如何将图像和发布数据上载到Azure移动服务ApiController终结点？
如何将图像和发布数据上载到Azure移动服务ApiController终结点？
提问于 2015-08-15 01:46:30
我正在尝试将图像和POST表单数据(尽管理想情况下我希望它是json)上传到我的Azure移动服务应用程序中的端点。
我有ApiController方法：
[HttpPost]
[Route("api/upload/{databaseId}/{searchingEnabled}/{trackingEnabled}")]
public async Task<IHttpActionResult> Upload(string databaseId, string searchingEnabled, string trackingEnabled, [FromBody]string metadata) {
if (!Request.Content.IsMimeMultipartContent()) {
return BadRequest("No image is uploaded.");
}
else {
var provider = new MultipartMemoryStreamProvider();
await Request.Content.ReadAsMultipartAsync(provider);
foreach (var file in provider.Contents) {
// Process each image uploaded
}
}
}这只在我移除[FromBody]string metadata时才起作用，但之后它的效果很好。
当包含[FromBody]string metadata时(如上所述)，我得到错误：
The request entity's media type 'multipart/form-data' is not supported for this resource.然而，我想要POST额外的metadata (它可能很长，所以我不想把它放在Uri中)。
如何保留文件上载逻辑，以及如何将POST 附加字符串数据保存到控制器？
我使用的是Azure移动服务，所以这段代码在System.Web.Http.ApiController中(如果有关系的话)。
回答 1
Stack Overflow用户
回答已采纳
发布于 2015-08-18 04:29:13
我之前所做的是让客户端发布一个同时包含元数据和实际文件的json模型。因此，每个文件都是实际文件内容的base64编码字符串。下面的代码应该能够处理数据uri + base64。
我的前端应用程序使用javascript File API来获取对FileReader对象的引用，该对象可以通过使用readAsDataURL方法返回base64 (data uri)字符串。它基本上是这样做的：
var attachment = {};
function loadAttachmentFromFileInput(element) {
var file = element.files[0];
var reader = new FileReader();
reader.onload = function(e) {
var result = reader.result;
attachment = {
data: result,
filename: file.name,
type: file.type,
size: file.size
}
}
reader.readAsDataURL(file);
}然后，我将构建一个POST模型，该模型产生以下json内容：
{
"messageId": 1,
"foo": "bar",
"bar": "foo",
"attachments": [{
"filename": "stackoverflow.jpg",
"data": "data:image/jpeg;base64,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",
"type": "image/jpeg"
}]
}控制器看起来像这样：
[Route("api/messages/{messageId:guid}")]
public async Task<IHttpActionResult> Post(Guid messageId, CreateMessageAttachments model)
{
// Access to all properties in your post model
Trace.WriteLine(model.Foo);
Trace.WriteLine(model.Bar);
foreach (var attachment in model.Attachments)
{
// Do what you need to with the bytes from the uploaded attachments
var bytes = attachment.GetByteArray();
}
return Ok();
}然后，我有以下模型来支持控制器：
public class CreateMessageAttachments
{
public Guid MessageId { get; set; }
public string Foo { get; set; }
public string Bar { get; set; }
public IList<CreateAttachment> Attachments { get; set; }
}
public class CreateAttachment
{
public string Data { get; set; }
public string Filename { get; set; }
public string Type { get; set; }
public string GetBase64()
{
if (string.IsNullOrWhiteSpace(Data))
return null;
var index = Data.LastIndexOf("base64");
if (index == -1)
return Data;
return Data.Substring(index + 7);
}
public byte[] GetByteArray()
{
try
{
var base64 = GetBase64();
if (string.IsNullOrWhiteSpace(base64))
return null;
return Convert.FromBase64String(base64);
}
catch
{
return null;
}
}
}页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/32015898
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