Generic framework for writing customized content spider/crawler

[howa]

Hello,

I want to write a number of content spider/crawlers to download and
analysis data from remote sites, they have different layout, data
format etc.

E.g.

Job1 : Download stock quote from Yahoo
Job2: Download weather information from weather.com
Job3: blah ...

Are there such as generic framework so that I can build my program
above it?

Thanks.