Simple implementation of QPdfJob for maximum compression of pdf files

.gitignore

@@ -37,3 +37,4 @@ _UpgradeReport_Files/
 Thumbs.db
 Desktop.ini
 .DS_Store
+/deploy.cmd

global.json

@@ -0,0 +1,6 @@
+{
+  "sdk": {
+    "version": "8.0.406",
+    "rollForward": "latestFeature"
+  }
+}

src/QPdfSharp/Converters/NullableIntToStringConverter.cs

@@ -0,0 +1,18 @@
+// Copyright © Stephen (Sven) Vernyi and Contributors. Licensed under the MIT License (MIT). See License.md in the repository root for more information.
+
+using System.Text.Json;
+using System.Text.Json.Serialization;
+
+namespace QPdfSharp.Converters;
+
+public class NullableIntToStringConverter : JsonConverter<int?>
+{
+    public override int? Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
+        => throw new NotImplementedException();
+
+    public override void Write(Utf8JsonWriter writer, int? value, JsonSerializerOptions options)
+    {
+        if (value.HasValue)
+            writer.WriteStringValue(value.Value.ToString());
+    }
+}

src/QPdfSharp/Converters/QPdfCompressStreamConverter.cs

@@ -0,0 +1,24 @@
+// Copyright © Stephen (Sven) Vernyi and Contributors. Licensed under the MIT License (MIT). See License.md in the repository root for more information.
+
+using System.Text.Json;
+using System.Text.Json.Serialization;
+using QPdfSharp.Enums;
+
+namespace QPdfSharp.Converters;
+
+public class QPdfCompressStreamConverter : JsonConverter<QPdfCompressStream>
+{
+    public override QPdfCompressStream Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
+        => throw new NotImplementedException();
+
+    public override void Write(Utf8JsonWriter writer, QPdfCompressStream value, JsonSerializerOptions options)
+    {
+        var result = value switch
+        {
+            QPdfCompressStream.No => "n",
+            QPdfCompressStream.Yes => "y",
+            _ => throw new JsonException($"Unknown value enum: {value}")
+        };
+        writer.WriteStringValue(result);
+    }
+}

src/QPdfSharp/Enums/QPdfCompressStream.cs

@@ -0,0 +1,9 @@
+// Copyright © Stephen (Sven) Vernyi and Contributors. Licensed under the MIT License (MIT). See License.md in the repository root for more information.
+
+namespace QPdfSharp.Enums;
+
+public enum QPdfCompressStream : uint
+{
+    No = 0,
+    Yes
+}

src/QPdfSharp/Options/QPdfJobOptions.cs

@@ -0,0 +1,37 @@
+// Copyright © Stephen (Sven) Vernyi and Contributors. Licensed under the MIT License (MIT). See License.md in the repository root for more information.
+
+using QPdfSharp.Converters;
+using System.Text.Json.Serialization;
+using QPdfSharp.Enums;
+
+namespace QPdfSharp.Options;
+
+public sealed class QPdfJobOptions
+{
+    // qpdf.exe in.pdf out.pdf --compress-streams=y --recompress-flate --compression-level=9 --object-streams=generate --decode-level=generalized --optimize-images
+    public string? InputFile { get; set; }
+    public string? OutputFile { get; set; }
+
+    [JsonConverter(typeof(QPdfCompressStreamConverter))]
+    public QPdfCompressStream? CompressStreams { get; set; }
+
+    [JsonConverter(typeof(NullableIntToStringConverter))]
+    public int? CompressionLevel { get; set; }
+    public string? RecompressFlate { get; set; }
+    public string? OptimizeImages { get; set; }
+    //public bool? NormalizeContent { get; set; }
+    public QPdfObjectStream? ObjectStreams { get; set; }
+    public QPdfStreamDecodeLevel? DecodeLevel { get; set; }
+
+    public static QPdfJobOptions CreateWithMaxCompression(string inputFile, string outputFile)
+        => new() {
+            InputFile = inputFile,
+            OutputFile = outputFile,
+            CompressStreams = QPdfCompressStream.Yes,
+            CompressionLevel = 9,
+            RecompressFlate = "",
+            OptimizeImages = "",
+            ObjectStreams = QPdfObjectStream.Generate,
+            DecodeLevel = QPdfStreamDecodeLevel.Generalized
+        };
+}

src/QPdfSharp/Options/QPdfWriteOptions.cs

@@ -1,4 +1,4 @@
-// Copyright © Stephen (Sven) Vernyi and Contributors. Licensed under the MIT License (MIT). See License.md in the repository root for more information.
+// Copyright © Stephen (Sven) Vernyi and Contributors. Licensed under the MIT License (MIT). See License.md in the repository root for more information.
 
 using QPdfSharp.Enums;
 

