Contents cache demo

Issue: 349

webpack proxy not work

build: {
    extend (config, ctx) {
      if (!ctx.isClient) {
        config.devServer = {
          proxy: {
             '/api/*': {
              target: 'http://127.0.0.1:8080/',
              secure: false
             }
          }
        }
       } 
    }
  }

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