Merge pull request #76 from willingc/refresh-docs

Edit documentation for install and usage

Author: minrk

README.md

@@ -1,3 +1,9 @@
+**[Install](#install)** |
+**[Using configurable-http-proxy](#using-configurable-http-proxy)** |
+**[Using the REST API](#using-the-rest-api)** |
+**[Custom error pages](#custom-error-pages)** |
+**[Host-based routing](#host-based-routing)**
+
 # configurable-http-proxy
 
 [![Build Status](https://travis-ci.org/jupyterhub/configurable-http-proxy.svg?branch=master)](https://travis-ci.org/jupyterhub/configurable-http-proxy)
@@ -19,11 +25,14 @@ node-http-proxy to provide this functionality to JupyterHub.
 
 ## Install
 
-To install `configurable-http-proxy` globally using the npm package manager:
+Prerequisite: [Node.js](https://nodejs.org/en/download/)
+
+To install globally from the `configurable-http-proxy` package release
+using the npm package manager:
 
     npm install -g configurable-http-proxy
 
-To install from source found in this GitHub repo:
+To install from the source code found in this GitHub repo:
 
     git clone https://github.com/jupyterhub/configurable-http-proxy.git
     cd configurable-http-proxy
@@ -41,10 +50,13 @@ The configurable proxy runs two HTTP(S) servers:
    localhost by default. The REST API uses token authorization, set by the
    `CONFIGPROXY_AUTH_TOKEN` environment variable.
 
-When you start the proxy, you can set a default target to be used when no
+### Setting a default target
+
+When you start the proxy from the command line, you can set a 
+default target (`--default-target` option) to be used when no
 matching route is found in the proxy table:
 
-    $ configurable-http-proxy --default-target=http://localhost:8888
+    configurable-http-proxy --default-target=http://localhost:8888
 
 ### Command-line options
 
@@ -57,6 +69,7 @@ matching route is found in the proxy table:
     -V, --version                    output the version number
     --ip <ip-address>                Public-facing IP of the proxy
     --port <n> (defaults to 8000)    Public-facing port of the proxy
+    
     --ssl-key <keyfile>              SSL key to use, if any
     --ssl-cert <certfile>            SSL certificate to use, if any
     --ssl-ca <ca-file>               SSL certificate authority, if any
@@ -66,13 +79,15 @@ matching route is found in the proxy table:
     --ssl-ciphers <ciphers>          `:`-separated ssl cipher list. Default excludes RC4
     --ssl-allow-rc4                  Allow RC4 cipher for SSL (disabled by default)
     --ssl-dhparam <dhparam-file>     SSL Diffie-Helman Parameters pem file, if any
+    
     --api-ip <ip>                    Inward-facing IP for API requests
     --api-port <n>                   Inward-facing port for API requests (defaults to --port=value+1)
     --api-ssl-key <keyfile>          SSL key to use, if any, for API requests
     --api-ssl-cert <certfile>        SSL certificate to use, if any, for API requests
     --api-ssl-ca <ca-file>           SSL certificate authority, if any, for API requests
     --api-ssl-request-cert           Request SSL certs to authenticate clients for API requests
     --api-ssl-reject-unauthorized    Reject unauthorized SSL connections (only meaningful if --api-ssl-request-cert is given)
+    
     --default-target <host>          Default proxy target (proto://host[:port])
     --error-target <host>            Alternate server for handling proxy errors (proto://host[:port])
     --error-path <path>              Alternate server for handling proxy errors (proto://host[:port])
@@ -89,19 +104,29 @@ matching route is found in the proxy table:
     --log-level <loglevel>           Log level (debug, info, warn, error)
 ```
 
+
 ## Using the REST API
 
-The REST API is authenticated via a token in the `Authorization` header.
-The API is served under the `/api/routes` base URL. For example:
+The configurable-http-proxy API is documented and available at the 
+interactive swagger site, [petstore](http://petstore.swagger.io/?url=https://raw.githubusercontent.com/jupyterhub/configurable-http-proxy/master/doc/rest-api.yml#/default)
+or as a [swagger specification file in this repo](https://github.com/jupyterhub/configurable-http-proxy/blob/master/doc/rest-api.yml).
+
+### Authenticating via passing a token
 
-    $> curl -H "Authorization: token $CONFIGPROXY_AUTH_TOKEN" http://localhost:8001/api/routes
+The REST API is authenticated via passing a token in the `Authorization` header.
+The API is served under the `/api/routes` base URL. For example, execute
+this `curl` command in the terminal to authenticate and retrieve the
+current routing table:
 
+    curl -H "Authorization: token $CONFIGPROXY_AUTH_TOKEN" http://localhost:8001/api/routes
 
 ### Getting the current routing table
 
+**Request**
+
     GET /api/routes[?inactive_since=ISO8601-timestamp]
 
-Returns a JSON dictionary of the current routing table.
+The GET request returns a JSON dictionary of the current routing table.
 
 This JSON dictionary *excludes* the default route. If the `inactive_since` URL
 parameter is given as an [ISO8601](http://en.wikipedia.org/wiki/ISO_8601)
@@ -110,8 +135,11 @@ will be returned.
 
 **Response**
 
+Status code:
+
     status: 200 OK
 
+Returned JSON dictionary of current routing table:
 
