thor怎么添加json

{
  "database": {
    "host": "localhost",
    "port": 5432,
    "username": "admin"
  },
  "api_key": "12345-67890"
}

使用方法：

thor json_file_demo:read_json_file config.json
# 输出
Data from config.json:
{
  "database": {
    "host": "localhost",
    "port": 5432,
    "username": "admin"
  },
  "api_key": "12345-67890"
}

关键点：

• 通过File.exist?检查文件是否存在，避免Errno::ENOENT错误；
• 使用pretty_generate（来自json模块）格式化输出,提升可读性。

生成JSON字符串

当需要将Ruby对象转换为JSON字符串时（如输出到文件或命令行），可使用JSON.generate或to_json方法。

示例：将Hash转换为JSON字符串

# lib/thor/json_generate_demo.rb
require 'thor'
require 'json'
class JsonGenerateDemo < Thor
  desc "generate_json", "Generate JSON string from Ruby Hash"
  option :pretty, type: :boolean, default: false, desc: "Pretty print JSON"
  def generate_json
    data = {
      tool: "Thor",
      purpose: "CLI development",
      features: ["task definition", "argument parsing", "JSON support"]
    }
    json_string = options[:pretty] ? JSON.pretty_generate(data) : JSON.generate(data)
    puts json_string
  end
end
JsonGenerateDemo.start(ARGV)

使用方法：

# 生成紧凑JSON
thor json_generate_demo:generate_json
# 输出: {"tool":"Thor","purpose":"CLI development","features":["task definition","argument parsing","JSON support"]}
# 生成格式化JSON
thor json_generate_demo:generate_json --pretty
# 输出:
# {
#   "tool": "Thor",
#   "purpose": "CLI development",
#   "features": [
#     "task definition",
#     "argument parsing",
#     "JSON support"
#   ]
# }

关键点：

• JSON.generate直接生成紧凑JSON，JSON.pretty_generate生成带缩进的格式化JSON；
• 通过options控制输出格式,提升用户体验。

进阶方法：集成JSON Schema验证

对于需要严格校验JSON数据结构的场景（如用户输入的配置），可结合JSON Schema确保数据格式正确。json-schema gem提供了Ruby端的JSON Schema验证功能。

添加json-schema依赖

在Gemfile中添加：

gem 'json-schema'

然后执行bundle install。

定义Schema并验证数据

假设我们有一个Thor工具，需接收用户提交的JSON配置，并验证其是否符合预定义的Schema（如必须包含name和version字段）。

示例：JSON Schema验证

# lib/thor/json_schema_demo.rb
require 'thor'
require 'json'
require 'json-schema'
class JsonSchemaDemo < Thor
  desc "validate_config", "Validate JSON config against a schema"
  argument :config_file, type: :string, desc: "Path to JSON config file"
  def validate_config
    unless File.exist?(config_file)
      puts "Error: File '#{config_file}' does not exist"
      return
    end
    # 定义JSON Schema
    schema = {
      "type" => "object",
      "required" => ["name", "version"],
      "properties" => {
        "name" => {"type" => "string"},
        "version" => {"type" => "string", "pattern" => "^\d+\.\d+\.\d+$"},
        "dependencies" => {
          "type" => "array",
          "items" => {"type" => "string"}
        }
      }
    }
    begin
      config_data = JSON.parse(File.read(config_file))
      JSON::Validator.validate!(schema, config_data)
      puts "✅ Config is valid!"
      puts "Name: #{config_data['name']}"
      puts "Version: #{config_data['version']}"
    rescue JSON::ParserError => e
      puts "Error: Invalid JSON in file - #{e.message}"
    rescue JSON::Schema::ValidationError => e
      puts "❌ Config validation failed: #{e.message}"
    end
  end
end
JsonSchemaDemo.start(ARGV)

假设配置文件app_config.json：

{
  "name": "my_app",
  "version": "1.2.3",
  "dependencies": ["rails", "webpacker"]
}

thor json_schema_demo:validate_config app_config.json
# 输出
✅ Config is valid!
Name: my_app
Version: 1.2.3

{
  "version": "1.2.3"
}