[英]How upload file to blob storage and reference it from cosmosdb document in attachment
我是 CosmosDb 和 azure blob 存儲的新手,作為一項要求,我需要引用從 CosmosDb 中的文檔上傳到 azure blob 存儲的文件,並在附件部分使用它來保存元數據。
我知道 json 元數據結構應該是這樣的:
{
"id":"image13d65101-90c4-4c2a-a423-fbf221c73233",
"contentType":"image/jpg",
"media":"www.bing.com",
"_rid":"rnYYAMVFUAUBAAAAAAAAAEC+LNM=",
"_ts":1408056025,
"_self":"dbs\/rnYYAA==\/colls\/rnYYAMVFUAU=\/docs\/rnYYAMVFUAUBAAAAAAAAAA==\/attachments\/rnYYAMVFUAUBAAAAAAAAAEC+LNM=",
"_etag":"00002a00-0000-0000-0000-53ed3ad90000"
}
但是如何在將文件上傳到 azure blob 存儲時獲取對媒體屬性的引用,更准確地說,如何將文件從 c# 上傳到 azure blob 存儲並通過將 url 設置為媒體屬性來引用它。
這是我的一個應用程序中的示例代碼,用於上傳到 blob 存儲,然后將 cosmosdb 的引用保存為 uri,
public async Task<IActionResult> UploadImageAsync([FromBody] ImageUploadRequest imageRequest)
{
if (string.IsNullOrEmpty(imageRequest?.Base64))
{
return BadRequest();
}
var tokens = imageRequest.Base64.Split(',');
var ctype = tokens[0].Replace("data:", "");
var base64 = tokens[1];
var content = Convert.FromBase64String(base64);
// Upload photo to storage...
var blobUri = await UploadImageToStorage(content);
// Then create a Document in CosmosDb to notify our Function
var identifier = await UploadDocument(blobUri, imageRequest.Name ?? "Bob");
return Ok(identifier);
}
private async Task<Guid> UploadDocument(Uri uri, string imageName)
{
var endpoint = new Uri(_settings.ImageConfig.CosmosUri);
var auth = _settings.ImageConfig.CosmosKey;
var client = new DocumentClient(endpoint, auth);
var identifier = Guid.NewGuid();
await client.CreateDatabaseIfNotExistsAsync(new Database() { Id = dbName });
await client.CreateDocumentCollectionIfNotExistsAsync(UriFactory.CreateDatabaseUri(dbName),
new DocumentCollection { Id = colName });
await client.CreateDocumentAsync(
UriFactory.CreateDocumentCollectionUri(dbName, colName),
new ImageDocument
{
Id = identifier,
IsApproved = null,
PetName = petName,
MediaUrl = uri.ToString(),
Created = DateTime.UtcNow
});
return identifier;
}
private async Task<Uri> UploadImageToStorage(byte[] content)
{
var storageName = _settings.PetsConfig.BlobName;
var auth = _settings.PetsConfig.BlobKey;
var uploader = new PhotoUploader(storageName, auth);
var blob = await uploader.UploadPetPhoto(content);
return blob.Uri;
}
如何將文件從 c# 上傳到 azure blob 存儲並通過將 url 設置為 media 屬性來引用它。
可以參考這篇文章設置和檢索元數據,上傳后應該會再次獲取blob。
示例代碼如下:
//the code to get the blob again after uploading.
var blockblob = blobContainer.GetBlockBlobReference(blobname);
//the code to set medadata.
blockblob.FetchAttributes();
blockblob.Metadata["media"] = "www.bing.com";
blockblob.SetMetadata();
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