[Fixes #318] Attempt to improve README a bit (#323)

* docs: Improve Getting Started section

* docs: Following Getting Started show Usage to the README reader

* docs: Move the configuration tip to the Usage section

* docs: Move the cache store configuration comment to Usage

* docs: Clarify Responses title

* docs: allow2ban also uses the cache store

* docs: Improve Usage docs for blocking, safelisting and throttling

* docs: Don't give the impression that the gem is not being maintained when it actually is

* docs: Be a bit more clear about cache store in README

* docs: Attempt to be a bit more concise in the README intro

* docs: Clarify sentence

README.md

@@ -1,10 +1,8 @@
-# Rack::Attack!!!
+# Rack::Attack
+
 *Rack middleware for blocking & throttling abusive requests*
 
-Rack::Attack is a rack middleware to protect your web app from bad clients.
+Protect your Rails and Rack apps from bad clients. Rack::Attack lets you easily decide when to *allow*, *block* and *throttle* based on properties of the request.
-It allows *safelisting*, *blocklisting*, *throttling*, and *tracking* based on arbitrary properties of the request.
-
-Throttle and fail2ban state is stored in a configurable cache (e.g. `Rails.cache`), presumably backed by memcached or redis ([at least gem v3.0.0](https://rubygems.org/gems/redis)).
 
 See the [Backing & Hacking blog post](http://www.kickstarter.com/backing-and-hacking/rack-attack-protection-from-abusive-clients) introducing Rack::Attack.
 
@@ -12,99 +10,97 @@ See the [Backing & Hacking blog post](http://www.kickstarter.com/backing-and-hac
 [![Build Status](https://travis-ci.org/kickstarter/rack-attack.svg?branch=master)](https://travis-ci.org/kickstarter/rack-attack)
 [![Code Climate](https://codeclimate.com/github/kickstarter/rack-attack.svg)](https://codeclimate.com/github/kickstarter/rack-attack)
 
-## Looking for maintainers
-
-I'm looking for new maintainers to help me support Rack::Attack. Check out
-[issue #219 for details](https://github.com/kickstarter/rack-attack/issues/219).
-
 ## Getting started
 
-Install the [rack-attack](http://rubygems.org/gems/rack-attack) gem; or add it to your Gemfile with bundler:
+### 1. Installing
+
+Add this line to your application's Gemfile:
 
 ```ruby
 # In your Gemfile
+
 gem 'rack-attack'
 ```
-Tell your app to use the Rack::Attack middleware.
+
-For Rails apps:
+And then execute:
+
+    $ bundle
+
+Or install it yourself as:
+
+    $ gem install rack-attack
+
+### 2. Plugging into the application
+
+Then tell your ruby web application to use rack-attack as a middleware.
+
+a) For __rails__ applications:
 
 ```ruby
 # In config/application.rb
+
 config.middleware.use Rack::Attack
 ```
 
-Or for Rackup files:
+b) For __rack__ applications:
 
 ```ruby
 # In config.ru
+
 require "rack/attack"
 use Rack::Attack
 ```
 
-Add a `rack_attack.rb` file to `config/initializers/`:
+__IMPORTANT__: By default, rack-attack won't perform any blocking or throttling, until you specifically tell it what to protect against by configuring some rules.
-```ruby
+
-# In config/initializers/rack_attack.rb
+## Usage
-class Rack::Attack
-  # your custom configuration...
-end
-```
 
 *Tip:* The example in the wiki is a great way to get started:
 [Example Configuration](https://github.com/kickstarter/rack-attack/wiki/Example-Configuration)
 
