mirror of https://github.com/scrapy/scrapy.git
124 lines
4.2 KiB
Python
124 lines
4.2 KiB
Python
import re
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import datetime
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import decimal
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import json
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from twisted.internet import defer
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from scrapy.spider import BaseSpider
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from scrapy.http import Request, Response
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from scrapy.item import BaseItem
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class SpiderReferencer(object):
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"""Class to serialize (and deserialize) objects (typically dicts)
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containing references to running spiders (ie. Spider objects). This is
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required because json library fails to serialize dicts containing
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non-primitive types as keys, even when you override
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ScrapyJSONEncoder.default() with a custom encoding mechanism.
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"""
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spider_ref_re = re.compile('^spider:([0-9a-f]+)?:?(.+)?$')
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def __init__(self, crawler):
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self.crawler = crawler
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def get_reference_from_spider(self, spider):
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return 'spider:%x:%s' % (id(spider), spider.name)
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def get_spider_from_reference(self, ref):
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"""Returns the Spider referenced by text, if text is a spider
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reference. Otherwise it returns the text itself. If the text references
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a non-running spider it raises a RuntimeError.
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"""
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m = self.spider_ref_re.search(ref)
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if m:
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spid, spname = m.groups()
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for spider in self.crawler.engine.open_spiders:
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if "%x" % id(spider) == spid or spider.name == spname:
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return spider
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raise RuntimeError("Spider not running: %s" % ref)
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return ref
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def encode_references(self, obj):
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"""Look for Spider objects and replace them with spider references"""
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if isinstance(obj, BaseSpider):
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return self.get_reference_from_spider(obj)
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elif isinstance(obj, dict):
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d = {}
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for k, v in obj.items():
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k = self.encode_references(k)
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v = self.encode_references(v)
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d[k] = v
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return d
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elif isinstance(obj, (list, tuple)):
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return [self.encode_references(x) for x in obj]
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else:
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return obj
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def decode_references(self, obj):
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"""Look for spider references and replace them with Spider objects"""
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if isinstance(obj, basestring):
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return self.get_spider_from_reference(obj)
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elif isinstance(obj, dict):
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d = {}
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for k, v in obj.items():
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k = self.decode_references(k)
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v = self.decode_references(v)
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d[k] = v
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return d
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elif isinstance(obj, (list, tuple)):
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return [self.decode_references(x) for x in obj]
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else:
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return obj
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class ScrapyJSONEncoder(json.JSONEncoder):
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DATE_FORMAT = "%Y-%m-%d"
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TIME_FORMAT = "%H:%M:%S"
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def __init__(self, *a, **kw):
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crawler = kw.pop('crawler', None)
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self.spref = kw.pop('spref', None) or SpiderReferencer(crawler)
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super(ScrapyJSONEncoder, self).__init__(*a, **kw)
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def encode(self, o):
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if self.spref:
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o = self.spref.encode_references(o)
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return super(ScrapyJSONEncoder, self).encode(o)
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def default(self, o):
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if isinstance(o, datetime.datetime):
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return o.strftime("%s %s" % (self.DATE_FORMAT, self.TIME_FORMAT))
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elif isinstance(o, datetime.date):
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return o.strftime(self.DATE_FORMAT)
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elif isinstance(o, datetime.time):
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return o.strftime(self.TIME_FORMAT)
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elif isinstance(o, decimal.Decimal):
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return str(o)
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elif isinstance(o, defer.Deferred):
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return str(o)
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elif isinstance(o, BaseItem):
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return dict(o)
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elif isinstance(o, Request):
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return "<%s %s %s>" % (type(o).__name__, o.method, o.url)
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elif isinstance(o, Response):
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return "<%s %s %s>" % (type(o).__name__, o.status, o.url)
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else:
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return super(ScrapyJSONEncoder, self).default(o)
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class ScrapyJSONDecoder(json.JSONDecoder):
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def __init__(self, *a, **kw):
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crawler = kw.pop('crawler', None)
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self.spref = kw.pop('spref', None) or SpiderReferencer(crawler)
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super(ScrapyJSONDecoder, self).__init__(*a, **kw)
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def decode(self, s):
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o = super(ScrapyJSONDecoder, self).decode(s)
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if self.spref:
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o = self.spref.decode_references(o)
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return o
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