基于koa2框架实现的API网关，使用koa2框架的中间件机制提供插件功能

"use strict"; /** * 应用入口 * Created by liamjung on 2018/5/21. */ require("co")(function* () { let config = require("./app_config"); let appConfig; //加载配置 if (typeof config === "function") { appConfig = yield config(); } else { appConfig = global.appConfig = config; } const {Log} = require("@libfintech/api-gateway-core/log/log"); global.Log = Log; const {Pipeline} = require("@libfintech/api-gateway-core/entity/pipeline"); const Koa = require("koa"); const bodyParser = require("@libfintech/api-gateway-core/util/koa_body_parser"); const logger = require("koa-logger"); const stripAnsi = require("strip-ansi"); const fs = require("fs"); const appRoot = require("app-root-path"); const app = new Koa(); app.on("error", (err, ctx) => Log.error("server error", err, ctx)); /** * 响应客户端 * @param ctx * @param resp */ async function responseClient(ctx, resp) { //设置状态 ctx.response.status = resp.status; if (resp.headers) { // fix: The response headers can't include "Content-Length" with chunked encoding delete resp.headers['transfer-encoding']; //设置响应头 await ctx.response.set(resp.headers); } if (!ctx.type && resp.body && resp.body.startsWith("{")) ctx.type = "application/json"; ctx.length = !resp.body ? 0 : Buffer.byteLength(resp.body, "utf8"); //刷新任何已设置的响应头，并开始主体 ctx.response.flushHeaders(); //设置响应体 ctx.response.body = resp.body; } //中间件 app.use(bodyParser({ enableTypes: ["json", "form", "file", "text"], extendTypes: { //will parse text/json type body as a JSON string json: ["text/json"], text: ["*/*"] } })); app.use(logger((str, args) => { Log.info(stripAnsi(str)); })); //初始化 app.use(async (ctx, next) => { //初始化管道 ctx.pipeline = new Pipeline(ctx); ctx.pipeline.logger.debug("headers:\t\t" + JSON.stringify(ctx.request.headers)); ctx.pipeline.logger.debug(ctx.request.method + ":" + ctx.pipeline.request.originalPath); ctx.pipeline.logger.debug("querystring:\t\t" + ctx.pipeline.request.querystring); let contentType = ctx.headers["content-type"]; if (!contentType || !contentType.toLowerCase().includes("multipart/form-data")) ctx.pipeline.logger.debug("body:\t\t" + ctx.pipeline.request.body); ctx.pipeline.logger.debug("----------------------------------------------------------------------------------------------------------------------"); await next(); }); //引入插件 appConfig.plugins.forEach((item, index) => { let path = item.path; if (!item.enable) { //未开启时，忽略 Log.info("Plugin (index: " + index + "; path: " + path + ") is not enabled"); return; } //入口方法名称必须为main let main = require(path + "/index").main; let configPath = item.config_path; //插件配置 let configs = {}; if (configPath) { let configFiles = fs.readdirSync(appRoot.path + item.config_path); for (let cf of configFiles) { if (cf.endsWith(".conf.js")) configs = Object.assign(configs, require("." + item.config_path + "/" + cf)); } } app.use(async (ctx, next) => { ctx.pipeline.logger.info("Plugin (index: " + index + "; path: " + path + ")"); try { await main(ctx.pipeline, configs); await next(); } catch (err) { if (err.status) { //响应客户端 await responseClient(ctx, { status: err.status, headers: err.headers, body: err.body }); } else ctx.pipeline.logger.error("server error", err, ctx) } }); Log.info("Load plugin (index: " + index + "; path: " + path + ")"); }); app.use(async (ctx, next) => await responseClient(ctx, ctx.pipeline.response)); Log.info("App has been started, listen " + appConfig.port + "."); app.listen(appConfig.port); });