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The client support H1 and H2 using blocking I/O. The biggest
differentiator is that the client has a simple blocking-style API made
for virtual threads, but still supports full bidirectional h2 streaming.
That is, concurrent request/response streaming over H2 using
InputStream and OutputStream, allowing you to read response data while
still writing request data.
Other protocols
- ALPN negotiation with automatic protocol selection
- H2C prior knowledge (cleartext HTTP/2)
Connection Management
- Per-route connection pooling with LIFO reuse
- HTTP/2 stream multiplexing with load spreading across connections
- Idle connection cleanup and validation
- Configurable limits (per-route, global, host-specific)
Request/Response
- h1: Chunked transfer encoding/decoding with trailer support
- h1: Expect: 100-continue handling
- Content-Length validation
- Streaming and buffered exchange APIs to support full bidirectional
streaming
Proxy
- HTTP/HTTPS CONNECT tunneling
- Proxy authentication (Basic)
- Non-proxy host patterns (wildcards)
- Double-TLS (HTTPS proxy to HTTPS target)
TLS
- TLS hostname verification (certificate CN/SAN matching)
- Custom SSLContext support (mTLS, custom CAs)
- Separate TLS negotiation timeout
Flow Control (H2)
- Stream and connection-level window management
- Backpressure with configurable write timeout
Extensibility
- Interceptor chain (request modification, short-circuit, response
handling, error recovery)
- Connection pool event listener for telemetry, leak detection, etc
- Pluggable DNS resolver
- Socket factory to customize sockets
Timeouts
- Connect, TLS, read, write, acquire, and 100-continue timeouts
- Fix H2Exchange to close H2DataOutputStream when request stream closes, ensuring DATA frame with END_STREAM is sent - Refactor DelegatedClosingInputStream/OutputStream to pass delegate to CloseCallback, enabling callers to close delegate when needed
Connection pool changes: - Track pending connection creations to prevent over-creation under load - Preserve original exception when connection creation fails - Always notify waiters after connection creation (success or failure) Read timeout improvements: - Move from per-stream timed waits to centralized timeout sweep (~100ms) - Add readSeq activity counter to detect stale timeout decisions - Use AtomicBoolean CAS for at-most-once timeout semantics - Clear deadline on stream completion to prevent spurious timeouts The timeout sweep approach scales better with high VT counts by avoiding thousands of concurrent timed wait registrations. Timeouts are approximate (±100ms) which is acceptable for network I/O.
Short spin before park. Only way when waiting.
- Add a *bunch* of integration tests and integ test library-ish code - Fix H1 connection pool race condition causing connections to be created instead of reused under high concurrency - Add batched flow control acquisition for H2 to prevent connection window starvation
- Wait for server's initial WINDOW_UPDATE before starting writes to avoid exhausting the 65KB default connection window on large uploads - Migrate H2ConnectionManager from synchronized to ReentrantLock - Add configurable h2BufferSize (default 256KB) for stream buffering - Use short polling in FlowControlWindow to avoid timed-wait contention - Fix buffer leak in H2DataInputStream.transferTo() - Simplify H2Exchange data signaling (signal endStream or buffer empty)
Avoids an intermediate InputStream in many cases.
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Add a virtual thread friendly, blocking HTTP client (h1, h2) that supports bidirectional streaming.
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