From b0da52a1bd5d254dbde54ef1b1b8b2f7efc50722 Mon Sep 17 00:00:00 2001
From: Leo Arnold <github@leoarnold.de>
Date: Mon, 8 Oct 2018 18:46:47 +0200
Subject: [PATCH] Move Wiki examples into version control. Closes #324

---
 README.md                      |  8 +--
 docs/advanced_configuration.md | 93 ++++++++++++++++++++++++++++++++++
 docs/example_configuration.md  | 83 ++++++++++++++++++++++++++++++
 3 files changed, 180 insertions(+), 4 deletions(-)
 create mode 100644 docs/advanced_configuration.md
 create mode 100644 docs/example_configuration.md

diff --git a/README.md b/README.md
index 8aa92cf..03b714c 100644
--- a/README.md
+++ b/README.md
@@ -88,8 +88,8 @@ __IMPORTANT__: By default, rack-attack won't perform any blocking or throttling,
 
 ## Usage
 
-*Tip:* The example in the wiki is a great way to get started:
-[Example Configuration](https://github.com/kickstarter/rack-attack/wiki/Example-Configuration)
+*Tip:*If you just want to get going asap, then you can take our [example configuration](docs/example_configuration.md)
+and tailor it to your needs, or check out the [advanced configuration](docs/advanced_configuration.md) examples.
 
 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.
 
