使用预签名URL访问me-central-1区域S3桶时触发IllegalLocationConstraintException错误

在使用预签名URL访问S3对象时遇到错误：

'IllegalLocationConstraintException' 'The me-central-1 location constraint is incompatible for the region specific endpoint this request was sent to'

已在me-central-1区域创建存储桶，文件上传成功，但通过预签名URL访问时抛出上述错误；而ap-south-1区域的存储桶使用预签名URL访问完全正常。确认端点应为https://s3.me-central-1.amazonaws.com，仍无法定位中东区域存储桶出现位置错误的原因。

以下是Python代码：

def save_to_s3_bucket(file, file_name):
    try:
        import base64,json
        import requests
        from io import BytesIO
        from botocore.exceptions import ClientError
        from botocore.config import Config

        format, imgstr = file.split(';base64,')

        s3 = boto3.client('s3', aws_access_key_id=settings.AWS_ACCESS_KEY_ID,
                            aws_secret_access_key=settings.AWS_SECRET_ACCESS_KEY, config=Config(signature_version='s3v4'), 
                            region_name=settings.AWS_DEFAULT_REGION)
        

        random_path = ''.join(random.choice(string.ascii_uppercase + string.digits) for _ in range(10))

        s3.put_object(Bucket=settings.AWS_STORAGE_BUCKET_NAME, Key='pvt/doc/ln-app/'+random_path+'/'+file_name, Body=base64.b64decode(imgstr), StorageClass='REDUCED_REDUNDANCY')

        img_url = settings.AWS_BUCKET_URL+'pvt/doc/ln-app/'+random_path+'/'+file_name
        
        url = s3.generate_presigned_url('get_object', Params = {'Bucket': settings.AWS_STORAGE_BUCKET_NAME, 'Key': 'pvt/doc/ln-app/'+random_path+'/'+file_name}, ExpiresIn = 10000)

        print('AWS-S3-URL--->>>>>>>>>', url)

        res = {
            'hasError': False,
            'message': 'Success',
            'response': {
                'key': 'pvt/doc/ln-app/'+random_path+'/'+file_name,
                'file_url': url
            }
        }
        return res
    except Exception as e:
        res = {
            'hasError': True,
            'message': str(e),
            'response': None
        }
        return res

• 显式指定区域端点：对于me-central-1这类较新的区域，boto3需要显式指定endpoint_url才能生成匹配区域的预签名URL。修改S3客户端初始化代码，添加该参数：

s3 = boto3.client('s3', 
                  aws_access_key_id=settings.AWS_ACCESS_KEY_ID,
                  aws_secret_access_key=settings.AWS_SECRET_ACCESS_KEY, 
                  config=Config(signature_version='s3v4'), 
                  region_name=settings.AWS_DEFAULT_REGION,
                  endpoint_url=f"https://s3.{settings.AWS_DEFAULT_REGION}.amazonaws.com")

• 校验区域配置一致性：确认settings.AWS_DEFAULT_REGION确实设置为me-central-1，避免客户端区域配置与存储桶实际区域不匹配。
• 验证预签名URL端点：生成URL后检查其域名是否为s3.me-central-1.amazonaws.com，若仍为通用端点s3.amazonaws.com，则说明客户端未正确识别区域，必须强制指定endpoint_url。

内容的提问来源于stack exchange，提问作者Sins97