JsonExtensions 1.2.0

JsonExtensions

✅ Project status: active.

This library provides a set of helpful utilities for types defined in the System.Text.Json namespace.

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📦 NuGet: dotnet add package JsonExtensions

Usage

Parsing JsonElement

You can use the static methods on Json class to parse JSON directly into a stateless JsonElement instance, without having to deal with JsonDocument in the process:

using JsonExtensions;

var jsonRaw = "{ \"foo\": \"bar\" }";

var jsonElement = Json.Parse(jsonRaw); // returns JsonElement
var jsonElement = Json.TryParse(jsonRaw); // returns null in case of invalid JSON

Null-safe reading

This library offers many extension methods for JsonElement that allow you to read content in a more fault-tolerant way:

using JsonExtensions.Reading;

var jsonElement = ...;

// Gets a property or returns null if:
// - element is not an object
// - property does not exist
// - property value is null
var maybeProperty = jsonElement.GetPropertyOrNull("prop");

// Gets an array child or returns null if:
// - element is not an array
// - index is out of bounds
// - child is null
var maybeChild = jsonElement.GetByIndexOrNull(3);

// Gets the value converted into specified type or returns null if:
// - element is null
// - element kind does not match the specified type
// - the value cannot be parsed into the specified type
var maybeString = jsonElement.GetStringOrNull();
var maybeInt32 = jsonElement.GetInt32OrNull();
var maybeGuid = jsonElement.GetGuidOrNull();

// Gets the value coerced into specified type or returns null if:
// - element is null
// - element kind does not match the specified type or a string
// - the value cannot be parsed into the specified type
var maybeInt32Coerced = jsonElement.GetInt32CoercedOrNull();
var maybeDoubleCoerced = jsonElement.GetDoubleCoercedOrNull();

// Enumerates an array or returns null if:
// - element is not an array
var arrayEnumerator = jsonElement.EnumerateArrayOrNull();

// Enumerates an object or returns null if:
// - element is not an object
var objectEnumerator = jsonElement.EnumerateObjectOrNull();

// Enumerates an array or returns an empty enumerator if:
// - element is not an array
foreach (var child in jsonElement.EnumerateArrayOrEmpty())
{
    // ...
}

// Enumerates an object or returns an empty enumerator if:
// - element is not an object
foreach (var (name, child) in jsonElement.EnumerateObjectOrEmpty())
{
    // ...
}

Most of these methods can also be chained together using the null-conditional operator:

// Returns null if:
// - element is not an object
// - property does not exist
// - property value is null
// - property value cannot be converted into the specified type
var maybeInt32 = jsonElement.GetPropertyOrNull("prop")?.GetInt32OrNull();

Null-safe writing

Similarly, there are also extension methods for Utf8JsonWriter that allow writing nullable versions of common value types:

using JsonExtensions.Writing;

var writer = new Utf8JsonWriter(...);

// Writes "prop":true
writer.WriteBoolean("prop", new bool?(true));

// Writes "prop":null
writer.WriteBoolean("prop", new bool?());

Parsing JSON from HTTP

To make it easier to read JSON that comes from HTTP responses, this library also provides a few helper extension methods on HttpContent and HttpClient:

using JsonExtensions.Http;

var httpClient = new HttpClient();

// Send GET request and retrieve JSON directly
var json = await httpClient.GetJsonAsync("..."); // returns JsonElement

// Read JSON from content
using var request = new HttpRequestMessage(HttpMethod.Post, "...");
using var response = await httpClient.SendAsync(request); 
var json = await response.Content.ReadAsJsonAsync(); // returns JsonElement

Accessing children by path

Using jsonElement.GetPropertyByPathOrNull(...) or jsonElement.GetPropertyByPath(...), you can get an inner child by its path:

var json = Json.Parse("{\"foo\":{\"bar\":{\"baz\":13}}}");

var child = json.GetPropertyByPath("foo.bar.baz");

var value = child.GetInt32(); // 13

Note this only supports basic paths involving child access operators. It doesn't (yet) have full support for JPath.