Error when generating presigned url from aws s3 using boto3

Question

When I try to return a generate presigned url using boto3 from bucket in aws s3 and the code:

import fastapi
import boto3
from botocore.exceptions import ClientError

s3 = boto3.client("s3",
                aws_access_key_id="...",
                aws_secret_access_key="...")

BUCKET_NAME = "tayibat-files"

app = FastAPI()                      

@app.get('/{file_name}')
async def method_name(file_name: str):
try:
    url = s3.generate_presigned_url(
                    'get_object',
                    Params={'Bucket': BUCKET_NAME,
                    'Key': f"products/{file_name}"},
                    ExpiresIn=3600
                    )
except ClientError as e:
    logging.error(e)
return url

the get request return an url, but when I try to open it in browsers, It generate:

This XML file does not appear to have any style information associated with it. The document 
tree is shown below.

InvalidRequest
The authorization mechanism you have provided is not supported. Please use AWS4-HMAC- 
SHA256.
ZW269CV1TAYC7CWC
1yozjolBbu4difnOjjopLeOk79i34WDOFwp1VQA4Nqd0RBdLNkaOkb/uJVjFtyNu78fx06JfCbI=

Coin Graham · Answer

The issue is not your code but your method of authentication or region.

I ran your code sample successfully:

import boto3

session = boto3.session.Session(profile_name="")
client = session.client('s3')

BUCKET_NAME = ""
file_name = ""

url = client.generate_presigned_url(
    'get_object',
    Params={'Bucket': BUCKET_NAME,
            'Key': f"products/{file_name}"},
    ExpiresIn=3600
)

print(url)

It worked fine because the region of my bucket aligned with the region of my credentials. When I tried to generate a presigned url from another region I got your same error:


InvalidRequest
The authorization mechanism you have provided is not supported. Please use AWS4-HMAC-SHA256.
JJPZYSMZTC7Z8H
TsgdZIibKxZ4GVL3h28OJYIvh59yfgeZwVf+eGPXVEzIJsAxdp1VQL67vw20LR/r9uIBxro=

Error when generating presigned url from aws s3 using boto3

1 Answers