TEAMModelOS/TEAMModelOS.SDK/Module/AzureBlob/Implements/AzureBlobDBRepository.cs

using TEAMModelOS.SDK.Module.AzureBlob.Configuration;
using TEAMModelOS.SDK.Module.AzureBlob.Container;
using TEAMModelOS.SDK.Module.AzureBlob.Interfaces;
using Microsoft.WindowsAzure.Storage;
using Microsoft.WindowsAzure.Storage.Blob;
using System;
using System.Collections.Generic;
using System.IO;
using System.Net.Http.Headers;
using System.Threading.Tasks;
using TEAMModelOS.SDK.Helper.Security.AESCrypt;
using TEAMModelOS.SDK.Context.Exception;
using Microsoft.AspNetCore.Http;
using TEAMModelOS.SDK.Extension.SnowFlake;
using TEAMModelOS.SDK.Context.Constant;
using TEAMModelOS.SDK.Helper.Common.JsonHelper;
using TEAMModelOS.SDK.Helper.Security.ShaHash;
using Microsoft.Extensions.Configuration;
using TEAMModelOS.SDK.Context.Configuration;
using Microsoft.AspNetCore.Hosting;

namespace TEAMModelOS.SDK.Module.AzureBlob.Implements
{
    public class AzureBlobDBRepository : IAzureBlobDBRepository
    {
        public CloudBlobClient blobClient;
        public CloudBlobContainer blobContainer;
        public AzureBlobOptions _options;
        public IConfiguration Configuration { get; }
        public AzureBlobDBRepository(IConfiguration configuration, IWebHostEnvironment env, AzureBlobOptions options, AzureBlobOptions azureBlobOptions)
        {
            Configuration = configuration;
           // BaseConfigModel.SetBaseConfig(Configuration, env.ContentRootPath, env.WebRootPath);
            _options = options;
            if (!string.IsNullOrEmpty(options.ConnectionString))
            {
                blobClient = BlobClientSingleton.getInstance(options.ConnectionString).GetBlobClient();
            }
            else { throw new BizException("请设置正确的AzureBlob文件存储配置信息！"); }
        }

        public AzureBlobDBRepository()
        {
            // _connectionString = BaseConfigModel.Configuration["AppSettings:Azure:TableStorageConnection"];

        }

        private   CloudBlobContainer  InitializeBlob(string container)
        {
            //https://teammodelstorage.blob.core.chinacloudapi.cn/wechatfilescontainer
            
                // Type t = typeof(T);
                //若要将权限设置为仅针对 blob 的公共读取访问，请将 PublicAccess 属性设置为 BlobContainerPublicAccessType.Blob。
                //要删除匿名用户的所有权限，请将该属性设置为 BlobContainerPublicAccessType.Off。
                blobContainer = blobClient.GetContainerReference(_options .Container+"/"+ container);

                // await blobContainer.CreateIfNotExistsAsync();
                // BlobContainerPermissions permissions = await blobContainer.GetPermissionsAsync();
                // permissions.PublicAccess = BlobContainerPublicAccessType.Blob;
                // await blobContainer.SetPermissionsAsync(permissions);
            
