From e5b23f4b00962df76d8302ebf869ef4a4319e142 Mon Sep 17 00:00:00 2001
From: BroodingKangaroo <johngolt33@gmail.com>
Date: Wed, 18 Mar 2020 11:26:59 +0300
Subject: [PATCH] fix #4250: add batch deliveries

---
 scrapy/extensions/feedexport.py     | 54 +++++++++++++++++++++--------
 scrapy/settings/default_settings.py |  1 +
 2 files changed, 41 insertions(+), 14 deletions(-)

diff --git a/scrapy/extensions/feedexport.py b/scrapy/extensions/feedexport.py
index 998d2a5d1..906f99fee 100644
--- a/scrapy/extensions/feedexport.py
+++ b/scrapy/extensions/feedexport.py
@@ -241,6 +241,7 @@ class FeedExporter:
 
         self.storages = self._load_components('FEED_STORAGES')
         self.exporters = self._load_components('FEED_EXPORTERS')
+        self.storage_batch = self.settings.getint('FEED_STORAGE_BATCH')
         for uri, feed in self.feeds.items():
             if not self._storage_supported(uri):
                 raise NotConfigured
@@ -250,19 +251,7 @@ class FeedExporter:
     def open_spider(self, spider):
         for uri, feed in self.feeds.items():
             uri = uri % self._get_uri_params(spider, feed['uri_params'])
-            storage = self._get_storage(uri)
-            file = storage.open(spider)
-            exporter = self._get_exporter(
-                file=file,
-                format=feed['format'],
-                fields_to_export=feed['fields'],
-                encoding=feed['encoding'],
-                indent=feed['indent'],
-            )
-            slot = _FeedSlot(file, exporter, storage, uri, feed['format'], feed['store_empty'])
-            self.slots.append(slot)
-            if slot.store_empty:
-                slot.start_exporting()
+            self.slots.append(self._start_new_batch(None, uri, feed, spider))
 
     def close_spider(self, spider):
         deferred_list = []
@@ -285,11 +274,48 @@ class FeedExporter:
             deferred_list.append(d)
         return defer.DeferredList(deferred_list) if deferred_list else None
 
+    def _start_new_batch(self, previous_batch_slot, uri, feed, spider):
+        """
+        Redirect the output data stream to a new file.
+        Execute multiple times if 'FEED_STORAGE_BATCH' setting is greater than zero.
+        """
+        if previous_batch_slot is not None:
+            previous_batch_slot.exporter.finish_exporting()
+            previous_batch_slot.storage.store(previous_batch_slot.file)
+        storage = self._get_storage(uri)
+        file = storage.open(spider)
+        exporter = self._get_exporter(
+            file=file,
+            format=feed['format'],
+            fields_to_export=feed['fields'],
+            encoding=feed['encoding'],
+            indent=feed['indent']
+        )
+        slot = _FeedSlot(file, exporter, storage, uri, feed['format'], feed['store_empty'])
+        if slot.store_empty:
+            slot.start_exporting()
+        return slot
+
+    def _get_uri_of_partial(self, slot, feed, spider):
+        """Get uri for each partial using datetime.now().isoformat()"""
+        uri = (slot.uri % self._get_uri_params(spider, feed['uri_params'])).split('.')[0] + '.'
+        uri = uri + datetime.now().isoformat() + '.' + feed['format']
+        return uri
+
     def item_scraped(self, item, spider):
-        for slot in self.slots:
+        slots = []
+        for idx, slot in enumerate(self.slots):
             slot.start_exporting()
             slot.exporter.export_item(item)
             slot.itemcount += 1
+            if self.storage_batch and slot.itemcount % self.storage_batch == 0:
+                uri = self._get_uri_of_partial(slot, self.feeds[slot.uri], spider)
+                slots.append(self._start_new_batch(slot, uri, self.feeds[slot.uri], spider))
+                self.feeds[uri] = self.feeds[slot.uri]
+                self.feeds.pop(slot.uri)
+                self.slots[idx] = None
+        self.slots = [slot for slot in self.slots if slot is not None]
+        self.slots.extend(slots)
 
     def _load_components(self, setting_prefix):
         conf = without_none_values(self.settings.getwithbase(setting_prefix))
diff --git a/scrapy/settings/default_settings.py b/scrapy/settings/default_settings.py
index 077317c81..690e044c5 100644
--- a/scrapy/settings/default_settings.py
+++ b/scrapy/settings/default_settings.py
@@ -146,6 +146,7 @@ FEED_STORAGES_BASE = {
     's3': 'scrapy.extensions.feedexport.S3FeedStorage',
     'ftp': 'scrapy.extensions.feedexport.FTPFeedStorage',
 }
+FEED_STORAGE_BATCH = 0
 FEED_EXPORTERS = {}
 FEED_EXPORTERS_BASE = {
     'json': 'scrapy.exporters.JsonItemExporter',