From 2da7dfe888d34884b8168b2c9f449f555d38c77b Mon Sep 17 00:00:00 2001
From: Alex Reisner <alex@alexreisner.com>
Date: Tue, 15 Mar 2011 22:47:50 -0400
Subject: [PATCH] Refactor: add Geocoder::Cache class.
This allows us to add a method for expiring cache keys and generally
gives us more control over the cache interface.
---
lib/geocoder.rb | 1 +
lib/geocoder/cache.rb | 81 ++++++++++++++++++++++++++++++++++++
lib/geocoder/lookups/base.rb | 27 +++---------
3 files changed, 88 insertions(+), 21 deletions(-)
create mode 100644 lib/geocoder/cache.rb
diff --git a/lib/geocoder.rb b/lib/geocoder.rb
index 22f14105..594f3df8 100644
--- a/lib/geocoder.rb
+++ b/lib/geocoder.rb
@@ -1,5 +1,6 @@
require "geocoder/configuration"
require "geocoder/calculations"
+require "geocoder/cache"
require "geocoder/railtie"
require "geocoder/request"
diff --git a/lib/geocoder/cache.rb b/lib/geocoder/cache.rb
new file mode 100644
index 00000000..82d47d09
--- /dev/null
+++ b/lib/geocoder/cache.rb
@@ -0,0 +1,81 @@
+module Geocoder
+
+ ##
+ # The working Cache object, or +nil+ if none configured.
+ #
+ def self.cache
+ if @cache.nil? and store = Geocoder::Configuration.cache
+ @cache = Cache.new(store, Geocoder::Configuration.cache_prefix)
+ end
+ @cache
+ end
+
+ class Cache
+
+ def initialize(store, prefix)
+ @store = store
+ @prefix = prefix
+ end
+
+ ##
+ # Read from the Cache.
+ #
+ def [](url)
+ interpret store[key_for(url)]
+ end
+
+ ##
+ # Write to the Cache.
+ #
+ def []=(url, value)
+ store[key_for(url)] = value
+ end
+
+ ##
+ # Expire cache entry for given URL,
+ # or pass <tt>:all</tt> to expire everything.
+ #
+ def expire(url)
+ if url == :all
+ urls.each{ |u| expire(u) }
+ else
+ self[url] = nil
+ end
+ end
+
+
+ private # ----------------------------------------------------------------
+
+ attr_reader :prefix, :store
+
+ ##
+ # Cache key for a given URL.
+ #
+ def key_for(url)
+ [prefix, url].join
+ end
+
+ ##
+ # Array of keys with the currently configured prefix
+ # that have non-nil values.
+ #
+ def keys
+ store.keys.select{ |k| k.match /^#{prefix}/ and interpret(store[k]) }
+ end
+
+ ##
+ # Array of cached URLs.
+ #
+ def urls
+ keys.map{ |k| k[/^#{prefix}(.*)/, 1] }
+ end
+
+ ##
+ # Clean up value before returning. Namely, convert empty string to nil.
+ # (Some key/value stores return empty string instead of nil.)
+ #
+ def interpret(value)
+ value == "" ? nil : value
+ end
+ end
+end
diff --git a/lib/geocoder/lookups/base.rb b/lib/geocoder/lookups/base.rb
index 65ff2128..90c17a30 100644
--- a/lib/geocoder/lookups/base.rb
+++ b/lib/geocoder/lookups/base.rb
@@ -60,7 +60,7 @@ module Geocoder
rescue TimeoutError
warn "Geocoding API not responding fast enough " +
"(see Geocoder::Configuration.timeout to set limit)."
- end
+ end
end
##
@@ -82,13 +82,12 @@ module Geocoder
# Fetches a raw search result (JSON string).
#
def fetch_raw_data(query, reverse = false)
- url = query_url(query, reverse)
- key = cache_key(url)
timeout(Geocoder::Configuration.timeout) do
- unless cache and (response = cache[key]) and response != ""
+ url = query_url(query, reverse)
+ unless cache and response = cache[url]
response = Net::HTTP.get_response(URI.parse(url)).body
if cache
- cache[key] = response
+ cache[url] = response
end
end
response
@@ -96,24 +95,10 @@ module Geocoder
end
##
- # Cache key for a given URL.
- #
- def cache_key(url)
- [cache_prefix, url].join
- end
-
- ##
- # The configured prefix for cache keys.
- #
- def cache_prefix
- Geocoder::Configuration.cache_prefix || "geocoder:"
- end
-
- ##
- # The configured cache store.
+ # The working Cache object.
#
def cache
- Geocoder::Configuration.cache
+ Geocoder.cache
end
##
--
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