來自 Koa.js 官方文檔中關於設置請求響應的部分 response.status=，列出了從 1xx ~ 5xx HTTP 狀態碼及含義，現摘錄如下：
- 100 "continue"
- 101 "switching protocols"
- 102 "processing"
- 200 "ok"
- 201 "created"
- 202 "accepted"
- 203 "non-authoritative information"
- 204 "no content"
- 205 "reset content"
- 206 "partial content"
- 207 "multi-status"
- 208 "already reported"
- 226 "im used"
- 300 "multiple choices"
- 301 "moved permanently"
- 302 "found" 資源臨時不可用，但在其他位置找到了，返回 302 同時帶上
Location: 新的資源地址響應頭。客戶端根據新地址再次請求。- 假如第一次請求使用的 POST，后面這次重新請求瀏覽器有可能變成 GET。
- 如果想要兩次請求保持一致的請求方式，使用 307
- 運用場景：某些原因資源無法訪問了，此時為了不讓搜索引擎更新，可使用 302 告訴引擎資源還在。
- 303 "see other"
- 304 "not modified"
- 305 "use proxy"
- 307 "temporary redirect"
- 和 302 一模一樣，區別在於兩次請求保持一致的 http verb
- 308 "permanent redirect"
- 400 "bad request"
- 由於請求有語法錯誤，服務器不能識別
- 401 "unauthorized"
- 402 "payment required"
- 403 "forbidden"
- 404 "not found"
- 405 "method not allowed"
- 406 "not acceptable" 內容協商后沒有合適的類型返回
- 407 "proxy authentication required"
- 408 "request timeout"
- 409 "conflict"
- 410 "gone"
- 411 "length required"
- 412 "precondition failed"
- 413 "payload too large"
- 比如 post 的數據也就是request body過大
- 414 "uri too long"
- 415 "unsupported media type"
- 416 "range not satisfiable"
- 417 "expectation failed"
- 418 "I'm a teapot"
- 422 "unprocessable entity"
- 423 "locked"
- 424 "failed dependency"
- 426 "upgrade required"
- 428 "precondition required"
- 429 "too many requests"
- 431 "request header fields too large"
- 500 "internal server error"
- 501 "not implemented"
- 502 "bad gateway"
- 503 "service unavailable"
- 504 "gateway timeout"
- 505 "http version not supported"
- 506 "variant also negotiates"
- 507 "insufficient storage"
- 508 "loop detected"
- 510 "not extended"
- 511 "network authentication required"