目录
前言
云服务器用起来感觉最难受的就是带宽了，国内的云服务器普遍带宽都很小，但买国外或者香港的话延迟大还容易被封IP。一般网站/app最占带宽的是图片和音视频等文件的上传下载，下面我们要聊的cos和cdn就是解决这个问题来的。
简介
对象存储COS
- 对象存储不同于我们平时操作系统里的文件存储，它就像一个map，存储的所有文件都有一个唯一的名称作为key，文件内容作为value。而没有目录的概念。
- 这样做的意义在于，当文件很多，目录结构深时，文件存储需要根据那颗目录树一步一步找到文件，显然是比对象存储直接按文件名一步到位得到要来得慢。
- 但目前很多云服务厂商都有在对象存储上提供目录功能，这大多是模拟出来的。比如腾讯云是将文件名中的 / 识别为目录模拟得到的。
- 比如：放进两个文件：
- aaa.txt
- wow/abc.cpp
- 由于 "wow/abc.cpp" 的文件名带有 / ，则可以模拟解析为是放在wow目录下，存在一个文件叫abc.cpp。
- 我们使用云服务提供的COS来替换我们的服务器实现文件的上传和下载。一般云服务COS不限制下载速度，且用户上传也免费。但用户的下载流量、存储空间占用、请求次数是要收钱的。
- 注意这不是三选一的问题，是三个方面都要收钱的！
- 比如：在一个月的时间里，我们向COS上传了 100 MB 文件，发送过 1 w 次读写请求，且用户外网下载文件使用过 10G 的流量。
- 那么结算时，需要支付：A + B + C
- A：100M/1个月 的存储空间占用费用
- B：1w次读取请求费用
- C：外网下载 10 G 流量费用
- 显然，外网下载流量很容易被人攻击，盗刷流量，然后疯狂扣流量包扣费，容易出现一觉醒来，没了一套海景房的刺激。后面我们用CDN来防止一部分攻击，因为COS的流量费比CDN贵非常多，而且CDN能设置更多的访问限制，降低被攻击的损失，所以可以用CDN抗在前面。
CDN
- cdn的用途很广泛，由于用户在地域上分布全国甚至全球各地，而我们的服务器一般是只在一个或几个地方而已，cdn在地域上可以分散多个节点，作为一个中间人，缓存用户访问服务器上的文件，并在用户下一次请求这个文件时，cdn就可以直接提供给用户，而不需要大老远来请求服务器，提高用户的访问速度。
- 这里我们可以利用这个特性，且其价格低，来帮助COS降低被攻击的损失。
使用问题
盗刷COS流量
- 前面我们已经提到，COS的外网下载流量是比较贵的，而且速度快，容易被攻击刷流量。
- 解决办法：
- 把COS访问权限设置为 私有读私有写
- 当用户需要上传文件时，使用云厂商提供的SDK，服务端预签名上传文件的URL，并将签名后的链接发送给用户，客户端只能按照签名链接指定参数、请求头、请求类型的上传文件到COS，上传不需要使用CDN。
- 当用户需要下载时，使用SDK获取COS上对应文件名的文件链接，并将链接的域名替换为CDN的域名，然后返回替换后的链接给用户下载文件，并在CDN设置限制IP访问速度、下载速度等限制即可。
防盗链/限速
- 由于浏览器不允许伪造请求头中的Referer、Host、Origin，因此可以在CDN/COS都配置防盗链，限制请求的Referer。这个可以阻止别人的网站直接把你的资源链接放到他的网站使用的情况，减少一些被偷资源流量的问题，但他直接下载你的资源然后上传到他的服务器还是可以的。
- 注意网页是可以指定浏览器不携带Referer的，即请求是空Referer。而在浏览器直接敲网址进入网页时的请求也是空Referer，你需要考虑是否需要允许空Referer的请求。防盗链挡不住客户端请求，因为客户端是可以随意伪造请求中的任意值的。如APP、nodejs、命令行、服务端程序等，只要是非标准浏览器环境就可以随意伪造。
- 在CDN中，可以限制下载速度、IP访问速度等。
https网站中使用http资源
- 由于CDN的Https目前很多云厂商是收费的，虽然不贵，但也是钱。
- 如果你CDN访问使用了http，但网站是https协议时，直接在https网站里获取http资源（图片、音视频等）会被浏览器认为是不安全的，并在浏览器的开发者工具中打印警告，但也是能用的。但默认不会带上Referer，因此如果你设置了防盗链不允许空Referer的话，就有问题了，这个时候可以在网页的<head></head>中添加配置：<meta content="always" name="referrer" >，这样浏览器在获取Http资源时也会带上Referer了
- https网站中发起http请求是不允许的！
上传文件大小/数量限制
- 用户向我们的服务端申请用于上传文件的预签名URL时，需要携带参数：文件大小、文件MD5，然后我们可以指定该链接发送时必须携带：
- Content-Length=500
- x-cos-meta-md5: {文件md5值}
- 由此就可以防止用户拿到预签名URL后，上传了其他文件的问题
- 文件大小限制，就是在我们服务端给预签名URL时进行检查。
- 文件数量限制，可以将用户、IP获取上传链接时写入数据库记录，根据这个记录来设计用户上传文件的数量和总大小等。
腾讯云COS的SDK/c++
- 整了老半天，终于写好了cmakelist能编译运行release，但debug版一直找不到链接符号。
- 看了大概是因为他是SDK源码里有一个文件夹three-party存放了已经编译好的第三方依赖库，但这些库是release的，因此需要我们编译debug的依赖库。但我的项目里也依赖openssl，改来改去才能release，最终debug版放弃了。
- 后来开始用上go了，学1天然后上手引入他的sdk和框架开发完cos相关的接口。有c基础还是很快上手的。
I’m really enjoying the theme/design of your web site.
Do you ever run into any internet browser compatibility problems?
A small number of my blog visitors have complained about my website not
