[WIP, lib v19] Source generators for Types and Requests with System.Text.Json support

[vova-lantsov-dev]

Summary

This PR introduces 2 source generators that generate the classes for Types and Requests folders. Also it brings an API parser app.

API parser

It produces a JSON file according to the following schema: https://github.com/TelegramBots/Telegram.Bot/blob/abdab6f0fdc5dcf9e84364dfc431abce766ddcf4/src/Telegram.Bot.ApiParser/schema.json

Types source generator

Scriban template that will be rendered for each Bot API type:

Telegram.Bot/src/Telegram.Bot.Generators/Templates.Types.cs

Lines 16 to 69 in abdab6f

	private const string TemplateText = @"//------------------------------------------------------------------------------
	// <auto-generated>
	// This code was generated by the Telegram.Bot.Generators.ApiTypesGenerator source generator
	//
	// Changes to this file may cause incorrect behavior and will be lost if
	// the code is regenerated.
	// </auto-generated>
	//------------------------------------------------------------------------------
	#nullable enable
	namespace {{ type_namespace }};
	/// <summary>
	{{~ for type_description_line in type_description | string.split '\n' ~}}
	/// {{ type_description_line }}
	{{~ end ~}}
	/// </summary>
	public partial class {{ type_name }}
	{
	{{~ for parameter in parameters ~}}
	{{
	func to_pascal_case(input)
	$separated = input | string.split ""_"" | array.each do
	ret $0 | string.capitalize
	end
	ret $separated | array.join """"
	end
	func get_parameter_type_name(input)
	if parameter.is_enum
	ret ""Telegram.Bot.Types.Enums."" | string.append input
	else
	ret input
	end
	end
	pascal_case_name = parameter.parameter_name | to_pascal_case
	is_required = parameter.parameter_description | !string.starts_with ""Optional""
	parameter_type_name = parameter.parameter_type_name | get_parameter_type_name
	}}
	/// <summary>
	{{~ for parameter_description_line in parameter.parameter_description | string.split '\n' ~}}
	/// {{ parameter_description_line }}
	{{~ end ~}}
	/// </summary>
	[System.Text.Json.Serialization.JsonPropertyName(""{{ parameter.parameter_name }}"")]
	{{~ if !is_required ~}}
	[System.Text.Json.Serialization.JsonIgnore(Condition = System.Text.Json.Serialization.JsonIgnoreCondition.WhenWritingDefault)]
	{{~ end ~}}
	[Newtonsoft.Json.JsonProperty(""{{ parameter.parameter_name }}"", {{ if is_required ~}}Required = Newtonsoft.Json.Required.Always{{~ else ~}}DefaultValueHandling = Newtonsoft.Json.DefaultValueHandling.Ignore{{~ end ~}})]
	public {{ parameter_type_name + "" "" + pascal_case_name }} { get; set; }
	{{~ end ~}}
	}";

where:

• {{ type_namespace }} is namespace (starts with Telegram.Bot.Types but can additionally contain sub-namespace such as Telegram.Bot.Types.InlineQueryResults)
• {{ type_description }} is type's multi-line description parsed from official Bot API page
• {{ type_name }} is the class'es name, for example for Bot API type Chat we will generate Chat class located in file Chat.generated.cs
• {{ parameter.parameter_description }} is property (parameter) multi-line description parsed from official Bot API page
• {{ parameter.parameter_name }} is snake_case name of parameter parsed from official Bot API page
• {{ parameter_type_name }} is fully qualified type name of property, including its namespace (if needed)
• {{ pascal_case_name }} is property name in PascalCase

The main concepts of this generation are:

• JsonIgnore attribute as well as Newtonsoft's Required and DefaultValueHandling arguments are only added when necessary
• Generated classes are partial so they can be extended with custom logic
• If class with corresponding name already exist and IS NOT partial - we skip generation of such class. If it exists and IS partial - class will be generated.

At the moment, the source generator looks for class types with public and without static modifiers, located inside Types folder and all sub-folders.

TODO

• Add support for Required and Ignore attributes/arguments
• Extend new Enum source generator with STJ serializers
• Allow sub-namespaces for some types (such as Telegram.Bot.Types.InlineQueryResults)
• Add support for custom mapping of type names (f.e. ForceReply -> ForceReplyMarkup)
• Write unit tests

Requests source generator

TODO

[vova-lantsov-dev]

@tuscen @karb0f0s @MihaZupan let's discuss this feature if we can bring it in 18.0.0 release

[Lorymi]

Any update?

[tuscen]

Unfortunately, I don’t have enough free time at the moment to review and test this PR.