Verify preconditions before revalidating. Closes #13

Author: aw

CHANGELOG.md

@@ -1,5 +1,12 @@
 # Changelog
 
+##  0.5.0 (2015-05-04)
+
+  * Add a check which verifies if a precondition exists before revalidating
+  * Fixes issue #13
+  * Add regression tests
+  * Adjust one broken test
+
 ##  0.4.1 (2015-05-04)
 
   * Update README.md

cache_rules.gemspec

@@ -6,7 +6,7 @@ require 'date'
 
 Gem::Specification.new do |s|
   s.name        = 'cache_rules'
-  s.version     = '0.4.1'
+  s.version     = '0.5.0'
 
   s.date        = Date.today.to_s
 

lib/cache_rules.rb

@@ -121,10 +121,16 @@ def validate(url, request_headers, cached_headers = {})
   # Revalidates a response by fetching headers from the origin server
   def revalidate_response(*args)
     url, request, cached = *args
-    res_headers = helper_response_headers.(helper_make_request_timer.(args))
+    has_preconditions    = helper_has_preconditions.(request, cached)
 
     # 1. get the column
-    column = RESPONSE_MAP[helper_run_validate.call(RESPONSE_TABLE[:conditions], request, cached, res_headers).join]
+    column = if has_preconditions
+      res_headers = helper_response_headers.(helper_make_request_timer.(args))
+      RESPONSE_MAP[helper_run_validate.call(RESPONSE_TABLE[:conditions], request, cached, res_headers).join]
+    else
+      res_headers = {}
+      2 # return column 2 (504 EXPIRED)
+    end
 
     # 2. return the response
     helper_response url, RESPONSE_TABLE[:actions], column, cached, res_headers

lib/helpers.rb

@@ -360,4 +360,11 @@ def helper_response_headers
     }
   end
 
+  # The validators are required for revalidation
+  # source: https://tools.ietf.org/html/rfc7232#section-2
+  def helper_has_preconditions
+    Proc.new {|request, cached|
+      request['If-None-Match'] || cached['ETag'] || cached['Last-Modified']
+    }
+  end
 end

test/test_cache_rules.rb

@@ -174,7 +174,7 @@ def test_revalidate_response_column2_5xx
   end
 
   def test_revalidate_response_column2_error
-    result = CacheRules.revalidate_response('ftp://test.url/test1', {}, {})
+    result = CacheRules.revalidate_response('ftp://test.url/test1', {}, {'Last-Modified'=>'Sat, 03 Jan 2015 07:03:45 GMT'})
 
     assert_equal result[:code], 504
     assert_equal result[:body], 'Gateway Timeout'

test/test_regressions.rb

@@ -66,4 +66,23 @@ def test_bugfix_10_request_header_max_age_is_checked
     assert_equal 1, current
     assert_equal 1, cached_max_age
   end
+
+  # https://github.com/aw/CacheRules/issues/13
+  def test_bugfix_13_revalidate_without_preconditions
+    if_none_match = CacheRules.helper_has_preconditions.({'If-None-Match'=>'*'},{})
+    etag          = CacheRules.helper_has_preconditions.({}, {'ETag'=>["abcdefg"]})
+    last_modified = CacheRules.helper_has_preconditions.({}, {'Last-Modified'=>{"httpdate"=>"Fri, 02 Jan 2015 11:03:45 GMT", "timestamp"=>1420196625}})
+    empty         = CacheRules.helper_has_preconditions.({}, {})
+    no_precond    = CacheRules.revalidate_response('ftp://test.url/test1', {}, {})
+
+    assert_equal "*", if_none_match
+    assert_equal ["abcdefg"], etag
+    assert_equal({"httpdate"=>"Fri, 02 Jan 2015 11:03:45 GMT", "timestamp"=>1420196625}, last_modified)
+    assert_nil empty
+
+    assert_equal no_precond[:code], 504
+    assert_equal no_precond[:body], 'Gateway Timeout'
+    assert_nil   no_precond[:error]
+  end
+
 end