Python 3 Boto 3, AWS S3: Get object URL

Question

I need to retrieve an public object URL directly after uploading a file, this to be able to store it in a database. This is my upload code:

   s3 = boto3.res         


        

Answer 1

Concatenating the the raw key will fail for some special characters in the key(ex: '+'), you have to quote them:

url = "https://s3-%s.amazonaws.com/%s/%s" % (
    location,
    bucket_name,
    urllib.parse.quote(key, safe="~()*!.'"),
)

Or you can call:

my_config = Config(signature_version = botocore.UNSIGNED)
url = boto3.client("s3", config=my_config).generate_presigned_url(
    "get_object", ExpiresIn=0, Params={"Bucket": bucket_name, "Key": key}
)

...as described here.

Answer 2

There's no simple way but you can construct the URL from the region where the bucket is located (get_bucket_location), the bucket name and the storage key:

bucket_name = "my-aws-bucket"
key = "upload-file"

s3 = boto3.resource('s3')
bucket = s3.Bucket(bucket_name)
bucket.upload_file("upload.txt", key)
location = boto3.client('s3').get_bucket_location(Bucket=bucket_name)['LocationConstraint']
url = "https://s3-%s.amazonaws.com/%s/%s" % (location, bucket_name, key)

Answer 3

Just a small note. The function call

location = 
    boto3.client('s3').get_bucket_location(Bucket=bucket_name['LocationConstraint']

may return location = None if the bucket is in the region 'us-east-1'. Therefore, I'd amend the above answer and add a line below that line:

if location == None: location = 'us-east-1'

Answer 4

Since 2010 you can use a virtual-hosted style S3 url, i.e. no need to mess with region specific urls:

url = f'https://{bucket}.s3.amazonaws.com/{key}'

Moreover, support for the path-style model (region specific urls) continues for buckets created on or before September 30, 2020. Buckets created after that date must be referenced using the virtual-hosted model.

See also this blog post.