working correctly in Explorer but looks great in Opera.
Do you have any recommendations to help fix this problem?
I strongly recommend steer clear of this platform. My personal experience with it has been only dismay and suspicion of scamming practices. Exercise extreme caution, or alternatively, look for a trustworthy site to fulfill your requirements.
Thank you great posting about essential oil. Hello Administ . 国产线播放免费人成视频播放
I urge you steer clear of this site. The experience I had with it has been purely disappointment and concerns regarding fraudulent activities. Exercise extreme caution, or even better, look for a trustworthy platform for your needs.
Привет всем!
Было ли у вас когда-нибудь так, что приходилось писать дипломную работу в очень сжатые сроки? Это действительно требует огромной ответственности и может быть очень тяжело, но важно не опускать руки и продолжать активно заниматься учебными процессами, как я.
Для тех, кто умеет быстро находить и использовать информацию в интернете, это действительно облегчает процесс согласования и написания дипломной работы. Больше не нужно тратить время на посещение библиотек или устраивать встречи с научным руководителем. Здесь, на этом ресурсе, предоставлены надежные данные для заказа и написания дипломных и курсовых работ с гарантией качества и доставкой по всей России. Можете ознакомиться с предложениями на сайте , это проверено!
http://astroroleplay.getbb.ru/viewtopic.php?f=6&t=341
купить диплом о среднем специальном
купить аттестат школы
купить диплом о высшем образовании
купить диплом специалиста
купить диплом цена
Желаю любому отличных отметок!
I urge you to avoid this site. My personal experience with it has been purely frustration along with suspicion of deceptive behavior. Exercise extreme caution, or better yet, seek out a more reputable service for your needs.
I strongly recommend to avoid this site. My own encounter with it has been purely disappointment and concerns regarding deceptive behavior. Be extremely cautious, or even better, seek out a trustworthy service for your needs.
I highly advise stay away from this site. My own encounter with it was nothing but frustration and doubts about deceptive behavior. Be extremely cautious, or better yet, seek out a more reputable platform to meet your needs.
Hi, just required you to know I he added your site to my Google bookmarks due to your layout. But seriously, I believe your internet site has 1 in the freshest theme I??ve came across.儿童色情
Як підтримувати водонепроникність у тактичних кросівках
тактичні кросівки https://vijskovikrosivkifvgh.kiev.ua/ .
