From ae0650d2bea1a68fc186ca7df731c1b946798711 Mon Sep 17 00:00:00 2001
From: Kanezoh <asfaltmanta114@gmail.com>
Date: Sun, 22 Aug 2021 09:47:10 +0900
Subject: [PATCH 1/4] file download

---
 spec/agent_spec.cr |  7 +++++++
 src/mechanize.cr   | 23 +++++++++++++++++++++--
 2 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/spec/agent_spec.cr b/spec/agent_spec.cr
index e6b9dbe..a729169 100644
--- a/spec/agent_spec.cr
+++ b/spec/agent_spec.cr
@@ -56,4 +56,11 @@ describe "Mechanize Agent test" do
     agent2.history.size.should eq 1
     agent2.history.pop.uri.to_s.should eq "http://example.com/form"
   end
+
+  it "can download page" do
+    agent = Mechanize.new
+    agent.download("http://example.com", "mechanizecr_example.html")
+    File.exists?("mechanizecr_example.html").should eq true
+    File.delete("mechanizecr_example.html")
+  end
 end
diff --git a/src/mechanize.cr b/src/mechanize.cr
index 5cd6dbc..83413bb 100644
--- a/src/mechanize.cr
+++ b/src/mechanize.cr
@@ -17,7 +17,9 @@ class Mechanize
     @agent.user_agent = AGENT["Mechanize"]
   end
 
-  def get(uri : String | URI, headers = HTTP::Headers.new, params : Hash(String, String | Array(String)) = Hash(String, String).new)
+  def get(uri : String | URI,
+          headers = HTTP::Headers.new,
+          params : Hash(String, String | Array(String)) = Hash(String, String).new)
     method = :get
     page = @agent.fetch uri, method, headers, params
     add_to_history(page)
@@ -25,7 +27,9 @@ class Mechanize
     page
   end
 
-  def post(uri : String | URI, headers = HTTP::Headers.new, query : Hash(String, String | Array(String)) = Hash(String, String).new)
+  def post(uri : String | URI,
+           headers = HTTP::Headers.new,
+           query : Hash(String, String | Array(String)) = Hash(String, String).new)
     node = Node.new
     node["method"] = "POST"
     node["enctype"] = "application/x-www-form-urlencoded"
@@ -119,4 +123,19 @@ class Mechanize
     href = link.href
     get href
   end
+
+  # download page body from given uri.
+  # TODO: except this request from history.
+  def download(uri, 
+               filename,
+               headers = HTTP::Headers.new,
+               params : Hash(String, String | Array(String)) = Hash(String, String).new)
+    page = get(uri, headers, params)
+
+    case page
+    when MechanizeCr::File
+      File.write(filename, page.body)
+    end
+    page
+  end
 end

From b98bb4eb2dd943986a80eab2da608495c419a376 Mon Sep 17 00:00:00 2001
From: Kanezoh <asfaltmanta114@gmail.com>
Date: Sun, 22 Aug 2021 09:47:57 +0900
Subject: [PATCH 2/4] format code

---
 src/mechanize.cr | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/mechanize.cr b/src/mechanize.cr
index 83413bb..5533293 100644
--- a/src/mechanize.cr
+++ b/src/mechanize.cr
@@ -126,7 +126,7 @@ class Mechanize
 
   # download page body from given uri.
   # TODO: except this request from history.
-  def download(uri, 
+  def download(uri,
                filename,
                headers = HTTP::Headers.new,
                params : Hash(String, String | Array(String)) = Hash(String, String).new)

From d344fadc44919b469175077a3f9fdccd56edc120 Mon Sep 17 00:00:00 2001
From: Kanezoh <asfaltmanta114@gmail.com>
Date: Tue, 24 Aug 2021 07:50:12 +0900
Subject: [PATCH 3/4] add transact method

