{"id":1749,"date":"2017-08-09T15:22:53","date_gmt":"2017-08-09T07:22:53","guid":{"rendered":"http:\/\/www.xttblog.com\/?p=1749"},"modified":"2017-08-09T15:22:53","modified_gmt":"2017-08-09T07:22:53","slug":"node-js-koa-%e6%a1%86%e6%9e%b6-%e7%9a%84%e4%b8%ad%e9%97%b4%e4%bb%b6%e7%94%a8%e6%b3%95","status":"publish","type":"post","link":"https:\/\/www.xttblog.com\/?p=1749","title":{"rendered":"node.js Koa \u6846\u67b6 \u7684\u4e2d\u95f4\u4ef6\u7528\u6cd5"},"content":{"rendered":"

\n\tKoa \u7684\u4e2d\u95f4\u4ef6\u901a\u8fc7\u4e00\u79cd\u66f4\u52a0\u4f20\u7edf\uff08\u60a8\u4e5f\u8bb8\u4f1a\u5f88\u719f\u6089\uff09\u7684\u65b9\u5f0f\u8fdb\u884c\u7ea7\u8054\uff0c\u6452\u5f03\u4e86\u4ee5\u5f80 node \u9891\u7e41\u7684\u56de\u8c03\u51fd\u6570\u9020\u6210\u7684\u590d\u6742\u4ee3\u7801\u903b\u8f91\u3002 \u6211\u4eec\u901a\u8fc7 generators \u6765\u5b9e\u73b0“\u771f\u6b63”\u7684\u4e2d\u95f4\u4ef6\u3002 Connect \u7b80\u5355\u5730\u5c06\u63a7\u5236\u6743\u4ea4\u7ed9\u4e00\u7cfb\u5217\u51fd\u6570\u6765\u5904\u7406\uff0c\u76f4\u5230\u51fd\u6570\u8fd4\u56de\u3002 \u4e0e\u4e4b\u4e0d\u540c\uff0c\u5f53\u6267\u884c\u5230 yield next \u8bed\u53e5\u65f6\uff0cKoa \u6682\u505c\u4e86\u8be5\u4e2d\u95f4\u4ef6\uff0c\u7ee7\u7eed\u6267\u884c\u4e0b\u4e00\u4e2a\u7b26\u5408\u8bf7\u6c42\u7684\u4e2d\u95f4\u4ef6('downstrem')\uff0c\u7136\u540e\u63a7\u5236\u6743\u518d\u9010\u7ea7\u8fd4\u56de\u7ed9\u4e0a\u5c42\u4e2d\u95f4\u4ef6('upstream')\u3002\n<\/p>\n

\n\t\"koa\u6846\u67b6\"\n<\/p>\n

\n\tLogger \u529f\u80fd
\n<\/h2>\n

\n\tKoa \u7684\u6700\u5927\u7279\u8272\uff0c\u4e5f\u662f\u6700\u91cd\u8981\u7684\u4e00\u4e2a\u8bbe\u8ba1\uff0c\u5c31\u662f\u4e2d\u95f4\u4ef6\uff08middleware\uff09\u3002\u4e3a\u4e86\u7406\u89e3\u4e2d\u95f4\u4ef6\uff0c\u6211\u4eec\u5148\u770b\u4e00\u4e0b Logger \uff08\u6253\u5370\u65e5\u5fd7\uff09\u529f\u80fd\u7684\u5b9e\u73b0\u3002\n<\/p>\n

\n\t\u6700\u7b80\u5355\u7684\u5199\u6cd5\u5c31\u662f\u5728main\u51fd\u6570\u91cc\u9762\u589e\u52a0\u4e00\u884c\u3002\n<\/p>\n

