How to: Extend the Aurelia Logger with additional methods

问题

Foremost I am following this example on implementing and customizing the aurelia-logger.

This approach only works fine. Any changes to the existing methods in the custom appender work fine. However if I change the CustomLogAppender.js to

export class CustomLogAppender {
  constructor(){}
  debug(logger, message, ...rest){
    console.debug(`DEBUG [${logger.id}] ${message}`, ...rest);
  }
  info(logger, message, ...rest){
    console.info(`INFO [${logger.id}] ${message}`, ...rest);
  }
  warn(logger, message, ...rest){
    console.warn(`WARN [${logger.id}] ${message}`, ...rest); 
  }
  error(logger, message, ...rest){
    console.error(`ERROR [${logger.id}] ${message}`, ...rest);
  }
  newMethod(logger, message, ...rest){
    //whatever
  }
}

Then logger.newMethod(“send error to backend”); is not a defined method when called in a view-model. I am trying to write additional logging methods that can send warns, info, errs, etc to the back-end for database logging should i deem it necessary but am having trouble adding these methods to the aurelia-logger. Any guidance would be appreciated.

回答1:

If you are following the example from the URL, the following lines are relevant for your: https://github.com/aurelia/logging/blob/21d92e79a5f924b25b1eae0648af5a7a0ab44527/src/index.js#L96-L115

As you can see, it creates a logger, which only has the default methods, i.e. what you get returned is not exactly your logger. What you need to do is enhance the existing methods (in there, you can use your custom methods).

See the following appender as an example:

import { inject } from 'aurelia-framework';
import {HttpClient} from 'aurelia-http-client';
import {Logger} from 'aurelia-logging';

@inject(HttpClient)
export class ServerLogAppender {
    constructor(http) {
        this.http = http;
    }

    debug(logger, message, ...rest) {
        this.sendToServer(logger, message, ...rest);
    }

    info(logger, message,...rest){
        this.sendToServer(logger, message,...rest);
    }

    warn(logger, message,...rest){
        this.sendToServer(logger, message,...rest);
    }

    error(logger, message,...rest){
        this.sendToServer(logger, message,...rest);
    }

    sendToServer(logger, message,...rest){
        this.http.post('myerrorhandler', {
            url: window.location.href,
            source: logger.id,
            message: message,
            additional: rest.join('\r\n')
        });
    }
}

As you can see, the default methods (debug, info, warn, error) use the custom method sendToServer().

来源：https://stackoverflow.com/questions/41448108/how-to-extend-the-aurelia-logger-with-additional-methods

标签

javascript

aurelia