如何将 JSON 字符串转换为 URL 参数（GET 请求）？

Question

我有以下 JSON 必须转换为 GET 请求的 URL 参数。

一个 example is given here，但是由于这个对象的复杂性，可能有多个 line_items_attributes 每个都具有如图所示的给定值，我很难传递正确的值。

我也尝试过只序列化 JSON 对象并传递该值，但这也没有解决问题。

{
    "purchase_invoice":
    {
        "date":"14/04/2015",
        "due_date":"14/04/2015",
        "contact_id":500,
        "contact_name":"TestContact",
        "reference":"TestReference",
        "line_items_attributes":[
            {
                "unit_price":10.00,
                "quantity":1,
                "description":"TestLineItemAttDesc",
                "tax_code_id":1,
                "ledger_account_id":501,
                "tax_rate_percentage":19.0,
                "tax_amount":1.60

            }]
    }
}

我已经搜索了一段时间，但运气不佳。任何见解都将受到赞赏和欢迎！

这是在调用不支持 JSON 格式的传入数据的 API，因此在服务器端执行此操作或更改 Web 服务以支持 JSON 格式的数据不可能。

Answer 1

所以最后的 URL 可以很容易地使用任何 URL Encoding mechanism 来计算。在 C# 中，我们可以执行以下操作：

string json = "...";
string baseUrl = "http://bla.com/somepage?myJson="
string urlWithJson = baseUrl + System.Net.WebUtility.UrlEncode(json)

有什么方法可以 POST 数据或以其他方式发送请求正文吗？好像有点easier/cleaner.

Answer 2

听起来你需要的东西是 x-www-form-urlencoded。

根据您的示例，它看起来像这样：

purchase_invoice%5Bdate%5D=14%2F04%2F2015&purchase_invoice%5Bdue_date%5D=14%2F04%2F2015&purchase_invoice%5Bcontact_id%5D=500&purchase_invoice%5Bcontact_name%5D=TestContact&purchase_invoice%5Breference%5D=TestReference&purchase_invoice%5Bline_items_attributes%5D%5B0%5D%5Bunit_price%5D=10&purchase_invoice%5Bline_items_attributes%5D%5B0%5D%5Bquantity%5D=1&purchase_invoice%5Bline_items_attributes%5D%5B0%5D%5Bdescription%5D=TestLineItemAttDesc&purchase_invoice%5Bline_items_attributes%5D%5B0%5D%5Btax_code_id%5D=1&purchase_invoice%5Bline_items_attributes%5D%5B0%5D%5Bledger_account_id%5D=501&purchase_invoice%5Bline_items_attributes%5D%5B0%5D%5Btax_rate_percentage%5D=19&purchase_invoice%5Bline_items_attributes%5D%5B0%5D%5Btax_amount%5D=1.6

据我所知，此编码的最佳参考是 jQuery JavaScript 库中未记录的 jQuery.param 方法。

Answer 3

x-www-form-urlencoded content is, essentially, a flat sequence of key/value tuples, and as explained in this answer to How do I use FormUrlEncodedContent for complex data types? by Tomalak，没有规范的方法可以将分层嵌套 key/value 结构转换为平面结构。

然而，从上面提到的 to this question, this example from the Stripe API, and the question 看来，通过将键括在括号中并将它们附加到最上面的键，将复杂嵌套对象中的参数展平是很常见的，如下所示：

{
    { "purchase_invoice[date]", "14/04/2015" } 
    { "purchase_invoice[due_date]", "14/04/2015" } 
    { "purchase_invoice[contact_id]", "500" } 
    { "purchase_invoice[contact_name]", "TestContact" } 
    { "purchase_invoice[reference]", "TestReference" } 
    { "purchase_invoice[line_items_attributes][0][unit_price]", "10" } 
    { "purchase_invoice[line_items_attributes][0][quantity]", "1" } 
    { "purchase_invoice[line_items_attributes][0][description]", "TestLineItemAttDesc" } 
    { "purchase_invoice[line_items_attributes][0][tax_code_id]", "1" } 
    { "purchase_invoice[line_items_attributes][0][ledger_account_id]", "501" } 
    { "purchase_invoice[line_items_attributes][0][tax_rate_percentage]", "19" } 
    { "purchase_invoice[line_items_attributes][0][tax_amount]", "1.6" } 
}

如果这是您想要的，您可以使用以下扩展方法生成这样的 key/value 与 json.net 对：

public static partial class JsonExtensions
{
    public static string ToUrlEncodedQueryString(this JContainer container)
    {
        return container.ToQueryStringKeyValuePairs().ToUrlEncodedQueryString();
    }

    public static IEnumerable<KeyValuePair<string, string>> ToQueryStringKeyValuePairs(this JContainer container)
    {
        return container.Descendants()
            .OfType<JValue>()
            .Select(v => new KeyValuePair<string, string>(v.ToQueryStringParameterName(), (string)v));
    }

    public static string ToUrlEncodedQueryString(this IEnumerable<KeyValuePair<string, string>> pairs)
    {
        return string.Join("&", pairs.Select(p => HttpUtility.UrlEncode(p.Key) + "=" + HttpUtility.UrlEncode(p.Value)));
        //The following works but it seems heavy to construct and await a task just to built a string:
        //return new System.Net.Http.FormUrlEncodedContent(pairs).ReadAsStringAsync().Result;
        //The following works and eliminates allocation of one intermediate string per pair, but requires more code:
        //return pairs.Aggregate(new StringBuilder(), (sb, p) => (sb.Length > 0 ? sb.Append("&") : sb).Append(HttpUtility.UrlEncode(p.Key)).Append("=").Append(HttpUtility.UrlEncode(p.Value))).ToString();
        //Answers from  that use HttpUtility.ParseQueryString() are wrong because that class doesn't correctly escape the keys names.
    }

    public static string ToQueryStringParameterName(this JToken token)
    {
        // Loosely modeled on JToken.Path
        // https://github.com/JamesNK/Newtonsoft.Json/blob/master/Src/Newtonsoft.Json/Linq/JToken.cs#L184
        // By https://github.com/JamesNK
        if (token == null || token.Parent == null)
            return string.Empty;
        var positions = new List<string>();
        for (JToken previous = null, current = token; current != null; previous = current, current = current.Parent)
        {
            switch (current)
            {
                case JProperty property:
                    positions.Add(property.Name);
                    break;
                case JArray array:
                case JConstructor constructor:
                    if (previous != null)
                        positions.Add(((IList<JToken>)current).IndexOf(previous).ToString(CultureInfo.InvariantCulture)); // Don't localize the indices!
                    break;
            }
        }
        var sb = new StringBuilder();
        for (var i = positions.Count - 1; i >= 0; i--)
        {
            var name = positions[i];
            // TODO: decide what should happen if the name contains the characters `[` or `]`.
            if (sb.Length == 0)
                sb.Append(name);
            else
                sb.Append('[').Append(name).Append(']');
        }

        return sb.ToString();
    }
}

然后如果你有一个 JSON 字符串，你可以将它解析成一个 LINQ-to-JSON JObject 并像这样生成查询字符串：

var obj = JObject.Parse(jsonString);
var queryString = obj.ToUrlEncodedQueryString();

或者，如果您有一些分层数据模型 POCO，您可以使用 JObject.FromObject():

从模型生成 JObject

var obj = JObject.FromObject(myModel);
var queryString = obj.ToUrlEncodedQueryString();

演示 fiddle here.

如何将 JSON 字符串转换为 URL 参数（GET 请求）？

How can I convert a JSON string to URL parameters (GET request)?

c#

json

url-parameters