ruby-sdk/test/mcp/server/transports/stdio_transport_test.rb
Koichi ITO 3d442d0a65
Merge pull request #448 from koic/handle_non_object_json_rpc_messages
Handle non-object JSON-RPC messages without raising
2026-07-12 02:12:46 +09:00

556 lines
18 KiB
Ruby

# frozen_string_literal: true
require "test_helper"
module MCP
class Server
module Transports
class StdioTransportTest < ActiveSupport::TestCase
include InstrumentationTestHelper
setup do
configuration = MCP::Configuration.new
configuration.instrumentation_callback = instrumentation_helper.callback
@server = Server.new(name: "test_server", configuration: configuration)
@transport = StdioTransport.new(@server)
end
test "initializes with server and closed state" do
server = @transport.instance_variable_get(:@server)
assert_equal @server.object_id, server.object_id
refute @transport.instance_variable_get(:@open)
end
test "processes JSON-RPC requests from stdin and sends responses to stdout" do
request = {
jsonrpc: "2.0",
method: "ping",
id: "123",
}
input = StringIO.new(JSON.generate(request) + "\n")
output = StringIO.new
original_stdin = $stdin
original_stdout = $stdout
begin
$stdin = input
$stdout = output
thread = Thread.new { @transport.open }
sleep(0.1)
@transport.close
thread.join
response = JSON.parse(output.string, symbolize_names: true)
assert_equal("2.0", response[:jsonrpc])
assert_equal("123", response[:id])
assert_equal({}, response[:result])
refute(@transport.instance_variable_get(:@open))
ensure
$stdin = original_stdin
$stdout = original_stdout
end
end
test "sends string responses to stdout" do
output = StringIO.new
original_stdout = $stdout
begin
$stdout = output
@transport.send_response("test response")
assert_equal("test response\n", output.string)
ensure
$stdout = original_stdout
end
end
test "sends JSON responses to stdout" do
output = StringIO.new
original_stdout = $stdout
begin
$stdout = output
response = { key: "value" }
@transport.send_response(response)
assert_equal(JSON.generate(response) + "\n", output.string)
ensure
$stdout = original_stdout
end
end
test "handles valid JSON-RPC requests" do
request = {
jsonrpc: "2.0",
method: "ping",
id: "123",
}
output = StringIO.new
original_stdout = $stdout
begin
$stdout = output
@transport.send(:handle_request, JSON.generate(request))
response = JSON.parse(output.string, symbolize_names: true)
assert_equal("2.0", response[:jsonrpc])
assert_nil(response[:id])
assert_nil(response[:result])
ensure
$stdout = original_stdout
end
end
test "open creates a ServerSession and processes requests through it" do
request = {
jsonrpc: "2.0",
method: "initialize",
id: "1",
params: {
protocolVersion: "2025-11-25",
capabilities: {},
clientInfo: { name: "stdio-client", version: "1.0" },
},
}
input = StringIO.new(JSON.generate(request) + "\n")
output = StringIO.new
original_stdin = $stdin
original_stdout = $stdout
begin
$stdin = input
$stdout = output
@transport.open
# Verify a session was created.
session = @transport.instance_variable_get(:@session)
assert_instance_of(ServerSession, session)
