面试:你了解中兴吗_HTTP简介：您需要了解的所有内容

面试:你了解中兴吗

In this article, I will walk you through how the world wide web works at a fundamental level.

在本文中，我将向您介绍基本的万维网工作原理。

The core technology is HTTP - Hypertext Transfer Protocol. It's the communication protocol you use when you browse the web.

核心技术是HTTP-超文本传输​​协议。 这是您浏览网络时使用的通信协议。

At a fundamental level, when you visit a website, your browser makes an HTTP request to a server. Then that server responds with a resource (an image, video, or the HTML of a web page) -  which your browser then displays for you.

从根本上讲，当您访问网站时，浏览器会向服务器发出HTTP请求。 然后，该服务器以资源(图像，视频或网页HTML)进行响应-然后您的浏览器会为您显示该资源。

This is HTTP's message-based model. Every HTTP interaction includes a request and a response.

这是HTTP的基于消息的模型。 每个HTTP交互都包括一个请求和一个响应。

By its nature, HTTP is stateless.

HTTP本质上是无状态的。

Stateless means that all requests are separate from each other. So each request from your browser must contain enough information on its own for the server to fulfill the request. That also means that each transaction of the message based model of HTTP is processed separately from the others.

无状态意味着所有请求都是相互独立的。 因此，来自浏览器的每个请求必须单独包含足够的信息，服务器才能满足该请求。 这也意味着基于消息的HTTP模型的每个事务都与其他事务分开处理。

网址 (URLs)

The URL (Uniform Resource Locator) is probably the most known concept of the Web. It is also one of most important and useful concepts. A URL is a web address used to identify resources on the Web.

URL(统一资源定位符)可能是Web上最知名的概念。 它也是最重要和有用的概念之一。 URL是用于标识Web资源的Web地址。

The idea of the web is structured around resources. From its beginnings the Web was the platform for sharing text/HTML files, documents, images etc, and as such it can be considered a collection of resources.

Web的思想围绕资源而构建。 从一开始，Web就是用于共享文本/ HTML文件，文档，图像等的平台，因此可以将其视为资源的集合。

Protocol — Most often they are HTTP (or HTTPS for a secure version of HTTP).

协议 -大多数情况下，它们是HTTP(或HTTPS(用于HTTP的安全版本))。

Other notable protocols are:

其他值得注意的协议是：

• File Transfer Protocol (FTP) — is a standard protocol used for transferring files between a client and a server over a network.

  文件传输协议(FTP)-是一种标准 用于传输的协议 网络上客户端和服务器之间的文件。

• Simple Mail Transfer Protocol (SMTP) is a standard for email transmission.
  简单邮件传输协议(SMTP)是电子邮件传输的标准。

Domain — Name that is used to identify one or more IP addresses where the resource is located.

域 -名称，用于标识资源所在的一个或多个IP地址。

Path —Specifies the resource location on the server. It uses the same logic as a resource location used on the device where you are reading this article (i.e. /search/cars/VWBeetle.pdf or C:/my cars/VWBeetle.pdf).

路径-指定服务器上的资源位置。 它使用与您在其中阅读本文的设备上使用的资源位置相同的逻辑(即/search/cars/VWBeetle.pdf或C：/ my cars / VWBeetle.pdf)。

Parameters — Additional data used to identify or filter the resource on the server.

参数 -用于标识或过滤服务器上资源的其他数据。

Note: When searching for articles and more information about HTTP, you may encounter the term URI (or uniform resource identifier). URI is sometimes being used instead of URL but mostly in formal specifications and by people who want to show off. :)

注意 ：在搜索有关HTTP的文章和更多信息时，您可能会遇到术语URI(或统一资源标识符)。 有时使用URI代替URL，但大多数情况是在正式规范中以及要炫耀的人们使用URI。 :)

HTTP请求 (HTTP Requests)

In HTTP, every request must have an URL address. Additionally, the request needs a method. The four main HTTP methods are:

在HTTP中，每个请求都必须具有URL地址。 此外，请求需要一个方法。 四种主要的HTTP方法是：

• GET
  得到
• PUT
  放
• POST
  开机自检
• DELETE
  删除

I will explain these methods, and more, in the HTTP Methods section of this article.

我将在本文的“ HTTP方法”部分中解释这些方法，以及更多内容。

And these methods directly correspond to actions:

这些方法直接对应于动作：

• read
  读
• update
  更新
• create
  创造
• delete
  删除

All HTTP messages have one or more headers, followed by an optional message body. The body contains the data that will be sent with the request or the data received with the response.

所有HTTP消息都有一个或多个标头，后跟可选的消息正文。 正文包含将与请求一起发送的数据或与响应一起接收的数据。

The first part of every HTTP request holds three items:

每个HTTP请求的第一部分包含三个项目：

Example:

例：

• GET /adds/search-result?item=vw+beetle HTTP/1.1
  GET / adds / search-result？item = vw + beetle HTTP / 1.1

When a URL contains a “?” sign, it means it contains a query. That means it sends parameters of the requested resource.

网址中包含“？”时 符号，表示它包含一个查询。 这意味着它将发送所请求资源的参数。

1. The first part is a method which tells which HTTP method is used. Most commonly used is the GET method. GET method retrieves a resource from the web server and since GET doesn’t have a message body nothing after the header is needed.
   第一部分是一种方法，用于说明使用哪种HTTP方法。 最常用的是GET方法。 GET方法从Web服务器检索资源，并且由于GET在没有标头之后没有任何消息正文。
2. The second part is a requested URL.
   第二部分是请求的URL。
3. The third part is a HTTP version being used. Version 1.1. is the most common version for most browsers, however, version 2.0 is taking over.
   第三部分是正在使用的HTTP版本。 版本1.1。 是大多数浏览器最常用的版本，但是2.0版正在取代。

There are also some other interesting things in an HTTP request:

HTTP请求中还有一些其他有趣的东西：

Referer header — tells the URL from where the request has originated.

引荐来源标头 -告知请求发起来源的网址。

User-Agent header — additional information about the browser being used to generate the request.

User-Agent标头 -有关用于生成请求的浏览器的其他信息。

Host header — uniquely identifies a host name; it is necessary when multiple web pages are hosted on the same server.

主机头 -唯一标识主机名； 在同一服务器上托管多个网页时，有必要。

Cookie header — submits additional parameters to the client.

Cookie标头 -向客户端提交其他参数。

HTTP响应 (HTTP Responses)

Just like in HTTP requests, HTTP responses also consist of three items:

就像HTTP请求一样，HTTP响应也包含三项：

Example:

例：

HTTP/1.1 200 OK

HTTP / 1.1 200 OK

1. The first part is the HTTP version being used.
   第一部分是所使用的HTTP版本。
2. The second part is the numeric code of the result for the request.
   第二部分是请求结果的数字代码。
3. The third part is a textual description of the second part.
   第三部分是第二部分的文字描述。

There are some other interesting things in an HTTP response:

HTTP响应中还有一些其他有趣的事情：

Server header — information about which web server software is being used.

服务器标头 -有关正在使用哪种Web服务器软件的信息。

Set-Cookie header — issues the cookie to the browser.

Set-Cookie标头 -将cookie发送给浏览器。

Message body — it is common for an HTTP response to hold a message body.

消息正文 -HTTP响应通常保存消息正文。

Content-Length header — tells the size of the message body in bytes.

Content-Length标头 -以字节为单位告知消息正文的大小。

HTTP方法 (HTTP Methods)

The most common methods are GET and POST. But there are a few others, too.

最常见的方法是GET和POST。 但是，还有其他一些。

GET —  You use this method to request data from a specified resource where data is not modified it in any way. GET requests do not change the state of resource.

GET —您使用此方法从指定的资源请求数据，而不会以任何方式修改数据。 GET请求不会更改资源状态。

POST — You use this method to send data to a server to create a resource.

POST-使用此方法将数据发送到服务器以创建资源。

PUT — You use this method to update the existing resource on a server by using the content in the body of the request. Think of this as a way to "edit" something.

PUT —您使用此方法通过使用请求正文中的内容来更新服务器上的现有资源。 可以将其视为“编辑”某些内容的一种方式。

HEAD —  You use this method the same way you use GET, but with the distinction that the return of a HEAD method should not contain body in the response. But the return will contain same headers as if GET was used. You use the HEAD method to check whether the resource is present prior of making a GET request.

HEAD —使用此方法的方式与使用GET的方式相同，但区别在于HEAD方法的返回结果不应在响应中包含主体。 但是返回将包含与使用GET相同的标头。 您可以使用HEAD方法在发出GET请求之前检查资源是否存在。

TRACE — You use this method for diagnostic purposes. The response will contain in its body the exact content of the request message.

跟踪—您将此方法用于诊断目的。 响应将在其主体中包含请求消息的确切内容。

OPTIONS — You use this method to describe the communication options (HTTP methods) that are available for the target resource.

选项 —您使用此方法来描述可用于目标资源的通信选项(HTTP方法)。

PATCH —  You use this method to apply partial modifications to a resource.

修补程序-您使用此方法对资源进行部分修改。

DELETE —You use this method to delete the specified resource.

DELETE —您使用此方法删除指定的资源。

休息 (REST)

Representational state transfer (REST) is an architecture style where requests and responses contain representations of the current state of the systems resource.

代表性状态转移(REST)是一种体系结构样式，其中请求和响应包含系统资源当前状态的代表性。

“Regular” way:

“常规”方式：

• http://carapp.com/search?make=wv&model=beetle

  http://carapp.com/search?make=wv&model=beetle

REST-style:

REST风格：

• http://carapp.com/search/vw/beetle

  http://carapp.com/search/vw/beetle

You can learn more about REST here if you're curious.

如果您好奇的话，可以在这里了解更多关于REST的信息 。

HTTP头 (HTTP Headers)

There are three main components that make up the request/response structure. These include:

请求/响应结构由三个主要部分组成。 这些包括：

• First line
  第一行
• Headers
  标头
• Body/Content
  正文/内容

We already talked about the first line in HTTP requests and responses, and body function was mentioned too. Now we'll talk about HTTP headers.

我们已经讨论过HTTP请求和响应的第一行，并且还提到了body函数。 现在，我们将讨论HTTP标头。

The HTTP headers are added after the first line and are defined as name:value pairs separated by a colon. HTTP headers are used to send additional parameters along with the request or response.

HTTP标头添加在第一行之后，并定义为以冒号分隔的name：value对。 HTTP标头用于与请求或响应一起发送其他参数。

As I already said, the body of the message includes the data to be sent with the request or the data received along with the response.

正如我已经说过的那样，消息的主体包括要与请求一起发送的数据或随响应一起接收的数据。

There are different types of headers that are grouped based on their usage into 4 broad categories:

根据标头的用法，可以将标头分为4大类：

• General header — Headers that can be used in both requests and response messages and that are independent of the data being exchanged.

  常规标头 -既可以在请求消息中也可以在响应消息中使用的标头，它们与正在交换的数据无关。

• Request header — These headers define parameters for the data requested or parameters that give important information about the client making the request.

  请求标头 -这些标头定义了所请求数据的参数或提供了有关发出请求的客户端的重要信息的参数。

• Response header — These headers contain information about the incoming response.

  响应标头 -这些标头包含有关传入响应的信息。

• Entity header — The entity headers describe the content that makes up the body of the message.

  实体标头 -实体标头描述了组成邮件正文的内容。

HTTP状态码 (HTTP status codes)

Browsing the web, you may have encountered "404 error: not found" pages or "500 errors: server is not responding" pages.

浏览Web时，您可能会遇到“ 404错误：未找到”页面或“ 500错误：服务器未响应”页面。

These are HTTP status codes.

这些是HTTP状态代码。

Every HTTP response message must contain an HTTP status code in its first line, telling us the result of the request.

每个HTTP响应消息的第一行必须包含HTTP状态代码，以告诉我们请求的结果。

There are five groups of status codes which are grouped by the first digit:

有五组状态代码，它们按第一位分组：

• 1xx — Informational.
  1xx-信息性
• 2xx — The request was successful.
  2xx —请求成功。
• 3xx — The client is redirected to a different resource.
  3xx —客户端被重定向到其他资源。
• 4xx — The request contains an error of some kind.
  4xx —请求包含某种错误。
• 5xx — The server encountered an error fulfilling the request.
  5xx —服务器在执行请求时遇到错误。

Here's a full list of HTTP Status Response Codes and their explanation.

这是HTTP状态响应代码及其说明的完整列表 。

HTTPS(安全超文本传输​​协议) (HTTPS (Hypertext Transfer Protocol Secure))

The secure version of HTTP protocol is HyperText Transfer Protocol Secure (HTTPS). HTTPS provides encrypted communication between a browser (client) and the website (server).

HTTP协议的安全版本是安全的超文本传输​​协议(HTTPS)。 HTTPS在浏览器(客户端)和网站(服务器)之间提供加密的通信。

In HTTPS, the communication protocol is encrypted using Transport Layer Security (TLS) or Secure Sockets Layer (SSL).

在HTTPS中，使用传输层安全性(TLS)或安全套接字层(SSL)对通信协议进行加密。

The protocol is therefore also often called HTTP over TLS, or HTTP over SSL.

因此，该协议通常也称为TLS上的HTTP或SSL上的HTTP。

Both the TLS and SSL protocols use an asymmetric encryption system. Asymmetric encryption systems use a public key (encryption key) and a private key (decryption keys) to encrypt a message.

TLS和SSL协议均使用非对称加密系统。 非对称加密系统使用公用密钥(加密密钥)和专用密钥(解密密钥)对消息进行加密。

Anyone can use the public key to encrypt a message. However, private keys are secret, and that means that only the intended receiver can decrypt the message.

任何人都可以使用公共密钥来加密消息。 但是，私钥是秘密的，这意味着只有预定的接收者才能解密该消息。

SSL / TLS握手 (SSL/TLS handshake)

When you request a HTTPS connection to a website, the website sends its SSL certificate to your browser. That process where your browser and website initiate communication is called the “SSL/TLS handshake.”

当您请求与网站的HTTPS连接时，该网站会将其SSL证书发送到您的浏览器。 您的浏览器和网站启动通信的过程称为“ SSL / TLS握手”。

The SSL/TLS handshake involves a series of steps where browser and website validate each other and start communication through the SSL/TLS tunnel.

SSL / TLS握手涉及一系列步骤，其中浏览器和网站相互验证并开始通过SSL / TLS隧道进行通信。

As you probably noticed, when a trusted secure tunnel is used during in a HTTPS connection, the green padlock icon is displayed in the browsers address bar.

您可能已经注意到，在HTTPS连接期间使用受信任的安全隧道时，绿色的挂锁图标会显示在浏览器的地址栏中。

HTTPS的好处 (Benefits of HTTPS)

The major benefits of a HTTPS are:

HTTPS的主要好处是：

• Customer information, like credit card numbers and other sensitive information, is encrypted and cannot be intercepted.
  客户信息(例如信用卡号和其他敏感信息)已加密，不能被截获。
• Visitors can verify you are a registered business and that you own the domain.
  访问者可以验证您是注册企业，并且您拥有该域。
• Customers know they are not suppose to visit sites without HTTPS, and therefore, they are more likely to trust and complete purchases from sites that use HTTPS.
  客户知道他们不应该访问没有HTTPS的站点，因此，他们更有可能信任和完成从使用HTTPS的站点进行的购买。

Thank you for reading! Check out more articles like this on my freeCodeCamp profile. And check out other fun stuff I build on my GitHub page.

感谢您的阅读！ 在我的freeCodeCamp个人资料中查看更多类似的文章。 并查看我在GitHub页面上构建的其他有趣的东西。

翻译自: https://www.freecodecamp.org/news/http-and-everything-you-need-to-know-about-it/

面试:你了解中兴吗