New feature: local cache

.gitignore

@@ -11,3 +11,4 @@ main.cr
 # Dependencies will be locked in application that uses them
 shard.lock
 .history/
+cache/

shard.yml

@@ -4,6 +4,6 @@ version: 0.6.0
 authors:
   - icyleaf <icyleaf.cn@gmail.com>
 
-crystal: 0.26.0
+crystal: 0.26.1
 
 license: MIT

spec/fixtures/cache_file.json

@@ -0,0 +1 @@
+{"name":"foo3"}

spec/halite/features/cache_spec.cr

@@ -0,0 +1,187 @@
+require "../../spec_helper"
+
+private struct CacheStruct
+  getter metadata, body, chain
+  def initialize(@body : String, @chain : Halite::Feature::Chain, @metadata : Hash(String, JSON::Any)? = nil)
+  end
+end
+
+private def cache_spec(cache, request, response, use_cache = false, wait_time : (Int32 | Time::Span)? = nil)
+  FileUtils.rm_rf(cache.path)
+
+  _chain = Halite::Feature::Chain.new(request, nil, Halite::Options.new) do
+    response
+  end
+
+  if file = cache.file
+    chain = cache.intercept(_chain)
+    body = File.read_lines(file).join("\n")
+    yield CacheStruct.new(body, chain)
+  else
+    key = Digest::MD5.hexdigest("#{request.verb}-#{request.uri}-#{request.body}")
+    path = File.join(cache.path, key)
+    metadata_file = File.join(path, "metadata.json")
+    body_file = File.join(path, "#{key}.cache")
+
+    cache.intercept(_chain) if use_cache
+
+    if seconds = wait_time
+      sleep seconds
+    end
+
+    chain = cache.intercept(_chain)
+
+    Dir.exists?(path).should be_true
+    File.file?(metadata_file).should be_true
+    File.file?(body_file).should be_true
+
+    metadata = JSON.parse(File.open(metadata_file)).as_h
+    body = File.read_lines(body_file).join("\n")
+
+    yield CacheStruct.new(body, chain, metadata)
+
+    FileUtils.rm_rf(cache.path)
+  end
+end
+
+describe Halite::Cache do
+  it "should register a format" do
+    Halite.has_feature?("cache").should be_true
+    Halite.feature("cache").should eq(Halite::Cache)
+  end
+
+  describe "getters" do
+    it "should default value" do
+      feature = Halite::Cache.new
+      feature.path.should eq(Halite::Cache::DEFAULT_PATH)
+      feature.expires.should be_nil
+      feature.debug.should be_true
+    end
+
+    it "should return setter value" do
+      feature = Halite::Cache.new(path: "/tmp/cache", expires: 1.day, debug: false)
+      feature.file.should be_nil
+      feature.path.should eq("/tmp/cache")
+      feature.expires.should eq(1.day)
+      feature.debug.should be_false
+
+      # expires accept Int32/Time::Span but return Time::Span
+      feature = Halite::Cache.new(expires: 60)
+      feature.file.should be_nil
+      feature.path.should eq(Halite::Cache::DEFAULT_PATH)
+      feature.expires.should eq(1.minutes)
+      feature.debug.should be_true
+    end
+  end
+
+  describe "intercept" do
+    it "should cache to local storage" do
+      body = {name: "foo"}.to_json
+      request = Halite::Request.new("get", SERVER.api("/anything?q=halite1#result"), HTTP::Headers{"Accept" => "application/json"})
+      response = Halite::Response.new(request.uri, 200, body, HTTP::Headers{"Content-Type" => "application/json", "Content-Length" => body.size.to_s})
+      feature = Halite::Cache.new
+      feature.file.should be_nil
+      feature.path.should eq(Halite::Cache::DEFAULT_PATH)
+      feature.expires.should be_nil
+      feature.debug.should be_true
+
+      # First return response on HTTP
+      cache_spec(feature, request, response, use_cache: false) do |result|
+        result.metadata.not_nil!["status_code"].should eq(200)
+        result.metadata.not_nil!["headers"].as_h["Content-Type"].should eq("application/json")
+        result.metadata.not_nil!["headers"].as_h["Content-Length"].should eq(response.body.size.to_s)
+        result.body.should eq(response.body)
+        result.chain.result.should eq(Halite::Feature::Chain::Result::Return)
+        result.chain.response.should eq(response)
+      end
+
+      # Second return response on Cache
+      cache_spec(feature, request, response, use_cache: true) do |result|
+        result.metadata.not_nil!["status_code"].should eq(200)
+        result.metadata.not_nil!["headers"].as_h["Content-Type"].should eq("application/json")
+        result.metadata.not_nil!["headers"].as_h["Content-Length"].should eq(response.body.size.to_s)
+        result.body.should eq(response.body)
+        result.chain.result.should eq(Halite::Feature::Chain::Result::Return)
+
+        result.chain.response.should_not be_nil
+        result.chain.response.not_nil!.headers["X-Cached-From"].should eq("cache")
+        result.chain.response.not_nil!.headers["X-Cached-Key"].should_not eq("")
+        result.chain.response.not_nil!.headers["X-Cached-At"].should_not eq("")