-Optionally configure the cache store for throttling or fail2ban filtering:
+Define rules by calling `Rack::Attack` public methods, in any file that runs when your application is being initialized. For rails applications this means creating a new file named `config/initializers/rack_attack.rb` and writing your rules there.
+
+### Safelisting
+
+Safelists have the most precedence, so any request matching a safelist would be allowed despite matching any number of blocklists or throttles.
+
+#### `safelist_ip(ip_address_string)`
+
+E.g.
 
 ```ruby
-Rack::Attack.cache.store = ActiveSupport::Cache::MemoryStore.new # defaults to Rails.cache
+# config/initializers/rack_attack.rb (for rails app)
+
+Rack::Attack.safelist_ip("5.6.7.8")
 ```
 
-Note that `Rack::Attack.cache` is only used for throttling and fail2ban filtering; not blocklisting & safelisting. Your cache store must implement `increment` and `write` like [ActiveSupport::Cache::Store](http://api.rubyonrails.org/classes/ActiveSupport/Cache/Store.html).
+#### `safelist_ip(ip_subnet_string)`
 
-## How it works
+E.g.
-
-The Rack::Attack middleware compares each request against *safelists*, *blocklists*, *throttles*, and *tracks* that you define. There are none by default.
-
- * If the request matches any **safelist**, it is allowed.
- * Otherwise, if the request matches any **blocklist**, it is blocked.
- * Otherwise, if the request matches any **throttle**, a counter is incremented in the Rack::Attack.cache. If any throttle's limit is exceeded, the request is blocked.
- * Otherwise, all **tracks** are checked, and the request is allowed.
-
-The algorithm is actually more concise in code: See [Rack::Attack.call](https://github.com/kickstarter/rack-attack/blob/master/lib/rack/attack.rb):
 
 ```ruby
-def call(env)
+# config/initializers/rack_attack.rb (for rails app)
-  req = Rack::Attack::Request.new(env)
 
-  if safelisted?(req)
+Rack::Attack.safelist_ip("5.6.7.0/24")
-    @app.call(env)
-  elsif blocklisted?(req)
-    self.class.blocklisted_response.call(env)
-  elsif throttled?(req)
-    self.class.throttled_response.call(env)
-  else
-    tracked?(req)
-    @app.call(env)
-  end
-end
 ```
 
-Note: `Rack::Attack::Request` is just a subclass of `Rack::Request` so that you
+#### `safelist(name, &block)`
-can cleanly monkey patch helper methods onto the
-[request object](https://github.com/kickstarter/rack-attack/blob/master/lib/rack/attack/request.rb).
 
-## About Tracks
+Name your custom safelist and make your ruby-block argument return a truthy value if you want the request to be blocked, and falsy otherwise.
 
-`Rack::Attack.track` doesn't affect request processing. Tracks are an easy way to log and measure requests matching arbitrary attributes.
+The request object is a [Rack::Request](http://www.rubydoc.info/gems/rack/Rack/Request).
 
-## Usage
+E.g.
-
-Define safelists, blocklists, throttles, and tracks as blocks that return truthy values if matched, falsy otherwise. In a Rails app
-these go in an initializer in `config/initializers/`.
-A [Rack::Request](http://www.rubydoc.info/gems/rack/Rack/Request) object is passed to the block (named 'req' in the examples).
-
-### Safelists
 
 ```ruby
+# config/initializers/rack_attack.rb (for rails apps)
+
+# Provided that trusted users use an HTTP request header named APIKey
+Rack::Attack.safelist("mark any authenticated access safe") do |request|
+  # Requests are allowed if the return value is truthy
+  request.env["APIKey"] == "secret-string"
+end
+
 # Always allow requests from localhost
 # (blocklist & throttles are skipped)
 Rack::Attack.safelist('allow from localhost') do |req|
@@ -113,16 +109,44 @@ Rack::Attack.safelist('allow from localhost') do |req|
 end
 ```
 
