可以使用JSONPath搜索不区分大小写的内容吗? [英] Possible to search case-insensitive with JSONPath?

问题描述

使用JSON.NET的 SelectToken方法要使用 JSONPath 选择令牌，我发现没有办法指定搜索不区分大小写.

Using the SelectToken method of JSON.NET to select a token with JSONPath, I found no way to specifiy that the search should be case-insensitive.

例如

json.SelectToken("$.maxAppVersion")

无论返回的是maxappversion，MAXAPPVERSION还是任何其他大小写形式，都应返回匹配的令牌.

should return a matching token, no matter whether it is written maxappversion, MAXAPPVERSION or any other casing.

我的问题:

是否存在以不区分大小写的方式使用JSONPath的官方方法或至少一种变通方法?

Is there an official way or at least a work-around to use JSONPath in a case-insensitive way?

(我找到的最接近的是这个类似的问题(对于Java的JSON实现)

(The closest I found was this similar question for a Java implementation of JSON)

推荐答案

从8.0.2版开始，此功能尚未在Json.NET中实现.

This is not implemented in Json.NET as of version 8.0.2.

JSONPath属性名称匹配通过两个类完成: FieldFilter 用于简单的名称匹配，以及

JSONPath property name matching is done with two classes: FieldFilter for simple name matches, and ScanFilter for recursive searches. FieldFilter has the following code, where o is a JObject:

JToken v = o[Name];
if (v != null)
{
    yield return v;
}

内部 JObject 使用 JPropertyKeyedCollection 保留其属性，该属性随后使用以下比较器进行属性名称查找:

Internally JObject uses a JPropertyKeyedCollection to hold its properties, which in turn uses the following comparer for property name lookups:

private static readonly IEqualityComparer<string> Comparer = StringComparer.Ordinal;

因此区分大小写.同样，ScanFilter具有:

It is thus case-sensitive. Similarly, ScanFilter has:

JProperty e = value as JProperty;
if (e != null)
{
    if (e.Name == Name)
    {
        yield return e.Value;
    }
}

这也是区分大小写的.

Which is also case sensitive.

JSONPath标准中没有提及不区分大小写的匹配，所以我认为您想要什么就是开箱即用.

There's no mention of case-insensitive matching in the JSONPath standard so I think what you want simply isn't available out of the box.

作为解决方法，您可以为此添加自己的扩展方法:

As a workaround, you could add your own extension methods for this:

public static class JsonExtensions
{
    public static IEnumerable<JToken> CaseSelectPropertyValues(this JToken token, string name)
    {
        var obj = token as JObject;
        if (obj == null)
            yield break;
        foreach (var property in obj.Properties())
        {
            if (name == null)
                yield return property.Value;
            else if (string.Equals(property.Name, name, StringComparison.OrdinalIgnoreCase))
                yield return property.Value;
        }
    }

    public static IEnumerable<JToken> CaseSelectPropertyValues(this IEnumerable<JToken> tokens, string name)
    {
        if (tokens == null)
            throw new ArgumentNullException();
        return tokens.SelectMany(t => t.CaseSelectPropertyValues(name));
    }
}

，然后将它们与标准的SelectTokens调用链接在一起，例如:

And then chain them together with standard SelectTokens calls, for instance:

var root = new { Array = new object[] { new { maxAppVersion = "1" }, new { MaxAppVersion = "2" } } };

var json = JToken.FromObject(root);

var tokens = json.SelectTokens("Array[*]").CaseSelectPropertyValues("maxappversion").ToList();
if (tokens.Count != 2)
    throw new InvalidOperationException(); // No exception thrown

(相关信息，请参见Json.NET问题提供一种区分大小写的方法属性反序列化，要求使用区分大小写的合同解析器，以确保与LINQ-to-JSON的区分大小写一致.)

(Relatedly, see the Json.NET issue Provide a way to do case-sensitive property deserialization which requests a case-sensitive contract resolver for consistency with the case-sensitivity of LINQ-to-JSON.)

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