How to write a file or data to an S3 object using boto3

Question

In boto 2, you can write to an S3 object using these methods:

• Key.set_contents_from_string()
• Key.set_contents_from_file()
• Key.set_contents_from_filename()
• Key.set_contents_from_stream()

Is there a boto 3 equivalent? What is the boto3 method for saving data to an object stored on S3?

Answer 1

In boto 3, the 'Key.set_contents_from_' methods were replaced by

• Object.put()

• Client.put_object()

For example:

import boto3

some_binary_data = b'Here we have some data'
more_binary_data = b'Here we have some more data'

# Method 1: Object.put()
s3 = boto3.resource('s3')
object = s3.Object('my_bucket_name', 'my/key/including/filename.txt')
object.put(Body=some_binary_data)

# Method 2: Client.put_object()
client = boto3.client('s3')
client.put_object(Body=more_binary_data, Bucket='my_bucket_name', Key='my/key/including/anotherfilename.txt')

Alternatively, the binary data can come from reading a file, as described in the official docs comparing boto 2 and boto 3:

Storing Data

Storing data from a file, stream, or string is easy:

# Boto 2.x
from boto.s3.key import Key
key = Key('hello.txt')
key.set_contents_from_file('/tmp/hello.txt')

# Boto 3
s3.Object('mybucket', 'hello.txt').put(Body=open('/tmp/hello.txt', 'rb'))