在内部,ASP.NET拥有2 GB的寻址空间,但实际上您只有不到1 GB的可用空间用于上传(请参见http://support.microsoft.com/?id=295626)。此外,IIS 7有一个30 MB的限制(请参见http://www.iislogs.com/steveschofield/iis7-post-40-adjusting-file-upload-size-in-iis7),而且你可能需要运行
appcmd set config "My Site/MyApp" -section:requestFiltering -requestLimits.maxAllowedContentLength:104857600 -commitpath:apphost
如何在我的Azure服务器上运行以超越30MB限制的内容?根据http://support.microsoft.com/?id=295626,在上传过程中,ASP.NET会将整个文件加载到内存中,然后用户才能将文件保存到磁盘中。因此,如果许多用户同时上传大文件,我很快就会耗尽内存限制。在下面的代码中,我使用流,但是我猜想整个文件仍然会被先上传到内存中。这是正确的吗?
using System;
using System.Web.Security;
using Microsoft.WindowsAzure;
using Microsoft.WindowsAzure.StorageClient;
namespace WebPages
{
public partial class Upload : System.Web.UI.Page
{
CloudBlobClient BlobClient = null;
CloudBlobContainer BlobContainer = null;
void InitBlob()
{
// Setup the connection to Windows Azure Storage
var storageAccount = CloudStorageAccount.FromConfigurationSetting("DataConnectionString");
BlobClient = storageAccount.CreateCloudBlobClient();
// Get and create the container
BlobContainer = BlobClient.GetContainerReference("publicfiles");
}
protected void Page_Load(object sender, EventArgs e)
{
//if (Membership.GetUser() == null) return; // Only allow registered users to upload files
InitBlob();
try
{
var file = Request.Files["Filedata"];
var storageAccount = CloudStorageAccount.FromConfigurationSetting("DataConnectionString");
BlobClient = storageAccount.CreateCloudBlobClient();
// Make a unique blob name
var extension = System.IO.Path.GetExtension(file.FileName);
// Create the Blob and upload the file
var blobAddressUri = String.Format("{0}{1}", Guid.NewGuid(), extension);
var blob = BlobContainer.GetBlobReference(blobAddressUri);
blob.UploadFromStream(file.InputStream);
// Set the metadata into the blob
blob.Metadata["FileName"] = file.FileName;
//blob.Metadata["Submitter"] = Membership.GetUser().UserName;
blob.Metadata["Type"] = "Video";
blob.Metadata["Description"] = "Test";
blob.SetMetadata();
// Set the properties
blob.Properties.ContentType = file.ContentType;
blob.SetProperties();
}
catch(Exception ex)
{
System.Diagnostics.Trace.TraceError("Upload file exception: {0}", ex.ToString());
// If any kind of error occurs return a 500 Internal Server error
Response.StatusCode = 500;
Response.Write("An error occured while uploading the file");
Response.End();
}
}
}
}
我知道非网页上传工具,例如http://azureblobuploader.codeplex.com/,但我确实需要从网页上载。
所以,我的问题是:
- 如何从网页上传大于2 GB的文件到 Blob
- 如何从网页上传大型文件流而不会占用所有内存
- 如果解决方案是编写自己的 HttpModule 或 HttpHandler 来处理上传,如何在 Azure 服务器上安装它?我可以在 Azure 上使用像http://neatupload.codeplex.com/这样的 HttpHandlers 吗?
- 此项目不在 SharePoint 上,但是我知道在 SharePoint 中有一种称为 Blob 提供程序的东西,您可以编写自己的提供程序,ASP.NET 是否也有 Blob Providers?
我还可以提到,我上面的代码对小于30 MB的文件默认有效,客户端使用 SWFUpload V2.2.0。
更新 6月19日19:09: Twitter 上的 @YvesGoeleven 给了我一个提示,即使用共享访问签名 (Shared Access Signature),直接将文件上传到 Azure Blob 存储,完全不经过 ASP.NET。我创建了一个返回有效 SAS ut 到我的 Blob 存储的 JSON WCF。
using System.ServiceModel;
using System.ServiceModel.Web;
namespace WebPages.Interfaces
{
[ServiceContract]
public interface IUpload
{
[OperationContract]
[WebInvoke(Method = "GET",
ResponseFormat = WebMessageFormat.Json)]
string GetUploadUrl();
}
}
--------
using System;
using System.IO;
using System.Runtime.Serialization.Json;
using System.ServiceModel.Activation;
using System.Text;
using Microsoft.WindowsAzure;
using Microsoft.WindowsAzure.StorageClient;
namespace WebPages.Interfaces
{
[AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)]
public class UploadService : IUpload
{
CloudBlobClient BlobClient;
CloudBlobContainer BlobContainer;
public UploadService()
{
// Setup the connection to Windows Azure Storage
var storageAccount = CloudStorageAccount.FromConfigurationSetting("DataConnectionString");
BlobClient = storageAccount.CreateCloudBlobClient();
// Get and create the container
BlobContainer = BlobClient.GetContainerReference("publicfiles");
}
string JsonSerialize(string url)
{
var serializer = new DataContractJsonSerializer(url.GetType());
