XMLDiff无法正确识别差异？ [英] XMLDiff fails to recognize differences correcly?

问题描述

我在这里想念什么？

一个用于在两个XML文件之间进行比较的Helper类： XMLDiff是否应该考虑元素名称并寻求最佳匹配以正确识别以下更改？ p>

a Helper class for making comparisons between two XML files:

public class XMLDiffer
{
    public XDocument Diff(string originalXML, string changedXML)
    {
        //http://msdn2.microsoft.com/en-us/library/aa302294.aspx
        XmlDiff xmlDiff = new XmlDiff(XmlDiffOptions.IgnoreChildOrder | XmlDiffOptions.IgnoreComments | XmlDiffOptions.IgnoreWhitespace);

        xmlDiff.Algorithm = XmlDiffAlgorithm.Precise;
        StringBuilder diffgramStringBuilder = new StringBuilder();
        bool xmlComparisonResult = false;
        using (StringReader legacySr = new StringReader(originalXML), nextgenSr = new StringReader(changedXML))
        {
            using (XmlReader legacyReader = XmlReader.Create(legacySr), nextgenReader = XmlReader.Create(nextgenSr))
            {
                using (StringWriter sw = new StringWriter(diffgramStringBuilder))
                {
                    using (XmlWriter diffgramWriter = XmlWriter.Create(sw))
                    {
                        xmlComparisonResult = xmlDiff.Compare(legacyReader, nextgenReader, diffgramWriter);
                    }
                }
            }
        }
        XDocument xdoc = XDocument.Parse(diffgramStringBuilder.ToString());
        return xdoc;
    }

    public string GetChangeHtml(string originalXML, string changedXML)
    {
        XmlDiffView view = new XmlDiffView();
        var diffgram = Diff(originalXML, changedXML);
        string ret = "";
        using (StringReader legacySr = new StringReader(originalXML), diffGramSr = new StringReader(diffgram.ToString()))
        {
            using (XmlReader legacyReader = XmlReader.Create(legacySr), diffgramReader = XmlReader.Create(diffGramSr))
            {
                using (StringWriter sw = new StringWriter())
                {
                    view.Load(legacyReader, diffgramReader);
                    view.GetHtml(sw);
                    ret = sw.ToString();
                }
            }
        }
        return ret;
    }

}

---

具有以下测试：

---

With Following test:

[TestMethod]
public void XMLDiff_AreNotSame_GetChangeHtmlAll()
{
    //Arrange
    string source = "<root><child>some text</child><child>more text</child><child1>REMOVED</child1></root>";
    //Ordering of the generic child nodes is not changed,  but it might
    string target = "<root><child>some text CHANGE</child><child>more text</child><child>ADDITION</child></root>";

    XMLDiffer differ = new XMLDiffer();

    //Act
    var diffview = differ.GetChangeHtml(source, target);

    //Assert
    Assert.IsNotNull(diffview);
}

产生以下内容（添加了html和table元素）：
https://pste.eu/p/Fm7Z.html

Produces following (html and table elements added): https://pste.eu/p/Fm7Z.html

有关库的更多信息： http://msdn2.microsoft .com / en-us / library / aa302294.aspx

参考链接： https://www.nuget.org/packages/XMLDiffPatch/

推荐答案

我最终实现了以下类来进行更改：

I ended up implementing following classes to get changes:

public class XMLComparer : IEqualityComparer<XNode>
{
    public bool Equals(XNode e1, XNode e2)
    {
        if (!(e1 is XElement)) return true;
        if (!(e2 is XElement)) return false;
        var el1 = e1 as XElement;
        var el2 = e2 as XElement;
        return Tuple.Create(el1.Name, el1.Value).Equals(Tuple.Create(el2.Name, el2.Value));
    }

    public int GetHashCode(XNode n)
    {
        if (!(n is XElement)) return 0;
        var el = n as XElement;
        return Tuple.Create(el.Name, el.Value).GetHashCode();
    }

}

public class XMLDifference
{
    public bool IsNew { get; set; }
    public XElement Node { get; set; }
}

public class XMLDifferenceComparer
{
    public List<XMLDifference> GetDifferences(string original, string changed)
    {
        List<XMLDifference> ret = new List<XMLDifference>();
        var originalDoc = XDocument.Parse(original);
        var changedDoc = XDocument.Parse(changed);
        //Get differences that are present in new xml version
        var differences = changedDoc.Root.Descendants().Except(originalDoc.Root.Descendants(), new XMLComparer());
        ret.AddRange(GetList(differences, true));
        //Get differences that have changed since the old xml version
        var oldValues = originalDoc.Root.Descendants().Except(changedDoc.Root.Descendants(), new XMLComparer());
        ret.AddRange(GetList(oldValues, false));
        return ret;
    }

    private List<XMLDifference> GetList(IEnumerable<XNode> nodes, bool isNew)
    {
        List<XMLDifference> ret = new List<XMLDifference>();
        foreach (XNode d in nodes)
        {
            var diff = new XMLDifference();
            diff.IsNew = isNew;

            var el = d as XElement;
            diff.Node = el;
            ret.Add(diff);
        }
        return ret;
    }
}

这可以识别更改，但不是特定于元素的由于缺少每个元素的唯一标识符，因此无法映射确切地更改了哪个元素以及更改的方式。

This can recognize changes but is not element specific, it cannot map which element exactly was changed and how, caused by lack of unique identifiers for each element.

此解决方案的主要思想来自于此： https://gist.github.com/krcourville/6933451

The main idea for this solution came from here: https://gist.github.com/krcourville/6933451

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