Is it possible to access stats from pipeline for a particular Spider in Scrapy?

Question

I am using Scrapy with several Spiders, and need custom json output, that would include some Spider stats (list of successful requests, list of errors, etc). I have made custom item pipeline, but I don't know how to access stats from there. This is my pipeline code so far:

class JsonWithEncodingPipeline(object):

    def open_spider(self, spider):
        self.file = codecs.open(spider.output_path, 'w', encoding='utf-8')

    def process_item(self, item, spider):
        line = json.dumps(dict(item), ensure_ascii=False, indent=2) + "\n"
        self.file.write(line)
        return item

    def spider_closed(self, spider):
        self.file.close()

Answer 1

You can access stats like this:

class MyPipeline:

    def __init__(self, stats):
        self.stats = stats

    @classmethod
    def from_crawler(cls, crawler):
        return cls(crawler.stats)