+to declare which hostname your server is expecting to recieve traffic under.
+Jetforce will respond to any requests containing URLs that don't match the hostname
+with a status of ``Proxy Request Refused``.
+
+Using python, you can modify this behavior to do fancy things like building a proxy
+server for HTTP requests. See [examples/http_proxy.py](examples/http_proxy.py) for
+more information.