\n\t\u770b\u4e0b\u9762\u7684 test.js\u3002\n<\/p>\n

\r\nconst main = ctx => {\r\n  console.log(`${Date.now()} ${ctx.request.method} ${ctx.request.url}`);\r\n  ctx.response.body = 'Hello World';\r\n};<\/pre>\n
\n\t\u8fd0\u884c\u4e0a\u9762\u7684 test.js\u3002\u8bbf\u95ee http:\/\/127.0.0.1:3000 \uff0c\u547d\u4ee4\u884c\u5c31\u4f1a\u8f93\u51fa\u65e5\u5fd7\u3002\n<\/p>\n
\r\n1502144902843 GET \/<\/pre>\n
\n\t\u4e2d\u95f4\u4ef6\u7684\u6982\u5ff5
\n<\/h2>\n
\n\t\u4e0a\u4e00\u4e2a\u4f8b\u5b50\u91cc\u9762\u7684 Logger \u529f\u80fd\uff0c\u53ef\u4ee5\u62c6\u5206\u6210\u4e00\u4e2a\u72ec\u7acb\u51fd\u6570\u3002\u770b\u4e0b\u9762\u7684 logger.js \u3002\n<\/p>\n
\r\nconst logger = (ctx, next) => {\r\n  console.log(`${Date.now()} ${ctx.request.method} ${ctx.request.url}`);\r\n  next();\r\n}\r\napp.use(logger);<\/pre>\n
\n\t\u50cf\u4e0a\u9762\u4ee3\u7801\u4e2d\u7684logger\u51fd\u6570\u5c31\u53eb\u505a"\u4e2d\u95f4\u4ef6"\uff08middleware\uff09\uff0c\u56e0\u4e3a\u5b83\u5904\u5728 HTTP Request \u548c HTTP Response \u4e2d\u95f4\uff0c\u7528\u6765\u5b9e\u73b0\u67d0\u79cd\u4e2d\u95f4\u529f\u80fd\u3002app.use()\u7528\u6765\u52a0\u8f7d\u4e2d\u95f4\u4ef6\u3002
\n\t\u57fa\u672c\u4e0a\uff0cKoa \u6240\u6709\u7684\u529f\u80fd\u90fd\u662f\u901a\u8fc7\u4e2d\u95f4\u4ef6\u5b9e\u73b0\u7684\uff0c\u524d\u9762\u4f8b\u5b50\u91cc\u9762\u7684main\u4e5f\u662f\u4e2d\u95f4\u4ef6\u3002\u6bcf\u4e2a\u4e2d\u95f4\u4ef6\u9ed8\u8ba4\u63a5\u53d7\u4e24\u4e2a\u53c2\u6570\uff0c\u7b2c\u4e00\u4e2a\u53c2\u6570\u662f Context \u5bf9\u8c61\uff0c\u7b2c\u4e8c\u4e2a\u53c2\u6570\u662fnext\u51fd\u6570\u3002\u53ea\u8981\u8c03\u7528next\u51fd\u6570\uff0c\u5c31\u53ef\u4ee5\u628a\u6267\u884c\u6743\u8f6c\u4ea4\u7ed9\u4e0b\u4e00\u4e2a\u4e2d\u95f4\u4ef6\u3002\n<\/p>\n
\n\t\u8fd0\u884c\u4e0a\u9762\u7684demo\uff0c\u5e76\u8bbf\u95ee\u67e5\u770b\u6548\u679c\u3002\u547d\u4ee4\u884c\u7a97\u53e3\u4f1a\u663e\u793a\u4e0e\u4e0a\u4e00\u4e2a\u4f8b\u5b50\u76f8\u540c\u7684\u65e5\u5fd7\u8f93\u51fa\u3002\n<\/p>\n
\n\t\u4e2d\u95f4\u4ef6\u6808
\n<\/h2>\n
\n\t\u591a\u4e2a\u4e2d\u95f4\u4ef6\u4f1a\u5f62\u6210\u4e00\u4e2a\u6808\u7ed3\u6784\uff08middle stack\uff09\uff0c\u4ee5"\u5148\u8fdb\u540e\u51fa"\uff08first-in-last-out\uff09\u7684\u987a\u5e8f\u6267\u884c\u3002\n<\/p>\n
    \n
  1. \n\t\t\u6700\u5916\u5c42\u7684\u4e2d\u95f4\u4ef6\u9996\u5148\u6267\u884c\u3002\n\t<\/li>\n
  2. \n\t\t\u8c03\u7528next\u51fd\u6570\uff0c\u628a\u6267\u884c\u6743\u4ea4\u7ed9\u4e0b\u4e00\u4e2a\u4e2d\u95f4\u4ef6\u3002\n\t<\/li>\n
  3. \n\t\t\u6700\u5185\u5c42\u7684\u4e2d\u95f4\u4ef6\u6700\u540e\u6267\u884c\u3002\n\t<\/li>\n
  4. \n\t\t\u6267\u884c\u7ed3\u675f\u540e\uff0c\u628a\u6267\u884c\u6743\u4ea4\u56de\u4e0a\u4e00\u5c42\u7684\u4e2d\u95f4\u4ef6\u3002\n\t<\/li>\n
  5. \n\t\t\u6700\u5916\u5c42\u7684\u4e2d\u95f4\u4ef6\u6536\u56de\u6267\u884c\u6743\u4e4b\u540e\uff0c\u6267\u884cnext\u51fd\u6570\u540e\u9762\u7684\u4ee3\u7801\u3002\n\t<\/li>\n<\/ol>\n
