gerg/net

Forked version of Golang's net/http package that implements the client-side H2C upgrade flow described in RFC 7540, Section 3.2.

Usage

This should be a drop-in replacment for net/http package, except with h2c upgrade support:

package main

import (
        "fmt"
        "github.com/gerg/net/http"
)

func main() {
        transport := &http.Transport{}
        client := http.Client{Transport: transport}

        req, _ := http.NewRequest("GET", "http://localhost:8080", nil)

        req.Header.Set("Connection", "Upgrade, HTTP2-Settings")
        req.Header.Set("Upgrade", "h2c")
        req.Header.Set("HTTP2-Settings", "AAMAAABkAARAAAAAAAIAAAAA")

        resp, _ := client.Do(req)

        fmt.Printf("Response:\n\t%+v\n\n", resp)
}

How it Works

See the diff for details.

In brief, we mirror the ALPN upgrade flow when we receive 101 Switching Protocols from the backend. This will:

1. Set the http.Transport's peristant connection to have a http2.Transport for future use
2. Add the existing TCP connection to the http2.Transport's connection pool
3. Seed that connection with Stream 1 (represented the upgrade request)
4. Send the HTTP/2 prefix, to complete the HTTP/2 upgrade and trigger the backend to send the response.

After we establish the HTTP/2 connection, we then call completeUpgrade on the http2.Transport to return the response for the upgrade request.