-### Blocklists
+### Blocking
+
+#### `blocklist_ip(ip_address_string)`
+
+E.g.
 
 ```ruby
-# Block requests from 1.2.3.4
+# config/initializers/rack_attack.rb (for rails apps)
-Rack::Attack.blocklist('block 1.2.3.4') do |req|
+
+Rack::Attack.blocklist_ip("1.2.3.4")
+```
+
+#### `blocklist_ip(ip_subnet_string)`
+
+E.g.
+
+```ruby
+# config/initializers/rack_attack.rb (for rails apps)
+
+Rack::Attack.blocklist_ip("1.2.0.0/16")
+```
+
+#### `blocklist(name, &block)`
+
+Name your custom blocklist and make your ruby-block argument returna a truthy value if you want the request to be blocked, and falsy otherwise.
+
+The request object is a [Rack::Request](http://www.rubydoc.info/gems/rack/Rack/Request).
+
+E.g.
+
+```ruby
+# config/initializers/rack_attack.rb (for rails apps)
+
+Rack::Attack.blocklist("block all access to admin") do |request|
   # Requests are blocked if the return value is truthy
-  '1.2.3.4' == req.ip
+  request.path.start_with?("/admin")
 end
 
-# Block logins from a bad user agent
 Rack::Attack.blocklist('block bad UA logins') do |req|
   req.path == '/login' && req.post? && req.user_agent == 'BadUA'
 end
@@ -135,6 +159,8 @@ This pattern is inspired by [fail2ban](http://www.fail2ban.org/wiki/index.php/Ma
 See the [fail2ban documentation](http://www.fail2ban.org/wiki/index.php/MANUAL_0_8#Jail_Options) for more details on
 how the parameters work.  For multiple filters, be sure to put each filter in a separate blocklist and use a unique discriminator for each fail2ban filter.
 
+Fail2ban state is stored in a [configurable cache](#cache-store-configuration) (which defaults to `Rails.cache` if present).
+
 ```ruby
 # Block suspicious requests for '/etc/password' or wordpress specific paths.
 # After 3 blocked requests in 10 minutes, block all requests from that IP for 5 minutes.
@@ -155,8 +181,12 @@ end
 Note that `Fail2Ban` filters are not automatically scoped to the blocklist, so when using multiple filters in an application the scoping must be added to the discriminator e.g. `"pentest:#{req.ip}"`.
 
 #### Allow2Ban
+
 `Allow2Ban.filter` works the same way as the `Fail2Ban.filter` except that it *allows* requests from misbehaving
 clients until such time as they reach maxretry at which they are cut off as per normal.
+
+Allow2ban state is stored in a [configurable cache](#cache-store-configuration) (which defaults to `Rails.cache` if present).
+
 ```ruby
 # Lockout IP addresses that are hammering your login page.
 # After 20 requests in 1 minute, block all requests from that IP for 1 hour.
@@ -171,33 +201,40 @@ Rack::Attack.blocklist('allow2ban login scrapers') do |req|
 end
 ```
 
+### Throttling
 
-### Throttles
+Throttle state is stored in a [configurable cache](#cache-store-configuration) (which defaults to `Rails.cache` if present).
+
+#### `throttle(name, options, &block)`
+
+Name your custom throttle, provide `limit` and `period` as options, and make your ruby-block argument return the __discriminator__. This discriminator is how you tell rack-attack whether you're limiting per IP address, per user email or any other.
+
+The request object is a [Rack::Request](http://www.rubydoc.info/gems/rack/Rack/Request).
+
+E.g.
 
 ```ruby
-# Throttle requests to 5 requests per second per ip
+# config/initializers/rack_attack.rb (for rails apps)
-Rack::Attack.throttle('req/ip', limit: 5, period: 1.second) do |req|
-  # If the return value is truthy, the cache key for the return value
-  # is incremented and compared with the limit. In this case:
-  #   "rack::attack:#{Time.now.to_i/1.second}:req/ip:#{req.ip}"
-  #
-  # If falsy, the cache key is neither incremented nor checked.
 
-  req.ip
+Rack::Attack.throttle("requests by ip", limit: 5, period: 2) do |request|
+  request.ip
 end
 
 # Throttle login attempts for a given email parameter to 6 reqs/minute
 # Return the email as a discriminator on POST /login requests
-Rack::Attack.throttle('logins/email', limit: 6, period: 60) do |req|
+Rack::Attack.throttle('limit logins per email', limit: 6, period: 60) do |req|
-  req.params['email'] if req.path == '/login' && req.post?
+  if req.path == '/login' && req.post?
+    req.params['email']
+  end
 end
 
 # You can also set a limit and period using a proc. For instance, after
 # Rack::Auth::Basic has authenticated the user:
 limit_proc = proc { |req| req.env["REMOTE_USER"] == "admin" ? 100 : 1 }
-period_proc = proc {|req| req.env["REMOTE_USER"] == "admin" ? 1.second : 1.minute}
+period_proc = proc { |req| req.env["REMOTE_USER"] == "admin" ? 1 : 60 }
-Rack::Attack.throttle('req/ip', limit: limit_proc, period: period_proc) do |req|
+
-  req.ip
+Rack::Attack.throttle('request per ip', limit: limit_proc, period: period_proc) do |request|
+  request.ip
 end
 ```
 
