xml - 解析多状态响应的性能不佳

问题描述

我正在使用 xml 库来解析多状态响应。该代码需要花费很多秒来解析一个简单的 xml。我可以做些什么来提高性能？我不能在工厂中使用异步代码。

我对 xml 库的解析速度感到惊讶，而且没有任何异步代码。我试图分析库的代码以将其作为我可以做什么的示例，但我无法理解。

import 'package:xml/xml.dart';

class MultiStatus {
  final List<Response> response;
  final String? syncToken;

  MultiStatus({required this.response, this.syncToken});

  factory MultiStatus.fromXml(XmlDocument element) {
    var response = <Response>[];

    var multistatus = element.firstElementChild;

    if (multistatus!.name.local == 'multistatus') {
      var elements = multistatus.children.whereType<XmlElement>();

      // add responses
      elements
          .where((element) => element.name.local == 'response')
          .forEach((element) {
        response.add(Response.fromXml(element));
      });

      try {
        var syncToken = elements
            .firstWhere((element) => element.name.local == 'sync-token');

        return MultiStatus(response: response, syncToken: syncToken.text);
      } catch (e) {
        return MultiStatus(response: response);
      }
    }

    throw Error();
  }

  factory MultiStatus.fromString(String string){
    var document = XmlDocument.parse(string);

    return MultiStatus.fromXml(document);
  }
}

class Response {
  final String href;
  final Propstat propstat;

  Response({required this.href, required this.propstat});

  factory Response.fromXml(XmlElement element) {
    if (element.name.local == 'response') {
      var elements = element.children.whereType<XmlElement>();

      var href =
          elements.firstWhere((element) => element.name.local == 'href').text;

      var propstatXml =
          elements.firstWhere((element) => element.name.local == 'propstat');

      return Response(href: href, propstat: Propstat.fromXml(propstatXml));
    }

    throw Error();
  }
}

class Propstat {
  final Map<String, dynamic> prop;
  final int status;

  Propstat({required this.prop, required this.status});

  factory Propstat.fromXml(XmlElement element) {
    if (element.name.local == 'propstat') {
      var prop = <String, dynamic>{};

      var elements = element.children.whereType<XmlElement>();

      var props = elements
          .firstWhere((element) => element.name.local == 'prop')
          .children
          .whereType<XmlElement>();

      props.forEach((element) {
        var value = element.text.isNotEmpty
            ? element.text
            : element.children.whereType<XmlElement>();

        prop[element.name.local] = value;
      });

      var status = elements
          .firstWhere((element) => element.name.local == 'status')
          .text
          .split(' ')[1];

      return Propstat(prop: prop, status: int.parse(status));
    }

    throw Error();
  }

  @override
  String toString() {
    var string = '';

    prop.forEach((key, value) {
      var valueString = value.toString();

      string += '$key: ${valueString.length > 200 ? '\n' : ''}$valueString';
    });

    return string;
  }
}

标签： xmlperformancedartwebdavcaldav

xml - 解析多状态响应的性能不佳

问题描述

解决方案

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