basic feed rebuilding

repub/pipelines.py

@@ -0,0 +1,84 @@
+# Define your item pipelines here
+#
+# Don't forget to add your pipeline to the ITEM_PIPELINES setting
+# See: https://docs.scrapy.org/en/latest/topics/item-pipeline.html
+
+
+# useful for handling different item types with a single interface
+# from itemadapter import ItemAdapter
+import six
+from scrapy import signals
+from scrapy.exceptions import NotConfigured, CloseSpider
+from scrapy.utils.misc import load_object
+
+from .items import RssItem
+from .exporters import RssItemExporter
+
+from .signals import feed_channel_discovered
+
+
+class RssExportPipeline(object):
+    def __init__(self):
+        self.files = {}
+        self.exporters = {}
+
+    @classmethod
+    def from_crawler(cls, crawler):
+        pipeline = cls()
+        crawler.signals.connect(pipeline.spider_closed, signals.spider_closed)
+        crawler.signals.connect(
+            pipeline.feed_channel_discovered, feed_channel_discovered
+        )
+        return pipeline
+
+    def feed_channel_discovered(self, spider, feed, channel):
+        try:
+            file = open(spider.settings.get("FEED_FILE"), "wb")
+        except TypeError:
+            raise NotConfigured("FEED_FILE parameter does not string or does not exist")
+        except (IOError, OSError) as e:
+            raise CloseSpider(
+                "Cannot open file {}: {}".format(
+                    spider.settings.get("FEED_FILE", None), e
+                )
+            )
+        self.files[spider] = file
+
+        item_cls = spider.settings.get(
+            "FEED_ITEM_CLASS", spider.settings.get("FEED_ITEM_CLS", RssItem)
+        )
+        if isinstance(item_cls, six.string_types):
+            item_cls = load_object(item_cls)
+
+        namespaces = spider.settings.get("FEED_NAMESPACES", {})
+
+        feed_exporter = spider.settings.get("FEED_EXPORTER", RssItemExporter)
+        if isinstance(feed_exporter, six.string_types):
+            feed_exporter = load_object(feed_exporter)
+        if not issubclass(feed_exporter, RssItemExporter):
+            raise TypeError(
+                "FEED_EXPORTER must be RssItemExporter or its subclass, not '{}'".format(
+                    feed_exporter
+                )
+            )
+        self.exporters[spider] = feed_exporter(
+            file,
+            channel,
+            namespaces=namespaces,
+            item_cls=item_cls,
+        )
+        self.exporters[spider].start_exporting()
+
+    def spider_closed(self, spider):
+        self.exporters[spider].finish_exporting()
+        file = self.files.pop(spider)
+        file.close()
+
+    def process_item(self, item, spider):
+        self.exporters[spider].export_item(item)
+        return item
+
+
+class RepubPipeline:
+    def process_item(self, item, spider):
+        return item