这个改动的原因基于两点：1）代理归还给代理池的时机应该是执行完http请求后就要尽早归还 2)http代理应该是HttpClientDownloader该考虑的事，不应该有Spider来处理，Spider并不知道它的downloader是个HttpClientDownloader

Author: zhangheng09

webmagic-core/src/main/java/us/codecraft/webmagic/Spider.java

@@ -325,10 +325,6 @@ public void run() {
                             onError(requestFinal);
                             logger.error("process request " + requestFinal + " error", e);
                         } finally {
-                            if (site.getHttpProxyPool()!=null && site.getHttpProxyPool().isEnable()) {
-                                site.returnHttpProxyToPool((HttpHost) requestFinal.getExtra(Request.PROXY), (Integer) requestFinal
-                                        .getExtra(Request.STATUS_CODE));
-                            }
                             pageCount.incrementAndGet();
                             signalNewUrl();
                         }

webmagic-core/src/main/java/us/codecraft/webmagic/downloader/HttpClientDownloader.java

@@ -109,6 +109,10 @@ public Page download(Request request, Task task) {
             return null;
         } finally {
         	request.putExtra(Request.STATUS_CODE, statusCode);
+            if (site.getHttpProxyPool()!=null && site.getHttpProxyPool().isEnable()) {
+                site.returnHttpProxyToPool((HttpHost) request.getExtra(Request.PROXY), (Integer) request
+                        .getExtra(Request.STATUS_CODE));
+            }
             try {
                 if (httpResponse != null) {
                     //ensure the connection is released back to pool