Move Path.PdfAsync to protocol streams (#1208)

* Move Path.PdfAsync to protocol streams

* CodeFactor

* Minor code change

Author: kblok

lib/PuppeteerSharp/Helpers/ProtocolStreamReader.cs

@@ -0,0 +1,91 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using PuppeteerSharp.Messaging;
+
+namespace PuppeteerSharp.Helpers
+{
+    internal static class ProtocolStreamReader
+    {
+        internal static async Task<string> ReadProtocolStreamStringAsync(CDPSession client, string handle, string path)
+        {
+            var result = new StringBuilder();
+            var fs = !string.IsNullOrEmpty(path) ? AsyncFileHelper.CreateStream(path, FileMode.Create) : null;
+
+            try
+            {
+                var eof = false;
+
+                while (!eof)
+                {
+                    var response = await client.SendAsync<IOReadResponse>("IO.read", new IOReadRequest
+                    {
+                        Handle = handle
+                    }).ConfigureAwait(false);
+
+                    eof = response.Eof;
+
+                    result.Append(response.Data);
+
+                    if (fs != null)
+                    {
+                        var data = Encoding.UTF8.GetBytes(response.Data);
+                        await fs.WriteAsync(data, 0, data.Length).ConfigureAwait(false);
+                    }
+                }
+
+                await client.SendAsync("IO.close", new IOCloseRequest
+                {
+                    Handle = handle
+                }).ConfigureAwait(false);
+
+                return result.ToString();
+            }
+            finally
+            {
+                fs?.Dispose();
+            }
+        }
+
+        internal static async Task<byte[]> ReadProtocolStreamByteAsync(CDPSession client, string handle, string path)
+        {
+            IEnumerable<byte> result = null;
+            var eof = false;
+            var fs = !string.IsNullOrEmpty(path) ? AsyncFileHelper.CreateStream(path, FileMode.Create) : null;
+
+            try
+            {
+                while (!eof)
+                {
+                    var response = await client.SendAsync<IOReadResponse>("IO.read", new IOReadRequest
+                    {
+                        Handle = handle
+                    }).ConfigureAwait(false);
+
+                    eof = response.Eof;
+                    var data = Convert.FromBase64String(response.Data);
+                    result = result == null ? data : result.Concat(data);
+
+                    if (fs != null)
+                    {
+                        await fs.WriteAsync(data, 0, data.Length).ConfigureAwait(false);
+                    }
+                }
+
+                await client.SendAsync("IO.close", new IOCloseRequest
+                {
+                    Handle = handle
+                }).ConfigureAwait(false);
+
+                return result.ToArray();
+            }
+            finally
+            {
+                fs?.Dispose();
+            }
+        }
+    }
+}

lib/PuppeteerSharp/Messaging/IOReadResponse.cs

@@ -4,5 +4,6 @@ internal class IOReadResponse
     {
         public bool Eof { get; set; }
         public string Data { get; set; }
+        public bool Base64Encoded { get; set; }
     }
 }

lib/PuppeteerSharp/Messaging/PagePrintToPDFRequest.cs

@@ -16,5 +16,6 @@ internal class PagePrintToPDFRequest
         public decimal MarginRight { get; set; }
         public string PageRanges { get; set; }
         public bool PreferCSSPageSize { get; set; }
+        public string TransferMode { get; set; }
     }
 }

lib/PuppeteerSharp/Messaging/PagePrintToPDFResponse.cs

@@ -3,5 +3,6 @@
     internal class PagePrintToPDFResponse
     {
         public string Data { get; set; }
+        public string Stream { get; set; }
     }
 }

lib/PuppeteerSharp/Page.cs

@@ -855,14 +855,7 @@ public Task<Response> GoToAsync(string url, WaitUntilNavigation waitUntil)
         /// Generating a pdf is currently only supported in Chrome headless
         /// </remarks>
         public async Task PdfAsync(string file, PdfOptions options)
-        {
-            var data = await PdfDataAsync(options).ConfigureAwait(false);
-
-            using (var fs = AsyncFileHelper.CreateStream(file, FileMode.Create))
-            {
-                await fs.WriteAsync(data, 0, data.Length).ConfigureAwait(false);
-            }
-        }
+            => await PdfInternalAsync(file, options).ConfigureAwait(false);
 
