什么是ETag？ETag作用有哪些_威海佰年网络技术有限公司_网站建设_软件开发_私有云_商标注册_公众号_小程序_APP_物联网_ChatGPT

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什么是ETag？ETag作用有哪些

ETag（Entity Tag）是HTTP协议中头部字段之一，它是服务器用来标识特定资源版本的字符串。 ETag的作用主要有以下几个： 1. 缓存控制：通过比较客户端请求中的If-Match或If-None-Match字段和服务器中资源的ETag值来判断资源是否可以使用缓存，从而控制浏览器是否需要重新请求资源。 2. 实现乐观锁定：ETag可以用来实现乐观锁定，即在多用户并发修改同一实体的情况下，可以通过比较各用户提交的If-Match和If-None-Match的值来判断是否可以进行更新操作，从而避免数据冲突。 3. 资源变更检测：当资源发生变化时，服务器会更新ETag的值，客户端可以通过比较新的ETag值和旧的ETag值来检测资源是否发生变化，从而判断是否需要重新加载资源。

Public @ 2023-06-08 14:00:12

使用搜索关键词查询工具能给您带来什么？

使用搜索关键词查询工具能给您带来什么？关键词查询工具可帮助站长了解网站在百度搜索引擎中的表现，站长可以通过点击率、热门关键词的展现量来决定网站优化方向。如：某关键词下，您网站的点击率较低，可查看标题和摘要是否还有优化空间等。来源：百度搜索资源平台

Public @ 2013-11-26 16:07:27

为什么抓取频次突然减少？

反馈抓取频次小，可能目前服务日志部分缺失，导致图示显示数量少于实际抓取数量。请关注实际的收录情况，未收录的url及时进行提交。

Public @ 2009-09-06 16:06:39

头条搜索站长平台-sitemapindex文件要求

sitemapindex文件根节点必须是<sitemapindex>。sitemapindex文件编码必须为UTF-8，第一行为: <?xml version="1.0" encoding="utf-8" ?>。sitemapindex文件禁止使用命名空间，禁止使用规定之外的属性。sitemapindex文件大小不得超过5M，site

Public @ 2013-06-03 16:09:47

Sitemap 中的网址需要完整地指定吗？

是的。您需要在网址中提供协议。例如，http://www.example.com/ 对 Sitemap 来说是有效网址，而 www.example.com 则不是。

