f7952e8aaf
## Motivation and Context `MCP::Client::HTTP` builds its Faraday connection internally in a private `client` method with no way to customize the middleware stack or adapter. Users who need observability (request/response recording, failure logging) or a different HTTP adapter must override a private method, coupling to an internal API. This accepts an optional block in `MCP::Client::HTTP.new` that yields the Faraday builder after default middleware is configured, allowing users to add custom middleware or swap the HTTP adapter. ## How Has This Been Tested? Added a test that verifies custom headers set via the block are included in requests. All existing tests continue to pass. ## Breaking Changes None. The block argument is optional, so existing code is unaffected. Resolves #303
107 lines
3.3 KiB
Ruby
107 lines
3.3 KiB
Ruby
# frozen_string_literal: true
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module MCP
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class Client
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class HTTP
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ACCEPT_HEADER = "application/json, text/event-stream"
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attr_reader :url
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def initialize(url:, headers: {}, &block)
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@url = url
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@headers = headers
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@faraday_customizer = block
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end
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def send_request(request:)
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method = request[:method] || request["method"]
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params = request[:params] || request["params"]
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response = client.post("", request)
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validate_response_content_type!(response, method, params)
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response.body
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rescue Faraday::BadRequestError => e
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raise RequestHandlerError.new(
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"The #{method} request is invalid",
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{ method: method, params: params },
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error_type: :bad_request,
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original_error: e,
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)
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rescue Faraday::UnauthorizedError => e
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raise RequestHandlerError.new(
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"You are unauthorized to make #{method} requests",
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{ method: method, params: params },
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error_type: :unauthorized,
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original_error: e,
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)
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rescue Faraday::ForbiddenError => e
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raise RequestHandlerError.new(
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"You are forbidden to make #{method} requests",
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{ method: method, params: params },
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error_type: :forbidden,
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original_error: e,
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)
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rescue Faraday::ResourceNotFound => e
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raise RequestHandlerError.new(
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"The #{method} request is not found",
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{ method: method, params: params },
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error_type: :not_found,
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original_error: e,
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)
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rescue Faraday::UnprocessableEntityError => e
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raise RequestHandlerError.new(
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"The #{method} request is unprocessable",
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{ method: method, params: params },
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error_type: :unprocessable_entity,
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original_error: e,
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)
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rescue Faraday::Error => e # Catch-all
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raise RequestHandlerError.new(
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"Internal error handling #{method} request",
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{ method: method, params: params },
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error_type: :internal_error,
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original_error: e,
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)
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end
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private
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attr_reader :headers
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def client
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require_faraday!
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@client ||= Faraday.new(url) do |faraday|
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faraday.request(:json)
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faraday.response(:json)
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faraday.response(:raise_error)
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faraday.headers["Accept"] = ACCEPT_HEADER
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headers.each do |key, value|
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faraday.headers[key] = value
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end
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@faraday_customizer&.call(faraday)
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end
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end
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def require_faraday!
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require "faraday"
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rescue LoadError
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raise LoadError, "The 'faraday' gem is required to use the MCP client HTTP transport. " \
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"Add it to your Gemfile: gem 'faraday', '>= 2.0'" \
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"See https://rubygems.org/gems/faraday for more details."
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end
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def validate_response_content_type!(response, method, params)
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content_type = response.headers["Content-Type"]
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return if content_type&.include?("application/json")
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raise RequestHandlerError.new(
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"Unsupported Content-Type: #{content_type.inspect}. This client only supports JSON responses.",
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{ method: method, params: params },
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error_type: :unsupported_media_type,
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)
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end
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end
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end
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end
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