    \n\t\u8bf7\u770b\u4e0b\u9762\u7684demo\u3002\n<\/p>\n
    \r\nconst one = (ctx, next) => {\r\n  console.log('>> one');\r\n  next();\r\n  console.log('<< one');\r\n}\r\nconst two = (ctx, next) => {\r\n  console.log('>> two');\r\n  next(); \r\n  console.log('<< two');\r\n}\r\nconst three = (ctx, next) => {\r\n  console.log('>> three');\r\n  next();\r\n  console.log('<< three');\r\n}\r\napp.use(one);\r\napp.use(two);\r\napp.use(three);<\/pre>\n
    \n\t\u8fd0\u884c\u4e0a\u9762\u8fd9\u4e2a demo\u3002\u6211\u4eec\u53d1\u73b0\u547d\u4ee4\u884c\u7a97\u53e3\u4e2d\u8f93\u51fa\u7684\u5185\u5bb9\u548c"\u5148\u8fdb\u540e\u51fa"\uff08first-in-last-out\uff09\u7684\u6267\u884c\u987a\u5e8f\u4e00\u81f4\u3002\n<\/p>\n
    \n\t\u5982\u679c\u4e2d\u95f4\u4ef6\u5185\u90e8\u6ca1\u6709\u8c03\u7528next\u51fd\u6570\uff0c\u90a3\u4e48\u6267\u884c\u6743\u5c31\u4e0d\u4f1a\u4f20\u9012\u4e0b\u53bb\u3002\n<\/p>\n
    \n\t\u5f02\u6b65\u4e2d\u95f4\u4ef6
    \n<\/h2>\n
    \n\t\u8fc4\u4eca\u4e3a\u6b62\uff0c\u6240\u6709\u4f8b\u5b50\u7684\u4e2d\u95f4\u4ef6\u90fd\u662f\u540c\u6b65\u7684\uff0c\u4e0d\u5305\u542b\u5f02\u6b65\u64cd\u4f5c\u3002\u5982\u679c\u6709\u5f02\u6b65\u64cd\u4f5c\uff08\u6bd4\u5982\u8bfb\u53d6\u6570\u636e\u5e93\uff09\uff0c\u4e2d\u95f4\u4ef6\u5c31\u5fc5\u987b\u5199\u6210 async \u51fd\u6570\u3002\n<\/p>\n
    \n\t\u770b\u4e0b\u9762\u7684 async.js \u6587\u4ef6\u4e2d\u7684\u4ee3\u7801\uff1b\n<\/p>\n
    \r\nconst fs = require('fs.promised');\r\nconst Koa = require('koa');\r\nconst app = new Koa();\r\nconst main = async function (ctx, next) {\r\n  ctx.response.type = 'html';\r\n  ctx.response.body = await fs.readFile('.\/demos\/template.html', 'utf8');\r\n};\r\napp.use(main);\r\napp.listen(3000);<\/pre>\n
    \n\t\u4e0a\u9762\u4ee3\u7801\u4e2d\uff0cfs.readFile\u662f\u4e00\u4e2a\u5f02\u6b65\u64cd\u4f5c\uff0c\u5fc5\u987b\u5199\u6210await fs.readFile()\uff0c\u7136\u540e\u4e2d\u95f4\u4ef6\u5fc5\u987b\u5199\u6210 async \u51fd\u6570\u3002\n<\/p>\n
    \n\tdemo \u7684\u8fd0\u884c\u6548\u679c\uff0c\u5927\u5bb6\u81ea\u5df1\u6267\u884c\u4e00\u4e0b\u3002\n<\/p>\n
    \n\t\u4e2d\u95f4\u4ef6\u7684\u5408\u6210
    \n<\/h2>\n
    \n\tkoa-compose<\/a>\u6a21\u5757\u53ef\u4ee5\u5c06\u591a\u4e2a\u4e2d\u4ef6\u5408\u6210\u4e3a\u4e00\u4e2a\u3002\n<\/p>\n
    \n\t\u770b\u4e0b\u9762\u7684 compose.js \u6587\u4ef6\u4e2d\u7684\u4ee3\u7801\u3002\n<\/p>\n
    \r\nconst compose = require('koa-compose');\r\nconst logger = (ctx, next) => {\r\n  console.log(`${Date.now()} ${ctx.request.method} ${ctx.request.url}`);\r\n  next();\r\n}\r\nconst main = ctx => {\r\n  ctx.response.body = 'Hello World';\r\n};\r\nconst middlewares = compose([logger, main]);\r\napp.use(middlewares);<\/pre>\n
    \n\tdemo \u6548\u679c\u6211\u5c31\u4e0d\u5728\u8bf4\u4e86\u3002\n<\/p>\n
