HTTP 101 Switching Protocol（协议切换）状态码表示服务器应客户端升级协议的请求（Upgrade请求头）正在进行协议切换。
服务器会发送一个Upgrade应答头来表示其正在切换过去的协议。
101 Switching Protocol
在使用 WebSockets 时会用到协议切换。
HTTP/1.1 101 Switching Protocols Upgrade: websocket Connection: Upgrade
| Specification | Title |
|---|---|
| RFC 7231, section 6.2.2: 101 Switching Protocol | Hypertext Transfer Protocol (HTTP/1.1): Semantics and Content |
Upgrade426 Upgrade RequiredAcceptAccept-CharsetAccept-EncodingAccept-LanguageAccept-RangesAccess-Control-Allow-CredentialsAccess-Control-Allow-Headers [我来译!]Access-Control-Allow-Methods [我来译!]Access-Control-Allow-OriginAccess-Control-Expose-Headers [我来译!]Access-Control-Max-Age [我来译!]Access-Control-Request-Headers [我来译!]Access-Control-Request-Method [我来译!]Age [我来译!]AllowAuthorization [我来译!]Cache-ControlConnectionContent-Disposition [我来译!]Content-Encoding [我来译!]Content-Language [我来译!]Content-Length [我来译!]Content-Location [我来译!]Content-Range [我来译!]Content-Security-PolicyContent-Security-Policy-Report-Only [我来译!]Content-TypeCookie [我来译!]Cookie2 [我来译!]DNT [我来译!]Date [我来译!]ETagExpect [我来译!]ExpiresForwarded [我来译!]From [我来译!]HostIf-Match [我来译!]If-Modified-Since [我来译!]If-None-Match [我来译!]If-RangeIf-Unmodified-Since [我来译!]Keep-Alive [我来译!]Large-Allocation [我来译!]Last-Modified [我来译!]Location [我来译!]OriginPragma [我来译!]Proxy-Authenticate [我来译!]Proxy-Authorization [我来译!]Public-Key-Pins [我来译!]Public-Key-Pins-Report-Only [我来译!]Range [我来译!]Referer [我来译!]Referrer-Policy [我来译!]Retry-After [我来译!]Server [我来译!]Set-Cookie [我来译!]Set-Cookie2 [我来译!]HTTP Strict Transport SecurityTE [我来译!]Tk [我来译!]Trailer [我来译!]Transfer-Encoding [我来译!]Upgrade-Insecure-Requests [我来译!]User-Agent [我来译!]VaryVia [我来译!]WWW-AuthenticateWarning [我来译!]X-Content-Type-Options [我来译!]DNS 预读取X-Forwarded-For [我来译!]X-Forwarded-Host [我来译!]X-Forwarded-Proto [我来译!]X-Frame-Options 响应头X-XSS-Protection100 Continue101 Switching Protocol [我来译!]200 OK201 Created [我来译!]202 Accepted [我来译!]203 Non-Authoritative Information [我来译!]204 No Content205 Reset Content [我来译!]206 Partial Content300 Multiple Choices [我来译!]301 Moved Permanently302 Found303 See Other304 Not Modified307 Temporary Redirect308 Permanent Redirect400 Bad Request401 Unauthorized [我来译!]403 Forbidden [我来译!]404 Not Found [我来译!]405 Method Not Allowed406 Not Acceptable [我来译!]407 Proxy Authentication Required [我来译!]408 Request Timeout [我来译!]409 Conflict [我来译!]410 Gone411 Length Required [我来译!]412 Precondition Failed（先决条件失败）413 Payload Too Large [我来译!]414 URI Too Long [我来译!]415 Unsupported Media Type [我来译!]416 Range Not Satisfiable [我来译!]417 Expectation Failed [我来译!]426 Upgrade Required [我来译!]428 Precondition Required [我来译!]429 Too Many Requests [我来译!]431 Request Header Fields Too Large [我来译!]451 Unavailable For Legal Reasons [我来译!]500 Internal Server Error [我来译!]501 Not Implemented502 Bad Gateway [我来译!]503 Service Unavailable [我来译!]504 Gateway Timeout [我来译!]505 HTTP Version Not Supported [我来译!]511 Network Authentication Required [我来译!]CSP: base-uri [我来译!]CSP: block-all-mixed-content [我来译!]CSP: child-src [我来译!]CSP: connect-src [我来译!]CSP: default-src [我来译!]CSP: font-src [我来译!]CSP: form-action [我来译!]CSP: frame-ancestors [我来译!]CSP: frame-src [我来译!]CSP: img-src [我来译!]CSP: manifest-src [我来译!]CSP: media-src [我来译!]CSP: object-src [我来译!]CSP: plugin-types [我来译!]CSP: referrer [我来译!]CSP: report-uri [我来译!]CSP: require-sri-for [我来译!]CSP: sandbox [我来译!]CSP: script-src [我来译!]CSP: style-src [我来译!]CSP: upgrade-insecure-requests [我来译!]CSP: worker-src [我来译!]