CODEWITHSUNDEEP
c#arraysjsonjson.netjsonpath
Allan Xu
Allan Xu

Reputation: 9318

How to use JSONPath (or any other option) to query an unnamed JSON array?

A REST API service provides the following JSON to my C# code: 

[
  {
    "contentUri": "https://somewhere.com/aGuid1",
    "contentId": "2"
  },
  {
    "contentUri": "https://somewhere.com/aGuid2",
    "contentId": "3"
  },
  {
    "contentUri": "https://somewhere.com/aGuid3",
    "contentId": "4"
  }
]

Above JSON is simplified and the actual response is a VERY large string ,so is string manipulations will be costly and memory intensive.

The problem is that the above JSON Array does not have a name. so I am not able to parse it into an JArray unless I manipulate the JSON string and add a name to it. I like to avoid that.

I can perfectly parse above JSON into a JToken. Now I like to query within the JToken by using JToken.SelectToken and JSONPath

I've tried many JSONPath queries, but no lock since the array does not have a name.

Upvotes: 2

Views: 1359

Answers (1)

Brian Rogers
Brian Rogers

Reputation: 129707

You can very easily parse the above json into a JArray:

JArray array = JArray.Parse(jsonString);

To get all objects in the array, you don't need a JSONPath expression, just loop over the array:

foreach (JObject child in array)
{
    Console.WriteLine("contentUri: " + (string)child["contentUri"]);
    Console.WriteLine("contentId: " + (string)child["contentId"]);
}

For completeness, the equivalent JSONPath expression to get all the array values is [*]. But it doesn't really buy you anything here.

To get all the contentUri values only, you can use SelectTokens with the JSONPath [*].contentUri:

foreach (JToken uri in array.SelectTokens("[*].contentUri"))
{
    Console.WriteLine(uri);
}

Alternatively, you could just Select them like this:

foreach (string uri in array.Select(t => (string)t["contentUri"]))
{
    Console.WriteLine(uri);
}

Fiddle: https://dotnetfiddle.net/C2gIWX

Upvotes: 3

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