I urge you to avoid this platform. My personal experience with it was purely frustration and doubts about fraudulent activities. Exercise extreme caution, or better yet, seek out a more reputable service to fulfill your requirements.
Thank you for great information. Hello Administ . 国产线播放免费人成视频播放
Тактичні кросівки для зимових тренувань: які краще вибрати
куплю тактичні кросівки https://vijskovikrosivkifvgh.kiev.ua/ .
I urge you to avoid this platform. My own encounter with it has been purely dismay along with concerns regarding deceptive behavior. Proceed with extreme caution, or even better, find an honest service to fulfill your requirements.
I urge you stay away from this platform. My own encounter with it was purely disappointment along with suspicion of deceptive behavior. Proceed with extreme caution, or better yet, find a more reputable site to meet your needs.
sandyterrace.com
Wang Shouren과 다른 사람들은 눈에 빛을 비추어 스승을 바라 보았습니다.
Hello there! This post could not be written much better!
Going through this article reminds me of my previous roommate!
He constantly kept preaching about this. I most certainly will send this information to him.
Fairly certain he’ll have a great read. Thanks for sharing!
Hi there, just wanted to mention, I liked this post.
It was practical. Keep on posting!
ankara tercüme bürosu
I urge you stay away from this platform. My personal experience with it was only disappointment and doubts about fraudulent activities. Proceed with extreme caution, or better yet, seek out a trustworthy site to fulfill your requirements.
I’m not that much of a internet reader to be honest but your blogs really nice,
keep it up! I’ll go ahead and bookmark your website to come back down the road.
All the best
Nedir Ne Demek
Тактичні кросівки для зимових тренувань: які краще вибрати
військові тактичні кросівки літні https://vijskovikrosivkifvgh.kiev.ua/ .
Привет всем!
Вы когда-нибудь писали диплом в сжатые сроки? Это очень ответственно и тяжело, но нужно не сдаваться и делать учебные процессы, чем Я и занимаюсь)
Тем кто умеет разбираться и гуглить информацию, это действительно помогает по ходу согласований и написания диплома, не нужно тратить время на библиотеки или встречи с дипломным руководителем, вот здесь есть хорошие данные для заказа и написания дипломов и курсовых с гарантией и доставкой по России, можете посмотреть здесь , проверено!
https://carbonfacesocial.org/blogs/62310/ѕокупка-академических-дипломов
купить диплом техникума
купить диплом о среднем специальном
где купить диплом
купить диплом Гознак
купить диплом о среднем образовании
Желаю любому отличных отметок!
bursa avukat
Hi, just required you to know I he added your site to my Google bookmarks due to your layout. But seriously, I believe your internet site has 1 in the freshest theme I??ve came across.儿童色情
I really love to read such an excellent article. Helpful article. Hello Administ . 国产线播放免费人成视频播放
Як підібрати розмір тактичних кросівок правильно
купити кросівки тактичні літні https://vijskovikrosivkifvgh.kiev.ua/ .
Hi would you mind stating which blog platform you’re working with?
I’m planning to start my own blog in the near future
but I’m having a difficult time selecting between BlogEngine/Wordpress/B2evolution and Drupal.
The reason I ask is because your design and style
seems different then most blogs and I’m looking for something completely unique.
P.S My apologies for getting off-topic but I had to
ask!
In the quest to boost online visibility and bring organic traffic, locating the best SEO services in your vicinity has turned into essential. Local enterprises acknowledge the significance of aimed search engine optimization strategies that serve their distinct geographic territory. The term “near me” has gained enormous importance in today’s digital landscape, as consumers often add it in their search questions to discover products and help in their area. The best SEO services close by apprehend the nuances of local SEO, merging location-based words, Google My Business optimization, and correct business directory entries. By concentrating on these elements, these offerings can help businesses achieve higher rankings in local search outcomes, ensuring that potential buyers discover them conveniently when searching for related services in their region.