            return blobContainer;
        }

        public async Task<List<AzureBlobModel>> UploadFiles(IFormFile[] file,string fileSpace= "common" , bool contentTypeDefault = false)
        {
            string groupName = fileSpace+"/" +DateTime.Now.ToString("yyyyMMdd");
            string newFileName = DateTime.Now.ToString("yyyyMMddHHmmss");
            // await InitializeBlob(DateTime.Now.ToString("yyyyMMdd"));
            blobContainer  =   InitializeBlob(groupName); //blobClient.GetContainerReference(groupName);
            //var serviceProperties = await blobClient.GetServicePropertiesAsync();
            //var corsSettings = serviceProperties.Cors;
            //var corsRule = corsSettings.CorsRules.FirstOrDefault(
            //    o => o.AllowedOrigins.Contains("http://localhost:3904"));//设置你自己的服务器地址
            //if (corsRule == null)
            //{
            //    //Add a new rule.
            //    corsRule = new CorsRule()
            //    {
            //        AllowedHeaders = new List<string> { "x-ms-*", "content-type", "accept" },
            //        AllowedMethods = CorsHttpMethods.Put| CorsHttpMethods.Head | CorsHttpMethods.Post | CorsHttpMethods.Merge | CorsHttpMethods.Get,//Since we'll only be calling Put Blob, let's just allow PUT verb
            //        AllowedOrigins = new List<string> { "http://localhost:3904" },//This is the URL of our application.
            //        ExposedHeaders = { },
            //        MaxAgeInSeconds = 1 * 60 * 60,//Let the browswer cache it for an hour
            //    };
            //    corsSettings.CorsRules.Add(corsRule);
            //    //Save the rule
            //    await blobClient.SetServicePropertiesAsync(serviceProperties);
            //}

            StorageUri url = blobContainer.StorageUri;
            List<AzureBlobModel> list = new List<AzureBlobModel>();
            foreach (FormFile f in file)
            {
               
                string[] names = f.FileName.Split(".");
                string name = "";
                for (int i = 0; i < names.Length-1; i++) {
                    name = name + names[i];
                }
                if (names.Length <= 1)
                {
                    name = f.FileName + "_" + newFileName;
                }
                else {
                    name = name + "_" + newFileName + "." + names[names.Length - 1];
                }
                string fileext = f.FileName.Substring(f.FileName.LastIndexOf(".")>0? f.FileName.LastIndexOf("."):0);
                
                var parsedContentDisposition = ContentDispositionHeaderValue.Parse(f.ContentDisposition);
                var filename = Path.Combine(parsedContentDisposition.FileName.Trim('"'));
                var blockBlob = blobContainer.GetBlockBlobReference(name);

                if (!contentTypeDefault) {
                    ContentTypeDict.dict.TryGetValue(fileext, out string content_type);
                    if (!string.IsNullOrEmpty(content_type))
                    {
                        blockBlob.Properties.ContentType = content_type;
                    }
                }
                await blockBlob.UploadFromStreamAsync(f.OpenReadStream());
                string sha1= ShaHashHelper.GetSHA1(f.OpenReadStream());
                AzureBlobModel model = new AzureBlobModel(f, _options.Container, groupName, name)
                {
                    BlobUrl = url.PrimaryUri.ToString().Split("?")[0] + "/" + name,
                    Sha1Code = sha1
                };
                list.Add(model);
            }
            return list;
        }
        public async Task<AzureBlobModel> UploadPath(string path, string fileSpace = "common" , bool contentTypeDefault = false) {
            string groupName = fileSpace + "/" + DateTime.Now.ToString("yyyyMMdd");
            string newFileName = DateTime.Now.ToString("HHmmssfffffff");
            blobContainer =   InitializeBlob(groupName); //blobClient.GetContainerReference(groupName);
            StorageUri url = blobContainer.StorageUri;
            FileInfo file = new FileInfo(path);
            string[] names = file.Name.Split(".");
            string name = "";
            for (int i = 0; i < names.Length - 1; i++)
            {
                name = name + names[i];
            }
            if (names.Length <= 1)
            {
                name = file.Name + "_" + newFileName;
            }
            else
            {
                name = name + "_" + newFileName + "." + names[names.Length - 1];
            }
            string fileext = file.Name.Substring(file.Name.LastIndexOf(".") > 0 ? file.Name.LastIndexOf(".") : 0);

