function code

StaticFileServer/function.json

@@ -0,0 +1,19 @@
+{
+  "bindings": [
+    {
+      "authLevel": "anonymous",
+      "name": "req",
+      "type": "httpTrigger",
+      "direction": "in",
+      "methods": [
+        "get"
+      ]
+    },
+    {
+      "name": "$return",
+      "type": "http",
+      "direction": "out"
+    }
+  ],
+  "disabled": false
+}

StaticFileServer/project.json

@@ -0,0 +1,9 @@
+{
+  "frameworks": {
+    "net46":{
+      "dependencies": {
+        "MediaTypeMap": "2.1.0"
+      }
+    }
+   }
+}

StaticFileServer/run.csx

@@ -0,0 +1,82 @@
+using System.Net;
+using System.Net.Http.Headers;
+using System.Threading.Tasks;
+using System.IO;
+using MimeTypes;
+
+const string staticFilesFolder = "www";
+static string defaultPage = string.IsNullOrEmpty(GetEnvironmentVariable("DEFAULT_PAGE")) ? 
+    "index.html" : GetEnvironmentVariable("DEFAULT_PAGE");
+
+public static HttpResponseMessage Run(HttpRequestMessage req, TraceWriter log)
+{
+    try
+    {
+        var filePath = GetFilePath(req, log);
+
+        var response = new HttpResponseMessage(HttpStatusCode.OK);
+        var stream = new FileStream(filePath, FileMode.Open);
+        response.Content = new StreamContent(stream);
+        response.Content.Headers.ContentType = new MediaTypeHeaderValue(GetMimeType(filePath));
+        return response;
+    }
+    catch
+    {
+        return new HttpResponseMessage(HttpStatusCode.NotFound);
+    }
+}
+
+private static string GetScriptPath()
+    => Path.Combine(GetEnvironmentVariable("HOME"), @"site\wwwroot");
+
+private static string GetEnvironmentVariable(string name)
+    => System.Environment.GetEnvironmentVariable(name, EnvironmentVariableTarget.Process);
+
+private static string GetFilePath(HttpRequestMessage req, TraceWriter log)
+{
+    var pathValue = req.GetQueryNameValuePairs()
+        .FirstOrDefault(q => string.Compare(q.Key, "file", true) == 0)
+        .Value;
+
+    var path = pathValue ?? "";
+
+    var staticFilesPath = Path.GetFullPath(Path.Combine(GetScriptPath(), staticFilesFolder));
+    var fullPath = Path.GetFullPath(Path.Combine(staticFilesPath, path));
+
+    if (!IsInDirectory(staticFilesPath, fullPath))
+    {
+        throw new ArgumentException("Invalid path");
+    }
+
+    var isDirectory = Directory.Exists(fullPath);
+    if (isDirectory)
+    {
+        fullPath = Path.Combine(fullPath, defaultPage);
+    }
+
+    return fullPath;
+}
+
+private static bool IsInDirectory(string parentPath, string childPath)
+{
+    var parent = new DirectoryInfo(parentPath);
+    var child = new DirectoryInfo(childPath);
+
+    var dir = child;
+    do
+    {
+        if (dir.FullName == parent.FullName)
+        {
+            return true;
+        }
+        dir = dir.Parent;
+    } while (dir != null);
+
+    return false;
+}
+
+private static string GetMimeType(string filePath)
+{
+    var fileInfo = new FileInfo(filePath);
+    return MimeTypeMap.GetMimeType(fileInfo.Extension);
+}

host.json

@@ -0,0 +1 @@
+{}

proxies.json

@@ -0,0 +1,10 @@
+{
+    "proxies": {
+        "files": {
+            "matchCondition": {
+                "route": "{*path}"
+            },
+            "backendUri": "https://%WEBSITE_SITE_NAME%.azurewebsites.net/api/StaticFileServer?file={path}"
+        }
+    }
+}