如何使用boto3从s3执行凭证下载而不保存文件？

Question

It is simple to perform a credentialed download from s3 to a file using

import boto3

s3 = boto3.resource('s3')
def save_file_from_s3(bucket_name, key_name, file_name):
    b = s3.Bucket(bucket_name)
    b.download_file(key_name, file_name)

It is easy to download from s3 to a file-like object using

import from StringIO import StringIO
import urllib

file_like_object = StringIO(urllib.urlopen(url).read())

(see How do I read image data from a URL in Python? )

But how do you perform a credentialed download from s3 to a file-like object?

Answer 1

You just need to make a call to s3.Bucket.Object.get :

import boto3

s3 = boto3.resource('s3')
# obj = s3.Object(bucket_name, key_name).get()
bucket = s3.Bucket(bucket_name)
obj = bucket.Object(key_name).get()
body = obj.get('Body')