          //  var parsedContentDisposition = ContentDispositionHeaderValue.Parse("form-data; name=\"files\"; filename=\"" + file.Name + "\"");
            var blockBlob = blobContainer.GetBlockBlobReference(name);
            string content_type = "application/octet-stream";
            if (!contentTypeDefault)
            {
                ContentTypeDict.dict.TryGetValue(fileext, out string contenttype);
                if (!string.IsNullOrEmpty(contenttype))
                {
                    blockBlob.Properties.ContentType = contenttype;
                    content_type = contenttype;
                }
                else
                {
                    blockBlob.Properties.ContentType = content_type;
                }
            }
            else
            {
                blockBlob.Properties.ContentType = content_type;
            }
            await blockBlob.UploadFromFileAsync(path);
            //var provider = new FileExtensionContentTypeProvider();
            //var memi = provider.Mappings[fileext];
            AzureBlobModel model = new AzureBlobModel(file, _options.Container, groupName, name , content_type)
            {
                Sha1Code=ShaHashHelper.GetSHA1(file.Create()),
                BlobUrl = url.PrimaryUri.ToString().Split("?")[0] + "/" + name
            };
            return model;
        }



        public async Task<AzureBlobModel> UploadText(string fileName, string text, string fileSpace = "common", bool contentTypeDefault = true)
        {
            string groupName = fileSpace + "/" + DateTime.Now.ToString("yyyyMMdd");
            string newFileName = DateTime.Now.ToString("HHmmssfffffff");
            blobContainer =   InitializeBlob(groupName); //blobClient.GetContainerReference(groupName); 
            StorageUri url = blobContainer.StorageUri;
            //FileInfo file = new FileInfo(path);
            string[] names = fileName.Split(".");
            string name = "";
            for (int i = 0; i < names.Length - 1; i++)
            {
                name = name + names[i];
            }
            if (names.Length <= 1)
            {
                name = fileName + "_" + newFileName;
            }
            else
            {
                name = name + "_" + newFileName + "." + names[names.Length - 1];
            }
            var blockBlob = blobContainer.GetBlockBlobReference(name);
            //  var parsedContentDisposition = ContentDispositionHeaderValue.Parse("form-data; name=\"files\"; filename=\"" + file.Name + "\"");
            string fileext = fileName.Substring(fileName.LastIndexOf(".") > 0 ? fileName.LastIndexOf(".") : 0);
            string content_type = "application/octet-stream";
            if (!contentTypeDefault)
            {
                ContentTypeDict.dict.TryGetValue(fileext, out string contenttype);
                if (!string.IsNullOrEmpty(contenttype))
                {
                    blockBlob.Properties.ContentType = contenttype;
                    content_type = contenttype;
                }
                else
                {
                    blockBlob.Properties.ContentType = content_type;
                }
            }
            else
            {
                blockBlob.Properties.ContentType = content_type;
            }
            
        
            await blockBlob.UploadTextAsync(text);
            byte[] bytes = System.Text.Encoding.Default.GetBytes(text);
            //var provider = new FileExtensionContentTypeProvider();
            //var memi = provider.Mappings[fileext];
            AzureBlobModel model = new AzureBlobModel(fileName, _options.Container, groupName, name, content_type, bytes.Length)
            {
                Sha1Code = ShaHashHelper.GetSHA1(bytes),
                BlobUrl = url.PrimaryUri.ToString().Split("?")[0] + "/" + name
            };
            return model;
        }

