一步一步教你实现一个简单的云服务

准备工作：

Windows Azure只能运行在Windows 7, Windows Server 2008 和Windows Vista 上。暂不支持Windows 2003和XP。昨天安装了Win7，打算尝试写一个Azure小程序，程序很简单，实现图片的简单上传和搜索功能，我顺便研究一下微软的Azure平台，下面是我的软件环境。

操作系统：Windows 7

开发工具：Visual Studio2010 RC,Windows Azure SDK ,Windows Azure Tools

第一步：安装Windows Azure SDK

首先确定你的操作系统满足要求，Visual Studio可以是Visual Studio2008或者Visual Studio2010。到下面网址下载Windows Azure SDK :

http://www.microsoft.com/downloads/details.aspx?FamilyID=772990da-8926-4db0-958f-95c1da572c84&displaylang=en

一旦你安装成功，你的电脑上会多出Windows Azure SDK v1.1 ，如下图：

启动Development Fabric和Development Stroage：

显示配置界面:

Development Fabric：

Development Storage：

以上证明你安装成功。

第二步：安装Windows Azure Tools for Microsoft Visual Studio

地址：http://www.microsoft.com/downloads/details.aspx?FamilyID=5664019e-6860-4c33-9843-4eb40b297ab6&displaylang=en

安装之后，Visual Studio会有如下模版：

第三步：新建一个云服务命名为BlobStorage，如下图：

使用简单的ASP.NET Web Role，并更名为BlobWebRole，如下图：

得到如下结构的项目：

第四步：修改代码，我们实现一个简单的图片上传和搜索的功能：

1、添加一个connectionstring，如下图

2、将WebRole的代码修改成如下所示：

代码

public class WebRole : RoleEntryPoint
    {
        public override bool OnStart()
        {
            DiagnosticMonitor.Start("BlobConnectionString");

            CloudStorageAccount.SetConfigurationSettingPublisher((configName, configSetter) =>
            {
                configSetter(RoleEnvironment.GetConfigurationSettingValue(configName));
            });

            // get the blob connection string
            CloudStorageAccount objStorage = CloudStorageAccount.FromConfigurationSetting("BlobConnectionString");

            // get the client reference
            CloudBlobClient objClient = new CloudBlobClient(objStorage.BlobEndpoint, objStorage.Credentials);

            // Get the reference to container
            CloudBlobContainer objContainer = objClient.GetContainerReference("mycontainer");

            // Create the container if it does not exist
            objContainer.CreateIfNotExist();

          RoleEnvironment.Changing += RoleEnvironmentChanging;

          return base.OnStart();

        }

        private void RoleEnvironmentChanging(object sender, RoleEnvironmentChangingEventArgs e)
        {
            // If a configuration setting is changing
            if (e.Changes.Any(change => change is RoleEnvironmentConfigurationSettingChange))
            {
                // Set e.Cancel to true to restart this role instance
                e.Cancel = true;
            }
        }
    }

3、在页面上拖放几个控件，简单地布局如下：

4、后台代码如下：

代码

    protected void Button1_Click(object sender, EventArgs e)
        {



            // Get the storage account reference
            CloudStorageAccount objStorage = CloudStorageAccount.FromConfigurationSetting("BlobConnectionString");
            // get the Client reference using storage blobend point
            CloudBlobClient objClient = new CloudBlobClient(objStorage.BlobEndpoint, objStorage.Credentials);
            // Get Container reference
            CloudBlobContainer objContainer = objClient.GetContainerReference("mycontainer");

            // Get blob reference
            CloudBlob obj = objContainer.GetBlobReference(FileUpload1.FileName.ToString());

            // Set meta values
            obj.Metadata["MetaName"] = "meta";
            // Open a stream using the cloud object
            BlobStream blobstream = obj.OpenWrite();
            // Write the stream to the blob database
            blobstream.Write(FileUpload1.FileBytes, 0, FileUpload1.FileBytes.Count());
            blobstream.Close();

            // Browse through blob list from the container
            IEnumerable<IListBlobItem> objBlobList = objContainer.ListBlobs();
            foreach (IListBlobItem objItem in objBlobList)
            {
                Response.Write(objItem.Uri + "<br>");
            }

        }

        protected void Button2_Click(object sender, EventArgs e)
        {
            // Get the storage account reference
            CloudStorageAccount objStorage = CloudStorageAccount.FromConfigurationSetting("BlobConnectionString");
            // get the Client reference using storage blobend point
            CloudBlobClient objClient = new CloudBlobClient(objStorage.BlobEndpoint, objStorage.Credentials);
            // Get Container reference
            CloudBlobContainer objContainer = objClient.GetContainerReference("mycontainer");
            // Get the blob reference using the blob name provided in the search
            CloudBlob obj = objContainer.GetBlobReference(txtSearch.Text);
            BlobStream blobstream = obj.OpenRead();
            // Create the image object and display the same on the browser response
            System.Drawing.Image objimg = null;
            objimg = System.Drawing.Image.FromStream(blobstream, true);
            Response.Clear();
            Response.ContentType = "image/gif";
            objimg.Save(Response.OutputStream, System.Drawing.Imaging.ImageFormat.Jpeg);
        }

运行效果：

上传：