How to Build a Hypermedia Collection Resource in Python

import json
import math


class HypermediaCollection:
    """A mock hypermedia collection resource."""

    def __init__(self, items, base_url="/api/items"):
        self.items = items
        self.base_url = base_url

    def to_dict(self, page=1, per_page=3):
        total = len(self.items)
        pages = math.ceil(total / per_page) if per_page > 0 else 1
        page = max(1, min(page, pages))
        start = (page - 1) * per_page
        end = start + per_page
        page_items = self.items[start:end]

        return {
            "_links": {
                "self": {"href": f"{self.base_url}?page={page}&per_page={per_page}"},
                "first": {"href": f"{self.base_url}?page=1&per_page={per_page}"},
                "last": {"href": f"{self.base_url}?page={pages}&per_page={per_page}"},
                "next": (
                    {"href": f"{self.base_url}?page={page + 1}&per_page={per_page}"}
                    if page < pages else None
                ),
                "prev": (
                    {"href": f"{self.base_url}?page={page - 1}&per_page={per_page}"}
                    if page > 1 else None
                ),
            },
            "page": page,
            "per_page": per_page,
            "total": total,
            "total_pages": pages,
            "_embedded": {
                "items": [
                    {
                        "id": item["id"],
                        "name": item["name"],
                        "_links": {
                            "self": {"href": f"{self.base_url}/{item['id']}"}
                        },
                    }
                    for item in page_items
                ]
            },
        }


if __name__ == "__main__":
    items = [
        {"id": 1, "name": "Alpha"},
        {"id": 2, "name": "Beta"},
        {"id": 3, "name": "Gamma"},
        {"id": 4, "name": "Delta"},
    ]
    collection = HypermediaCollection(items)
    print(json.dumps(collection.to_dict(page=2), indent=2))