README
¶
httprevproxy
httprevproxy is a TinyGo-compatible reverse proxy whose public API mirrors
the reverse-proxy portion of net/http/httputil. The distinct package name
keeps imports unambiguous. Applications that want a later one-line migration
can import it with the httputil alias, then change only the import path:
import httputil "github.com/shibukawa/tinygodriver/httprevproxy"
target, _ := url.Parse("http://127.0.0.1:8080/base")
proxy := &httputil.ReverseProxy{
Rewrite: func(r *httputil.ProxyRequest) {
r.SetURL(target)
r.SetXForwarded()
},
}
http.Handle("/", proxy)
Supported behavior includes Rewrite, the deprecated Director,
NewSingleHostReverseProxy, hop-by-hop header removal, forwarding helpers,
response modification, error handling, trailers, bounded-buffer streaming,
and periodic or immediate flushing.
Director does not work under TinyGo
Use Rewrite, as the example above does. TinyGo's HTTP client takes the dial
address from Request.Host where standard net/http takes it from
Request.URL.Host (see rule:tinygo-dials-request-host), so preserving the
inbound Host — which is exactly what Director and NewSingleHostReverseProxy
are for — means dialing it, and the proxy ends up calling itself.
Rewrite with SetURL is unaffected: SetURL leaves Out.Host empty, and
this package fills it in from the target URL on the TinyGo path, which is the
same Host header standard net/http would have written. A Rewrite that sets
Out.Host itself is left alone. Only a Host that disagrees with the target URL
is refused, and it is refused through ErrorHandler rather than looping.
The stdlib net/http/httputil.ReverseProxy that TinyGo 0.42 ships has the same
problem and no such compensation.
Protocol upgrades (including WebSockets), 1xx forwarding, and HTTP/2-specific
proxy features are intentionally unsupported. A protocol-upgrade request or
response is passed to ErrorHandler and produces 502 with the default handler.
Documentation
¶
Overview ¶
Package httprevproxy provides a TinyGo-compatible subset of net/http/httputil's reverse proxy API.
The public API intentionally follows net/http/httputil so applications can migrate without redesigning proxy configuration when TinyGo supports the standard implementation. Protocol upgrades and 1xx forwarding are not supported.
Index ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type BufferPool ¶
A BufferPool gets and returns temporary byte slices used when copying a response body.
type ProxyRequest ¶
type ProxyRequest struct {
// In is the request received by the proxy. Rewrite must not modify In.
In *http.Request
// Out is the request sent by the proxy. Rewrite may modify or replace Out.
Out *http.Request
}
A ProxyRequest contains a request to be rewritten by a ReverseProxy.
func (*ProxyRequest) SetURL ¶
func (r *ProxyRequest) SetURL(target *url.URL)
SetURL routes the outbound request to target, joining target's base path to the incoming path. It also makes the outbound Host header use target.Host.
func (*ProxyRequest) SetXForwarded ¶
func (r *ProxyRequest) SetXForwarded()
SetXForwarded sets X-Forwarded-For, X-Forwarded-Host, and X-Forwarded-Proto from the inbound request. An existing X-Forwarded-For value on Out is preserved and appended to.
type ReverseProxy ¶
type ReverseProxy struct {
Rewrite func(*ProxyRequest)
Transport http.RoundTripper
FlushInterval time.Duration
ErrorLog *log.Logger
BufferPool BufferPool
ModifyResponse func(*http.Response) error
ErrorHandler func(http.ResponseWriter, *http.Request, error)
// Director is deprecated. Use Rewrite instead. Exactly one of Director or
// Rewrite must be set.
Director func(*http.Request)
}
ReverseProxy is an HTTP Handler that proxies requests to another server. Its public fields match net/http/httputil.ReverseProxy. This implementation does not support protocol upgrades or forwarding 1xx responses.
func NewSingleHostReverseProxy ¶
func NewSingleHostReverseProxy(target *url.URL) *ReverseProxy
NewSingleHostReverseProxy returns a proxy that routes requests to target. Like net/http/httputil, it uses the deprecated Director field for backwards compatibility and preserves the inbound Host header.
That last part is why this constructor does not work under TinyGo, whose transport dials Request.Host rather than Request.URL.Host: preserving the inbound Host means dialing it, which sends the proxy back to its own address. It reports an error there rather than looping. Use Rewrite with ProxyRequest.SetURL instead, which every other example in this package does.
func (*ReverseProxy) ServeHTTP ¶
func (p *ReverseProxy) ServeHTTP(rw http.ResponseWriter, req *http.Request)
ServeHTTP implements http.Handler.
Source Files