This code is for changing the permission of all the files in an amazon S3 bucket. This program will add read permissions to all the files present in the specified S3 bucket.

ChangeBucketPermissions.py

class ChangeBucketPermissions(object):

    ##Initializer
    def __init__(self):
        self.aws_access_key = "XXXXXXXX"
        self.aws_secret_key = "XXXXXXXX"
        aws_region = 'us-east-1'
        self.s3_conn = boto.connect_s3(aws_access_key_id=self.aws_access_key,
                                   aws_secret_access_key=self.aws_secret_key,
                                   calling_format=boto.s3.connection.OrdinaryCallingFormat()))
        self.all_users = 'http://acs.amazonaws.com/groups/global/AllUsers'


    ##This method changes the permission of all files in a bucket
    def add_read_permissions(self, bucket_name):
        try:
            bucket = self.s3_conn.get_bucket(bucket_name)
            for key in bucket:
                 readable = False
                 acl = key.get_acl()
                 for grant in acl.acl.grants:
                     if grant.permission == 'READ':
                         if grant.uri == self.all_users:
                             readable = True
                 if not readable:
                     key.make_public()
        except Exception, e:
            print "Exception occurred while changing all permissions : " + str(e)