        public async Task<AzureBlobModel> UploadObject(string fileName,object obj, string fileSpace = "common", bool contentTypeDefault =true)
        {
            string groupName = fileSpace + "/" + DateTime.Now.ToString("yyyyMMdd");
            string newFileName = DateTime.Now.ToString("HHmmssfffffff");
            blobContainer =   InitializeBlob(groupName); //blobClient.GetContainerReference(groupName); 
            StorageUri url = blobContainer.StorageUri;
            //FileInfo file = new FileInfo(path);
            string[] names = fileName.Split(".");
            string name = "";
            for (int i = 0; i < names.Length - 1; i++)
            {
                name = name + names[i];
            }
            if (names.Length <= 1)
            {
                name = fileName + "_" + newFileName;
            }
            else
            {
                name = name + "_" + newFileName + "." + names[names.Length - 1];
            }
            var blockBlob = blobContainer.GetBlockBlobReference(name);
            //  var parsedContentDisposition = ContentDispositionHeaderValue.Parse("form-data; name=\"files\"; filename=\"" + file.Name + "\"");
            string fileext = fileName.Substring(fileName.LastIndexOf(".") > 0 ? fileName.LastIndexOf(".") : 0);
            string content_type = "application/octet-stream";
            if (!contentTypeDefault)
            {
                ContentTypeDict.dict.TryGetValue(fileext, out string contenttype);
                if (!string.IsNullOrEmpty(contenttype))
                {
                    blockBlob.Properties.ContentType = contenttype;
                    content_type = contenttype;
                }
                else
                {
                    blockBlob.Properties.ContentType = content_type;
                }
            }
            else {
                blockBlob.Properties.ContentType = content_type;
            }
            string objStr = obj.ToJsonAbs();
         
            await blockBlob.UploadTextAsync(objStr);
            //var provider = new FileExtensionContentTypeProvider();
            //var memi = provider.Mappings[fileext];
            byte[] bytes = System.Text.Encoding.Default.GetBytes(objStr);
            AzureBlobModel model = new AzureBlobModel(fileName, _options.Container, groupName, name, content_type , bytes.Length)
            {
                Sha1Code = ShaHashHelper.GetSHA1(bytes),
                BlobUrl = url.PrimaryUri.ToString().Split("?")[0] + "/" + name
            };
            return model;
        }


        public async Task<AzureBlobModel> UploadFile(IFormFile file, string fileSpace = "wordfiles", bool contentTypeDefault = true)
        {
            long  bizno= IdWorker.getInstance().NextId();
            string groupName = fileSpace + "/" + DateTime.Now.ToString("yyyyMMdd")+"/"+ bizno;
            string newFileName = DateTime.Now.ToString("yyyyMMddHHmmss");
            // await InitializeBlob(DateTime.Now.ToString("yyyyMMdd"));
            blobContainer =   InitializeBlob(groupName); //blobClient.GetContainerReference(groupName); 
            StorageUri url = blobContainer.StorageUri;
            string[] names = file.FileName.Split(".");
            string name = "";
            for (int i = 0; i < names.Length - 1; i++)
            {
                name = name + names[i];
            }
            if (names.Length <= 1)
            {
                name = name + "_" + newFileName;
            }
            else
            {
                name = name + "_" + newFileName + "." + names[names.Length - 1];
            }
            var parsedContentDisposition = ContentDispositionHeaderValue.Parse(file.ContentDisposition);
            var filename = Path.Combine(parsedContentDisposition.FileName.Trim('"'));
            var blockBlob = blobContainer.GetBlockBlobReference(name);
            string fileext = filename.Substring(filename.LastIndexOf(".") > 0 ? filename.LastIndexOf(".") : 0);
            if (!contentTypeDefault)
            {
                ContentTypeDict.dict.TryGetValue(fileext, out string content_type);
                if (!string.IsNullOrEmpty(content_type))
                {
                    blockBlob.Properties.ContentType = content_type;
                }
            }
            await blockBlob.UploadFromStreamAsync(file.OpenReadStream());
            string sha1 = ShaHashHelper.GetSHA1(file.OpenReadStream());
            AzureBlobModel model = new AzureBlobModel(file, _options.Container, groupName, name)
            {   
                Sha1Code=sha1,
                BlobUrl = url.PrimaryUri.ToString().Split("?")[0] + "/" + name
            };
            return model;
        }


        public  AzureBlobModel  UploadFileByFolderNAsyn(Stream fileSteam, string folder, string fileName, string fileSpace = "pptx", bool contentTypeDefault = true)
        {

