request文件源码解析

依赖模块

  1. const URL = require('url').URL
  2. // 处理 url
  4. const net = require('net')
  5. // 模块 net 提供了异步的网络 API
  7. const accepts = require('accepts')
  8. // HTTP 内容协商，可获取网络请求支持的编码、语言、类型等信息 
  10. const contentType = require('content-type')
  11. // 创建和解析 Http Content-Type
  13. const stringify = require('url').format
  14. // 序列化 url
  16. const parse = require('parseurl')
  17. // 类似于 url.parse，但是具有缓存功能
  19. const qs = require('querystring')
  20. // 模块 querystring 提供了用于解析和格式化网址查询字符串的实用工具
  22. const typeis = require('type-is')
  23. // 提供对请求的类型检查
  25. const fresh = require('fresh')
  26. // 判断缓存是否过期
  28. const only = require('only')
  29. // 设置对象白名单属性
  31. const util = require('util')
  32. // 工具模块，支持 Node.js 内部 API 的需求

全局变量

  1. const IP = Symbol('context#ip')
  2. // 创建全局唯一变量 IP

导出对象

  1. module.exports = {
  2.     // 内容如下
  3. }

header

  1. // 保持 header & headers 一致
  3. get header () {
  4.     return this.req.headers
  5. }
  7. set header (val) {
  8.     this.req.headers = val
  9. }
  11. get headers () {
  12.     return this.req.headers
  13. }
  15. set headers (val) {
  16.     this.req.headers = val
  17. }

url

  1. get url () {
  2.     return this.req.url
  3. }
  5. set url (val) {
  6.     this.req.url = val
  7. }

origin

  1. get origin () {
  2.     return `${this.protocol}://${this.host}`
  3. }

href

  1. get href () {
  2.     if (/^https?:\/\//i.test(this.originalUrl)) return this.originalUrl
  3.     return this.origin + this.originalUrl
  4. }

method

  1. get method () {
  2.     return this.req.method
  3. }
  5. set method (val) {
  6.     this.req.method = val
  7. }

path

  1. get path () {
  2.     return parse(this.req).pathname
  3. }
  5. set path (path) {
  6.     const url = parse(this.req)
  7.     if (url.pathname === path) return
  9.     url.pathname = path
  10.     url.path = null
  12.     this.url = stringify(url)
  13. }

query

  1. get query () {
  2.     const str = this.querystring
  3.     const c = this._querycache = this._querycache || {}
  4.     return c[str] || (c[str] = qs.parse(str))
  5. }
  7. set query (obj) {
  8.     this.querystring = qs.stringify(obj)
  9. }

querystring

  1. get querystring () {
  2.     if (!this.req) return ''
  3.     return parse(this.req).query || ''
  4. }
  6. set querystring (str) {
  7.     const url = parse(this.req)
  8.     if (url.search === `?${str}`) return
  10.     url.search = str
  11.     url.path = null
  13.     this.url = stringify(url)
  14. }

search

  1. get search () {
  2.     if (!this.querystring) return ''
  3.     return `?${this.querystring}`
  4. }
  6. set search (str) {
  7.     this.querystring = str
  8. }

host

  1. get host () {
  2.     const proxy = this.app.proxy
  3.     let host = proxy && this.get('X-Forwarded-Host')
  4.     if (!host) {
  5.         if (this.req.httpVersionMajor >= 2) host = this.get(':authority')
  6.         if (!host) host = this.get('Host')
  7.     }
  8.     if (!host) return ''
  9.     return host.split(/\s*,\s*/, 1)[0]
  10. }

hostname

  1. get hostname () {
  2.     const host = this.host
  3.     if (!host) return ''
  4.     if (host[0] === '[') return this.URL.hostname || '' 
  5.     return host.split(':', 1)[0]
  6. }