@@ -378,7 +378,7 @@ The Rack::Attack middleware compares each request against *safelists*, *blocklis
  * 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):
+The algorithm is actually more concise in code: See [Rack::Attack.call](lib/rack/attack.rb):
 
 ```ruby
 def call(env)
@@ -399,7 +399,7 @@ 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).
+[request object](lib/rack/attack/request.rb).
 
 ### About Tracks
 
diff --git a/docs/advanced_configuration.md b/docs/advanced_configuration.md
new file mode 100644
index 0000000..b4f877a
--- /dev/null
+++ b/docs/advanced_configuration.md
@@ -0,0 +1,93 @@
+## Advanced Configuration
+
+If you're feeling ambitious or you have a very particular use-case for Rack::Attack, these advanced configurations may help.
+
+:beetle::warning: Much of this code is untested. Copy-paste at your own risk!
+
+### Exponential Backoff
+
+By layering throttles with linearly increasing limits and exponentially increasing periods, you can mimic an exponential backoff throttle. See [#106](https://github.com/kickstarter/rack-attack/issues/106) for more discussion.
+
+```ruby
+# Allows 20 requests in 8  seconds
+#        40 requests in 64 seconds
+#        ...
+#        100 requests in 0.38 days (~250 requests/day)
+(1..5).each do |level|
+  throttle("logins/ip/#{level}", :limit => (20 * level), :period => (8 ** level).seconds) do |req|
+    if req.path == '/login' && req.post?
+      req.ip
+    end
+  end
+end
+```
+
+### Rack::Attack::Request Helpers
+
+You can define helpers on requests like `localhost?` or `subdomain` by monkey-patching `Rack::Attack::Request`. See [#73](https://github.com/kickstarter/rack-attack/issues/73) for more discussion.
+
+```ruby
+class Rack::Attack::Request < ::Rack::Request
+  def localhost?
+    ip == "127.0.0.1"
+  end
+end
+
+Rack::Attack.safelist("localhost") { |req| req.localhost? }
+```
+
+### Blocklisting From ENV Variables
+
+You can have `Rack::Attack` configure its blocklists from ENV variables to simplify maintenance. See [#110](https://github.com/kickstarter/rack-attack/issues/110) for more discussion.
+
+```ruby
+class Rack::Attack
+  # Split on a comma with 0 or more spaces after it.
+  # E.g. ENV['HEROKU_VARIABLE'] = "foo.com, bar.com"
+  # spammers = ["foo.com", "bar.com"]
+  spammers = ENV['HEROKU_VARIABLE'].split(/,\s*/)
+
+  # Turn spammers array into a regexp
+  spammer_regexp = Regexp.union(spammers) # /foo\.com|bar\.com/
+  blocklist("block referer spam") do |request|
+    request.referer =~ spammer_regexp
+  end
+end
+```
+
+### Reset Specific Throttles
+
+By doing a bunch of monkey-patching, you can add a helper for resetting specific throttles. The implementation is kind of long, so see [#113](https://github.com/kickstarter/rack-attack/issues/113) for more discussion.
+
+```ruby
+Rack::Attack.reset_throttle "logins/email", "user@example.com"
+```
+
+### Blocklisting From Rails.cache
+
+You can configure blocklists to check values stored in `Rails.cache` to allow setting blocklists from inside your application. See [#111](https://github.com/kickstarter/rack-attack/issues/111) for more discussion.
+
+```ruby
+# Block attacks from IPs in cache
+# To add an IP: Rails.cache.write("block 1.2.3.4", true, expires_in: 2.days)
+# To remove an IP: Rails.cache.delete("block 1.2.3.4")
+Rack::Attack.blocklist("block IP") do |req|
+  Rails.cache.read("block #{req.ip}")
+end
+```
+
+### Throttle Basic Auth Crackers
+
+An example implementation for blocking hackers who spam basic auth attempts. See [#47](https://github.com/kickstarter/rack-attack/issues/47) for more discussion.
+
+```ruby
+# After 5 requests with incorrect auth in 1 minute,
+# block all requests from that IP for 1 hour.
+Rack::Attack.blocklist('basic auth crackers') do |req|
+  Rack::Attack::Allow2Ban.filter(req.ip, :maxretry => 5, :findtime => 1.minute, :bantime => 1.hour) do
+    # Return true if the authorization header not incorrect
+    auth = Rack::Auth::Basic::Request.new(req.env)
+    auth.credentials != [my_username, my_password]
+  end
+end
+```
\ No newline at end of file
diff --git a/docs/example_configuration.md b/docs/example_configuration.md
new file mode 100644
index 0000000..706ed99
--- /dev/null
+++ b/docs/example_configuration.md
@@ -0,0 +1,83 @@
+## Example Configuration
+
+If you just go ahead and copy this to `/config/initializers/rack_attack.rb`, then you'll be safe from 95% of bad requests. This won't stop sophisticated hackers, but at least you can sleep more soundly knowing that your application isn't going to be accidentally taken down by a misconfigured web scraper in the middle of the night. If this isn't enough for you, check out [Advanced Configuration](advanced_configuration.md) too.
+
+```ruby
+class Rack::Attack
+
+  ### Configure Cache ###
+
+  # If you don't want to use Rails.cache (Rack::Attack's default), then
+  # configure it here.
+  #
+  # Note: The store is only used for throttling (not blacklisting and
+  # whitelisting). It must implement .increment and .write like
+  # ActiveSupport::Cache::Store
+
+  # Rack::Attack.cache.store = ActiveSupport::Cache::MemoryStore.new 
+
+  ### Throttle Spammy Clients ###
+
+  # If any single client IP is making tons of requests, then they're
+  # probably malicious or a poorly-configured scraper. Either way, they
+  # don't deserve to hog all of the app server's CPU. Cut them off!
+  #
+  # Note: If you're serving assets through rack, those requests may be
+  # counted by rack-attack and this throttle may be activated too
+  # quickly. If so, enable the condition to exclude them from tracking.
+
+  # Throttle all requests by IP (60rpm)
+  #
+  # Key: "rack::attack:#{Time.now.to_i/:period}:req/ip:#{req.ip}"
+  throttle('req/ip', limit: 300, period: 5.minutes) do |req|
+    req.ip # unless req.path.start_with?('/assets')
+  end
+
+  ### Prevent Brute-Force Login Attacks ###
+
+  # The most common brute-force login attack is a brute-force password
+  # attack where an attacker simply tries a large number of emails and
+  # passwords to see if any credentials match.
+  #
+  # Another common method of attack is to use a swarm of computers with
+  # different IPs to try brute-forcing a password for a specific account.
+
+  # Throttle POST requests to /login by IP address
+  #
+  # Key: "rack::attack:#{Time.now.to_i/:period}:logins/ip:#{req.ip}"
+  throttle('logins/ip', limit: 5, period: 20.seconds) do |req|
+    if req.path == '/login' && req.post?
+      req.ip
+    end
+  end
+
+  # Throttle POST requests to /login by email param
+  #
+  # Key: "rack::attack:#{Time.now.to_i/:period}:logins/email:#{req.email}"
+  #
+  # Note: This creates a problem where a malicious user could intentionally
+  # throttle logins for another user and force their login requests to be
+  # denied, but that's not very common and shouldn't happen to you. (Knock
+  # on wood!)
+  throttle("logins/email", limit: 5, period: 20.seconds) do |req|
+    if req.path == '/login' && req.post?
+      # return the email if present, nil otherwise
+      req.params['email'].presence
+    end
+  end
+
+  ### Custom Throttle Response ###
+
+  # By default, Rack::Attack returns an HTTP 429 for throttled responses,
+  # which is just fine.
+  #
+  # If you want to return 503 so that the attacker might be fooled into
+  # believing that they've successfully broken your app (or you just want to
+  # customize the response), then uncomment these lines.
+  # self.throttled_response = lambda do |env|
+  #  [ 503,  # status
+  #    {},   # headers
+  #    ['']] # body
+  # end
+end
+```
\ No newline at end of file