@@ -223,7 +260,17 @@ ActiveSupport::Notifications.subscribe("rack.attack") do |name, start, finish, r
 end
 ```
 
-## Responses
+### Cache store configuration
+
+Throttle, allow2ban and fail2ban state is stored in a configurable cache (which defaults to `Rails.cache` if present), presumably backed by memcached or redis ([at least gem v3.0.0](https://rubygems.org/gems/redis)).
+
+```ruby
+Rack::Attack.cache.store = ActiveSupport::Cache::MemoryStore.new # defaults to Rails.cache
+```
+
+Note that `Rack::Attack.cache` is only used for throttling, allow2ban and fail2ban filtering; not blocklisting and safelisting. Your cache store must implement `increment` and `write` like [ActiveSupport::Cache::Store](http://api.rubyonrails.org/classes/ActiveSupport/Cache/Store.html).
+
+## Customizing responses
 
 Customize the response of blocklisted and throttled requests using an object that adheres to the [Rack app interface](http://rack.rubyforge.org/doc/SPEC.html).
 
@@ -288,6 +335,43 @@ ActiveSupport::Notifications.subscribe('rack.attack') do |name, start, finish, r
 end
 ```
 
+## How it works
+
+The Rack::Attack middleware compares each request against *safelists*, *blocklists*, *throttles*, and *tracks* that you define. There are none by default.
+
+ * If the request matches any **safelist**, it is allowed.
+ * Otherwise, if the request matches any **blocklist**, it is blocked.
+ * Otherwise, if the request matches any **throttle**, a counter is incremented in the Rack::Attack.cache. If any throttle's limit is exceeded, the request is blocked.
+ * Otherwise, all **tracks** are checked, and the request is allowed.
+
+The algorithm is actually more concise in code: See [Rack::Attack.call](https://github.com/kickstarter/rack-attack/blob/master/lib/rack/attack.rb):
+
+```ruby
+def call(env)
+  req = Rack::Attack::Request.new(env)
+
+  if safelisted?(req)
+    @app.call(env)
+  elsif blocklisted?(req)
+    self.class.blocklisted_response.call(env)
+  elsif throttled?(req)
+    self.class.throttled_response.call(env)
+  else
+    tracked?(req)
+    @app.call(env)
+  end
+end
+```
+
+Note: `Rack::Attack::Request` is just a subclass of `Rack::Request` so that you
+can cleanly monkey patch helper methods onto the
+[request object](https://github.com/kickstarter/rack-attack/blob/master/lib/rack/attack/request.rb).
+
+### About Tracks
+
+`Rack::Attack.track` doesn't affect request processing. Tracks are an easy way to log and measure requests matching arbitrary attributes.
+
+
 ## Testing
 
 A note on developing and testing apps using Rack::Attack - if you are using throttling in particular, you will