如何将文件上传到Amazon S3签名url ?

Question

我已经成功地用boto3生成了一个Amazon S3签名URL。

import logging
import boto3
from botocore.exceptions import ClientError
def create_presigned_url(bucket_name, object_name, expiration=3600):
"""Generate a presigned URL to share an S3 object
:param bucket_name: string
:param object_name: string
:param expiration: Time in seconds for the presigned URL to remain valid - 1 hour in this case
:return: Presigned URL as string. If error, returns None.
"""
# Generate a presigned URL for the S3 object
s3_client = boto3.client('s3')
try:
response = s3_client.generate_presigned_url('get_object', Params={'Bucket': bucket_name, 'Key': object_name}, ExpiresIn=expiration)
except ClientError as e:
logging.error(e)
return None
# The response contains the presigned URL
return response
result = create_presigned_url("bucket123", "test.txt")

假设bucket123存在。这段代码返回一个URL，如下所示:

https://bucket123.s3.amazonaws.com/test.txt?AWSAccessKeyId=AKIA56EZ34KPFKO5366J&Signature=7aAZXXDwtvKGLaeu1ATHRJuaFCs%3D&Expires=1635117707

我的问题是:

使用python和boto3，是否可以在此预签名url中上传文件?我要怎么继续说下去?

Answer 1

一旦有了预签名url，就根本不需要boto3了。相反，您可以使用常规python函数将文件上传到S3。例如使用python的请求。你还应该使用generate_presigned_post

def create_presigned_post(bucket_name, object_name,
fields=None, conditions=None, expiration=3600):
"""Generate a presigned URL S3 POST request to upload a file
:param bucket_name: string
:param object_name: string
:param fields: Dictionary of prefilled form fields
:param conditions: List of conditions to include in the policy
:param expiration: Time in seconds for the presigned URL to remain valid
:return: Dictionary with the following keys:
url: URL to post to
fields: Dictionary of form fields and values to submit with the POST
:return: None if error.
"""
# Generate a presigned S3 POST URL
s3_client = boto3.client('s3')
try:
response = s3_client.generate_presigned_post(bucket_name,
object_name,
Fields=fields,
Conditions=conditions,
ExpiresIn=expiration)
except ClientError as e:
logging.error(e)
return None
# The response contains the presigned URL and required fields
return response
result = create_presigned_post("bucket123", "test.txt")

import requests    # To install: pip install requests
# Generate a presigned S3 POST URL
object_name = 'test.txt'
result = create_presigned_post("marcin3", object_name)
# Demonstrate how another Python program can use the presigned URL to upload a file
with open(object_name, 'rb') as f:
files = {'file': (object_name, f)}
http_response = requests.post(result['url'], data=result['fields'], files=files)
# If successful, returns HTTP status code 204
logging.info(f'File upload HTTP status code: {http_response.status_code}')