            string groupName = fileSpace + "/" + folder;
            //  string newFileName = sha1Code;
            // await InitializeBlob(DateTime.Now.ToString("yyyyMMdd"));
            blobContainer =   InitializeBlob(groupName); //blobClient.GetContainerReference(groupName); 
            StorageUri url = blobContainer.StorageUri;
            string[] names = fileName.Split(".");
            //  string name ;
            //for (int i = 0; i < names.Length - 1; i++)
            //{
            //    name = name + names[i];
            //}
            //if (names.Length <= 1)
            //{
            //    name =  newFileName;
            //}
            //else
            //{
            //    name = newFileName + "." + names[names.Length - 1];
            //}
            //var parsedContentDisposition = ContentDispositionHeaderValue.Parse(file.ContentDisposition);
            //var filename = Path.Combine(parsedContentDisposition.FileName.Trim('"'));
            var blockBlob = blobContainer.GetBlockBlobReference(fileName);
            string fileext = fileName.Substring(fileName.LastIndexOf(".") > 0 ? fileName.LastIndexOf(".") : 0);
            if (!contentTypeDefault)
            {
                ContentTypeDict.dict.TryGetValue(fileext, out string content_type);
                if (!string.IsNullOrEmpty(content_type))
                {
                    blockBlob.Properties.ContentType = content_type;
                }
                else
                {
                    blockBlob.Properties.ContentType = "application/octet-stream";
                }
            }
            blockBlob.UploadFromStreamAsync(fileSteam).GetAwaiter().GetResult() ;
            AzureBlobModel model = new AzureBlobModel(fileName, _options.Container, groupName, fileName, folder, blockBlob.Properties.ContentType, fileSteam.Length)
            {
                Sha1Code = ShaHashHelper.GetSHA1(fileSteam),
                BlobUrl = url.PrimaryUri.ToString().Split("?")[0] + "/" + fileName
            };
            return model;
        }





        public async Task<AzureBlobModel> UploadFileByFolder(Stream fileSteam, string folder, string fileName, string fileSpace = "pptx", bool contentTypeDefault = true)
        {
            
            string groupName = fileSpace + "/" + folder;
          //  string newFileName = sha1Code;
            // await InitializeBlob(DateTime.Now.ToString("yyyyMMdd"));
            blobContainer =   InitializeBlob(groupName); //blobClient.GetContainerReference(groupName); 
            StorageUri url = blobContainer.StorageUri;
            string[] names = fileName.Split(".");
          //  string name ;
            //for (int i = 0; i < names.Length - 1; i++)
            //{
            //    name = name + names[i];
            //}
            //if (names.Length <= 1)
            //{
            //    name =  newFileName;
            //}
            //else
            //{
            //    name = newFileName + "." + names[names.Length - 1];
            //}
            //var parsedContentDisposition = ContentDispositionHeaderValue.Parse(file.ContentDisposition);
            //var filename = Path.Combine(parsedContentDisposition.FileName.Trim('"'));
            var blockBlob = blobContainer.GetBlockBlobReference(fileName);
            string fileext = fileName.Substring(fileName.LastIndexOf(".") > 0 ? fileName.LastIndexOf(".") : 0);
            if (!contentTypeDefault)
            {
                ContentTypeDict.dict.TryGetValue(fileext, out string content_type);
                if (!string.IsNullOrEmpty(content_type))
                {
                    blockBlob.Properties.ContentType = content_type;
                }
                else {
                    blockBlob.Properties.ContentType = "application/octet-stream";
                }
            }
            await blockBlob.UploadFromStreamAsync(fileSteam);
            string sha1 = ShaHashHelper.GetSHA1(fileSteam);
            AzureBlobModel model = new AzureBlobModel(fileName, _options.Container, groupName, fileName, folder, blockBlob.Properties.ContentType, fileSteam.Length)
            {
                Sha1Code = sha1,
                BlobUrl = url.PrimaryUri.ToString().Split("?")[0] + "/" + fileName
            };
            return model;
        }


