Fix encoding and mutable string issues

Author: route

README.md

@@ -346,7 +346,7 @@ browser.screenshot(path: "google.jpg") # => 30902
 browser.screenshot(full: true, quality: 60) # "iVBORw0KGgoAAAANSUhEUgAABAAAAAMACAYAAAC6uhUNAAAAAXNSR0IArs4c6Q...
 ```
 
-#### pdf(\*\*options) : `String` | `Integer`
+#### pdf(\*\*options) : `String` | `Boolean`
 
 Saves PDF on a disk or returns it as base64.
 
@@ -366,7 +366,7 @@ Saves PDF on a disk or returns it as base64.
 ```ruby
 browser.go_to("https://google.com/")
 # Save to disk as a PDF
-browser.pdf(path: "google.pdf", paper_width: 1.0, paper_height: 1.0) # => 14983
+browser.pdf(path: "google.pdf", paper_width: 1.0, paper_height: 1.0) # => true
 ```
 
 #### mhtml(\*\*options) : `String` | `Integer`

lib/ferrum/page/screenshot.rb

@@ -24,6 +24,8 @@ module Screenshot
         A6:       { width:  4.13, height:  5.83 },
       }.freeze
 
+      STREAM_CHUNK = 128 * 1024
+
       def screenshot(**opts)
         path, encoding = common_options(**opts)
         options = screenshot_options(path, **opts)
@@ -34,14 +36,15 @@ def screenshot(**opts)
         save_file(path, bin)
       end
 
-      def pdf(**opts)
+    def pdf(**opts)
         path, encoding = common_options(**opts)
         options = pdf_options(**opts).merge(transferMode: "ReturnAsStream")
-        stream_handle = command("Page.printToPDF", **options).fetch("stream")
+        handle = command("Page.printToPDF", **options).fetch("stream")
+
         if path
-          stream_to_file(stream_handle, path)
+          stream_to_file(handle, path: path)
         else
-          stream_to_memory(stream_handle)
+          stream_to_memory(handle, encoding: encoding)
         end
       end
 
@@ -71,25 +74,26 @@ def save_file(path, data)
         File.open(path.to_s, "wb") { |f| f.write(data) }
       end
 
-      def stream_to_file(stream_handle, path)
-        File.open(path, 'wb') do |output_file|
-          stream_to stream_handle, output_file
-        end
+      def stream_to_file(handle, path:)
+        File.open(path, "wb") { |f| stream_to(handle, f) }
+        true
       end
 
-      def stream_to_memory(stream_handle)
-        in_memory_data = ''
-        stream_to stream_handle, in_memory_data
-        in_memory_data
+      def stream_to_memory(handle, encoding:)
+        data = String.new("") # Mutable string has << and compatible to File
+        stream_to(handle, data)
+        encoding == :base64 ? Base64.encode64(data) : data
       end
 
-      def stream_to(stream_handle, output)
+      def stream_to(handle, output)
         loop do
-          read_result = command("IO.read", handle: stream_handle, size: 131072)
-          data_chunk = read_result['data']
-          data_chunk = Base64.decode64(data_chunk) if read_result['base64Encoded']
+          result = command("IO.read", handle: handle, size: STREAM_CHUNK)
+
+          data_chunk = result["data"]
+          data_chunk = Base64.decode64(data_chunk) if result["base64Encoded"]
           output << data_chunk
-          break if read_result['eof']
+
+          break if result["eof"]
         end
       end
 

spec/screenshot_spec.rb

@@ -312,23 +312,24 @@ def create_screenshot(path: file, **options)
                scale: 1,
             )) { { "stream" => "1" } }
 
-            allow(browser.page).to receive(:command).with("IO.read", hash_including(
-              handle: "1"
-            )) { { "data" => "", "base64Encoded" => false, "eof" => true } }
-
-            browser.pdf(path: file, landscape: false,
-                                    display_header_footer: false,
-                                    print_background: false,
-                                    scale: 1,
-                                    paper_width: 8.5,
-                                    paper_height: 11,
-                                    margin_top: 0.4,
-                                    margin_bottom: 0.4,
-                                    margin_left: 0.4,
-                                    margin_right: 0.4,
-                                    page_ranges: "",
-                                    ignore_invalid_page_ranges: false,
-                                    prefer_css_page_size: false)
+            allow(browser.page).to receive(:command).with("IO.read", hash_including(handle: "1")) {
+              { "data" => "", "base64Encoded" => false, "eof" => true }
+            }
+
+            browser.pdf(path: file,
+                        landscape: false,
+                        display_header_footer: false,
+                        print_background: false,
+                        scale: 1,
+                        paper_width: 8.5,
+                        paper_height: 11,
+                        margin_top: 0.4,
+                        margin_bottom: 0.4,
+                        margin_left: 0.4,
+                        margin_right: 0.4,
+                        page_ranges: "",
+                        ignore_invalid_page_ranges: false,
+                        prefer_css_page_size: false)
           end
         end
       end