Feathers.js Request Id Middleware

#feathersjs #typescript #middleware #express

Prepare your project

Generate the app (if you don't have existing app), please seehere. Basically you need to install the generator with:npm install @feathersjs/cli -g
You can follow the step-by-step in the generate app page. Some notes: I use Typescript for the codebase.

Generate and write the Middleware

Usefeathers generate middleware. You can see how I generate the middleware here.

I want to useuuidv4 as my request id. So please install the uuid use:npm install uuid @types/uuid oryarn install uuid @types/uuid (if you use yarn).
Write the middleware. We put the requestId at feathers object. You can found the file atsrc/middleware/request-id.ts.

import{v4asuuidv4}from'uuid';import{Request,Response,NextFunction}from'express';exportdefault()=>{// eslint-disable-next-line @typescript-eslint/no-unused-vars, @typescript-eslint/explicit-module-boundary-typesreturn(req:Request,res:Response,next:NextFunction)=>{constrequestId=uuidv4();if(!req.feathers){req.feathers={};}req.feathers.requestId=requestId;next();};};

Update log hooks for capture ourrequestId. I update thesrc/hooks/log.ts.

// A hook that logs service method before, after and error// See https://github.com/winstonjs/winston for documentation// about the logger.importloggerfrom'../logger';importutilfrom'util';import{HookContext,Hook}from'@feathersjs/feathers';// To see more detailed messages, uncomment the following line:logger.level='debug';exportdefaultfunction():Hook{return(context:HookContext)=>{const{params}=context;constrequestId=params.requestId;logger.debug(`Request Id:${requestId}`);// This debugs the service call and a stringified version of the hook context// You can customize the message (and logger) to your needslogger.debug(`${context.type} app.service('${context.path}').${context.method}()`,);if(// eslint-disable-next-line @typescript-eslint/no-explicit-anytypeof(contextasany).toJSON==='function'&&logger.level==='debug'){logger.debug('Hook Context',util.inspect(context,{colors:false}));}if(context.error&&!context.result){logger.error(context.error.stack);}};}

I want to use error handler and bring the request id. First I will disable html output for error handler. Because I don't want to handle HTML output. You can update thesrc/app.ts like this.

// another code...// Configure a middleware for 404s and the error handlerapp.use(express.notFound());app.use(express.errorHandler({html:false}));app.hooks(appHooks);exportdefaultapp;

Generate application wide error hooks. You can see picture below. For more information. You can checkthis.

Write the hooks. You can found atsrc/hooks/common-error.ts.

// Use this hook to manipulate incoming or outgoing data.// For more information on hooks see: http://docs.feathersjs.com/api/hooks.htmlimport{Hook,HookContext}from'@feathersjs/feathers';// eslint-disable-next-line @typescript-eslint/no-unused-varsexportdefault(options={}):Hook=>{returnasync(context:HookContext):Promise<HookContext>=>{if(context.error){console.log(context);const{params}=context;constrequestId=params.requestId;constrequestIdObject={requestId,};context.error.errors=Object.assign(context.error.errors,requestIdObject,);}returncontext;};};