304 Not Modified

You already have the latest version of this file in your browser cache. I’m not going to send it again.

When and Why to Use It

Use this for massive performance gains. If the client asks ‘Has this image changed since yesterday?’ and it hasn’t, respond with 304 instead of sending the heavy image again.

Usage Examples

Shokupan (Functional)

import { HttpCode, get } from 'shokupan';

export const getResource = get('/resource', () => {
    return { message: 'Not Modified' };
}).pipe(HttpCode(304));

Shokupan (Controller)

import { Controller, Get, HttpCode } from 'shokupan';

@Controller('/api')
export class ExampleController {
    @Get('/resource')
    @HttpCode(304)
    getResource() {
        return { message: 'Not Modified' };
    }
}

Express

import express from 'express';
const app = express();

app.get('/resource', (req, res) => {
    res.status(304).json({ message: 'Not Modified' });
});

Nest

import { Controller, Get, HttpCode } from '@nestjs/common';

@Controller('api')
export class ExampleController {
  @Get('resource')
  @HttpCode(304)
  getResource() {
    return { message: 'Not Modified' };
  }
}

Koa

import Koa from 'koa';
const app = new Koa();

app.use(async ctx => {
  if (ctx.path === '/resource' && ctx.method === 'GET') {
    ctx.status = 304;
    ctx.body = { message: 'Not Modified' };
  }
});