topscrape 0.1.4

Declarative, resilient, and typed web scraping with Pydantic and selector fallback chains.

topscrape

📖 Landing Page  ·  📦 PyPI  ·  🐛 Issues

Declarative, resilient, and typed web scraping.
Define what you want — topscrape figures out how to get it, even when the site changes.

---

✨ Why topscrape?

Scrapers break when websites update their HTML. Fixing them means hunting down changed CSS selectors — tedious, repetitive, and always at the worst time.

❌ Standard approach — brittle

soup = BeautifulSoup(html, "html.parser")
price = soup.select_one(".price")
if not price:
    price = soup.select_one(".cost")

Manual fallback. Manual debugging. Constant maintenance.

---

✅ The topscrape Approach

from topscrape import ScraperModel, Field

class Product(ScraperModel):
    title: str = Field(selectors=["h1.title", "h1"])
    price: float = Field(
        selectors=[".product-price", "[data-price]", "//span[@itemprop='price']"],
        transform=lambda v: v.replace("$", "").replace(",", ""),
    )
    image: str = Field(selectors=["img.hero"], attr="src", default="")

product = Product.from_url("https://example.com/item/1")
print(product.price)

If .product-price disappears but [data-price] still works:

1. topscrape returns the correct value
2. Emits a Selector Drift Warning
3. Keeps your scraper alive

That’s resilience by design.

---

🚀 Features

Feature	Description
Declarative models	Define fields with Field(selectors=[...])
Selector chains	CSS → XPath → Regex fallback
Drift detection	Warns before total breakage
Pydantic validation	Strong typing enforced
Transforms	Clean data before validation
Async ready	from_url_async() supported
CLI included	Quick one-off extraction

---

📦 Installation

pip install topscrape

Requires Python 3.9+.

---

⚡ Quick Start

Google Colab Example - Link

Basic Extraction

from topscrape import ScraperModel, Field

class Article(ScraperModel):
    title: str = Field(selectors=["h1", ".article-title"])
    author: str = Field(selectors=[".byline", "[rel='author']"], default="Unknown")
    content: str = Field(selectors=["article p", ".body-text"])

article = Article.from_html(html_string)
print(article.title)

---

Fetch From URL

product = Product.from_url("https://example.com/item/1")
print(product.title)

---

Async Usage

import asyncio

async def main():
    product = await Product.from_url_async("https://example.com/item/1")
    print(product.price)

asyncio.run(main())

---

Multiple Values

class Page(ScraperModel):
    tags: list[str] = Field(selectors=[".tag"], multiple=True)
    links: list[str] = Field(selectors=["nav a"], multiple=True, attr="href")

---

🛡 Drift Detection

If a fallback selector fires:

UserWarning: [Selector Drift] Field 'price':
primary selector '.product-price' failed;
used fallback '[data-price]'.

Catch programmatically:

import warnings
from topscrape import SelectorDriftWarning

with warnings.catch_warnings(record=True) as w:
    warnings.simplefilter("always")
    product = Product.from_url(url)

drifted = [x for x in w if issubclass(x.category, SelectorDriftWarning)]

---

🖥 CLI Usage

topscrape https://example.com "title"
topscrape https://example.com ".price" "[data-price]"
topscrape https://example.com "a.buy-link" --attr href
topscrape https://example.com "li.feature" --all
topscrape https://example.com "h1" --json

---

🧩 API Reference

Field

Parameter	Description
selectors	Ordered CSS / XPath / Regex list
attr	Attribute to extract
transform	Pre-validation function
default	Fallback value
multiple	Return all matches

ScraperModel

Method	Description
from_html	Parse raw HTML
from_url	Fetch & parse (sync)
from_url_async	Fetch & parse (async)
from_selector	Parse existing selector

---

👨‍💻 Developer Guide — Run & Contribute via GitHub

Want to run topscrape locally or contribute improvements? Follow this streamlined workflow.

---

🍴 1. Fork the Repository

1. Go to: https://github.com/ronaldgosso/topscrape
2. Click Fork
3. Clone your fork

---

📥 2. Clone Your Fork

git clone https://github.com/<your-username>/topscrape.git
cd topscrape

Add upstream:

git remote add upstream https://github.com/ronaldgosso/topscrape.git

Sync later with:

git fetch upstream
git merge upstream/main

---

🐍 3. Create Virtual Environment

python -m venv .venv

Activate:

Mac/Linux

source .venv/bin/activate

Windows

.venv\Scripts\activate

---

📦 4. Install in Editable Mode

pip install -e ".[dev]"

Editable mode ensures changes apply instantly.

---

🧪 5. Run Tests

pytest

No green tests, no merge.

---

🧹 6. Lint & Type Check

ruff check .
black .
mypy topscrape/

Clean, typed, consistent.

---

🌿 7. Create Feature Branch

git checkout -b feature/your-feature

Never commit directly to main.

---

💾 8. Commit Properly

git commit -m "feat: improve fallback logging"

Conventional commit prefixes:

• feat:
• fix:
• docs:
• refactor:
• test:

---

🚀 9. Push & Open Pull Request

git push origin feature/your-feature

Then open a Pull Request against ronaldgosso/main.

---

🧠 Development Principles

topscrape prioritizes:

• Resilience over cleverness
• Declarative design
• Type safety
• Drift transparency

Every contribution should reduce brittleness.

---

🏆 Contribution Standards

Pull requests must:

• Pass CI
• Include tests (if applicable)
• Maintain backward compatibility
• Follow existing style

Quality > Speed.

---

📄 License

MIT © Ronald Isack Gosso