C# 类型安全 JSON-行反序列化

Question

目前我正在使用 Shopify GraphQL Bulk Query。
此查询 returns 一个 JSON Lines 文件。这样的文件可能如下所示：

{"id":"gid:\/\/shopify\/Product\/5860091625632","title":"Levis Jeans","description":"Cool Jeans","vendor":"Levis","status":"ACTIVE"}
{"id":"gid:\/\/shopify\/ProductImage\/20289865679008","__parentId":"gid:\/\/shopify\/Product\/5860091625632"}
{"id":"gid:\/\/shopify\/ProductVariant\/37178118963360","title":"32","position":1,"image":null,"selectedOptions":[{"name":"Size","value":"32"}],"inventoryItem":{},"__parentId":"gid:\/\/shopify\/Product\/5860091625632"}
{"available":10,"location":{"id":"gid:\/\/shopify\/Location\/57510625440"},"__parentId":"gid:\/\/shopify\/ProductVariant\/37178118963360"}
{"id":"gid:\/\/shopify\/ProductVariant\/37178118996128","title":"31","position":2,"image":null,"selectedOptions":[{"name":"Size","value":"31"}],"inventoryItem":{},"__parentId":"gid:\/\/shopify\/Product\/5860091625632"}
{"available":5,"location":{"id":"gid:\/\/shopify\/Location\/57510625440"},"__parentId":"gid:\/\/shopify\/ProductVariant\/37178118996128"}
{"available":3,"location":{"id":"gid:\/\/shopify\/Location\/57951518880"},"__parentId":"gid:\/\/shopify\/ProductVariant\/37178118996128"}
{"id":"gid:\/\/shopify\/ProductVariant\/37178119028896","title":"34","position":3,"image":null,"selectedOptions":[{"name":"Size","value":"34"}],"inventoryItem":{},"__parentId":"gid:\/\/shopify\/Product\/5860091625632"}
{"available":5,"location":{"id":"gid:\/\/shopify\/Location\/57510625440"},"__parentId":"gid:\/\/shopify\/ProductVariant\/37178119028896"}
{"available":15,"location":{"id":"gid:\/\/shopify\/Location\/57951518880"},"__parentId":"gid:\/\/shopify\/ProductVariant\/37178119028896"}

此文件的每一行都是一个有效的 JSON-object 并且这些行通过 __parentId 相互连接。
我的目标是将其反序列化为 C# 类，如下所示：

class Product
{
    public string Id { get; set; }
    public string Title { get; set; }
    public string Description { get; set; }
    public IEnumerable<ProductImage> Images { get; set; }
    public IEnumerable<ProductVariant> Variants { get; set; }
}
class ProductImage
{
    public string Id { get; set; }
}
class ProductVariant
{
    public string Id { get; set; }
    public IEnumerable<IDictionary<string, string>> SelectedOptions { get; set; }
    public IEnumerable<InventoryLevel> Levels { get; set; }
}
class InventoryLevel
{
    public int Available { get; set; }
}

以及执行反序列化的潜在函数的输出：

var file = new System.IO.StreamReader(@"c:\test.jsonl");
var products = DeserializeJsonL<IEnumerable<Product>>(file);

Shopify建议反向读取文件。我明白了。但是我无法想象如何以类型安全的方式反序列化这个文件。我如何确定当前行是 ProductVariant、ProductImage 还是其他内容？我无法影响 JSONL 输出以包含类型信息。

我很确定没有类型信息我不能安全地反序列化它。但是我应该如何处理这些数据然后插入数据库？

编辑 {"id":"gid:\/\/shopify\/Product\/5860091625632"} 中的类名不能用于确定类型！

Answer 1

我最终通过为每种类型定义一个唯一的字段名来向我的 graphql 查询添加某种类型信息，该字段名可能在生成的 JSON 行文件中的新行上。

为此我使用了 GraphQL 字段别名：

someQuery {
   uniqueFieldAlias : fieldName
}

当我阅读文件时，我会在每一行中搜索唯一的字段名。然后我将该行反序列化为相应的 class.

using (var file = new StreamReader(await res.Content.ReadAsStreamAsync()))
{
    string line;

    while ((line = await file.ReadLineAsync()) != null)
    {
        if (line.Contains("\"uniqueFieldAlias\""))
        {
            var product = JsonSerializer.Deserialize<Product>(line);
            products.Add(product);
            continue;
        }
        if (line.Contains("\"otherUniqueAlias\""))
        {
            var somethingElse = JsonSerializer.Deserialize<SomeClass>(line);
            products[productIndex].Something.Add(somethingElse);
            continue;
        }
    }
}

这个想法受到@Caius Jard 评论的启发

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