如何在 Python 中为 Azure Blob 存储 SAS 令牌生成签名？

Question

我正在尝试按照 MSDN.

中的说明，在 Python 中构建 blob 下载 URL 所需的 SAS 令牌

我要签名的字符串如下所示：

r\n
2016-12-22T14%3A00%3A00Z\n
2016-12-22T15%3A00%3A00Z\n
%2Fblob%2Fmytest%2Fprivatefiles%2F1%2Fqux.txt\n
\n
\n
https\n
2015-12-11\n
\n
\n
\n
\n
_

为了清楚起见，我添加了换行符，最后一行应该是空行（末尾没有换行符）。

我用来签名字符串的Python方法是：

def sign(self, string):
    hashed = hmac.new(base64.b64decode(self.account_key), digestmod=sha256)
    hashed.update(string)
    base64_str = base64.encodestring(hashed.digest()).strip()
    return base64_str

我构建的最终 URL 看起来像：

https://mytest.blob.core.windows.net/privatefiles/1/qux.txt?sv=2015-12-11&st=2016-12-22T14%3A00%3A00Z&se=2016-12-22T15%3A00%3A00Z&sr=b&sp=r&spr=https&sig=BxkcpoRq3xanEHwU6u5%2FYsULEtOCJebHmupUZaPmBgM%3D

仍然，URL 失败并显示 403。知道我做错了什么吗？

Answer 1

在 python 中生成 SAS 令牌的最简单方法是利用 Azure Storage SDK for Python。请考虑以下代码片段：

import time
import uuid
import hmac
import base64
import hashlib
import urllib
from datetime import datetime, timedelta
from azure.storage import (
    AccessPolicy,
    ResourceTypes,
    AccountPermissions,
    CloudStorageAccount,
)
from azure.storage.blob import (
    BlockBlobService,
    ContainerPermissions,
    BlobPermissions,
    PublicAccess,
)

AZURE_ACC_NAME = '<account_name>'
AZURE_PRIMARY_KEY = '<account_key>'
AZURE_CONTAINER = '<container_name>'
AZURE_BLOB='<blob_name>'

def generate_sas_with_sdk():
    block_blob_service = BlockBlobService(account_name=AZURE_ACC_NAME, account_key=AZURE_PRIMARY_KEY)    
    sas_url = block_blob_service.generate_blob_shared_access_signature(AZURE_CONTAINER,AZURE_BLOB,BlobPermissions.READ,datetime.utcnow() + timedelta(hours=1))
    #print sas_url
    print 'https://'+AZURE_ACC_NAME+'.blob.core.windows.net/'+AZURE_CONTAINER+'/'+AZURE_BLOB+'?'+sas_url

generate_sas_with_sdk()

此外，要通过纯 python 脚本生成 SAS 令牌，您可以参考 https://github.com/Azure/azure-storage-python/blob/master/azure/storage/sharedaccesssignature.py#L173 处的源代码以获取更多提示。

Answer 2

基于documentation（请参阅Constructing the Signature String部分），传递给要签名的字符串的参数必须URL解码。来自 link:

To construct the signature string of a shared access signature, first construct the string-to-sign from the fields comprising the request, then encode the string as UTF-8 and compute the signature using the HMAC-SHA256 algorithm. Note that fields included in the string-to-sign must be URL-decoded.

请在您的字符串中使用未编码的参数值进行签名，这应该可以解决问题。

Answer 3

这是 Python3 的更新代码片段和更新的 Azure 存储 Blob SDK：

from datetime import datetime, timedelta
from azure.storage.blob import (
    BlockBlobService,
    ContainerPermissions,
    BlobPermissions,
    PublicAccess,
)

AZURE_ACC_NAME = '<account_name>'
AZURE_PRIMARY_KEY = '<account_key>'
AZURE_CONTAINER = '<container_name>'
AZURE_BLOB='<blob_name>'

block_blob_service = BlockBlobService(account_name=AZURE_ACC_NAME, account_key=AZURE_PRIMARY_KEY)
sas_url = block_blob_service.generate_blob_shared_access_signature(AZURE_CONTAINER,AZURE_BLOB,permission=BlobPermissions.READ,expiry= datetime.utcnow() + timedelta(hours=1))
print('https://'+AZURE_ACC_NAME+'.blob.core.windows.net/'+AZURE_CONTAINER+'/'+AZURE_BLOB+'?'+sas_url)

Answer 4

更新，用最新的存储python库，这是我用来生成sas token的：

def generate_sas_token(file_name):
    sas = generate_blob_sas(account_name=AZURE_ACC_NAME,
                            account_key=AZURE_PRIMARY_KEY,
                            container_name=AZURE_CONTAINER,
                            blob_name=file_name,
                            permission=BlobSasPermissions(read=True),
                            expiry=datetime.utcnow() + timedelta(hours=2))

    logging.info('https://'+AZURE_ACC_NAME+'.blob.core.windows.net/'+AZURE_CONTAINER+'/'+file_name+'?'+sas)
    sas_url ='https://'+AZURE_ACC_NAME+'.blob.core.windows.net/'+AZURE_CONTAINER+'/'+file_name+'?'+sas
    return sas_url

Python 3.6 和 azure-storage-blob 包。

如何在 Python 中为 Azure Blob 存储 SAS 令牌生成签名？

How do you generate the signature for an Azure Blob storage SAS token in Python?

python

authentication

azure

azure-blob-storage