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什么是ETag？ETag作用有哪些

ETag是HTTP头的一部分，它是一个字符串标识一个web资源的特定版本。它由web服务器生成，用于标识文件的实体标签。ETag可以用来确定同一资源是否已被修改，这在缓存和验证客户端缓存文件是否过期时很有用。ETag的作用如下： 1.缓存控制：在HTTP响应头部中包含ETag可以帮助浏览器缓存和验证资源。如果资源没有发生任何改变，浏览器可以直接从本地缓存中获取资源，而不需要重新从服务器获取。 2.资源验证：如果浏览器的缓存过期或需要更新，它可以使用请求头中的ETag来验证资源是否已被修改。如果资源没有被修改，服务器可以发送一个响应代码为304的响应，告诉浏览器它可以继续使用缓存中的资源。 3.负载均衡：在使用多个Web服务器负载均衡时，ETag可以确保客户端的请求被重定向到与其之前请求相同的服务器。如果不使用ETag，则可能会发生客户端请求一个资源，但它需要从新的服务器获取，即使其他服务器已经有缓存。

Public @ 2023-06-10 23:50:20

百度站长平台《VIP大讲堂》上海开讲

百度站长平台《VIP大讲堂》已在北京连续举办两期，收获颇多赞誉，为了让更多城市的VIP成员享受到此项特权，10月31日，《VIP大讲堂》走进上海百度办公室，来自携程、大众点评、前程无忧、返利网等30余家上海及周边城市的VIP俱乐部成员，现场聆听百度站长平台高级工程师孙权讲解《如何建设对百度Spider友好的站点》，全程2个多小时的讲解、互动、问答，大家仍然表示意犹未尽。孙工从百度Spider抓取、

Public @ 2019-11-21 16:07:26

站点流量或品牌词排名下降怎么办？

网站流量和排名问题是由多种原因引起的，例如网站使用特殊优化手段、网站关闭等因素。如您站没有使用，同时在品牌词下的排名异常，请填写网站品牌词或可确切体现寻找您网站内信息的关键词，及其对应的url地址。注：品牌词：能明确寻找某个网站的关键词。例如：www.baidu.com对应的品牌词为“百度”。泛需求词：可指向多个网站的关键词。来源：百度搜索资源平台

Public @ 2016-09-24 16:08:10

站点地图分类

1、sitemap（sitemap.xml，sitemap.txt）这一类站点地图包含了该网站的所有连接，一般提交给爬虫去爬。让搜索引擎去收录网站内容。2、站点导航，主要是面向访问网站的用户。将网站连接分类，整理后展现在用户面前。

Public @ 2013-10-14 16:11:50

什么是ETag？ETag作用有哪些

ETag是HTTP协议提供的一种用于判断资源是否发生变化的机制。ETag是一个字符串，由服务器生成，在资源被更新时会发生变化。客户端请求资源时，服务器会将资源的ETag值一起返回，客户端可以缓存资源，并记录ETag值。当客户端再次请求该资源时，会将上次记录的ETag值一同发送给服务器。如果此时服务器返回的ETag值与客户端记录的值相同，就说明资源没有变化，客户端可以直接使用缓存的资源，减少网络请求

