Add JArray case for binding;

support file-based scripts (like MS-Batch; Python)

Author: MikeStall

src/WebJobs.Script/Binding/ExtensionBinding.cs

@@ -11,6 +11,7 @@
 using System.Threading.Tasks;
 using Microsoft.Azure.WebJobs.Script.Description;
 using Microsoft.Azure.WebJobs.Script.Extensibility;
+using Newtonsoft.Json;
 using Newtonsoft.Json.Linq;
 
 namespace Microsoft.Azure.WebJobs.Script.Binding
@@ -46,6 +47,8 @@ public override async Task BindAsync(BindingContext context)
         {
             context.Attributes = _attributes.ToArray();
 
+            object inputValue = null;
+
             if (_binding.DefaultType == typeof(IAsyncCollector<byte[]>))
             {
                 await BindAsyncCollectorAsync<byte[]>(context);
@@ -67,13 +70,32 @@ public override async Task BindAsync(BindingContext context)
                 var result = await context.Binder.BindAsync<JObject>(_attributes.ToArray());
                 if (Access == FileAccess.Read)
                 {
-                    context.Value = result;
+                    inputValue = result;
                 }
             }
+            else if (_binding.DefaultType == typeof(JArray))
+            {
+                JArray entityArray = await context.Binder.BindAsync<JArray>(_attributes.ToArray());
+                inputValue = entityArray;
+            }
             else
             {
                 throw new NotSupportedException($"ScriptBinding type {_binding.DefaultType} is not supported");
             }
+
+            if (inputValue != null)
+            {
+                if (context.DataType == DataType.Stream)
+                {
+                    // In file-based scripting (like Python), arguments may need to be copied to the file system. 
+                    var inputStream = (Stream)context.Value;
+                    ConvertValueToStream(inputValue, inputStream);
+                }
+                else
+                {
+                    context.Value = inputValue;
+                }
+            }
         }
 
         internal static CustomAttributeBuilder GetAttributeBuilder(Attribute attribute)

src/WebJobs.Script/Binding/FunctionBinding.cs

@@ -12,6 +12,7 @@
 using Microsoft.Azure.WebJobs.Host;
 using Microsoft.Azure.WebJobs.Script.Description;
 using Microsoft.Azure.WebJobs.Script.Extensibility;
+using Newtonsoft.Json;
 using Newtonsoft.Json.Linq;
 
 namespace Microsoft.Azure.WebJobs.Script.Binding
@@ -236,6 +237,23 @@ public static void ConvertValueToStream(object value, Stream stream)
                 {
                     bytes = BitConverter.GetBytes((double)value);
                 }
+                else
+                {
+                    var jValue = value as JToken;
+                    if (jValue != null)
+                    {
+                        string json = jValue.ToString(Formatting.None);
+
+                        // Use StreamWriter to handle encoding. 
+                        // We're explicitly NOT disposing the StreamWriter because
+                        // we don't want to close the underlying Stream
+                        StreamWriter sw = new StreamWriter(stream);
+                        sw.Write(json);
+                        sw.Flush();
+
+                        return;
+                    }
+                }
 
                 using (valueStream = new MemoryStream(bytes))
                 {