Public @ 2010-11-06 16:11:55

更多您感兴趣的搜索

基本文件流程错误 SQL 调试

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/www/wwwroot/briline.net/public/public.php ( 1.08 KB )
/www/wwwroot/briline.net/thinkphp/start.php ( 0.73 KB )
/www/wwwroot/briline.net/thinkphp/base.php ( 2.66 KB )
/www/wwwroot/briline.net/thinkphp/library/think/Loader.php ( 19.47 KB )
/www/wwwroot/briline.net/vendor/composer/autoload_namespaces.php ( 0.21 KB )
/www/wwwroot/briline.net/vendor/composer/autoload_psr4.php ( 0.84 KB )
/www/wwwroot/briline.net/vendor/composer/autoload_classmap.php ( 0.14 KB )
/www/wwwroot/briline.net/vendor/composer/autoload_files.php ( 0.42 KB )
/www/wwwroot/briline.net/vendor/qiniu/php-sdk/src/Qiniu/functions.php ( 7.10 KB )
/www/wwwroot/briline.net/vendor/qiniu/php-sdk/src/Qiniu/Config.php ( 0.70 KB )
/www/wwwroot/briline.net/vendor/topthink/think-captcha/src/helper.php ( 1.59 KB )
/www/wwwroot/briline.net/thinkphp/library/think/Route.php ( 59.82 KB )
/www/wwwroot/briline.net/thinkphp/library/think/Config.php ( 6.03 KB )
/www/wwwroot/briline.net/thinkphp/library/think/Validate.php ( 40.27 KB )
/www/wwwroot/briline.net/vendor/topthink/think-queue/src/config.php ( 0.77 KB )
/www/wwwroot/briline.net/thinkphp/library/think/Console.php ( 21.22 KB )
/www/wwwroot/briline.net/thinkphp/library/think/Error.php ( 3.59 KB )
/www/wwwroot/briline.net/thinkphp/convention.php ( 10.31 KB )
/www/wwwroot/briline.net/thinkphp/library/think/App.php ( 21.04 KB )
/www/wwwroot/briline.net/thinkphp/library/think/Request.php ( 50.94 KB )
/www/wwwroot/briline.net/app/config.php ( 11.25 KB )
/www/wwwroot/briline.net/app/database.php ( 1.41 KB )
/www/wwwroot/briline.net/thinkphp/library/think/Hook.php ( 4.76 KB )
/www/wwwroot/briline.net/app/tags.php ( 1.16 KB )
/www/wwwroot/briline.net/app/common/behavior/InitBase.php ( 8.17 KB )
/www/wwwroot/briline.net/app/common.php ( 23.29 KB )
/www/wwwroot/briline.net/thinkphp/library/think/Env.php ( 1.25 KB )
/www/wwwroot/briline.net/thinkphp/helper.php ( 17.86 KB )
/www/wwwroot/briline.net/app/function.php ( 0.78 KB )
/www/wwwroot/briline.net/app/extend.php ( 13.29 KB )
/www/wwwroot/briline.net/thinkphp/library/think/Debug.php ( 7.06 KB )
/www/wwwroot/briline.net/app/common/model/Config.php ( 0.78 KB )
/www/wwwroot/briline.net/app/common/model/ModelBase.php ( 12.18 KB )
/www/wwwroot/briline.net/thinkphp/library/think/Model.php ( 66.83 KB )
/www/wwwroot/briline.net/thinkphp/library/think/Db.php ( 6.54 KB )
/www/wwwroot/briline.net/thinkphp/library/think/Log.php ( 5.84 KB )
/www/wwwroot/briline.net/thinkphp/library/think/db/connector/Mysql.php ( 3.94 KB )
/www/wwwroot/briline.net/thinkphp/library/think/db/Connection.php ( 29.97 KB )
/www/wwwroot/briline.net/thinkphp/library/think/db/Query.php ( 86.80 KB )
/www/wwwroot/briline.net/thinkphp/library/think/db/builder/Mysql.php ( 2.16 KB )
/www/wwwroot/briline.net/thinkphp/library/think/db/Builder.php ( 30.47 KB )
/www/wwwroot/briline.net/thinkphp/library/think/Cache.php ( 6.17 KB )
/www/wwwroot/briline.net/thinkphp/library/think/cache/driver/File.php ( 7.46 KB )
/www/wwwroot/briline.net/thinkphp/library/think/cache/Driver.php ( 5.52 KB )
/www/wwwroot/briline.net/app/common/behavior/InitHook.php ( 1.25 KB )
/www/wwwroot/briline.net/app/common/model/Hook.php ( 0.77 KB )
/www/wwwroot/briline.net/thinkphp/library/think/Lang.php ( 6.95 KB )
/www/wwwroot/briline.net/thinkphp/lang/zh-cn.php ( 3.85 KB )
/www/wwwroot/briline.net/app/route.php ( 0.91 KB )
/www/wwwroot/briline.net/app/index/config.php ( 0.96 KB )
/www/wwwroot/briline.net/app/index/common.php ( 0.68 KB )
/www/wwwroot/briline.net/app/index/controller/Wiki.php ( 2.44 KB )
/www/wwwroot/briline.net/app/index/controller/IndexBase.php ( 1.10 KB )
/www/wwwroot/briline.net/app/common/controller/ControllerBase.php ( 4.75 KB )
/www/wwwroot/briline.net/thinkphp/library/think/Controller.php ( 6.20 KB )
/www/wwwroot/briline.net/thinkphp/library/traits/controller/Jump.php ( 4.97 KB )
/www/wwwroot/briline.net/thinkphp/library/think/View.php ( 6.86 KB )
/www/wwwroot/briline.net/thinkphp/library/think/view/driver/Think.php ( 5.61 KB )
/www/wwwroot/briline.net/thinkphp/library/think/Template.php ( 46.46 KB )
/www/wwwroot/briline.net/thinkphp/library/think/template/driver/File.php ( 2.24 KB )
/www/wwwroot/briline.net/app/index/logic/Wiki.php ( 6.16 KB )
/www/wwwroot/briline.net/app/index/logic/IndexBase.php ( 0.79 KB )
/www/wwwroot/briline.net/app/common/logic/LogicBase.php ( 0.83 KB )
/www/wwwroot/briline.net/app/common/model/Article.php ( 0.78 KB )
/www/wwwroot/briline.net/app/common/model/ArticleTongji.php ( 0.79 KB )
/www/wwwroot/briline.net/thinkphp/library/think/paginator/driver/Bootstrap.php ( 5.90 KB )
/www/wwwroot/briline.net/thinkphp/library/think/Paginator.php ( 9.45 KB )
/www/wwwroot/briline.net/thinkphp/library/think/Collection.php ( 8.63 KB )
/www/wwwroot/briline.net/runtime/temp/ead4923c25a6b3f986358f7070f93dfa.php ( 56.51 KB )
/www/wwwroot/briline.net/thinkphp/library/think/Response.php ( 8.64 KB )
/www/wwwroot/briline.net/thinkphp/library/think/debug/Html.php ( 4.27 KB )

[ DB ] CONNECT:[ UseTime:0.021288s ] mysql:dbname=briline.net;host=106.14.77.182;port=3306;charset=utf8
[ SQL ] SHOW COLUMNS FROM `ob_article` [ RunTime:0.015386s ]
[ SQL ] SELECT * FROM `ob_article` WHERE `id` = 8620 LIMIT 1 [ RunTime:0.014779s ]
[ 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:0.014733s ]
[ 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:0.014882s ]
[ 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:0.014899s ]
[ 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` = 8620 LIMIT 1 [ RunTime:0.014341s ]
[ 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=8620 [ RunTime:0.017554s ]
[ 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:0.021825s ]
[ EXPLAIN : array ( 'id' => 1, 'select_type' => 'SIMPLE', 'table' => 'ob_article', 'type' => 'ALL', 'possible_keys' => NULL, 'key' => NULL, 'key_len' => NULL, 'ref' => NULL, 'rows' => 9562, '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:0.045391s ]
[ EXPLAIN : array ( 'id' => 1, 'select_type' => 'SIMPLE', 'table' => 'ob_article', 'type' => 'ALL', 'possible_keys' => NULL, 'key' => NULL, 'key_len' => NULL, 'ref' => NULL, 'rows' => 9562, '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:0.021777s ]
[ EXPLAIN : array ( 'id' => 1, 'select_type' => 'SIMPLE', 'table' => 'ob_article', 'type' => 'ALL', 'possible_keys' => NULL, 'key' => NULL, 'key_len' => NULL, 'ref' => NULL, 'rows' => 9562, '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:0.030877s ]
[ EXPLAIN : array ( 'id' => 1, 'select_type' => 'SIMPLE', 'table' => 'ob_article', 'type' => 'ALL', 'possible_keys' => NULL, 'key' => NULL, 'key_len' => NULL, 'ref' => NULL, 'rows' => 9562, 'extra' => 'Using where; Using temporary; Using filesort', ) ]

0.408283s

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