caddy/modules/internal/network/networkproxy.go

145 lines
3.7 KiB
Go

package network
import (
"errors"
"net/http"
"net/url"
"strings"
"go.uber.org/zap"
"github.com/caddyserver/caddy/v2"
"github.com/caddyserver/caddy/v2/caddyconfig/caddyfile"
)
func init() {
caddy.RegisterModule(ProxyFromURL{})
caddy.RegisterModule(ProxyFromNone{})
}
// The "url" proxy source uses the defined URL as the proxy
type ProxyFromURL struct {
URL string `json:"url"`
ctx caddy.Context
logger *zap.Logger
}
// CaddyModule implements Module.
func (p ProxyFromURL) CaddyModule() caddy.ModuleInfo {
return caddy.ModuleInfo{
ID: "caddy.network_proxy.source.url",
New: func() caddy.Module {
return &ProxyFromURL{}
},
}
}
func (p *ProxyFromURL) Provision(ctx caddy.Context) error {
p.ctx = ctx
p.logger = ctx.Logger()
return nil
}
// Validate implements Validator.
func (p ProxyFromURL) Validate() error {
if _, err := url.Parse(p.URL); err != nil {
return err
}
return nil
}
// ProxyFunc implements ProxyFuncProducer.
func (p ProxyFromURL) ProxyFunc() func(*http.Request) (*url.URL, error) {
if strings.Contains(p.URL, "{") && strings.Contains(p.URL, "}") {
// courtesy of @ImpostorKeanu: https://github.com/caddyserver/caddy/pull/6397
return func(r *http.Request) (*url.URL, error) {
// retrieve the replacer from context.
repl, ok := r.Context().Value(caddy.ReplacerCtxKey).(*caddy.Replacer)
if !ok {
err := errors.New("failed to obtain replacer from request")
p.logger.Error(err.Error())
return nil, err
}
// apply placeholders to the value
// note: h.ForwardProxyURL should never be empty at this point
s := repl.ReplaceAll(p.URL, "")
if s == "" {
p.logger.Error("network_proxy URL was empty after applying placeholders",
zap.String("initial_value", p.URL),
zap.String("final_value", s),
zap.String("hint", "check for invalid placeholders"))
return nil, errors.New("empty value for network_proxy URL")
}
// parse the url
pUrl, err := url.Parse(s)
if err != nil {
p.logger.Warn("failed to derive transport proxy from network_proxy URL")
pUrl = nil
} else if pUrl.Host == "" || strings.Split("", pUrl.Host)[0] == ":" {
// url.Parse does not return an error on these values:
//
// - http://:80
// - pUrl.Host == ":80"
// - /some/path
// - pUrl.Host == ""
//
// Super edge cases, but humans are human.
err = errors.New("supplied network_proxy URL is missing a host value")
pUrl = nil
} else {
p.logger.Debug("setting transport proxy url", zap.String("url", s))
}
return pUrl, err
}
}
return func(r *http.Request) (*url.URL, error) {
return url.Parse(p.URL)
}
}
// UnmarshalCaddyfile implements caddyfile.Unmarshaler.
func (p *ProxyFromURL) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {
d.Next()
d.Next()
p.URL = d.Val()
return nil
}
// The "none" proxy source module disables the use of network proxy.
type ProxyFromNone struct{}
func (p ProxyFromNone) CaddyModule() caddy.ModuleInfo {
return caddy.ModuleInfo{
ID: "caddy.network_proxy.source.none",
New: func() caddy.Module {
return &ProxyFromNone{}
},
}
}
// UnmarshalCaddyfile implements caddyfile.Unmarshaler.
func (p ProxyFromNone) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {
return nil
}
// ProxyFunc implements ProxyFuncProducer.
func (p ProxyFromNone) ProxyFunc() func(*http.Request) (*url.URL, error) {
return nil
}
var (
_ caddy.Module = ProxyFromURL{}
_ caddy.Provisioner = &ProxyFromURL{}
_ caddy.Validator = ProxyFromURL{}
_ caddy.ProxyFuncProducer = ProxyFromURL{}
_ caddyfile.Unmarshaler = &ProxyFromURL{}
_ caddy.Module = ProxyFromNone{}
_ caddy.ProxyFuncProducer = ProxyFromNone{}
_ caddyfile.Unmarshaler = ProxyFromNone{}
)