修改engine，兼容基类

baid_spider/core/downloader.py

@@ -1,3 +1,5 @@
+import time
+
 import requests
 
 
@@ -7,5 +9,8 @@ class Downloader:
         pass
 
     def download(self,url):
-        response = requests.get(url)
-        print(response)
+        # response = requests.get(url)
+        # print(response)
+
+        time.sleep(0.1)
+        print('aaaa')

baid_spider/core/engine.py

@@ -1,10 +1,18 @@
+from typing import Optional,Generator
 from baid_spider.core.downloader import Downloader
 
 class Engine:
 
     def __init__(self):
-        self.downloader = Downloader()
+        self.downloader :Optional[Downloader] = Downloader()
+        self.start_requests: Optional[Generator] = None
 
     def start_spider(self,spider):
-        start_url = spider.start_requests()
-        self.downloader.download(start_url)
+        self.start_requests = iter(spider.start_requests())
+        self.crawl()
+        #self.downloader.download(start_url)
+
+    def crawl(self):
+        '''主逻辑'''
+        start_request = next(self.start_requests)
+        self.downloader.download(start_request)

baid_spider/spider/__init__.py

@@ -8,7 +8,7 @@ class Spider:
     def start_requests(self):
         if self.start_urls:
             for url in self.start_urls:
-                return url
+                yield url
         else:
             if hasattr(self,'start_url') and isinstance(getattr(self,'start_url'),str):
-                return  getattr(self,'start_url')
+                yield  getattr(self,'start_url')

test/baidu_spider/baidu.py

@@ -1,7 +1,7 @@
 from baid_spider.spider import Spider
 class Baidu_Spider(Spider):
 
-    start_urls = ['https://www.baidu.com']
+    start_urls = ['https://www.baidu.com','https://www.baidu.com']
 
     # def start_requests(self):
     #