+        result.chain.response.not_nil!.headers["X-Cached-Expires-At"].should eq("None")
+      end
+    end
+
+    it "should cache without debug mode" do
+      body = {name: "foo1"}.to_json
+      request = Halite::Request.new("get", SERVER.api("/anything?q=halite2#result"), HTTP::Headers{"Accept" => "application/json"})
+      response = Halite::Response.new(request.uri, 200, body, HTTP::Headers{"Content-Type" => "application/json", "Content-Length" => body.size.to_s})
+      feature = Halite::Cache.new(debug: false)
+      feature.file.should be_nil
+      feature.path.should eq(Halite::Cache::DEFAULT_PATH)
+      feature.expires.should be_nil
+      feature.debug.should be_false
+
+      cache_spec(feature, request, response, use_cache: true) do |result|
+        result.metadata.not_nil!["status_code"].should eq(200)
+        result.metadata.not_nil!["headers"].as_h["Content-Type"].should eq("application/json")
+        result.metadata.not_nil!["headers"].as_h["Content-Length"].should eq(response.body.size.to_s)
+        result.body.should eq(response.body)
+        result.chain.result.should eq(Halite::Feature::Chain::Result::Return)
+
+        result.chain.response.should_not be_nil
+        result.chain.response.not_nil!.headers.has_key?("X-Cached-From").should be_false
+        result.chain.response.not_nil!.headers.has_key?("X-Cached-Key").should be_false
+        result.chain.response.not_nil!.headers.has_key?("X-Cached-At").should be_false
+      end
+    end
+
+    it "should return no cache if expired" do
+      body = {name: "foo2"}.to_json
+      request = Halite::Request.new("get", SERVER.api("/anything?q=halite3#result"), HTTP::Headers{"Accept" => "application/json"})
+      response = Halite::Response.new(request.uri, 200, body, HTTP::Headers{"Content-Type" => "application/json", "Content-Length" => body.size.to_s})
+      feature = Halite::Cache.new(expires: 1.milliseconds)
+      feature.file.should be_nil
+      feature.path.should eq(Halite::Cache::DEFAULT_PATH)
+      feature.expires.should eq(1.milliseconds)
+      feature.debug.should be_true
+
+      cache_spec(feature, request, response, use_cache: true, wait_time: 500.milliseconds) do |result|
+        result.metadata.not_nil!["status_code"].should eq(200)
+        result.metadata.not_nil!["headers"].as_h["Content-Type"].should eq("application/json")
+        result.metadata.not_nil!["headers"].as_h["Content-Length"].should eq(response.body.size.to_s)
+        result.body.should eq(response.body)
+        result.chain.result.should eq(Halite::Feature::Chain::Result::Return)
+
+        result.chain.response.should_not be_nil
+        result.chain.response.not_nil!.headers.has_key?("X-Cached-From").should be_false
+        result.chain.response.not_nil!.headers.has_key?("X-Cached-Key").should be_false
+        result.chain.response.not_nil!.headers.has_key?("X-Cached-At").should be_false
+        result.chain.response.not_nil!.headers.has_key?("X-Cached-Expires-At").should be_false
+      end
+    end
+
+    it "should load cache from file" do
+      file = fixture_path("cache_file.json")
+      body = load_fixture("cache_file.json")
+      request = Halite::Request.new("get", SERVER.api("/anything?q=halite4#result"), HTTP::Headers{"Accept" => "application/json"})
+      response = Halite::Response.new(request.uri, 200, body, HTTP::Headers{"Content-Type" => "application/json", "Content-Length" => body.size.to_s})
+      feature = Halite::Cache.new(file: file)
+      feature.file.should eq(file)
+      feature.path.should eq(Halite::Cache::DEFAULT_PATH)
+      feature.expires.should be_nil
+      feature.debug.should be_true
+
+      cache_spec(feature, request, response, file) do |result|
+        result.metadata.should be_nil
+        result.body.should eq(response.body)
+        result.chain.result.should eq(Halite::Feature::Chain::Result::Return)
+
+        result.chain.response.should_not be_nil
+        result.chain.response.not_nil!.headers["X-Cached-From"].should eq("file")
+        result.chain.response.not_nil!.headers.has_key?("X-Cached-Key").should be_false
+        result.chain.response.not_nil!.headers["X-Cached-At"].should_not eq("")
+        result.chain.response.not_nil!.headers.has_key?("X-Cached-Expires-At").should be_false
+      end
+    end
+  end
+end

spec/spec_helper.cr

@@ -66,6 +66,14 @@ class SimpleLogger < Halite::Logging::Abstract
   Halite::Logging.register "simple", self
 end
 
+def fixture_path(file)
+  File.join(File.dirname(__FILE__), "fixtures", file)
+end
+
+def load_fixture(file)
+  File.read_lines(fixture_path(file)).join("\n")
+end
+
 ####################
 # Start mock server
 ####################