JsonParser

Fast Forward reader using Utf8JsonReader.

This fast forward reader is useful if you want to iterate all over the JSON data with a minimum memory allocation.

This extensions is using the Utf8JsonReader that is a high-performance JSON parser that reads from a ReadOnlySpan<byte> and is able to read the JSON data without allocating memory for the JSON data.

You can read more about the Utf8JsonReader here.

As the Utf8JsonReader is a ref struct, it's complicated to use it to return an IENumerable<T> (using yield), and even from an async method.

This JsonReader class allows you to iterate over the JSON data using a simple foreach loop.

using var jsonReader = new JsonReader(GetFileStream(), 1024); // test 10 to see buffer increase in debug console

foreach (var prop in jsonReader.Values())
{
    if (prop.TokenType == JsonTokenType.StartObject || prop.TokenType == JsonTokenType.StartArray || prop.TokenType == JsonTokenType.EndObject || prop.TokenType == JsonTokenType.EndArray)
        Console.WriteLine($"- ({prop.TokenType})");
    else if (prop.TokenType == JsonTokenType.PropertyName)
        Console.WriteLine($"Property: {prop.Name}");
    else
        Console.WriteLine($"Value: {prop.Value}");
}

- (StartObject)
Property: tableName
Value: Address
Property: schemaName
Value: dbo
Property: version
Value: 1
Property: columns
- (StartArray)
- (StartObject)
Property: name
Value: AddressID
Property: type
Value: int
- (EndObject)
- (StartObject)
Property: name
Value: Country
Property: type
Value: string
- (EndObject)
- (EndArray)
- (EndObject)