Notion page duplication requires recursive blocks population and extra tricks to duplicate images. Hope this example will help someone who also struggle with notion API.

Notion duplicate page script example (python)

import logging
import os

from io import BytesIO

import boto3
import click
import requests


logger = logging.getLogger(__name__)


s3 = boto3.client("s3")
# should be created manually and configured for public access
S3_BUCKET = "notion-images-for-page-duplication"


def request(request_func, *args, **kwargs):
    """Simple wrapper for requests with error handling"""
    try:
        response = request_func(*args, **kwargs)
        response.raise_for_status()
    except requests.exceptions.RequestException as e:
        click.echo(args)
        click.echo(kwargs)
        click.echo(response.content)
        raise e
    return response


def upload_from_url_to_s3(url):
    """Download file to memory and upload to s3 with original filename"""
    response = request(requests.get, url)
    file_name = url.split("/")[-1].split("?")[0]
    s3.upload_fileobj(
        BytesIO(response.content),
        S3_BUCKET,
        file_name,
        ExtraArgs={"ACL": "public-read"},
    )
    bucket_location = s3.get_bucket_location(Bucket=S3_BUCKET)["LocationConstraint"]
    return f"https://s3-{bucket_location}.amazonaws.com/{S3_BUCKET}/{file_name}"


def recursive_block_creation(original_blocks, new_blocks, headers, depth=0):
    """
    Recursively populate child blocks for a given lists of original blocks and new blocks
    """
    blocks_count = len(original_blocks)
    for i, (block, new_block) in enumerate(zip(original_blocks, new_blocks)):
        click.echo(f"{'    ' * depth}Block depth={depth} {i}/{blocks_count}")
        if not block.get("has_children"):
            continue

        # Get child blocks

        block_id = block["id"]
        new_block_id = new_block["id"]
        response = request(
            requests.get,
            f"https://api.notion.com/v1/blocks/{block_id}/children",
            headers=headers,
        )
        children = response.json()["results"]

        # Redefine image blocks.
        # It's not possible to use notion image url for creating new image blocks
        # https://developers.notion.com/reference/file-object#externally-hosted-files-vs-files-hosted-by-notion
        # Workaround: use upload_from_url_to_s3 to download images from notion and upload them to s3 instead
        # so that we can use s3 public link as extarnal for notion block creation
        children = [
            {
                "type": "image",
                "image": {
                    "external": {
                        "url": upload_from_url_to_s3(child["image"]["file"]["url"])
                    }
                },
            }
            if child["type"] == "image"
            else child
            for child in children
        ]

        # Append child blocks to a specific block

        response = request(
            requests.patch,
            f"https://api.notion.com/v1/blocks/{new_block_id}/children",
            json={"children": children},
            headers=headers,
        )
        new_children = response.json()["results"]

        recursive_block_creation(children, new_children, headers, depth=depth + 1)


@click.command()
@click.option(
    "--new_title", help="New title for a page", required=False,
)
@click.option(
    "--from_page_id", help="Specify page id to copy", required=False,
)
@click.option(
    "--parent_page_id", help="Specify which page will be used as parent", required=False,
)
def duplicate_notion_page(new_title, from_page_id, parent_page_id):
    NOTION_API_KEY = os.environ.get("NOTION_API_KEY")

    if not NOTION_API_KEY:
        raise click.UsageError("NOTION_API_KEY env variable not set")

    headers = {
        "Authorization": f"Bearer {NOTION_API_KEY}",
        "Notion-Version": "2021-08-16",
        "Content-Type": "application/json",
    }

    # Get template blocks

    response = request(
        requests.get,
        f"https://api.notion.com/v1/blocks/{from_page_id}/children?page_size=100",
        headers=headers,
    )

    root_blocks = response.json()["results"]

    # Create a new page from template with root blocks

    response = request(
        requests.post,
        "https://api.notion.com/v1/pages",
        json={
            "parent": {"page_id": parent_page_id},
            "properties": {
                "title": [{"text": {"content": new_title}}]
            },
            "children": root_blocks,
        },
        headers=headers,
    )
    response_data = response.json()
    new_page_url = response_data["url"]
    new_page_id = response_data["id"]

    # Retrieve new blocks from the new page

    response = request(
        requests.get,
        f"https://api.notion.com/v1/blocks/{new_page_id}/children?page_size=100",
        headers=headers,
    )
    new_root_blocks = response.json()["results"]

    # Populate nested blocks

    recursive_block_creation(root_blocks, new_root_blocks, headers)

    # Done
    # Usage example:
    # `export NEW_PAGE_URL=$(script.py duplicate-notion-page --new_title ... | tail -1 )`
    click.echo(new_page_url)