URL

  1. get URL () {
  2.     if (!this.memoizedURL) {
  3.         const originalUrl = this.originalUrl || ''
  4.         try {
  5.             this.memoizedURL = new URL(`${this.origin}${originalUrl}`)
  6.         } catch (err) {
  7.             this.memoizedURL = Object.create(null)
  8.         }
  9.     }
  10.     return this.memoizedURL
  11. }

fresh

  1. get fresh () {
  2.     const method = this.method
  3.     const s = this.ctx.status
  5.     if (method !== 'GET' && method !== 'HEAD') return false
  7.     if ((s >= 200 && s < 300) || s === 304) {
  8.         return fresh(this.header, this.response.header)
  9.     }
  11.     return false
  12. }

stale

  1. get stale () {
  2.     return !this.fresh
  3. }

idempotent

  1. // 判断请求方法是否幂等
  2. get idempotent () {
  3.     const methods = ['GET', 'HEAD', 'PUT', 'DELETE', 'OPTIONS', 'TRACE']
  4.     return !!~methods.indexOf(this.method)
  5. }

socket

  1. // 获取对底层套接字的引用
  2. get socket () {
  3.     return this.req.socket
  4. }

charset

  1. get charset () {
  2.     try {
  3.         const { parameters } = contentType.parse(this.req)
  4.         return parameters.charset || ''
  5.     } catch (e) {
  6.         return ''
  7.     }
  8. }

length

  1. get length () {
  2.     const len = this.get('Content-Length')
  3.     if (len === '') return
  4.     return ~~len
  5. }

protocol

  1. get protocol () {
  2.     if (this.socket.encrypted) return 'https'
  3.     if (!this.app.proxy) return 'http'
  4.     const proto = this.get('X-Forwarded-Proto')
  5.     return proto ? proto.split(/\s*,\s*/, 1)[0] : 'http'
  6. }

secure

  1. get secure () {
  2.     return this.protocol === 'https'
  3. }

ips

  1. get ips () {
  2.     const proxy = this.app.proxy
  3.     const val = this.get(this.app.proxyIpHeader)
  4.     let ips = proxy && val
  5.     ? val.split(/\s*,\s*/)
  6.     : []
  7.     if (this.app.maxIpsCount > 0) {
  8.         ips = ips.slice(-this.app.maxIpsCount)
  9.     }
  10.     return ips
  11. }

ip

  1. get ip () {
  2.     if (!this[IP]) {
  3.         this[IP] = this.ips[0] || this.socket.remoteAddress || ''
  4.     }
  5.     return this[IP]
  6. }
  8. set ip (_ip) {
  9.     this[IP] = _ip
  10. }

subdomains

  1. get subdomains () {
  2.     const offset = this.app.subdomainOffset
  3.     const hostname = this.hostname
  4.     if (net.isIP(hostname)) return []
  5.     return hostname
  6.         .split('.')
  7.         .reverse()
  8.         .slice(offset)
  9. }

accept

  1. get accept () {
  2.     return this._accept || (this._accept = accepts(this.req))
  3. }
  5. set accept (obj) {
  6.     this._accept = obj
  7. }

type

  1. get type () {
  2.     const type = this.get('Content-Type')
  3.     if (!type) return ''
  4.     return type.split(';')[0]
  5. }

^accepts 判断请求支持类型|编码|语言

  1. accepts (...args) {
  2.     return this.accept.types(...args)
  3. }
  5. acceptsEncodings (...args) {
  6.     return this.accept.encodings(...args)
  7. }
  9. acceptsCharsets (...args) {
  10.     return this.accept.charsets(...args)
  11. }
  13. acceptsLanguages (...args) {
  14.     return this.accept.languages(...args)
  15. }

is 检查请求类型

  1. is (type, ...types) {
  2.     return typeis(this.req, type, ...types)
  3. }

get 获取请求头属性值

  1. get (field) {
  2.     const req = this.req
  3.     switch (field = field.toLowerCase()) {
  4.         case 'referer':
  5.         case 'referrer':
  6.             return req.headers.referrer || req.headers.referer || ''
  7.         default:
  8.             return req.headers[field] || ''
  9.     }
  10. }

inspect 检查函数

  1. inspect () {
  2.     if (!this.req) return
  3.     return this.toJSON()
  4. }

toJSON 格式化函数

  1. toJSON () {
  2.     return only(this, [
  3.         'method',
  4.         'url',
  5.         'header'
  6.     ])
  7. }

自定义检查函数

  1. if (util.inspect.custom) {
  2.     module.exports[util.inspect.custom] = module.exports.inspect
  3. }