Per the Streamable HTTP spec, a server returns 202 Accepted with no
body as the ACK for a JSON-RPC notification or response. The client
previously errored on 202 because it fell through Content-Type
dispatch. Short-circuit to return nil before Content-Type handling so
fire-and-forget messages (e.g. notifications/initialized) no longer
raise.
https://modelcontextprotocol.io/specification/2025-11-25/basic/transports#sending-messages-to-the-server
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
The Streamable HTTP spec allows servers to respond with either
`application/json` or `text/event-stream`. The client previously
rejected the latter. Add SSE parsing via the optional
`event_stream_parser` gem (users add it to their Gemfile when their
server uses SSE), dispatch on the response Content-Type, and scan the
event stream for the first JSON-RPC response message.
Document the new optional dependency in both the README's HTTP
Transport Layer section and docs/building-clients.md.
No other Streamable HTTP features (202 handling, session IDs,
`connect`, DELETE termination) are included here; those will land in
follow-up PRs.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
## 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
- Set Accept header to request JSON or SSE responses
- Validate response Content-Type and raise error for non-JSON responses
- Add Accept header to test fixtures
- Use explicit hash syntax for Ruby 2.7 compatibility