var memoryStream = new MemoryStream();
serializer.WriteObject(memoryStream, url);
return Encoding.Default.GetString(memoryStream.ToArray());
}
public string GetUploadUrl()
{
var sasWithIdentifier = BlobContainer.GetSharedAccessSignature(new SharedAccessPolicy()
{
Permissions = SharedAccessPermissions.Write,
SharedAccessExpiryTime =
DateTime.UtcNow.AddMinutes(60)
});
return JsonSerialize(BlobContainer.Uri.AbsoluteUri + "/" + Guid.NewGuid() + sasWithIdentifier);
}
}
}
它可以工作,但我不能与SWFUpload一起使用,因为它使用HTTP POST动词而不是Azure Blob Storage在创建新的blob项目时所需的HTTP PUT动词。有人知道如何解决这个问题,而不用制作自己的自定义Silverlight或Flash客户端组件来使用HTTP PUT动词吗?我想要一个上传文件时的进度条,因此使用PUT提交的表单不是最佳选择。
对于那些对客户端代码感兴趣(该代码不起作用,因为SWFUpload使用HTTP POST而不是Azure Blob Storage所期望的PUT):
<div id="header">
<h1 id="logo"><a href="/">SWFUpload</a></h1>
<div id="version">v2.2.0</div>
</div>
<div id="content">
<h2>Application Demo (ASP.Net 2.0)</h2>
<div id="swfu_container" style="margin: 0px 10px;">
<div>
<span id="spanButtonPlaceholder"></span>
</div>
<div id="divFileProgressContainer" style="height: 75px;"></div>
<div id="thumbnails"></div>
</div>
</div>
<script type="text/javascript" language="javascript">
$(document).ready(function () {
$.ajax({
url: '/Interfaces/UploadService.svc/GetUploadUrl',
success: function (result) {
var parsedResult = $.parseJSON(result);
InitUploadFile(parsedResult);
}
});
function InitUploadFile(uploadUrl) {
//alert(uploadUrl);
var swfu = new SWFUpload({
// Backend Settings
upload_url: uploadUrl,
post_params: {
"ASPSESSID": "<%=Session.SessionID %>"
},
// File Upload Settings
file_size_limit: "100 MB",
file_types: "*.*",
file_types_description: "All file types",
file_upload_limit: "0", // Zero means unlimited
// Event Handler Settings - these functions as defined in Handlers.js
// The handlers are not part of SWFUpload but are part of my website and control how
// my website reacts to the SWFUpload events.
file_queue_error_handler: fileQueueError,
file_dialog_complete_handler: fileDialogComplete,
upload_progress_handler: uploadProgress,
upload_error_handler: uploadError,
upload_success_handler: uploadSuccess,
upload_complete_handler: uploadComplete,
// Button settings
button_image_url: "Images/swfupload/XPButtonNoText_160x22.png",
button_placeholder_id: "spanButtonPlaceholder",
button_width: 160,
button_height: 22,
button_text: '<span class="button">Select files <span class="buttonSmall">(2 MB Max)</span></span>',
button_text_style: '.button { font-family: Helvetica, Arial, sans-serif; font-size: 14pt; } .buttonSmall { font-size: 10pt; }',
button_text_top_padding: 1,
button_text_left_padding: 5,
// Flash Settings
flash_url: "Js/swfupload-2.2.0/swfupload.swf", // Relative to this file
custom_settings: {
upload_target: "divFileProgressContainer"
},
// Debug Settings
debug: false
});
}
});
</script>
更新时间:6月19日 21:07
我发现SWFUpload是开源的,所以我下载了源代码并将动词从POST更改为PUT,但是很遗憾,Flash Player URLRequestMethod不支持除GET和POST之外的其他动词。我找到了一个据说可以解决问题的方法。
private function BuildRequest():URLRequest {
// Create the request object
var request:URLRequest = new URLRequest();
request.method = URLRequestMethod.POST;
request.requestHeaders.push(new URLRequestHeader("X-HTTP-Method-Override", "PUT"));
只有在Adobe Air中才能使用,而不能与Flash Player一起使用。
我读过SilverLight 3及以上版本支持HTTP PUT动词,所以我认为我需要编写一些SilverLight代码来实现我的目标。我找到了这个博客文章系列,它可能会对我有所帮助:http://blog.smarx.com/posts/uploading-windows-azure-blobs-from-silverlight-part-1-shared-access-signatures。
更新 @ 2011年6月27日:
我现在已经成功地通过使用我基于http://blog.smarx.com/posts/uploading-windows-azure-blobs-from-silverlight-part-1-shared-access-signatures 项目的自定义Silverlight客户端从网页上传大文件(用4.5 GB文件进行了测试)。由于Silverlight同时支持Azure Blob Storage所需的HTTP PUT动词并支持渐进式上传,因此我现在有可能将大文件直接上传到Azure Blob Storage,而不必经过ASP.NET解决方案,我还可以得到一些漂亮的进度条,如果用户希望可以在上传过程中取消。服务器上的内存使用量很小,因为整个文件在放置到Azure Blob Storage之前不会被完全上传。我使用一个共享访问签名(请参见msdn.microsoft.com/en-us/library/ee395415.aspx),该签名是根据请求从WCF RESTful服务提供的。我认为这个解决方案是我们发现的最好的解决方案。谢谢。
更新@ 2011年7月18日:
我创建了一个开源项目,其中包含我在此处找到的内容: