HTTP 协议
2018-05-15 本文已影响29人
michael_jia
HTTP（Hypertext Transfer Protocol） 是万维网通信的基石。
- initiated by Tim Berners-Lee in 1989.
- HTTP/1.0：RFC 1945；
May 1996； - HTTP/1.1：RFC 2068 -> 2616 -> 7230-7235；
January 1997 -> June 1999 -> June 2014 - HTTP/2：RFC 7540；
May 2015 - List of HTTP status codes（标准 HTTP 状态码）；
- NGINX HTTP Return Codes；
- List of HTTP header fields；
- HTTP 标准 Header；
- online URL Parser / Query String Splitter @ freeformatter.com；
- base64，base64 在线编码、解码；
http status code
- URL 可以多长？
What is the maximum length of a URL in different browsers？
最长保持在 2000 字节以内没问题； -
451
Unavailable For Legal Reasons (RFC 7725)； - Nginx 499 Client Closed Request（了解 LXR）
Used when the client has closed the request before the server could send a response.
Used in Nginx logs to indicate when the connection has been closed by client while the server is still processing its request, making server unable to send a status code back.
Client Error
The 4XX class of codes indicate you did something wrong. Specifically, there's an error on the client side.
http server @ github
a simple zero-configuration command-line http server.
使用非常简单；
Transfer-Encoding Header
Transfer-Encoding: chunked
开发 PHP 服务时，如果确切地知道返回的内容长度，一定要指定 Content-Length头，否则 Nginx 默认使用 chunked，因为它不知道何时结束，导致即使0字节的返回，网络上也有5个字节的内容传送（不包括 http header 的长度）。
mdn上的例子很好地诠释了这个原因，如下图：
mozilla.org上的 chunked 编码示例
Meta refresh
<meta http-equiv="refresh" content="5; url=http://example.com/">
- drawbacks：impairs the web browser's "back" button；user dissatisfaction；
- legitimate uses：Many large websites use it to refresh news or status updates, especially when dependencies on JavaScript and redirect headers are unwanted.
- You should mention that automatic refresh can be disabled in some browsers.
Refresh Header
- 不是 HTTP 标准 Header；
- Netscape 创建的；
- 被 W3C 通过 Meta refresh 方式所接纳；
3 ways of redirection
- Via 3xx response (in the Location HTTP response header)
- Via Javascript (or any other client side code) in the response page (e.g. document.location=...)
- Via "META REFRESH" (<meta http-equiv="Refresh" content="0; url=...">)
- Refresh Header was invented by Netscape ；
URL Redirection
- URL 跳转
The simplest way of JavaScript redirect using the onload property of the body tag:
<body onload="window.location = 'http://example.com/'">
<!-- Your content here -->
</body>
