Rust sockets, ureq and reqwest

Integration · Sockets · Messages · Official networking research

src/main.rs runs the examples. session.rs owns a local Device, and ur_http.rs supplies a ureq connector, resolver and transport over urnetwork_sdk::Conn.

Install and run

Use Rust 1.85+ for this edition-2024 example:

cargo add urnetwork-sdk@<socket-release-version>
cargo run -- --version
cargo run -- --new-id
cargo run -- ureq https://example.com/
cargo run -- reqwest https://example.com/
cargo run -- tls example.com:443
cargo run -- udp echo.example:9000
cargo run -- dtls dtls.example:9001

Before first publication, make -C sdk/rust package check-package produces a staged Cargo project. Use a local Cargo patch, for example cargo run --config 'patch.crates-io.urnetwork-sdk.path="/absolute/path/to/sdk/rust/dist/project"' -- --version. If testing the release-download variant before GitHub assets are public, also set SDK_RUST_NATIVE_CACHE to the directory of checked native gzip assets.

The public crate downloads a version-pinned, checksum-verified native asset at build time and embeds it in the resulting binary. It never downloads “latest” at runtime. Go is not needed by registry consumers. Offline/restricted builds can prepopulate the documented checksum-checked cache. Set the Device variables below for direct modes.

Replace HTTP connection creation

ureq's connector/transport API is explicitly unversioned, so do not loosen its exact dependency pin without retesting. The custom resolver returns a placeholder; the connector passes the URI hostname directly to the SDK and performs verified SDK TLS for HTTPS. It supplies the buffer/deadline contract expected by ureq. This HTTP/1.1 example disables idle pooling because Conn has no nonblocking peek for a safe reusable-connection probe.

reqwest's public connector_layer wraps its existing connector; it does not accept an arbitrary SDK I/O object. The proxy example preserves its normal TLS and HTTP behavior while routing the upstream through the Go Device. Raw sockets expose no Unix AsRawFd or Windows socket handle.

Sources checked September 14, 2026: ureq Connector, ureq Transport, ureq Resolver, reqwest ClientBuilder.

Device setup

The executable creates a local Device with the scoped client JWT issued by your service backend and chooses the best available location. Follow the integration guide: the JWT must contain its assigned client_id; only the backend holds the root JWT. Generate an instance ID once with this program's --new-id mode, save it, and reuse it for this installation.

export URNETWORK_CLIENT_JWT='your-scoped-client-jwt'
export URNETWORK_INSTANCE_ID='your-persisted-instance-uuid'

Keep the network-space manager alive until the Device closes. The sample owns and releases these objects in that order. HTTP proxy modes use the Go proxy's Device instead.

Clients that need a kernel socket

Start the Go example in a second terminal:

cd examples/go/socket
go run . -mode proxy

It prints URNETWORK_HTTP_PROXY=http://127.0.0.1:. Export that exact value in the client terminal. This is a loopback HTTP/CONNECT proxy: the library uses a local OS connection to it, and its upstream dial calls Device.DialContext. HTTPS remains end-to-end encrypted and verified by the HTTP library. The original destination hostname reaches the SDK. The proxy listener is ordinary local application plumbing, not a new SDK listener API.

Only an application configured to use this proxy gets UR routing. Native socket factories, system-wide proxy settings, and unrelated traffic do not change.

Socket behavior

The destination connection lives in the SDK's user-space network stack and sends packets through the Device's URnetwork connection. It is not a kernel socket: its handle cannot be passed to select, poll, an OS socket option, or a library that requires a native file descriptor. Creating these application sockets does not require installing a system VPN or opening a kernel TUN device.

Pass the hostname unchanged with tcp or udp. The SDK resolves A and AAAA records through its connection and applies Happy Eyeballs; use tcp4/tcp6 or udp4/udp6 to force a family. Plain UDP races the initial application datagram and selects the address that sends the first reply. That initial datagram can be delivered to both addresses. Subsequent writes use the winner; a silent server cannot select a winner, so set a read/write deadline. Use an echo server you control for UDP examples. An empty datagram is data, not stream EOF.

TLS verifies the certificate and destination hostname. TLS-over-TCP and DTLS-over-UDP use the same Device packet path. DTLS needs a DTLS server, not a plain UDP echo server. Deadlines are absolute Unix milliseconds in portable bindings; zero clears them. Close each connection and then its Device. Listener/server sockets are a future API.

These are application integration examples. The core SDK suite separately tests real TCP/UDP packets, IPv4/IPv6, hostname races, TLS/DTLS, deadlines, close, and local/RPC transport behavior. A version/self-test command checks installation without using account credentials; live examples require a working account and provider path.