added File async append extensions

added File async append extensions
corrected reference path in AsyncFileExtensions.fsx

Author: Ian144

samples/AsyncFileExtensions.fsx

@@ -1,7 +1,7 @@
 
 
-//#r @"..\build\FSharpx.Core.dll"
-#r @"C:\Users\Ian\Documents\GitHub\Ian144\fsharpx\build\debug\FSharpx.Core.dll"
+#r @"..\build\FSharpx.Core.dll"
+
 
 open Microsoft.FSharp.Control
 
@@ -16,15 +16,27 @@ let asyncWriteA =  System.IO.File.AsyncWriteAllLines(@"c:\tmp\a.txt", lines)
 let asyncWriteB =  System.IO.File.AsyncWriteAllLines(@"c:\tmp\b.txt", lines)
 let asyncWriteC =  System.IO.File.AsyncWriteAllLines(@"c:\tmp\c.txt", lines)
 let asyncWriteD =  System.IO.File.AsyncWriteAllLines(@"c:\tmp\d.txt", lines)
-let asyncWriteE =  System.IO.File.AsyncWriteAllText( @"c:\tmp\e.txt", "this is some text")
+let asyncWriteE =  System.IO.File.AsyncWriteAllText( @"c:\tmp\e.txt", "this is some text\n")
 
-printfn "async write all lines begining"
+printfn "async write all lines beginning"
 
-[|asyncWriteA; asyncWriteB; asyncWriteC; asyncWriteD; asyncWriteE|] 
+[|asyncWriteA; asyncWriteB; asyncWriteC; asyncWriteD; asyncWriteE|]
     |> Async.Parallel 
     |> Async.RunSynchronously 
     |> ignore
 
 
+let asyncAppendA =  System.IO.File.AsyncAppendAllLines(@"c:\tmp\a.txt", lines)
+let asyncAppendB =  System.IO.File.AsyncAppendAllLines(@"c:\tmp\b.txt", lines)
+let asyncAppendC =  System.IO.File.AsyncAppendAllLines(@"c:\tmp\c.txt", lines)
+let asyncAppendD =  System.IO.File.AsyncAppendAllLines(@"c:\tmp\d.txt", lines)
+let asyncAppendE =  System.IO.File.AsyncAppendAllText( @"c:\tmp\e.txt", "this is some more text\n")
+
+
+[|asyncAppendA;asyncAppendB;asyncAppendC;asyncAppendD; asyncAppendE|]
+    |> Async.Parallel 
+    |> Async.RunSynchronously 
+    |> ignore
+
 
-printfn "async write all lines complete"
+printfn "async append all lines complete"

src/FSharpx.Core/AsyncOperations.fs

@@ -165,6 +165,37 @@ namespace Microsoft.FSharp.Control
                     return! System.IO.File.AsyncWriteAllBytes(path, bs)
               }
 
+            // Aims to take advantage of IO completion ports using FileStream.AsyncWrite and FileOptions.Asynchronous, so no FX_NO_FILE_OPTIONS version
+            static member AsyncAppendAllBytes(path, bytes) =
+                let bufferSize = 4096 // as per File.WriteAllBytes
+                async{
+                    use! fs = System.IO.File.AsyncOpen( path, System.IO.FileMode.Append, System.IO.FileAccess.Write, System.IO.FileShare.Read, bufferSize, System.IO.FileOptions.Asynchronous)
+                    let! ret = fs.AsyncWrite bytes
+                    return ret
+                }
+
+            static member AsyncAppendAllText(path, (txt:string), ?encoder) =
+                let enc = match encoder with Some e -> e | None -> System.Text.Encoding.Default
+                async{
+                    let bs = enc.GetBytes txt
+                    return! System.IO.File.AsyncAppendAllBytes(path, bs)
+                }
+            
+            // Different memory profile to File.WriteAllLines, converts all lines to a byte[] before doing any writing, then a single write op.
+            // Not good for writing huge files, but writing one line at a time, as per File.WriteAllLines has its own issues, 
+            // e.g. sequential application of async IO (so lines are written in order)
+            static member AsyncAppendAllLines(path, (lines:string array), ?encoder) = 
+                let enc = match encoder with Some e -> e | None -> System.Text.Encoding.Default
+                async{
+                    use memStrm = new System.IO.MemoryStream()
+                    use sWriter = new System.IO.StreamWriter(memStrm, enc)
+                    lines |> Array.iter (fun line -> sWriter.WriteLine(line))
+                    do sWriter.Flush()
+                    let bs = memStrm.ToArray()
+                    return! System.IO.File.AsyncAppendAllBytes(path, bs)
+              }
+
+
 
 #endif
 

src/FSharpx.Core/AsyncOperations.fsi

@@ -65,9 +65,12 @@ namespace Microsoft.FSharp.Control
 
             // Aims to take advantage of IO completion ports using FileStream.AsyncWrite and FileOptions.Asynchronous, so no FX_NO_FILE_OPTIONS version
             static member AsyncWriteAllBytes: path:string * bytes:byte array -> Async<unit>
-
             static member AsyncWriteAllText: path:string * txt:string * ?encoder:System.Text.Encoding -> Async<unit>
             static member AsyncWriteAllLines: path:string * lines:string array * ?encoder:System.Text.Encoding -> Async<unit>
+            static member AsyncAppendAllBytes: path:string * bytes:byte array -> Async<unit>
+            static member AsyncAppendAllText: path:string * txt:string * ?encoder:System.Text.Encoding -> Async<unit>
+            static member AsyncAppendAllLines: path:string * lines:string array * ?encoder:System.Text.Encoding -> Async<unit>
+
 #endif
 
 #if FX_NO_WEB_REQUESTS