        public async Task<AzureBlobModel> UploadTextByFolder(string text, string folder, string fileName, string fileSpace = "pptx", bool contentTypeDefault = true)
        {
            string groupName = fileSpace + "/" + folder;
            blobContainer =   InitializeBlob(groupName); //blobClient.GetContainerReference(groupName); 
            StorageUri url = blobContainer.StorageUri;
        
            var blockBlob = blobContainer.GetBlockBlobReference(fileName);
            string fileext = fileName.Substring(fileName.LastIndexOf(".") > 0 ? fileName.LastIndexOf(".") : 0);
            string content_type = "application/octet-stream";
            if (!contentTypeDefault)
            {
                ContentTypeDict.dict.TryGetValue(fileext, out string contenttype);
                if (!string.IsNullOrEmpty(contenttype))
                {
                    blockBlob.Properties.ContentType = contenttype;
                    content_type = contenttype;
                }
                else
                {
                    blockBlob.Properties.ContentType = content_type;
                }
            }
            else
            {
                blockBlob.Properties.ContentType = content_type;
            }

            
            await blockBlob.UploadTextAsync(text);
            byte[] bytes = System.Text.Encoding.Default.GetBytes(text);
            AzureBlobModel model = new AzureBlobModel(fileName, _options.Container, groupName, fileName, folder, blockBlob.Properties.ContentType, bytes.Length)
            {
                Sha1Code = ShaHashHelper.GetSHA1(bytes),
                BlobUrl = url.PrimaryUri.ToString().Split("?")[0] + "/" + fileName
            };
            return model;
        }


        /// <summary>
        /// 在容器上创建共享访问策略。
        /// </summary>
        /// <param name="container">A reference to the container.</param>
        /// <param name="policyName">The name of the stored access policy.</param>
        public async Task<bool> CreateSharedAccessPolicyAsync(string policyName,
            string  containerName = null)
        {
            
            blobContainer = GetSASBoloClent(_options.Container);
            //Create a new shared access policy and define its constraints.
            SharedAccessBlobPolicy sharedPolicy = new SharedAccessBlobPolicy()
            {
                SharedAccessExpiryTime = DateTime.UtcNow.AddMinutes(15),
                Permissions =  SharedAccessBlobPermissions.Delete
            };

            //Get the container's existing permissions.
            BlobContainerPermissions permissions = await blobContainer.GetPermissionsAsync();

            if (permissions.SharedAccessPolicies.Count < 5)
            {
                //Add the new policy to the container's permissions, and set the container's permissions.
                permissions.SharedAccessPolicies.TryAdd(policyName, sharedPolicy);
                await blobContainer.SetPermissionsAsync(permissions);
                return true;
            }
            else return false;
        }

        /// <summary>
        /// 删除容器上共享访问策略。
        /// </summary>
        /// <param name="container">A reference to the container.</param>
        /// <param name="policyName">The name of the stored access policy.</param>
        public async Task DeleteSharedAccessPolicyAsync(string policyName,
            string  containerName = null)
        {
            
            blobContainer = GetSASBoloClent(_options.Container);
            BlobContainerPermissions permissions = await blobContainer.GetPermissionsAsync();
            permissions.SharedAccessPolicies.Remove(policyName);
            await blobContainer.SetPermissionsAsync(permissions);
           
        }


        /// <summary>
        ///为 blob 容器创建服务 SAS
        /// 若要为容器创建服务 SAS，请调用 CloudBlobContainer.GetSharedAccessSignature 方法。
        ///下面的代码示例在容器上创建 SAS。 如果提供现有存储访问策略的名称，则该策略与 SAS 关联。 如果未提供存储访问策略，则代码会在容器上创建一个临时 SAS。
        /// </summary>
        /// <param name="container"></param>
        /// <param name="storedPolicyName"></param>
        /// <returns></returns>
        public  (string, string) GetContainerSasUri(string containerName = null, string storedPolicyName = null)
        {
            string sasContainerToken;
           