---
 spec/agent_spec.cr       | 10 ++++++++++
 src/mechanize.cr         | 12 ++++++++++++
 src/mechanize/history.cr |  6 +++---
 3 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/spec/agent_spec.cr b/spec/agent_spec.cr
index a729169..ed7e8f8 100644
--- a/spec/agent_spec.cr
+++ b/spec/agent_spec.cr
@@ -63,4 +63,14 @@ describe "Mechanize Agent test" do
     File.exists?("mechanizecr_example.html").should eq true
     File.delete("mechanizecr_example.html")
   end
+
+  it "doesn't add page to history within transact block" do
+    agent = Mechanize.new
+    agent.get("http://example.com/")
+    agent.history.size.should eq 1
+    agent.transact do
+      agent.get("http://example.com/")
+    end
+    agent.history.size.should eq 1
+  end
 end
diff --git a/src/mechanize.cr b/src/mechanize.cr
index 5533293..3bd9b7a 100644
--- a/src/mechanize.cr
+++ b/src/mechanize.cr
@@ -138,4 +138,16 @@ class Mechanize
     end
     page
   end
+
+  # Runs given block, then resets the page history as it was before.
+  def transact
+    # save the previous history status.
+    history_backup = MechanizeCr::History.new(@agent.history.max_size, @agent.history.array.dup)
+    begin
+      yield self
+    ensure
+      # restore the previous history.
+      @agent.history = history_backup
+    end
+  end
 end
diff --git a/src/mechanize/history.cr b/src/mechanize/history.cr
index 183a90b..6e1600b 100644
--- a/src/mechanize/history.cr
+++ b/src/mechanize/history.cr
@@ -4,11 +4,11 @@ class MechanizeCr::History
   property max_size : Int32
   property array : Array(MechanizeCr::Page)
 
-  forward_missing_to @array
+  delegate :size, :empty?, :last, to: array
 
-  def initialize(max_size = 100)
+  def initialize(max_size = 100, array = Array(MechanizeCr::Page).new)
     @max_size = max_size
-    @array = Array(MechanizeCr::Page).new
+    @array = array
   end
 
   def push(page, uri = nil)

From cfa824c9091d4e33d3c7b3578a68849837105195 Mon Sep 17 00:00:00 2001
From: Kanezoh <asfaltmanta114@gmail.com>
Date: Tue, 24 Aug 2021 08:09:43 +0900
Subject: [PATCH 4/4] download file within transact

---
 spec/agent_spec.cr | 16 +++++++++-------
 src/mechanize.cr   | 12 ++++++------
 2 files changed, 15 insertions(+), 13 deletions(-)

diff --git a/spec/agent_spec.cr b/spec/agent_spec.cr
index ed7e8f8..86b7300 100644
--- a/spec/agent_spec.cr
+++ b/spec/agent_spec.cr
@@ -57,13 +57,6 @@ describe "Mechanize Agent test" do
     agent2.history.pop.uri.to_s.should eq "http://example.com/form"
   end
 
-  it "can download page" do
-    agent = Mechanize.new
-    agent.download("http://example.com", "mechanizecr_example.html")
-    File.exists?("mechanizecr_example.html").should eq true
-    File.delete("mechanizecr_example.html")
-  end
-
   it "doesn't add page to history within transact block" do
     agent = Mechanize.new
     agent.get("http://example.com/")
@@ -73,4 +66,13 @@ describe "Mechanize Agent test" do
     end
     agent.history.size.should eq 1
   end
+
+  it "can download page" do
+    agent = Mechanize.new
+    agent.history.size.should eq 0
+    agent.download("http://example.com", "mechanizecr_example.html")
+    agent.history.size.should eq 0
+    File.exists?("mechanizecr_example.html").should eq true
+    File.delete("mechanizecr_example.html")
+  end
 end
diff --git a/src/mechanize.cr b/src/mechanize.cr
index 3bd9b7a..6fcf332 100644
--- a/src/mechanize.cr
+++ b/src/mechanize.cr
@@ -130,13 +130,13 @@ class Mechanize
                filename,
                headers = HTTP::Headers.new,
                params : Hash(String, String | Array(String)) = Hash(String, String).new)
-    page = get(uri, headers, params)
-
-    case page
-    when MechanizeCr::File
-      File.write(filename, page.body)
+    transact do
+      page = get(uri, headers, params)
+      case page
+      when MechanizeCr::File
+        File.write(filename, page.body)
+      end
     end
-    page
   end
 
   # Runs given block, then resets the page history as it was before.