Add Serdes stream methods (#83)

CHANGELOG.md

@@ -9,6 +9,8 @@ The `Unreleased` section name is replaced by the expected version of next releas
 ## [Unreleased]
 
 ### Added
+- Add `SerializeToStream` and `DeserializeFromStream` methods to Serdes [#83](https://github.com/jet/FsCodec/pull/83)
+
 ### Changed
 ### Removed
 ### Fixed

src/FsCodec.NewtonsoftJson/Serdes.fs

@@ -1,17 +1,39 @@
 namespace FsCodec.NewtonsoftJson
 
 open Newtonsoft.Json
+open System.IO
+open System.Text
 
 /// Serializes to/from strings using the supplied JsonSerializerSettings
 type Serdes(options : JsonSerializerSettings) =
+    // Why are we creating a serializer here instead of using JsonConvert.Serialize?
+    // Because, under the hood, JsonConvert creates a serializer instance for *each* call
+    // Source:
+    // https://github.com/JamesNK/Newtonsoft.Json/blob/4dc9af66e07dea321ad101bfb379326127251a80/Src/Newtonsoft.Json/JsonConvert.cs#L817
+    // It's consistent with the stream implementation
+    let serializer = JsonSerializer.Create(options)
 
     /// <summary>The <c>JsonSerializerSettings</c> used by this instance.</summary>
     member _.Options : JsonSerializerSettings = options
 
     /// Serializes given value to a JSON string.
-    member _.Serialize<'T>(value : 'T) =
-        JsonConvert.SerializeObject(value, options)
+    member _.Serialize<'T>(value : 'T) : string =
+        use sw = new StringWriter()
+        use writer = new JsonTextWriter(sw)
+        serializer.Serialize(writer, value)
+        sw.ToString()
 
     /// Deserializes value of given type from JSON string.
-    member x.Deserialize<'T>(json : string) : 'T =
-        JsonConvert.DeserializeObject<'T>(json, options)
+    member _.Deserialize<'T>(json : string) : 'T =
+        use reader = new JsonTextReader(new StringReader(json))
+        serializer.Deserialize<'T>(reader)
+
+    /// Serializes and writes given value to a stream.
+    member _.SerializeToStream<'T>(value : 'T, utf8Stream : Stream) =
+        use writer = new JsonTextWriter(new StreamWriter(utf8Stream, Encoding.UTF8), CloseOutput = false)
+        serializer.Serialize(writer, value)
+
+    /// Deserializes by reading from a stream.
+    member x.DeserializeFromStream<'T>(utf8Stream : Stream) =
+        use reader = new JsonTextReader(new StreamReader(utf8Stream, Encoding.UTF8))
+        serializer.Deserialize<'T>(reader)

src/FsCodec.SystemTextJson/Serdes.fs

@@ -1,10 +1,11 @@
 namespace FsCodec.SystemTextJson
 
+open System.IO
 open System.Text.Json
 
 /// Serializes to/from strings using the supplied Options
 type Serdes(options : JsonSerializerOptions) =
-
+    
     /// <summary>The <c>JsonSerializerOptions</c> used by this instance.</summary>
     member _.Options : JsonSerializerOptions = options
 
@@ -13,5 +14,14 @@ type Serdes(options : JsonSerializerOptions) =
         JsonSerializer.Serialize<'T>(value, options)
 
     /// Deserializes value of given type from JSON string.
-    member x.Deserialize<'T>(json : string) : 'T =
+    member _.Deserialize<'T>(json : string) : 'T =
         JsonSerializer.Deserialize<'T>(json, options)
+
+    /// Serializes and writes given value to a stream.
+    member _.SerializeToStream<'T>(value : 'T, utf8Stream : Stream) =
+        JsonSerializer.Serialize<'T>(utf8Stream, value, options)
+
+    /// Deserializes by reading from a stream.
+    member _.DeserializeFromStream<'T>(utf8Stream : Stream) =
+        JsonSerializer.Deserialize<'T>(utf8Stream, options)
+

tests/FsCodec.NewtonsoftJson.Tests/FsCodec.NewtonsoftJson.Tests.fsproj

@@ -12,6 +12,7 @@
     <Compile Include="UnionConverterTests.fs" />
     <Compile Include="VerbatimUtf8ConverterTests.fs" />
     <Compile Include="SomeNullHandlingTests.fs" />
+    <Compile Include="StreamTests.fs" />
   </ItemGroup>
 
   <ItemGroup>

tests/FsCodec.NewtonsoftJson.Tests/StreamTests.fs

@@ -0,0 +1,23 @@
+#if SYSTEM_TEXT_JSON
+module FsCodec.SytemTextJson.Tests.StreamTests
+open FsCodec.SystemTextJson
+#else
+module FsCodec.NewtonsoftJson.Tests.StreamTests
+open FsCodec.NewtonsoftJson
+#endif
+
+open Xunit
+open System.IO
+open Swensen.Unquote
+
+let serdes = Serdes Options.Default
+
+type Rec = { a : int; b : string; c : string }
+
+let [<Fact>] ``Can serialize/deserialize to stream`` () =
+    let value = { a = 10; b = "10"; c = null }
+    use stream = new MemoryStream()    
+    serdes.SerializeToStream(value, stream)
+    stream.Seek(0L, SeekOrigin.Begin) |> ignore
+    let value' = serdes.DeserializeFromStream(stream)
+    <@ value = value' @>

tests/FsCodec.SystemTextJson.Tests/FsCodec.SystemTextJson.Tests.fsproj

@@ -28,6 +28,7 @@
     <Compile Include="SerdesTests.fs" />
     <Compile Include="UmxInteropTests.fs" />
     <Compile Include="TypeSafeEnumConverterTests.fs" />
+    <Compile Include="..\FsCodec.NewtonsoftJson.Tests\StreamTests.fs" Link="StreamTests.fs" />
     <Compile Include="..\FsCodec.NewtonsoftJson.Tests\Fixtures.fs">
       <Link>Fixtures.fs</Link>
     </Compile>