How do I upload a file into an Amazon S3 signed url with python?-CodePudding

I have managed to generate an Amazon S3 Signed URL with boto3.

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")

assuming bucket123 exists. This code returns me a URL like this:

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

My question is:

Using python and boto3, is it possible to upload a file in this pre-signed url? How do I go on about this?

CodePudding user response：

Once you have the pre-signed url, you don't need boto3 at all. Instead you can use regular python functions for uploading files to S3. For example using python's requests. Also you should be using 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}')