src/QPdfSharp/QPdfJob.cs

@@ -0,0 +1,79 @@
+// Copyright © Stephen (Sven) Vernyi and Contributors. Licensed under the MIT License (MIT). See License.md in the repository root for more information.
+
+using System.Text;
+using System.Text.Json.Serialization;
+using System.Text.Json;
+using QPdfSharp.Extensions;
+using QPdfSharp.Interop;
+using QPdfSharp.Options;
+
+namespace QPdfSharp;
+
+public unsafe class QPdfJob : IDisposable
+{
+    public static readonly string Version = new(QPdfInterop.qpdf_get_qpdf_version());
+
+    private readonly QPdfJobHandle* _qPdfJob = QPdfInterop.qpdfjob_init();
+
+    private QPdfLoggerHandle* _qPdfLogger = null;
+
+    private readonly StringBuilder _errorBuilder = new();
+
+    public QPdfJob(string filePath, string outFilePath)
+        => InitializeQPdfJob(QPdfJobOptions.CreateWithMaxCompression(filePath, outFilePath));
+
+    ~QPdfJob() => ReleaseUnmanagedResources();
+
+    public void Run()
+        => CheckError(QPdfInterop.qpdfjob_run(_qPdfJob));
+
+    private void CheckError(int? errorCode = null)
+    {
+        if (errorCode == 0)
+            return;
+
+        var errorMessage = _errorBuilder.ToString();
+        if (string.IsNullOrWhiteSpace(errorMessage))
+            return;
+
+        _errorBuilder.Clear();
+
+        throw new QPdfException(errorMessage);
+    }
+
+    public void Dispose()
+    {
+        ReleaseUnmanagedResources();
+        GC.SuppressFinalize(this);
+    }
+
+    private void ReleaseUnmanagedResources()
+    {
+        fixed (QPdfLoggerHandle** logHandle = &_qPdfLogger)
+            QPdfInterop.qpdflogger_cleanup(logHandle);
+
+        fixed (QPdfJobHandle** jobHandle = &_qPdfJob)
+            QPdfInterop.qpdfjob_cleanup(jobHandle);
+    }
+
+    private void InitializeQPdfJob(QPdfJobOptions? options)
+    {
+        QPdfLogFunction writeError = (data, len, _) => {
+            _errorBuilder.Append(new string(data, 0, (int)len));
+            return 0;
+        };
+
+        _qPdfLogger = QPdfInterop.qpdflogger_create();
+        QPdfInterop.qpdflogger_set_error(_qPdfLogger, QPdfLogDestination.qpdf_log_dest_custom, writeError, null);
+        QPdfInterop.qpdfjob_set_logger(_qPdfJob, _qPdfLogger);
+
+        var serializerOptions = new JsonSerializerOptions {
+            DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull,
+            PropertyNamingPolicy = JsonNamingPolicy.CamelCase,
+            Converters = { new JsonStringEnumConverter(JsonNamingPolicy.CamelCase) }
+        };
+        var json = JsonSerializer.Serialize(options, serializerOptions);
+        fixed (sbyte* jsonBytes = json.ToSByte())
+            CheckError(QPdfInterop.qpdfjob_initialize_from_json(_qPdfJob, jsonBytes));
+    }
+}

src/QPdfSharp/QPdfSharp.csproj

@@ -10,6 +10,7 @@
   <ItemGroup>
     <PackageReference Include="QPdfSharp.Interop" Version="1.0.1" />
     <PackageReference Include="System.Memory" Version="4.5.5" />
+    <PackageReference Include="System.Text.Json" Version="8.0.5" />
   </ItemGroup>
 
 </Project>

tests/QPdfSharp.Tests/QPdfJobTests.cs

@@ -0,0 +1,55 @@
+// Copyright © Stephen (Sven) Vernyi and Contributors. Licensed under the MIT License (MIT). See License.md in the repository root for more information.
+
+namespace QPdfSharp.Tests;
+
+public class QPdfJobTests
+{
+    [Fact]
+    public void Can_read_qpdf_version()
+    {
+        // Arrange
+        // Act
+        var version = QPdfJob.Version;
+
+        // Assert
+        Version.TryParse(version, out _).Should().BeTrue();
+    }
+
+    [Theory]
+    [InlineData(TestAssets.Grug)]
+    public void Can_compress_pdf_from_file_path(string filePath)
+    {
+        // Arrange
+        var outputFileName = "small.pdf";
+
+        // Act
+        var run = () => {
+            using var qPdfJob = new QPdfJob(filePath, outputFileName);
+            qPdfJob.Run();
+        };
+
+        // Assert
+        run.Should().NotThrow();
+        File.Exists(outputFileName).Should().BeTrue();
+        new FileInfo(outputFileName).Length.Should().BeLessThan(new FileInfo(filePath).Length);
+        File.Delete(outputFileName);
+    }
+
+    [Theory]
+    [InlineData("abc.pdf")]
+    [InlineData("Assets/abc.pdf")]
+    public void Should_throw_exception_if_file_not_found(string filePath)
+    {
+        // Arrange
+        var outputFileName = "small.pdf";
+
+        // Act
+        var run = () => {
+            using var qPdfJob = new QPdfJob(filePath, outputFileName);
+            qPdfJob.Run();
+        };
+
+        // Assert
+        run.Should().Throw<QPdfException>($"qpdfjob json: open {filePath}: No such file or directory");
+    }
+}

tests/QPdfSharp.Tests/QPdfReadingTests.cs

@@ -46,4 +46,3 @@ public async Task Can_read_pdf_from_memory(string filePath)
         createPdfFromBytes.Should().NotThrow();
     }
 }
-

tests/QPdfSharp.Tests/QPdfSharp.Tests.csproj

@@ -1,5 +1,9 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
+  <PropertyGroup>
+    <TargetFramework>net8.0</TargetFramework>
+  </PropertyGroup>
+
   <ItemGroup>
     <PackageReference Include="FluentAssertions" Version="6.12.0" />
     <PackageReference Include="FluentAssertions.Analyzers" Version="0.30.0">

tests/QPdfSharp.Tests/TestAssets.cs

@@ -1,4 +1,4 @@
-// Copyright © Stephen (Sven) Vernyi and Contributors. Licensed under the MIT License (MIT). See License.md in the repository root for more information.
+// Copyright © Stephen (Sven) Vernyi and Contributors. Licensed under the MIT License (MIT). See License.md in the repository root for more information.
 
 namespace QPdfSharp.Tests;