The rivalry for online visibility has increased, making it vital for businesses to put money into excellent SEO assistance. Seeking “best SEO providers near me” displays the modern inclination towards personalized and localized resolutions. Collaborating with such providers gives several upsides, including face-to-face discussions, a deeper comprehension of local competition, and the ability to tailor strategies based on the individual attributes of your audience. The prime SEO solutions in your proximity will not only enhance your website but also create comprehensive digital marketing methods that may encompass content creation, social media involvement, and even paid advertising promotions. By harnessing the strength of localized SEO, businesses can establish a strong online appearance that successfully engages local patrons and sets the stage for long-term growth.
Telegram: @exrumer
https://XRumer.cc/
Skype: XRumer.pro
Hi there to all, for the reason that I am genuinely keen of reading this website’s post to be updated on a regular basis. It carries pleasant stuff.
ankara diş kliniği
I urge you stay away from this site. My own encounter with it was purely frustration along with concerns regarding fraudulent activities. Exercise extreme caution, or better yet, look for a more reputable service to meet your needs.
I highly advise to avoid this site. My personal experience with it was only disappointment and suspicion of scamming practices. Be extremely cautious, or even better, find a more reputable platform for your needs.
Wonderful blog you have here but I was wondering if you knew of
any discussion boards that cover the same topics talked about
here? I’d really like to be a part of group where I can get feedback from other experienced individuals that share the
same interest. If you have any recommendations, please let
me know. Thank you!
very informative articles or reviews at this time.
After all, what a great site and informative posts, I will upload inbound link – bookmark this web site? Regards, Reader.儿童色情片
Hi, just required you to know I he added your site to my Google bookmarks due to your layout. But seriously, I believe your internet site has 1 in the freshest theme I??ve came across.国产线播放免费人成视频播放
sandyterrace.com
하지만 누가 알았겠어요… 그의 손에 있던 비장의 카드가 그렇게 사라졌습니다.
I highly advise steer clear of this site. My personal experience with it was nothing but dismay along with doubts about deceptive behavior. Be extremely cautious, or alternatively, look for a more reputable service for your needs.
aydın çıkışlı turlar
I urge you steer clear of this site. My own encounter with it was only dismay as well as concerns regarding scamming practices. Proceed with extreme caution, or alternatively, find a more reputable service for your needs.
I highly advise stay away from this site. The experience I had with it has been purely disappointment and suspicion of scamming practices. Proceed with extreme caution, or alternatively, look for a more reputable service to fulfill your requirements.
Thank you for content. Area rugs and online home decor store. Hello Administ . 国产线播放免费人成视频播放
denizli çıkışlı turlar
I strongly recommend stay away from this platform. The experience I had with it was nothing but disappointment and suspicion of fraudulent activities. Proceed with extreme caution, or better yet, find an honest service to fulfill your requirements.
I have encouraged your blog site to my colleagues, and they like it much too. https://buzziova.com/mastering-onlyfans-how-to-promote-your-page-via-social-media/
Inside the constantly changing arena of SEO, instruments and strategies that could effectively boost a website’s internet appearance are in continuous request. Introduce XRumer, a advanced software designed to boost link-building campaigns. Through the ability to post on forums, blogs, guestbooks, and different platforms automatically, XRumer transforms the way online marketers handle off-page SEO. This robust tool avoids typical online obstacles like CAPTCHAs, making sure an unbroken and effective backlink production process. A well-executed XRumer SEO run could considerably increase a site’s search engine rankings, pushing organic traffic and enhancing online presence.
Yet, while the potential of XRumer is undeniable, its use requires a strategic and careful strategy. Like all SEO tools, the outcomes are solely as superb as the method following them. Too much reliance or misuse could lead to unfavorable results, such as penalties from search engines for artificial link building. Thus, when embarking on an XRumer SEO run, it’s essential to focus on quality over number, aiming at pertinent and high-authority sites that match with the brand’s ethos. In the grip of a proficient SEO specialist, XRumer turns into a strong asset, connecting the gap between a brand and its internet possibility.
Telegram: @xrumers
https://XRumer.cc/
Skype: XRumer.pro
qiyezp.com
솔직히 말해서 그의 눈에는 단순한 황실 하인이 아무것도 아닙니다.
sitenizi takip ediyorum makaleler Faydalı bilgiler için teşekkürler