# Verify client info was stored on the session, not on the server.
assert_equal({ name: "stdio-client", version: "1.0" }, session.client)
ensure
$stdin = original_stdin
$stdout = original_stdout
end
end
test "open handles a malformed JSON-RPC batch element and emits an error response" do
input = StringIO.new("[[]]\n")
output = StringIO.new
original_stdin = $stdin
original_stdout = $stdout
begin
$stdin = input
$stdout = output
@transport.open
response = JSON.parse(output.string, symbolize_names: true)
assert_nil(response[:id])
assert_equal(-32600, response[:error][:code])
assert_equal("Invalid Request", response[:error][:message])
ensure
$stdin = original_stdin
$stdout = original_stdout
end
end
test "rejects duplicate initialize on the same stdio session with -32600" do
first = {
jsonrpc: "2.0",
method: "initialize",
id: "first",
params: {
protocolVersion: "2025-11-25",
capabilities: {},
clientInfo: { name: "original", version: "1.0" },
},
}
second = {
jsonrpc: "2.0",
method: "initialize",
id: "second",
params: {
protocolVersion: "2024-11-05",
capabilities: {},
clientInfo: { name: "intruder", version: "9.9" },
},
}
input = StringIO.new("#{JSON.generate(first)}\n#{JSON.generate(second)}\n")
output = StringIO.new
original_stdin = $stdin
original_stdout = $stdout
begin
$stdin = input
$stdout = output
@transport.open
lines = output.string.lines
assert_equal(2, lines.length)
first_response = JSON.parse(lines[0], symbolize_names: true)
second_response = JSON.parse(lines[1], symbolize_names: true)
assert_equal("first", first_response[:id])
refute_nil(first_response[:result])
assert_equal("second", second_response[:id])
assert_equal(-32600, second_response[:error][:code])
assert_equal("Invalid Request", second_response[:error][:message])
session = @transport.instance_variable_get(:@session)
assert_equal({ name: "original", version: "1.0" }, session.client)
ensure
$stdin = original_stdin
$stdout = original_stdout
end
end
test "handles invalid JSON requests" do
invalid_json = "invalid json"
output = StringIO.new
original_stdout = $stdout
begin
$stdout = output
@transport.send(:handle_request, invalid_json)
response = JSON.parse(output.string, symbolize_names: true)
assert_equal("2.0", response[:jsonrpc])
assert_nil(response[:id])
assert_equal(-32600, response[:error][:code])
assert_equal("Invalid Request", response[:error][:message])
assert_equal("Request must be an array or a hash", response[:error][:data])
ensure
$stdout = original_stdout
end
end
test "send_request sends request to stdout and waits for response" do
reader, writer = IO.pipe
output = StringIO.new
original_stdin = $stdin
original_stdout = $stdout
begin
$stdin = reader
$stdout = output
@transport.instance_variable_set(:@open, true)
# Send response from client in a thread.
Thread.new do
sleep(0.05) # Wait for request to be written to `StringIO`.
request = JSON.parse(output.string.lines.first, symbolize_names: true)
response = {
jsonrpc: "2.0",
id: request[:id],
result: { content: "test response" },
}
writer.puts(response.to_json)
writer.flush
end
result = @transport.send_request("test/method", { param: "value" })
assert_equal({ content: "test response" }, result)
# Verify request was sent.
request = JSON.parse(output.string.lines.first, symbolize_names: true)
assert_equal("2.0", request[:jsonrpc])
assert_equal("test/method", request[:method])
assert_equal({ param: "value" }, request[:params])
assert(request[:id])
ensure
$stdin = original_stdin
$stdout = original_stdout
begin
writer.close
rescue
nil
end
begin
reader.close
rescue
nil
end
end
end
test "send_request raises on error response from client" do
reader, writer = IO.pipe
output = StringIO.new
original_stdin = $stdin
original_stdout = $stdout
begin
$stdin = reader
$stdout = output
@transport.instance_variable_set(:@open, true)
Thread.new do
sleep(0.05) # Wait for request to be written to `StringIO`.
request = JSON.parse(output.string.lines.first, symbolize_names: true)
error_response = {
jsonrpc: "2.0",
id: request[:id],
error: { code: -1, message: "User rejected sampling request" },
}
writer.puts(error_response.to_json)
writer.flush
end
error = assert_raises(StandardError) do
@transport.send_request("sampling/createMessage", { messages: [] })
end
assert_equal("Client returned an error for sampling/createMessage request (code: -1): User rejected sampling request", error.message)
ensure
$stdin = original_stdin
$stdout = original_stdout
begin
writer.close
rescue
nil
end
begin
reader.close
rescue
nil
end
end
end
test "send_request does not double-report intentional raises via exception_reporter" do
reader, writer = IO.pipe
output = StringIO.new
original_stdin = $stdin
original_stdout = $stdout
reported_errors = []
original_reporter = MCP.configuration.exception_reporter
begin
MCP.configuration.exception_reporter = ->(e, ctx) { reported_errors << [e, ctx] }
$stdin = reader
$stdout = output
@transport.instance_variable_set(:@open, true)
Thread.new do
sleep(0.05) # Wait for request to be written to `StringIO`.
request = JSON.parse(output.string.lines.first, symbolize_names: true)
error_response = {
jsonrpc: "2.0",
id: request[:id],
error: { code: -1, message: "rejected" },
}
writer.puts(error_response.to_json)
writer.flush
end
assert_raises(StandardError) do
@transport.send_request("sampling/createMessage", { messages: [] })
end
assert_empty(reported_errors)
ensure
MCP.configuration.exception_reporter = original_reporter
$stdin = original_stdin
$stdout = original_stdout
begin
writer.close
rescue
nil
end
begin
reader.close
rescue
nil
end
end
end
test "send_request processes interleaved requests via session" do
reader, writer = IO.pipe
output = StringIO.new
original_stdin = $stdin
original_stdout = $stdout
begin
$stdin = reader
$stdout = output
@transport.instance_variable_set(:@open, true)
# Initialize a session so @session is set.
session = MCP::ServerSession.new(server: @server, transport: @transport)
@transport.instance_variable_set(:@session, session)
Thread.new do
sleep(0.05) # Wait for request to be written to `StringIO`.
request = JSON.parse(output.string.lines.first, symbolize_names: true)
# Send an interleaved ping request before the response.
ping = { jsonrpc: "2.0", method: "ping", id: "ping-1" }
writer.puts(ping.to_json)
writer.flush
sleep(0.05) # Wait for the ping to be processed.
