/WP7.1/Templates/VB/WPCloud.Mem/WindowsPhoneCloud.Web/Handlers/StorageProxyHandler.vb

' ----------------------------------------------------------------------------------

' Microsoft Developer & Platform Evangelism

' 

' Copyright (c) Microsoft Corporation. All rights reserved.

' 

' THIS CODE AND INFORMATION ARE PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, 

' EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES 

' OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE.

' ----------------------------------------------------------------------------------

' The example companies, organizations, products, domain names,

' e-mail addresses, logos, people, places, and events depicted

' herein are fictitious.  No association with any real company,

' organization, product, domain name, email address, logo, person,

' places, or events is intended or should be inferred.

' ----------------------------------------------------------------------------------



Imports Microsoft.WindowsAzure

Imports Microsoft.Samples.WindowsPhoneCloud.Web.Serializers

Imports Microsoft.Samples.WindowsPhoneCloud.Web.Infrastructure

Imports System.Xml

Imports System.Net

Imports System.IO

Imports System.Globalization



Namespace Handlers



    Public MustInherit Class StorageProxyHandler

        Implements IHttpHandler

        Private ReadOnly formatSerializerFactory As IFormatSerializerFactory

        Private webRequestCreatorValue As IWebRequestCreate



        Protected Sub New(ByVal cloudStorageAccount As CloudStorageAccount, ByVal requestValidator As IStorageRequestValidator, ByVal formatSerializerFactory As IFormatSerializerFactory)

            Me.RequestValidator = requestValidator

            Me.formatSerializerFactory = formatSerializerFactory



            Me.CloudStorageAccount = cloudStorageAccount

        End Sub



        Public ReadOnly Property IsReusable() As Boolean Implements IHttpHandler.IsReusable

            Get

                Return True

            End Get

        End Property



        Friend Property WebRequestCreator() As IWebRequestCreate

            Get

                If Me.webRequestCreatorValue Is Nothing Then

                    Me.webRequestCreatorValue = New WebRequestCreator()

                End If



                Return Me.webRequestCreatorValue

            End Get



            Set(ByVal value As IWebRequestCreate)

                Me.webRequestCreatorValue = value

            End Set

        End Property



        Private privateCloudStorageAccount As CloudStorageAccount

        Protected Property CloudStorageAccount() As CloudStorageAccount

            Get

                Return privateCloudStorageAccount

            End Get

            Private Set(ByVal value As CloudStorageAccount)

                privateCloudStorageAccount = value

            End Set

        End Property



        Private privateRequestValidator As IStorageRequestValidator

        Protected Property RequestValidator() As IStorageRequestValidator

            Get

                Return privateRequestValidator

            End Get

            Private Set(ByVal value As IStorageRequestValidator)

                privateRequestValidator = value

            End Set

        End Property



        Protected MustOverride ReadOnly Property AzureStorageUrl() As String



        Public Sub ProcessRequest(ByVal context As HttpContext) Implements IHttpHandler.ProcessRequest

            If Me.RequestValidator.ValidateRequest(context) Then

                Dim azureResponse = Me.GetAzureStorageResponse(Me.GetAzureStorageRequestUri(context.Request), context.Request)



                Dim serializer = Me.formatSerializerFactory.GetSerializer(context.Request.Headers, context.Request.QueryString)

                Dim azureStorageResponseBody = azureResponse.ExtractBodyString()

                Dim serializedContentType = String.Empty

                If Not String.IsNullOrWhiteSpace(azureStorageResponseBody) Then

                    Dim xmlDoc = New XmlDocument()

                    xmlDoc.LoadXml(azureStorageResponseBody)



                    azureStorageResponseBody = serializer.SerializeReply(xmlDoc, serializedContentType)

                End If



                azureResponse.CopyResponseHeadersTo(context.Response, serializedContentType)



                context.Response.Write(Me.GetProxyResponseBody(azureStorageResponseBody, context.Request))



                Me.PostProcessProxyRequest(context)



                context.Response.End()

            End If

        End Sub



        Protected Overridable Function GetAzureStorageRequestBody(ByVal proxyRequestBody As String, ByVal proxyRequest As HttpRequest) As String

            Dim oldValue = String.Format(CultureInfo.InvariantCulture, "{0}{1}", proxyRequest.Url.GetComponents(UriComponents.SchemeAndServer And (Not UriComponents.Port), UriFormat.SafeUnescaped), proxyRequest.FilePath)

            Dim newValue = Me.AzureStorageUrl



            Return proxyRequestBody.Replace(oldValue, newValue)

        End Function



        Protected Overridable Function GetProxyResponseBody(ByVal azureStorageResponseBody As String, ByVal proxyRequest As HttpRequest) As String

            Dim oldValue = Me.AzureStorageUrl

            Dim newValue = String.Format(CultureInfo.InvariantCulture, "{0}{1}", proxyRequest.Url.GetComponents(UriComponents.SchemeAndServer And (Not UriComponents.Port), UriFormat.SafeUnescaped), proxyRequest.FilePath)



            Return azureStorageResponseBody.Replace(oldValue, newValue)

        End Function



        Protected MustOverride Sub SignRequest(ByVal webRequest As WebRequest)



        Protected MustOverride Sub PostProcessProxyRequest(ByVal context As HttpContext)



        Private Function GetAzureStorageRequestUri(ByVal request As HttpRequest) As Uri

            Dim relativeUrl = If(request.QueryString.Count > 0, String.Format(CultureInfo.InvariantCulture, "{0}?{1}", request.PathInfo, request.QueryString.ToString()), request.PathInfo)



            Return New Uri(String.Format(CultureInfo.InvariantCulture, "{0}{1}", Me.AzureStorageUrl, relativeUrl), UriKind.Absolute)

        End Function



        Private Function GetAzureStorageResponse(ByVal azureStorageRequestUri As Uri, ByVal proxyRequest As HttpRequest) As WebResponse

            Dim azureStorageRequest = Me.WebRequestCreator.Create(azureStorageRequestUri)

            Dim azureStorageRequestBody = Me.GetAzureStorageRequestBody(New StreamReader(proxyRequest.InputStream).ReadToEnd(), proxyRequest)



            azureStorageRequest.Method = proxyRequest.HttpMethod

            If azureStorageRequestBody.Length > 0 OrElse ((Not proxyRequest.HttpMethod.Equals("GET", StringComparison.OrdinalIgnoreCase)) AndAlso (Not proxyRequest.HttpMethod.Equals("DELETE", StringComparison.OrdinalIgnoreCase))) Then

                azureStorageRequest.ContentLength = azureStorageRequestBody.Length

            End If



            proxyRequest.CopyRequestHeadersTo(azureStorageRequest)



            Me.SignRequest(azureStorageRequest)



            If (Not proxyRequest.HttpMethod.Equals("GET", StringComparison.OrdinalIgnoreCase)) AndAlso (Not proxyRequest.HttpMethod.Equals("DELETE", StringComparison.OrdinalIgnoreCase)) AndAlso proxyRequest.ContentLength > 0 Then

                Dim azureStorageRequestStream = azureStorageRequest.GetRequestStream()

                Using writer = New StreamWriter(azureStorageRequestStream)

                    azureStorageRequestStream = Nothing

                    writer.Write(azureStorageRequestBody)

                End Using

            End If



            Try

                Return azureStorageRequest.GetResponse()

            Catch webException As WebException

                Return webException.Response

            End Try

        End Function

    End Class

End Namespace