Class: JSONRPC_Rails::Middleware::Validator

Inherits:
Object
  • Object
show all
Defined in:
lib/jsonrpc_rails/middleware/validator.rb

Overview

Rack middleware that validates incoming JSON-RPC 2.0 payloads and injects fully-typed Ruby objects (Request / Notification / Response) into env[:jsonrpc] for easy downstream use.

Validation always runs on the raw Hash/Array first; objects are only instantiated after the structure has been deemed valid, so malformed IDs or empty batches no longer raise before we can return a proper -32600 “Invalid Request”.

Constant Summary collapse

CONTENT_TYPE = 
"application/json"
ENV_PAYLOAD_KEY = 
:jsonrpc
BATCH_POLICIES = 
%i[allow reject].freeze
RESERVED_MEMBERS = 
%w[jsonrpc method params id result error].freeze

Instance Method Summary collapse

Constructor Details

#initialize(app, paths = nil, payload_validator: nil, batch_policy: :allow, require_json_content_type: false) ⇒ Validator

Returns a new instance of Validator.

Parameters:

  • app (#call)
  • paths (Array<String, Regexp, Proc>) (defaults to: nil) —

    paths to validate

  • payload_validator (#valid?, #call, nil) (defaults to: nil) —

    optional protocol validator

  • batch_policy (Symbol) (defaults to: :allow) —

    either :allow or :reject

  • require_json_content_type (Boolean) (defaults to: false) —

    reject matching POST requests that do not use application/json instead of passing them downstream



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# File 'lib/jsonrpc_rails/middleware/validator.rb', line 30

def initialize(app, paths = nil, payload_validator: nil, batch_policy: :allow,
               require_json_content_type: false)
  unless BATCH_POLICIES.include?(batch_policy)
    raise ArgumentError, "batch_policy must be one of: #{BATCH_POLICIES.join(", ")}"
  end

  @app = app
  @paths = Array(paths || Rails.configuration.jsonrpc_rails.validated_paths)
  @payload_validator = payload_validator
  @batch_policy = batch_policy
  @require_json_content_type = require_json_content_type
end

Instance Method Details

#call(env) ⇒ Object

Rack entry point



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# File 'lib/jsonrpc_rails/middleware/validator.rb', line 44

def call(env)
  return @app.call(env) unless validate_path?(env["PATH_INFO"])
  return @app.call(env) unless env["REQUEST_METHOD"] == "POST"

  unless json_content_type?(env["CONTENT_TYPE"])
    return @app.call(env) unless @require_json_content_type

    return jsonrpc_error_response(
      :server_error,
      status: 415,
      message: "Unsupported Media Type: Content-Type must be application/json"
    )
  end

  body = env["rack.input"].read
  # Replace consumed input with fresh StringIO for downstream middleware
  # This is Rack 3.0+ compatible and works with all input stream types
  env["rack.input"] = StringIO.new(body)

  begin
    raw_payload = ActiveSupport::JSON.decode(body)
  rescue ActiveSupport::JSON.parse_error
    return jsonrpc_error_response(:parse_error)
  end

  unless raw_payload.is_a?(Hash) || raw_payload.is_a?(Array)
    return jsonrpc_error_response(:invalid_request)
  end

  return invalid_request_response(raw_payload) unless valid_batch_policy?(raw_payload)
  return invalid_request_response(raw_payload) unless valid_payload_structure?(raw_payload)
  return invalid_request_response(raw_payload) unless valid_protocol_payload?(raw_payload)

  begin
    env[ENV_PAYLOAD_KEY] = convert_to_objects(raw_payload)
  rescue JSON_RPC::JsonRpcError, ArgumentError, TypeError
    return invalid_request_response(raw_payload)
  end

  @app.call(env)
end