挂钩 OData 的 $metadata 响应并将其从 XML 转换为 JSON

Question

The answer of Get OData $metadata in JSON format states that OData cannot return the metadata as JSON by default.

But is it possible then to capture or hook its response for the $metadata URL, and then convert it on the fly to JSON before sending it to the client?

I imagine pseudocode like this:

[HttpGet]
[ODataRoute("$metadata")]
public string GetMetadataAsJson()
{
    string xml = GetOdataMetadataAsXML();
    string json = ConvertToJson(xml);
    return json;
}

I don't know how to implement it correctly, though, in particular I'm not sure how to get the standard OData response as a string, and how to hook the $metadata URL.

Answer 1

Newtonsoft supports the Json part checkout https://www.newtonsoft.com/json/help/html/ConvertXmlToJson.htm

So the actual solution for the Json Part would be quite simple, as soon as you have your XML

[HttpGet]
[ODataRoute("$metadata")]
public string GetMetadataAsJson()
{
    string xml = GetOdataMetadataAsXML();
    XmlDocument doc = new XmlDocument();
    doc.LoadXml(xml);
    string json = JsonConvert.SerializeXmlNode(doc);
    return json;
}

Also you should probably first check if eg a format query is set for example with this code

[HttpGet]
[ODataRoute("$metadata")]
public string GetMetadataAsJson([FromQuery(Name="Format")]string format)
{
    string metaResult = GetOdataMetadataAsXML();
    if(format.Equals("json",StringComparison.OrdinalIgnoreCase))
    {
        XmlDocument metaDoc = new XmlDocument();
        doc.LoadXml(metaResult);
        metaResult = JsonConvert.SerializeXmlNode(doc);
    }
    return metaResult;
}