# BLOB Storing Aliyun Provider

BLOB Storing Aliyun Provider can store BLOBs in [Aliyun Blob storage](https://help.aliyun.com/product/31815.html).

> Read the [BLOB Storing document](Blob-Storing.md) to understand how to use the BLOB storing system. This document only covers how to configure containers to use a Aliyun BLOB as the storage provider.

## Installation

Use the ABP CLI to add [Volo.Abp.BlobStoring.Aliyun](https://www.nuget.org/packages/Volo.Abp.BlobStoring.Aliyun) NuGet package to your project:

* Install the [ABP CLI](https://docs.abp.io/en/abp/latest/CLI) if you haven't installed before.
* Open a command line (terminal) in the directory of the `.csproj` file you want to add the `Volo.Abp.BlobStoring.Aliyun` package.
* Run `abp add-package Volo.Abp.BlobStoring.Aliyun` command.

If you want to do it manually, install the [Volo.Abp.BlobStoring.Aliyun](https://www.nuget.org/packages/Volo.Abp.BlobStoring.Aliyun) NuGet package to your project and add `[DependsOn(typeof(AbpBlobStoringAliyunModule))]` to the [ABP module](Module-Development-Basics.md) class inside your project.

## Configuration

Configuration is done in the `ConfigureServices` method of your [module](Module-Development-Basics.md) class, as explained in the [BLOB Storing document](Blob-Storing.md).

**Example: Configure to use the Aliyun storage provider by default**

````csharp
Configure<AbpBlobStoringOptions>(options =>
{
    options.Containers.ConfigureDefault(container =>
    {
        container.UseAliyun(aliyun =>
        {
            aliyun.AccessKeyId = "your aliyun access key id";
            aliyun.AccessKeySecret = "your aliyun access key secret";
            aliyun.Endpoint = "your oss endpoint";
            aliyun.RegionId = "your sts region id";
            aliyun.RoleArn = "the arn of ram role";
            aliyun.RoleSessionName = "the name of the certificate";
            aliyun.Policy = "policy";
            aliyun.DurationSeconds = "expiration date";
            aliyun.ContainerName = "your aliyun container name";
            aliyun.CreateContainerIfNotExists = true;
        });
    });
});
````

> See the [BLOB Storing document](Blob-Storing.md) to learn how to configure this provider for a specific container.

### Options

* **AccessKeyId** ([NotNull]string): AccessKey is the key to access the Alibaba Cloud API. It has full permissions for the account. Please keep it safe! Recommend to follow [Alibaba Cloud security best practicess](https://help.aliyun.com/document_detail/102600.html),Use RAM sub-user AccessKey to call API.
* **AccessKeySecret** ([NotNull]string): Same as above.
* **Endpoint** ([NotNull]string): Endpoint is the external domain name of OSS. See the [document](https://help.aliyun.com/document_detail/31837.html) for details. 
* **UseSecurityTokenService** (bool): Use [STS temporary credentials](https://help.aliyun.com/document_detail/100624.html) to access OSS services,default: `false`.
* **RegionId** (string): Access address of STS service. See the [document](https://help.aliyun.com/document_detail/66053.html) for details.
* **RoleArn** ([NotNull]string): STS required role ARN. See the [document](https://help.aliyun.com/document_detail/100624.html) for details.
* **RoleSessionName** ([NotNull]string): Used to identify the temporary access credentials, it is recommended to use different application users to distinguish.
* **Policy** (string): Additional permission restrictions. See the [document](https://help.aliyun.com/document_detail/100680.html) for details.
* **DurationSeconds** (int): Validity period(s) of a temporary access certificate,minimum is 900 and the maximum is 3600.
* **ContainerName** (string): You can specify the container name in Aliyun. If this is not specified, it uses the name of the BLOB container defined with the `BlobContainerName` attribute (see the [BLOB storing document](Blob-Storing.md)). Please note that Aliyun has some **rules for naming containers**. A container name must be a valid DNS name, conforming to the [following naming rules](https://help.aliyun.com/knowledge_detail/39668.html):
    * Container names must start or end with a letter or number, and can contain only letters, numbers, and the dash (-) character.
    * Container names Must start and end with lowercase letters and numbers.
    * Container names must be from **3** through **63** characters long.
* **CreateContainerIfNotExists** (bool): Default value is `false`, If a container does not exist in Aliyun, `AliyunBlobProvider` will try to create it.
* **TemporaryCredentialsCacheKey** (bool): The cache key of STS credentials.


## Aliyun Blob Name Calculator

Aliyun Blob Provider organizes BLOB name and implements some conventions. The full name of a BLOB is determined by the following rules by default:

* Appends `host` string if [current tenant](Multi-Tenancy.md) is `null` (or multi-tenancy is disabled for the container - see the [BLOB Storing document](Blob-Storing.md) to learn how to disable multi-tenancy for a container).
* Appends `tenants/<tenant-id>` string if current tenant is not `null`.
* Appends the BLOB name.

## Other Services

* `AliyunBlobProvider` is the main service that implements the Aliyun BLOB storage provider, if you want to override/replace it via [dependency injection](Dependency-Injection.md) (don't replace `IBlobProvider` interface, but replace `AliyunBlobProvider` class).
* `IAliyunBlobNameCalculator` is used to calculate the full BLOB name (that is explained above). It is implemented by the `DefaultAliyunBlobNameCalculator` by default.
* `IOssClientFactory` is used create OSS client. It is implemented by the `DefaultOssClientFactory` by default. You can override/replace it,if you want customize.