    \n\t\u5230\u8fd9\u91cc koa \u6846\u67b6\u7684\u4e2d\u95f4\u4ef6\u5df2\u7ecf\u8bb2\u5b8c\u4e86\uff0c\u5982\u679c\u4f60\u8fd8\u6709\u4e0d\u61c2\uff0c\u53ef\u4ee5\u7559\u8a00\uff01\u9650\u4e8e\u7bc7\u5e45\uff0c\u6211\u4eec\u4e0b\u4e00\u7ae0\u5c06\u5b66\u4e60 koa \u6846\u67b6\u7684\u9519\u8bef\u5904\u7406\u90e8\u5206\uff0c\u6b22\u8fce\u9605\u8bfb\u3002<\/p>\n
    \"\u4e1a\u4f59\u8349\u516c\u4f17\u53f7\"\/<\/p>
    \u6700\u540e\uff0c\u6b22\u8fce\u5173\u6ce8\u6211\u7684\u4e2a\u4eba\u5fae\u4fe1\u516c\u4f17\u53f7\uff1a\u4e1a\u4f59\u8349\uff08yyucao\uff09\uff01\u53ef\u52a0\u4f5c\u8005\u5fae\u4fe1\u53f7\uff1axttblog2<\/font>\u3002\u5907\u6ce8\uff1a\u201c1\u201d\uff0c\u6dfb\u52a0\u535a\u4e3b\u5fae\u4fe1\u62c9\u4f60\u8fdb\u5fae\u4fe1\u7fa4\u3002\u5907\u6ce8\u9519\u8bef\u4e0d\u4f1a\u540c\u610f\u597d\u53cb\u7533\u8bf7\u3002<\/b>\u518d\u6b21\u611f\u8c22\u60a8\u7684\u5173\u6ce8\uff01\u540e\u7eed\u6709\u7cbe\u5f69\u5185\u5bb9\u4f1a\u7b2c\u4e00\u65f6\u95f4\u53d1\u7ed9\u60a8\uff01\u539f\u521b\u6587\u7ae0\u6295\u7a3f\u8bf7\u53d1\u9001\u81f3532009913@qq.com\u90ae\u7bb1\u3002\u5546\u52a1\u5408\u4f5c\u4e5f\u53ef\u6dfb\u52a0\u4f5c\u8005\u5fae\u4fe1\u8fdb\u884c\u8054\u7cfb\uff01<\/p>
    \u672c\u6587\u539f\u6587\u51fa\u5904\uff1a\u4e1a\u4f59\u8349<\/a>\uff1a » node.js Koa \u6846\u67b6 \u7684\u4e2d\u95f4\u4ef6\u7528\u6cd5<\/a><\/p>","protected":false},"excerpt":{"rendered":"
    Koa \u7684\u4e2d\u95f4\u4ef6\u901a\u8fc7\u4e00\u79cd\u66f4\u52a0\u4f20\u7edf\uff08\u60a8\u4e5f\u8bb8\u4f1a\u5f88\u719f\u6089\uff09\u7684\u65b9\u5f0f\u8fdb\u884c\u7ea7\u8054\uff0c\u6452\u5f03\u4e86\u4ee5\u5f80 node \u9891\u7e41\u7684\u56de\u8c03\u51fd\u6570\u9020\u6210\u7684\u590d […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4],"tags":[1416,1415,48],"class_list":["post-1749","post","type-post","status-publish","format-standard","hentry","category-html5","tag-koa","tag-node-js","tag-web"],"_links":{"self":[{"href":"https:\/\/www.xttblog.com\/index.php?rest_route=\/wp\/v2\/posts\/1749","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.xttblog.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.xttblog.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.xttblog.com\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.xttblog.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1749"}],"version-history":[{"count":1,"href":"https:\/\/www.xttblog.com\/index.php?rest_route=\/wp\/v2\/posts\/1749\/revisions"}],"predecessor-version":[{"id":1750,"href":"https:\/\/www.xttblog.com\/index.php?rest_route=\/wp\/v2\/posts\/1749\/revisions\/1750"}],"wp:attachment":[{"href":"https:\/\/www.xttblog.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1749"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.xttblog.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1749"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.xttblog.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1749"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}