         /// <summary>
         /// generates a pdf of the page with <see cref="MediaType.Print"/> css media. To generate a pdf with <see cref="MediaType.Screen"/> media call <see cref="EmulateMediaAsync(MediaType)"/> with <see cref="MediaType.Screen"/>
@@ -901,7 +894,9 @@ public async Task<Stream> PdfStreamAsync(PdfOptions options)
         /// <remarks>
         /// Generating a pdf is currently only supported in Chrome headless
         /// </remarks>
-        public async Task<byte[]> PdfDataAsync(PdfOptions options)
+        public Task<byte[]> PdfDataAsync(PdfOptions options) => PdfInternalAsync(null, options);
+
+        internal async Task<byte[]> PdfInternalAsync(string file, PdfOptions options)
         {
             var paperWidth = PaperFormat.Letter.Width;
             var paperHeight = PaperFormat.Letter.Height;
@@ -930,6 +925,7 @@ public async Task<byte[]> PdfDataAsync(PdfOptions options)
 
             var result = await Client.SendAsync<PagePrintToPDFResponse>("Page.printToPDF", new PagePrintToPDFRequest
             {
+                TransferMode = "ReturnAsStream",
                 Landscape = options.Landscape,
                 DisplayHeaderFooter = options.DisplayHeaderFooter,
                 HeaderTemplate = options.HeaderTemplate,
@@ -946,7 +942,7 @@ public async Task<byte[]> PdfDataAsync(PdfOptions options)
                 PreferCSSPageSize = options.PreferCSSPageSize
             }).ConfigureAwait(false);
 
-            return Convert.FromBase64String(result.Data);
+            return await ProtocolStreamReader.ReadProtocolStreamByteAsync(Client, result.Stream, file).ConfigureAwait(false);
         }
 
         /// <summary>

lib/PuppeteerSharp/Tracing.cs

@@ -4,6 +4,7 @@
 using System.Text;
 using System.Threading.Tasks;
 using Microsoft.Extensions.Logging;
+using PuppeteerSharp.Helpers;
 using PuppeteerSharp.Messaging;
 
 namespace PuppeteerSharp
@@ -93,9 +94,10 @@ async void EventHandler(object sender, MessageEventArgs e)
                     if (e.MessageID == "Tracing.tracingComplete")
                     {
                         var stream = e.MessageData.ToObject<TracingCompleteResponse>().Stream;
-                        var tracingData = await ReadStream(stream, _path).ConfigureAwait(false);
+                        var tracingData = await ProtocolStreamReader.ReadProtocolStreamStringAsync(_client, stream, _path).ConfigureAwait(false);
+
                         _client.MessageReceived -= EventHandler;
-                        taskWrapper.TrySetResult(tracingData);
+                        taskWrapper.TrySetResult(tracingData);
                     }
                 }
                 catch (Exception ex)
@@ -114,38 +116,5 @@ async void EventHandler(object sender, MessageEventArgs e)
 
             return await taskWrapper.Task.ConfigureAwait(false);
         }
-
-        private async Task<string> ReadStream(string stream, string path)
-        {
-            var result = new StringBuilder();
-            var eof = false;
-
-            while (!eof)
-            {
-                var response = await _client.SendAsync<IOReadResponse>("IO.read", new IOReadRequest
-                {
-                    Handle = stream
-                }).ConfigureAwait(false);
-
-                eof = response.Eof;
-
-                result.Append(response.Data);
-            }
-
-            if (!string.IsNullOrEmpty(path))
-            {
-                using (var fs = new StreamWriter(path))
-                {
-                    await fs.WriteAsync(result.ToString()).ConfigureAwait(false);
-                }
-            }
-
-            await _client.SendAsync("IO.close", new IOCloseRequest
-            {
-                Handle = stream
-            }).ConfigureAwait(false);
-
-            return result.ToString();
-        }
     }
 }