            blobContainer = GetSASBoloClent(_options.Container);
            // If no stored policy is specified, create a new access policy and define its constraints.
            if (storedPolicyName == null)
            {
                // Note that the SharedAccessBlobPolicy class is used both to define the parameters of an ad hoc SAS, and
                // to construct a shared access policy that is saved to the container's shared access policies.
                SharedAccessBlobPolicy adHocPolicy = new SharedAccessBlobPolicy()
                {
                    // When the start time for the SAS is omitted, the start time is assumed to be the time when the storage service receives the request.
                    // Omitting the start time for a SAS that is effective immediately helps to avoid clock skew.
                    SharedAccessStartTime = DateTime.UtcNow.AddMinutes(-15),
                    SharedAccessExpiryTime = DateTime.UtcNow.AddHours(2),
                    Permissions = SharedAccessBlobPermissions.Write | SharedAccessBlobPermissions.Create| SharedAccessBlobPermissions.Read
                };

                // Generate the shared access signature on the container, setting the constraints directly on the signature.
                sasContainerToken = blobContainer.GetSharedAccessSignature(adHocPolicy, null);

            }
            else
            {
                // Generate the shared access signature on the container. In this case, all of the constraints for the
                // shared access signature are specified on the stored access policy, which is provided by name.
                // It is also possible to specify some constraints on an ad hoc SAS and others on the stored access policy.
                sasContainerToken = blobContainer.GetSharedAccessSignature(null, storedPolicyName);

            }

            // Return the URI string for the container, including the SAS token.
            
            return (blobContainer.Uri.ToString() , sasContainerToken);
        }
        public (string, string) GetContainerSasUriRead(string containerName, string storedPolicyName = null)
        {
            string sasContainerToken;

            blobContainer = GetSASBoloClent(containerName);
            // If no stored policy is specified, create a new access policy and define its constraints.
            if (storedPolicyName == null)
            {
                // Note that the SharedAccessBlobPolicy class is used both to define the parameters of an ad hoc SAS, and
                // to construct a shared access policy that is saved to the container's shared access policies.
                SharedAccessBlobPolicy adHocPolicy = new SharedAccessBlobPolicy()
                {
                    // When the start time for the SAS is omitted, the start time is assumed to be the time when the storage service receives the request.
                    // Omitting the start time for a SAS that is effective immediately helps to avoid clock skew.
                    SharedAccessStartTime = DateTime.UtcNow.AddMinutes(-15),
                    SharedAccessExpiryTime = DateTime.UtcNow.AddHours(2),
                    Permissions =  SharedAccessBlobPermissions.Read
                };

                // Generate the shared access signature on the container, setting the constraints directly on the signature.
                sasContainerToken = blobContainer.GetSharedAccessSignature(adHocPolicy, null);

            }
            else
            {
                // Generate the shared access signature on the container. In this case, all of the constraints for the
                // shared access signature are specified on the stored access policy, which is provided by name.
                // It is also possible to specify some constraints on an ad hoc SAS and others on the stored access policy.
                sasContainerToken = blobContainer.GetSharedAccessSignature(null, storedPolicyName);

            }

            // Return the URI string for the container, including the SAS token.
            return (blobContainer.Uri.ToString(), sasContainerToken);
        }


        /// <summary>
        /// 若要为 blob 创建服务 SAS，请调用 CloudBlob.GetSharedAccessSignature 方法。
        ///下面的代码示例在 blob 上创建 SAS。 如果提供现有存储访问策略的名称，则该策略与 SAS 关联。 如果未提供存储访问策略，则代码会在 Blob 上创建一个临时 SAS。
        /// </summary>
        /// <param name="container"></param>
        /// <param name="blobName"></param>
        /// <param name="policyName"></param>
        /// <returns></returns>
        public string GetBlobSasUri(string blobName, string containerName=null, string policyName = null)
        {
            string sasBlobToken;
            