 ```json
 {
@@ -129,69 +157,84 @@ will be returned.
 The `last_activity` timestamp is updated whenever the proxy passes data to
 or from the proxy target.
 
-
 ### Adding new routes
 
 POST requests create new routes. The body of the request should be a JSON
 dictionary with at least one key: `target`, the target host to be proxied.
 
+**Request**
+
     POST /api/routes/[:path]
 
-**Input**
+*Input - request body*
 
 `target`: The host URL
 
 **Response**
 
     status: 201 Created
 
-Any request to `/path/prefix` on the proxy's public interface will be proxied
-to `target`.
+After adding the new route, any request to `/path/prefix` on the proxy's
+public interface will be proxied to `target`.
 
 ### Deleting routes
 
+**Request**
+
     DELETE /api/routes/[:path]
 
 **Response**
 
     status: 204 No Content
 
+Removes a route from the proxy's routing table.
+
+
 ## Custom error pages
 
 With version 0.5, configurable-host-proxy (CHP) adds two ways to provide
 custom error pages when the proxy encounters an error, and has no proxy target
-to handle a request. There are two typical errors that CHP can hit:
+to handle a request. There are two typical errors that CHP can hit, along
+with their status code:
 
 - 404: a client has requested a URL for which there is no routing target.
-  This is impossible if a default target has been specified.
+  This can be prevented if a `default target` is specified when starting
+  the configurable-http-proxy.
 
 - 503: a route exists, but the upstream server isn't responding.
   This is more common, and can be due to any number of reasons,
   including the target service having died or not finished starting.
 
 ### error-path
 
-If you specify `--error-path /usr/share/chp-errors`, then when a proxy error 
-occurs, CHP will look in `/usr/share/chp-errors/CODE.html` for an html page
-to serve, e.g. `404.html` or `503.html`.
+If you specify an error path `--error-path /usr/share/chp-errors` when
+starting the CHP:
+ 
+    configurable-http-proxy --error-path /usr/share/chp-errors
+ 
+then when a proxy error occurs, CHP will look in 
+`/usr/share/chp-errors/<CODE>.html` (where CODE is the status code number)
+for an html page to serve, e.g. `404.html` or `503.html`.
 
 If no file exists for the error code, `error.html` file will be used.
-If you use this approach, make sure you have created `error.html`.
+If you specify an error path, make sure you also create `error.html`.
 
 ### error-target
 
+When starting the CHP, you can pass a command line option for `--error-target`.
 If you specify `--error-target http://localhost:1234`,
-then when the proxy encounters an error, it will make a GET request to this
-server, with URL `/CODE`, and the URL of the failing request escaped in a URL
-parameter, e.g.:
+then when the proxy encounters an error, it will make a GET request to 
+this server, with URL `/CODE`, and the URL of the failing request
+escaped in a URL parameter, e.g.:
 
     GET /404?url=%2Fescaped%2Fpath
 
 
 ## Host-based routing
 
-If `--host-routing` is given, the proxy will pick a target based on the host
-of the incoming request, instead of the URL prefix.
+If the CHP is started with the `--host-routing` option, the proxy will
+pick a target based on the host of the incoming request, instead of the
+URL prefix.
 
 The API when using host-based routes is the same as if the hostname were the
 first part of the URL path, e.g.: