From aaaa4da7a4e1fe75396028189de88fb9a6604200 Mon Sep 17 00:00:00 2001
From: Paul Tremberth <paul.tremberth@gmail.com>
Date: Wed, 24 May 2017 12:42:54 +0200
Subject: [PATCH] Add template for a downloader middleware

---
 .../project/module/middlewares.py.tmpl        | 47 +++++++++++++++++++
 .../templates/project/module/settings.py.tmpl |  2 +-
 2 files changed, 48 insertions(+), 1 deletion(-)

diff --git a/scrapy/templates/project/module/middlewares.py.tmpl b/scrapy/templates/project/module/middlewares.py.tmpl
index 292bf572e..1a4b0caa5 100644
--- a/scrapy/templates/project/module/middlewares.py.tmpl
+++ b/scrapy/templates/project/module/middlewares.py.tmpl
@@ -54,3 +54,50 @@ class ${ProjectName}SpiderMiddleware(object):
 
     def spider_opened(self, spider):
         spider.logger.info('Spider opened: %s' % spider.name)
+
+
+class ${ProjectName}DownloaderMiddleware(object):
+    # Not all methods need to be defined. If a method is not defined,
+    # scrapy acts as if the downloader middleware does not modify the
+    # passed objects.
+
+    @classmethod
+    def from_crawler(cls, crawler):
+        # This method is used by Scrapy to create your spiders.
+        s = cls()
+        crawler.signals.connect(s.spider_opened, signal=signals.spider_opened)
+        return s
+
+    def process_request(self, request, spider):
+        # Called for each request that goes through the downloader
+        # middleware.
+
+        # Must either:
+        # - return None: continue processing this request
+        # - or return a Response object
+        # - or return a Request object
+        # - or raise IgnoreRequest: process_exception() methods of
+        #   installed downloader middleware will be called
+        return None
+
+    def process_response(self, request, response, spider):
+        # Called with the response returned from the downloader.
+
+        # Must either;
+        # - return a Response object
+        # - return a Request object
+        # - or raise IgnoreRequest
+        return response
+
+    def process_exception(self, request, exception, spider):
+        # Called when a download handler or a process_request()
+        # (from other downloader middleware) raises an exception.
+
+        # Must either:
+        # - return None: continue processing this exception
+        # - return a Response object: stops process_exception() chain
+        # - return a Request object: stops process_exception() chain
+        pass
+
+    def spider_opened(self, spider):
+        spider.logger.info('Spider opened: %s' % spider.name)
diff --git a/scrapy/templates/project/module/settings.py.tmpl b/scrapy/templates/project/module/settings.py.tmpl
index 486df6b71..35a0f9a45 100644
--- a/scrapy/templates/project/module/settings.py.tmpl
+++ b/scrapy/templates/project/module/settings.py.tmpl
@@ -53,7 +53,7 @@ ROBOTSTXT_OBEY = True
 # Enable or disable downloader middlewares
 # See http://scrapy.readthedocs.org/en/latest/topics/downloader-middleware.html
 #DOWNLOADER_MIDDLEWARES = {
-#    '$project_name.middlewares.MyCustomDownloaderMiddleware': 543,
+#    '$project_name.middlewares.${ProjectName}DownloaderMiddleware': 543,
 #}
 
 # Enable or disable extensions