Windows Azure 系列-- 使用Azure + Web API实现图片上传
1. 创建1个Azure账号，登录之后创建1个AzureStorage。左下方点Manage Access会看到Primary Access Key和Storage Account，记住它们的位置，等下须要配置到Web.config中。2. 创建Web.Api project，上传图片的代码：
public async Task<HttpResponseMessage> PostFile()
{
HttpRequestMessage request = Request;
if (!request.Content.IsMimeMultipartContent())
{
throw new HttpResponseException(HttpStatusCode.UnsupportedMediaType);
}
string root = System.Web.HttpContext.Current.Server.MapPath("~/App_Data/uploads");
var provider = new MultipartFormDataStreamProvider(root);
var task = await request.Content.ReadAsMultipartAsync(provider);
string accountName = "your account stro";
string accountKey = "your key";
var creds = new StorageCredentials(accountName, accountKey);
var account = new CloudStorageAccount(creds, useHttps: true);
CloudBlobClient client = account.CreateCloudBlobClient();
CloudBlobContainer sampleContainer = client.GetContainerReference("samples");
sampleContainer.CreateIfNotExists();
sampleContainer.SetPermissions(new BlobContainerPermissions()
{
PublicAccess = BlobContainerPublicAccessType.Blob
});
foreach (MultipartFileData file in provider.FileData)
{
var name = file.Headers.ContentDisposition.FileName.Replace("\"","");
CloudBlockBlob blob = sampleContainer.GetBlockBlobReference(name);
using (var filestream = File.OpenRead(file.LocalFileName))
{
blob.UploadFromStream(filestream);
}
}
return Request.CreateResponse(HttpStatusCode.OK);
}
public IEnumerable<string> AzureImageUrls()
{
HttpContext.Current.Response.AddHeader("Access-Control-Allow-Origin", "*");
var connStr = ConfigurationManager.AppSettings["AzureImageStorage"];
var accnt = CloudStorageAccount.Parse(connStr);
var client = accnt.CreateCloudBlobClient();
var blobs = client.GetContainerReference("samples" /*container name*/).ListBlobs();
var urls = blobs.Select(blob => blob.Uri.AbsoluteUri).ToList();
return urls;
}
包括了两个Action，PostFile和AzureImageUrls，前者用来接收post过来的文件对象，后者用于从Azure中获取uri返回到客户端。 首先，在上传时，须要设置这行代码：
PublicAccess = BlobContainerPublicAccessType.Blob
假设不设置的话，默认的訪问权限是不能够在客户端直接訪问Blob图片的。因而显示不出图片。
其次，在客户端获取URI时，API中须要设置这行代码：
HttpContext.Current.Response.AddHeader("Access-Control-Allow-Origin", "*");
由于跨域做AJAX默认是不同意的，这行代码的实现方式为CORS(Cross Origin Resource sharing)，另外还有JSONP能够做到，可是须要server端返回js函数的调用代码，有关跨域AJAX请求，详细能够參见这篇不错的文章：
https://jvaneyck.wordpress.com/2014/01/07/cross-domain-requests-in-javascript/
3. web config
<appSettings>
<add key="AzureImageStorage" value="DefaultEndpointsProtocol=http;AccountName=name;AccountKey=yourkey" />
</appSettings>须要注意的地方就是。value中不同意出现空格。这个链接字符串是标准形式，很多其它azure链接字符串，能够參照：
https://www.connectionstrings.com/windows-azure/
4. 推荐下载cloud berry这样的相似FTP的管理工具。方便查看上传的图片，假设传错了能够进行删除：
http://www.cloudberrylab.com
5. 客户端html实现：
<html>
<script src="jquery-2.1.1.js"></script>
<form method="post" enctype="multipart/form-data" action="http://localhost:55006/api/values/postfile">
<input type="file" name ="uploadfile" ></input>
<input type="submit" value="submit" ></input>
<ul class="imgs">
</ul>
</form>
<script>
$(document).ready(function(){
$.get("http://localhost:55006/api/values/AzureImageUrls", function(data, status){
var html = "";
for(var i = 0;i < data.length; i++){
var d = data;
html += "<img src='" + d + "' width='300px' height='300px'/>";
}
$(".imgs").html(html);
});
});
</script>
</html>
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