Public @ 2023-03-25 23:50:19

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[ DB ] CONNECT:[ UseTime:0.021682s ] mysql:dbname=briline.net;host=106.14.77.182;port=3306;charset=utf8
[ SQL ] SHOW COLUMNS FROM `ob_config` [ RunTime:0.015573s ]
[ SQL ] SELECT * FROM `ob_config` [ RunTime:0.014636s ]
[ EXPLAIN : array ( 'id' => 1, 'select_type' => 'SIMPLE', 'table' => 'ob_config', 'type' => 'ALL', 'possible_keys' => NULL, 'key' => NULL, 'key_len' => NULL, 'ref' => NULL, 'rows' => 25, 'extra' => NULL, ) ]
[ SQL ] SHOW COLUMNS FROM `ob_hook` [ RunTime:0.015549s ]
[ SQL ] SELECT `id`,`name`,`addon_list` FROM `ob_hook` [ RunTime:0.014528s ]
[ EXPLAIN : array ( 'id' => 1, 'select_type' => 'SIMPLE', 'table' => 'ob_hook', 'type' => 'ALL', 'possible_keys' => NULL, 'key' => NULL, 'key_len' => NULL, 'ref' => NULL, 'rows' => 3, 'extra' => NULL, ) ]
[ SQL ] SHOW COLUMNS FROM `ob_article` [ RunTime:0.015593s ]
[ SQL ] SELECT * FROM `ob_article` WHERE `id` = 8735 LIMIT 1 [ RunTime:0.014712s ]
[ EXPLAIN : array ( 'id' => 1, 'select_type' => 'SIMPLE', 'table' => 'ob_article', 'type' => 'const', 'possible_keys' => 'PRIMARY', 'key' => 'PRIMARY', 'key_len' => '4', 'ref' => 'const', 'rows' => 1, 'extra' => NULL, ) ]
[ SQL ] select * from `ob_article_tongji` where category_id=12 and mark_type='cate' order by times desc limit 15 [ RunTime:0.014918s ]
[ EXPLAIN : array ( 'id' => 1, 'select_type' => 'SIMPLE', 'table' => 'ob_article_tongji', 'type' => 'ALL', 'possible_keys' => NULL, 'key' => NULL, 'key_len' => NULL, 'ref' => NULL, 'rows' => 608, 'extra' => 'Using where; Using filesort', ) ]
[ SQL ] select * from `ob_article_tongji` where category_id=12 and mark_type='tags' order by times desc limit 100 [ RunTime:0.015079s ]
[ EXPLAIN : array ( 'id' => 1, 'select_type' => 'SIMPLE', 'table' => 'ob_article_tongji', 'type' => 'ALL', 'possible_keys' => NULL, 'key' => NULL, 'key_len' => NULL, 'ref' => NULL, 'rows' => 608, 'extra' => 'Using where; Using filesort', ) ]
[ SQL ] select * from `ob_article_tongji` where category_id=12 and mark_type='tags' order by rand() limit 30 [ RunTime:0.015220s ]
[ EXPLAIN : array ( 'id' => 1, 'select_type' => 'SIMPLE', 'table' => 'ob_article_tongji', 'type' => 'ALL', 'possible_keys' => NULL, 'key' => NULL, 'key_len' => NULL, 'ref' => NULL, 'rows' => 608, 'extra' => 'Using where; Using temporary; Using filesort', ) ]
[ SQL ] SELECT * FROM `ob_article` WHERE `id` = 8735 LIMIT 1 [ RunTime:0.014607s ]
[ EXPLAIN : array ( 'id' => 1, 'select_type' => 'SIMPLE', 'table' => 'ob_article', 'type' => 'const', 'possible_keys' => 'PRIMARY', 'key' => 'PRIMARY', 'key_len' => '4', 'ref' => 'const', 'rows' => 1, 'extra' => NULL, ) ]
[ SQL ] update `ob_article` set views=views+2 where id=8735 [ RunTime:0.016531s ]
[ SQL ] SELECT COUNT(*) AS tp_count FROM `ob_article` WHERE `category_id` = 12 AND `cate` = '威海百度搜索资源平台' AND `status` <> -1 LIMIT 1 [ RunTime:0.021512s ]
[ EXPLAIN : array ( 'id' => 1, 'select_type' => 'SIMPLE', 'table' => 'ob_article', 'type' => 'ALL', 'possible_keys' => NULL, 'key' => NULL, 'key_len' => NULL, 'ref' => NULL, 'rows' => 8035, 'extra' => 'Using where', ) ]
[ SQL ] SELECT * FROM `ob_article` WHERE `category_id` = 12 AND `cate` = '威海百度搜索资源平台' AND `status` <> -1 ORDER BY rand() LIMIT 0,2 [ RunTime:0.040190s ]
[ EXPLAIN : array ( 'id' => 1, 'select_type' => 'SIMPLE', 'table' => 'ob_article', 'type' => 'ALL', 'possible_keys' => NULL, 'key' => NULL, 'key_len' => NULL, 'ref' => NULL, 'rows' => 8035, 'extra' => 'Using where; Using temporary; Using filesort', ) ]
[ SQL ] SELECT COUNT(*) AS tp_count FROM `ob_article` WHERE `category_id` = 12 AND `tags` = '威海Sitemap' AND `status` <> -1 LIMIT 1 [ RunTime:0.021992s ]
[ EXPLAIN : array ( 'id' => 1, 'select_type' => 'SIMPLE', 'table' => 'ob_article', 'type' => 'ALL', 'possible_keys' => NULL, 'key' => NULL, 'key_len' => NULL, 'ref' => NULL, 'rows' => 8035, 'extra' => 'Using where', ) ]
[ SQL ] SELECT * FROM `ob_article` WHERE `category_id` = 12 AND `tags` = '威海Sitemap' AND `status` <> -1 ORDER BY rand() LIMIT 0,2 [ RunTime:0.031279s ]
[ EXPLAIN : array ( 'id' => 1, 'select_type' => 'SIMPLE', 'table' => 'ob_article', 'type' => 'ALL', 'possible_keys' => NULL, 'key' => NULL, 'key_len' => NULL, 'ref' => NULL, 'rows' => 8035, 'extra' => 'Using where; Using temporary; Using filesort', ) ]

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