Scrapy 1.2.0 发布，web 爬虫框架

Scrapy 1.2.0 发布了。

Scrapy 是一套基于基于Twisted的异步处理框架，纯python实现的爬虫框架，用户只需要定制开发几个模块就可以轻松的实现一个爬虫，用来抓取网页内容以及各种图片。

New FEED_EXPORT_ENCODING setting to customize the encoding used when writing items to a file. This can be used to turn off \uXXXX escapes in JSON output. This is also useful for those wanting something else than UTF-8 for XML or CSV output (#2034).
startproject command now supports an optional destination directory to override the default one based on the project name (#2005).
New SCHEDULER_DEBUG setting to log requests serialization failures (#1610).
JSON encoder now supports serialization of set instances (#2058).
Interpret application/json-amazonui-streaming as TextResponse (#1503).
scrapy is imported by default when using shell tools (shell,inspect_response) (#2248).

DefaultRequestHeaders middleware now runs before UserAgent middleware (#2088). Warning: this is technically backwards incompatible, though we consider this a bug fix.
HTTP cache extension and plugins that use the .scrapy data directory now work outside projects (#1581). Warning: this is technically backwards incompatible, though we consider this a bug fix.
Selector does not allow passing both response and text anymore (#2153).
Fixed logging of wrong callback name with scrapy parse (#2169).
Fix for an odd gzip decompression bug (#1606).
Fix for selected callbacks when using CrawlSpider with scrapy parse(#2225).
Fix for invalid JSON and XML files when spider yields no items (#872).
Implement flush() for StreamLogger avoiding a warning in logs (#2125).