# Then send the actual response.
response = {
jsonrpc: "2.0",
id: request[:id],
result: { content: "done" },
}
writer.puts(response.to_json)
writer.flush
end
result = @transport.send_request("test/method", { param: "value" })
assert_equal({ content: "done" }, result)
# Verify the interleaved ping was handled (response sent to output).
lines = output.string.lines
ping_response = lines.find { |l| l.include?("ping-1") }
assert(ping_response, "Interleaved ping request should have been handled")
ensure
$stdin = original_stdin
$stdout = original_stdout
begin
writer.close
rescue
nil
end
begin
reader.close
rescue
nil
end
end
end
test "send_request raises when transport is closed while waiting" do
reader, writer = IO.pipe
output = StringIO.new
original_stdin = $stdin
original_stdout = $stdout
begin
$stdin = reader
$stdout = output
@transport.instance_variable_set(:@open, true)
# Close transport while waiting for response.
Thread.new do
sleep(0.05) # Wait for request to be written to `StringIO`.
@transport.instance_variable_set(:@open, false)
writer.close
end
error = assert_raises(RuntimeError) do
@transport.send_request("sampling/createMessage", { messages: [] })
end
assert_equal("Transport closed while waiting for response to sampling/createMessage request.", error.message)
ensure
$stdin = original_stdin
$stdout = original_stdout
begin
writer.close
rescue IOError
nil
end
begin
reader.close
rescue IOError
nil
end
end
end
test "raises ArgumentError when max_line_bytes is not a positive Integer" do
[nil, 0, -1, 1.5, "1024"].each do |invalid|
error = assert_raises(ArgumentError) do
StdioTransport.new(@server, max_line_bytes: invalid)
end
assert_equal("max_line_bytes must be a positive Integer", error.message)
end
end
test "open stops and reports when a stdin frame exceeds max_line_bytes without a newline" do
transport = StdioTransport.new(@server, max_line_bytes: 64)
input = StringIO.new("A" * 200) # No newline: an unbounded frame.
output = StringIO.new
reported = []
original_stdin = $stdin
original_stdout = $stdout
original_reporter = MCP.configuration.exception_reporter
begin
$stdin = input
$stdout = output
MCP.configuration.exception_reporter = ->(e, ctx) { reported << [e, ctx] }
transport.open
refute(transport.instance_variable_get(:@open))
assert_equal(1, reported.size)
error, _ctx = reported.first
assert_instance_of(RequestHandlerError, error)
assert_match(/exceeds 64 bytes without a newline/, error.message)
ensure
$stdin = original_stdin
$stdout = original_stdout
MCP.configuration.exception_reporter = original_reporter
end
end
test "open processes a valid final frame that ends at EOF without a trailing newline" do
request = { jsonrpc: "2.0", method: "ping", id: "eof" }
input = StringIO.new(JSON.generate(request)) # No trailing newline.
output = StringIO.new
original_stdin = $stdin
original_stdout = $stdout
begin
$stdin = input
$stdout = output
@transport.open
response = JSON.parse(output.string, symbolize_names: true)
assert_equal("eof", response[:id])
assert_equal({}, response[:result])
ensure
$stdin = original_stdin
$stdout = original_stdout
end
end
test "send_request raises when a response frame exceeds max_line_bytes without a newline" do
transport = StdioTransport.new(@server, max_line_bytes: 64)
input = StringIO.new("A" * 200) # No newline: an unbounded frame.
output = StringIO.new
original_stdin = $stdin
original_stdout = $stdout
begin
$stdin = input
$stdout = output
transport.instance_variable_set(:@open, true)
error = assert_raises(RequestHandlerError) do
transport.send_request("sampling/createMessage", { messages: [] })
end
assert_match(/exceeds 64 bytes without a newline/, error.message)
ensure
$stdin = original_stdin
$stdout = original_stdout
end
end
end
end
end
end