ruia 0.3.3

An async web scraping micro-framework based on asyncio.

Overview

An async web scraping micro-framework, written with asyncio and aiohttp, aims to make crawling url as convenient as possible.

Write less, run faster:

• Documentation: 中文文档 |documentation

• Plugins: https://github.com/ruia-plugins

Features

• Easy: Declarative programming

• Fast: Powered by asyncio

• Extensible: Middlewares and plugins

• Powerful: JavaScript support

Installation

# For Linux & Mac
pip install -U ruia[uvloop]

# For Windows
pip install -U ruia

# New features
pip install git+https://github.com/howie6879/ruia

Tutorials

1. Overview

2. Installation

3. Define Data Items

4. Spider Control

5. Request & Response

6. Customize Middleware

7. Write a Plugins

Usage

Item

Item can be used standalone, for testing, and for tiny crawlers.

import asyncio

from ruia import AttrField, TextField, Item


class HackerNewsItem(Item):
    target_item = TextField(css_select='tr.athing')
    title = TextField(css_select='a.storylink')
    url = AttrField(css_select='a.storylink', attr='href')

items = asyncio.run(HackerNewsItem.get_items(url="https://news.ycombinator.com/"))
for item in items:
    print(item.title, item.url)

Run: python demo.py

Notorious ‘Hijack Factory’ Shunned from Web https://krebsonsecurity.com/2018/07/notorious-hijack-factory-shunned-from-web/
 ......

Spider Control

Spider is used for control requests better. Spider supports concurrency control, which is very important for spiders.

import aiofiles

from ruia import AttrField, TextField, Item, Spider


class HackerNewsItem(Item):
    target_item = TextField(css_select='tr.athing')
    title = TextField(css_select='a.storylink')
    url = AttrField(css_select='a.storylink', attr='href')

    async def clean_title(self, value):
        """Define clean_* functions for data cleaning"""
        return value.strip()


class HackerNewsSpider(Spider):
    start_urls = [f'https://news.ycombinator.com/news?p={index}' for index in range(1, 3)]

    async def parse(self, response):
        items = await HackerNewsItem.get_items(html=response.html)
        for item in items:
            async with aiofiles.open('./hacker_news.txt', mode='a', encoding='utf-8') as f:
                await f.write(item.title + '\n')


if __name__ == '__main__':
    HackerNewsSpider.start()

Run hacker_news_spider.py:

[2018-09-21 17:27:14,497]-ruia-INFO  spider::l54: Spider started!
[2018-09-21 17:27:14,502]-Request-INFO  request::l77: <GET: https://news.ycombinator.com/news?p=2>
[2018-09-21 17:27:14,527]-Request-INFO  request::l77: <GET: https://news.ycombinator.com/news?p=1>
[2018-09-21 17:27:16,388]-ruia-INFO  spider::l122: Stopping spider: ruia
[2018-09-21 17:27:16,389]-ruia-INFO  spider::l68: Total requests: 2
[2018-09-21 17:27:16,389]-ruia-INFO  spider::l71: Time usage: 0:00:01.891688
[2018-09-21 17:27:16,389]-ruia-INFO  spider::l72: Spider finished!

Custom middleware

ruia provides an easy way to customize requests.

The following middleware is based on the above example:

from ruia import Middleware

middleware = Middleware()


@middleware.request
async def print_on_request(request):
    request.metadata = {
        'index': request.url.split('=')[-1]
    }
    print(f"request: {request.metadata}")
    # Just operate request object, and do not return anything.


@middleware.response
async def print_on_response(request, response):
    print(f"response: {response.metadata}")

# Add HackerNewsSpider

if __name__ == '__main__':
    HackerNewsSpider.start(middleware=middleware)

JavaScript Support

You can load js by using ruia-pyppeteer.

For example:

import asyncio

from ruia_pyppeteer import PyppeteerRequest as Request

request = Request("https://www.jianshu.com/", load_js=True)
response = asyncio.run(request.fetch()) # Python 3.7
print(response.html)

TODO

• Cache for debug, to decreasing request limitation

• Distributed crawling/scraping

Contribution

Ruia is still under developing, feel free to open issues and pull requests:

• Report or fix bugs

• Require or publish plugins

• Write or fix documentation

• Add test cases

Thanks

• sanic

• demiurge