NodeJS仿WebApi路由示例

import { WebApiRouter } from 'webapi-router';

app.use(new WebApiRouter().router('sample/controllers', 'api'));

export class TestController extends BaseController
{

}

@POST('/user/:name')
postWithPathParam(@PathParam('name') name: string, @QueryParam('id') id: string, @BodyParam body: any) {
  console.info(`TestController - post with name: ${name}, body: ${JSON.stringify(body)}`);
  return 'ok';
}

initRouterForControllers() {
  //找出指定目录下的所有继承自BaseController的.js文件
  let files = FileUtil.getFiles(this.controllerFolder);

  files.forEach(file => {
    let exportClass = require(file).default;

    if(this.isAvalidController(exportClass)){
      this.setRouterForClass(exportClass, file);
    }
  });
}

private buildControllerRouter(file: string){

  let relativeFile = Path.relative(Path.join(FileUtil.getApiDir(), this.controllerFolder), file);
  let controllerPath = '/' + relativeFile.replace(/\\/g, '/').replace('.js','').toLowerCase();

  if(controllerPath.endsWith('controller'))
    controllerPath = controllerPath.substring(0, controllerPath.length - 10);

  return controllerPath;
}

export function GET(path?: string) {
  return (target: BaseController, name: string) => setMethodDecorator(target, name, 'GET', path);
} 

function setMethodDecorator(target: BaseController, name: string, method: string, path?: string){
  target[Router] = target[Router] || {};
  target[Router][name] = target[Router][name] || {};
  target[Router][name].method = method;
  target[Router][name].path = path;
}

export function BodyParam(target: BaseController, name: string, index: number) {
  setParamDecorator(target, name, index, { name: "", type: ParamType.Body });
}

function setParamDecorator(target: BaseController, name: string, index: number, value: {name: string, type: ParamType}) {
  let paramTypes = Reflect.getMetadata("design:paramtypes", target, name);
  target[Router] = target[Router] || {};
  target[Router][name] = target[Router][name] || {};
  target[Router][name].params = target[Router][name].params || [];
  target[Router][name].params[index] = { type: paramTypes[index], name: value.name, paramType: value.type };
}

private setRouterForClass(exportClass: any, file: string) { 

  let controllerRouterPath = this.buildControllerRouter(file);
  let controller = new exportClass();

  for(let funcName in exportClass.prototype[Router]){
    let method = exportClass.prototype[Router][funcName].method.toLowerCase();
    let path = exportClass.prototype[Router][funcName].path;

    this.setRouterForFunction(method, controller, funcName, path ? `/${this.urlPrefix}${path}` : `/${this.urlPrefix}${controllerRouterPath}/${funcName}`);
  }
}

private setRouterForFunction(method: string, controller: any, funcName: string, routerPath: string){
  this.koaRouter[method](routerPath, async (ctx, next) => { await this.execApi(ctx, next, controller, funcName) });
}

private async execApi(ctx: Koa.Context, next: Function, controller: any, funcName: string) : Promise<void> { //这里就是执行controller的api方法了
  try
  {
    ctx.body = await controller[funcName](...this.buildFuncParams(ctx, controller, controller[funcName]));
  }
  catch(err)
  {
    console.error(err);
    next(); 
  }
}

private buildFuncParams(ctx: any, controller: any, func: Function) { //把参数具体的值收集起来
  let paramsInfo = controller[Router][func.name].params;
  let params = [];
  if(paramsInfo)
  {
    for(let i = 0; i < paramsInfo.length; i++) {
      if(paramsInfo[i]){
        params.push(paramsInfo[i].type(this.getParam(ctx, paramsInfo[i].paramType, paramsInfo[i].name)));
      } else {
        params.push(ctx);
      }
    }
  }
  return params;
}

private getParam(ctx: any, paramType: ParamType, name: string){ // 从ctx里把需要的参数拿出来
  switch(paramType){
    case ParamType.Query:
      return ctx.query[name];
    case ParamType.Path:
      return ctx.params[name];
    case ParamType.Body:
      return ctx.request.body;
    default:
      console.error('does not support this param type');
  }
}