如何在自定义rxcpp运算符上调用on_error [英] How to call on_error on a custom rxcpp operator

问题描述

我创建了一个简单的rx运算符，该运算符将字符串流转换为jsons流，并且工作正常.但是，我希望能够引发一个自定义异常，并且我不确定如何调用订阅的on_error方法

I've created a simple rx operator that converts a stream of strings to a stream of jsons and it works fine. However, I would like to be able to raise a custom exception and I am not sure how to call the on_error method of the subscription

运算符称为convertStringToJson，可以在这里找到工作示例: https://github.com/cipriancaba/rxcpp-examples/blob/master/src/SimpleOperators.cpp

The operator is called convertStringToJson and a working sample can be found here: https://github.com/cipriancaba/rxcpp-examples/blob/master/src/SimpleOperators.cpp

function<observable<json>(observable<string>)> SimpleOperators::convertFromStringToJson() {
  return [](observable<string> $str) {
    return $str |
      Rx::map([](const string s) {
        return json::parse(s);
      });
  };
}

推荐答案

如果使用try/catch转换异常，则rxcpp将起作用.

rxcpp will work if you use try/catch to translate the exception.

但是，预期的模式是使用on_error_resume_next()转换异常.

However, the intended pattern is to use on_error_resume_next() to translate the exception.

这是代码:

function<observable<json>(observable<string>)> SimpleOperators::convertFromStringToJson() {
  return [](observable<string> $str) {
    return $str |
      Rx::map([](const string& s) {
          return json::parse(s);
      }) |
      Rx::on_error_resume_next([](std::exception_ptr){
        return Rx::error<json>(runtime_error("custom exception"));
      });
  };
}

我用这段代码在github上打开了一个拉取请求.

I opened a pull request on github with this code.

https://github.com/cipriancaba/rxcpp-examples/pull/1

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