Amazon S3 boto3 how to iterate through objects in a bucket?
You are exiting the loop by returning too early.
def list_of_files(): s3_resource = boto3.resource('s3') my_bucket = s3_resource.Bucket(S3_BUCKET) summaries = my_bucket.objects.all() files = [] for file in summaries: files.append(file.key) return jsonify({"files": files})