Added two more HttpContext extension methods and default computation …

…expressions

src/Giraffe/Common.fs

@@ -5,11 +5,28 @@ open System.IO
 open System.Xml.Serialization
 open Newtonsoft.Json
 
+/// ---------------------------
+/// Helper functions
+/// ---------------------------
+
 let inline isNotNull x = isNull x |> not
 
 let inline strOption (str : string) =
     if String.IsNullOrEmpty str then None else Some str
 
+let readFileAsString (filePath : string) =
+    async {
+        use stream = new FileStream(filePath, FileMode.Open)
+        use reader = new StreamReader(stream)
+        return!
+            reader.ReadToEndAsync()
+            |> Async.AwaitTask
+    }
+
+/// ---------------------------
+/// Serializers
+/// ---------------------------
+
 let inline serializeJson x = JsonConvert.SerializeObject x
 
 let inline deserializeJson<'T> str = JsonConvert.DeserializeObject<'T> str
@@ -23,13 +40,4 @@ let serializeXml x =
 let deserializeXml<'T> str =
     let serializer = XmlSerializer(typeof<'T>)
     use reader = new StringReader(str)
-    serializer.Deserialize reader :?> 'T
-
-let readFileAsString (filePath : string) =
-    async {
-        use stream = new FileStream(filePath, FileMode.Open)
-        use reader = new StreamReader(stream)
-        return!
-            reader.ReadToEndAsync()
-            |> Async.AwaitTask
-    }
+    serializer.Deserialize reader :?> 'T

src/Giraffe/ComputationExpressions.fs

@@ -0,0 +1,15 @@
+module Giraffe.ComputationExpressions
+
+open System
+
+type OptionBuilder() =
+    member x.Bind(v, f) = Option.bind f v
+    member x.Return v   = Some v
+
+let opt = OptionBuilder()
+
+type ResultBuilder() =
+    member x.Bind(v, f) = Result.bind f v
+    member x.Return v   = Ok v
+
+let res = ResultBuilder()

src/Giraffe/Giraffe.fsproj

@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <AssemblyName>Giraffe</AssemblyName>
-    <VersionPrefix>0.1.0-alpha017</VersionPrefix>
+    <VersionPrefix>0.1.0-alpha018</VersionPrefix>
     <Description>A native functional ASP.NET Core web framework for F# developers.</Description>
     <Copyright>Copyright 2017 Dustin Moris Gorski</Copyright>
     <NeutralLanguage>en-GB</NeutralLanguage>
@@ -40,6 +40,7 @@
 
   <ItemGroup>
     <Compile Include="Common.fs" />
+    <Compile Include="ComputationExpressions.fs" />
     <Compile Include="FormatExpressions.fs" />
     <Compile Include="HttpContextExtensions.fs" />
     <Compile Include="HtmlEngine.fs" />

src/Giraffe/HttpContextExtensions.fs

@@ -22,6 +22,22 @@ type HttpContext with
     member this.GetLogger<'T>() =
         this.GetService<ILogger<'T>>()
 
+    /// ---------------------------
+    /// Common helpers
+    /// ---------------------------
+
+    member this.TryGetRequestHeader (key : string) =
+        let strValue = ref (StringValues())
+        match this.Request.Headers.TryGetValue(key, strValue) with
+        | true  -> Some (strValue.Value.ToString())
+        | false -> None
+
+    member this.GetRequestHeader (key : string) =
+        let strValue = ref (StringValues())
+        match this.Request.Headers.TryGetValue(key, strValue) with
+        | true  -> Ok (strValue.Value.ToString())
+        | false -> Error (sprintf "HTTP request header '%s' is missing." key)
+
     /// ---------------------------
     /// Model binding
     /// ---------------------------