            blobContainer = GetSASBoloClent(_options.Container);
            // Get a reference to a blob within the container.
            // Note that the blob may not exist yet, but a SAS can still be created for it.
            CloudBlockBlob blob = blobContainer.GetBlockBlobReference( blobName );
            if (policyName == null)
            {
                // Create a new access policy and define its constraints.
                // Note that the SharedAccessBlobPolicy class is used both to define the parameters of an ad hoc SAS, and
                // to construct a shared access policy that is saved to the container's shared access policies.
                SharedAccessBlobPolicy adHocSAS = new SharedAccessBlobPolicy()
                {
                    // When the start time for the SAS is omitted, the start time is assumed to be the time when the storage service receives the request.
                    // Omitting the start time for a SAS that is effective immediately helps to avoid clock skew.
                    SharedAccessStartTime = DateTime.UtcNow.AddMinutes(-15),
                    SharedAccessExpiryTime = DateTime.UtcNow.AddHours(2),
                    Permissions =  SharedAccessBlobPermissions.Write | SharedAccessBlobPermissions.Create | SharedAccessBlobPermissions.Read
                };

                // Generate the shared access signature on the blob, setting the constraints directly on the signature.
                sasBlobToken = blob.GetSharedAccessSignature(adHocSAS);

            }
            else
            {
                // Generate the shared access signature on the blob. In this case, all of the constraints for the
                // shared access signature are specified on the container's stored access policy.
                sasBlobToken = blob.GetSharedAccessSignature(null, policyName);
            }

            // Return the URI string for the container, including the SAS token.
            return blob.Uri + sasBlobToken;
        }


        public string GetBlobSasUriRead(string containerName, string blobName, string policyName = null)
        {
            string sasBlobToken;
            blobContainer = GetSASBoloClent(containerName);
            CloudBlockBlob blob = blobContainer.GetBlockBlobReference(blobName);
            if (policyName == null)
            {
                SharedAccessBlobPolicy adHocSAS = new SharedAccessBlobPolicy()
                {
                    SharedAccessStartTime = DateTime.UtcNow.AddMinutes(-15),
                    SharedAccessExpiryTime = DateTime.UtcNow.AddHours(2),
                    Permissions =  SharedAccessBlobPermissions.Read
                };
                sasBlobToken = blob.GetSharedAccessSignature(adHocSAS);

            }
            else
            {
                sasBlobToken = blob.GetSharedAccessSignature(null, policyName);
            }
            return blob.Uri + sasBlobToken;
        }


        private  CloudBlobContainer GetSASBoloClent(string containerName)
        {
            CloudStorageAccount storageAccount = CloudStorageAccount.Parse(_options.ConnectionString);
            CloudBlobClient blobClient = storageAccount.CreateCloudBlobClient();
            CloudBlobContainer container = blobClient.GetContainerReference(containerName);
            return container;
        }


        public async Task Deleteblob(string azureBlobSAS)
        {
            
            (string, string) a = BlobUrlString(azureBlobSAS);
            string ContainerName = a.Item1;
            string BlobName = a.Item2;
            string PolicyName = "DeletePolicy";
            bool flg = await CreateSharedAccessPolicyAsync(PolicyName);
            if (flg)
            {
                string SAS = GetBlobSasUri(BlobName, null, PolicyName);
                CloudBlockBlob blob = new CloudBlockBlob(new Uri(SAS));
                await blob.DeleteAsync();
            }
            await DeleteSharedAccessPolicyAsync(PolicyName);
        }

        private static (string, string) BlobUrlString(string sasUrl)
        {
            sasUrl = sasUrl.Substring(8);
            string[] sasUrls = sasUrl.Split("/");
            string ContainerName;
            ContainerName = sasUrls[1].Clone().ToString();
            string item = sasUrls[0] + "/" + sasUrls[1] + "/";
            string blob = sasUrl.Replace(item, "");
            return (ContainerName, blob);
        }
    }
}