From a557e877388cbba34c42423013336f2844b3649c Mon Sep 17 00:00:00 2001
From: petems <p.morsou@gmail.com>
Date: Sat, 13 Jul 2013 00:15:46 +0100
Subject: [PATCH] Added filter method for logger middleware

Allows you to filter sensitive information with a regex, allowing a gsub with redaction:

```ruby
conn = Faraday.new(:url => 'http://sushi.com/api_key=s3cr3t') do |faraday|
  faraday.response :logger do | logger |
    logger.filter(/(api_key=)(\w+)/,'\1[REMOVED]')
  end
end
```
---
 README.md                      |  8 ++++++++
 lib/faraday/response/logger.rb | 19 ++++++++++++++-----
 test/adapters/logger_test.rb   | 21 +++++++++++++++++++++
 3 files changed, 43 insertions(+), 5 deletions(-)

diff --git a/README.md b/README.md
index 4ae634327..edeecf21a 100644
--- a/README.md
+++ b/README.md
@@ -26,6 +26,14 @@ conn = Faraday.new(:url => 'http://sushi.com') do |faraday|
   faraday.adapter  Faraday.default_adapter  # make requests with Net::HTTP
 end
 
+# filter sensitive information from logs with a regex matcher
+
+conn = Faraday.new(:url => 'http://sushi.com/api_key=s3cr3t') do |faraday|
+  faraday.response :logger do | logger |
+    logger.filter(/(api_key=)(\w+)/,'\1[REMOVED]')
+  end
+end
+
 ## GET ##
 
 response = conn.get '/nigiri/sake.json'     # GET http://sushi.com/nigiri/sake.json
diff --git a/lib/faraday/response/logger.rb b/lib/faraday/response/logger.rb
index 0b4d7140d..e34ca8366 100644
--- a/lib/faraday/response/logger.rb
+++ b/lib/faraday/response/logger.rb
@@ -12,22 +12,24 @@ def initialize(app, logger = nil, options = {})
         require 'logger'
         ::Logger.new(STDOUT)
       end
+      @filter = []
       @options = DEFAULT_OPTIONS.merge(options)
+      yield self if block_given?
     end
 
     def_delegators :@logger, :debug, :info, :warn, :error, :fatal
 
     def call(env)
-      info "#{env.method} #{env.url.to_s}"
-      debug('request') { dump_headers env.request_headers }
-      debug('request') { dump_body(env[:body]) } if env[:body] && log_body?(:request)
+      info "#{env.method} #{apply_filters(env.url.to_s)}"
+      debug('request') { apply_filters(dump_headers env.request_headers) }
+      debug('request') { apply_filters(dump_body(env[:body])) } if env[:body] && log_body?(:request)
       super
     end
 
     def on_complete(env)
       info('Status') { env.status.to_s }
-      debug('response') { dump_headers env.response_headers }
-      debug('response') { dump_body env[:body] } if env[:body] && log_body?(:response)
+      debug('response') { apply_filters(dump_headers env.response_headers) }
+      debug('response') { apply_filters(dump_body env[:body]) } if env[:body] && log_body?(:response)
     end
 
     private
@@ -55,5 +57,12 @@ def log_body?(type)
       else @options[:bodies]
       end
     end
+
+    def apply_filters(output)
+      @filter.each do |pattern, replacement|
+        output = output.to_s.gsub(pattern, replacement)
+      end
+      output
+    end
   end
 end
diff --git a/test/adapters/logger_test.rb b/test/adapters/logger_test.rb
index f75dcf5a5..9be4ee30a 100644
--- a/test/adapters/logger_test.rb
+++ b/test/adapters/logger_test.rb
@@ -9,6 +9,10 @@ def conn(logger, logger_options={})
 
       Faraday.new do |b|
         b.response :logger, logger, logger_options
+        b.response :logger, @logger do | logger |
+          logger.filter(/foo/,'[REDACTED]')
+          logger.filter(/(api_key:).*"(.+)."/,'\1[API_KEY]')
+        end
         b.adapter :test do |stubs|
           stubs.get('/hello') { [200, {'Content-Type' => 'text/html'}, 'hello'] }
           stubs.post('/ohai') { [200, {'Content-Type' => 'text/html'}, 'fred'] }
@@ -79,5 +83,22 @@ def test_log_response_body_object
       app.get '/rubbles', nil, :accept => 'text/html'
       assert_match %([\"Barney\", \"Betty\", \"Bam Bam\"]\n), @io.string
     end
+
+    def test_logs_filter_url
+      app = conn(@logger)
+      app.get '/foo', nil, :accept => 'text/html'
+      assert_match %([REDACTED]), @io.string
+      refute_match %(foo), @io.string
+    end
+
+    def test_logs_filter_header
+      app = conn(@logger)
+      app.headers = {'api_key' => 'ABC123'}
+      app.get '/bar', nil, :accept => 'text/html'
+      assert_match %(api_key:), @io.string
+      assert_match %([API_KEY]), @io.string
+      refute_match %(ABC123), @io.string
+    end
+
   end
 end