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// Copyright 2015 Matthew Holt and The Caddy Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package reverseproxy
import (
"encoding/json"
"flag"
"fmt"
"net"
"net/http"
"net/url"
"strings"
"github.com/caddyserver/caddy/v2"
"github.com/caddyserver/caddy/v2/caddyconfig"
"github.com/caddyserver/caddy/v2/caddyconfig/httpcaddyfile"
caddycmd "github.com/caddyserver/caddy/v2/cmd"
"github.com/caddyserver/caddy/v2/modules/caddyhttp"
"github.com/caddyserver/caddy/v2/modules/caddyhttp/headers"
"github.com/mholt/certmagic"
)
func init() {
caddycmd.RegisterCommand(caddycmd.Command{
Name: "reverse-proxy",
Func: cmdReverseProxy,
Usage: "[--from <addr>] [--to <addr>]",
Short: "A quick and production-ready reverse proxy",
Long: `
A simple but production-ready reverse proxy. Useful for quick deployments,
demos, and development.
Simply shuttles HTTP traffic from the --from address to the --to address.
If the --from address has a domain name, Caddy will attempt to serve the
proxy over HTTPS with a certificate.
`,
Flags: func() *flag.FlagSet {
fs := flag.NewFlagSet("file-server", flag.ExitOnError)
fs.String("from", "", "Address to receive traffic on")
fs.String("to", "", "Upstream address to proxy traffic to")
return fs
}(),
})
}
func cmdReverseProxy(fs caddycmd.Flags) (int, error) {
from := fs.String("from")
to := fs.String("to")
if from == "" {
from = "localhost:" + httpcaddyfile.DefaultPort
}
// URLs need a scheme in order to parse successfully
if !strings.Contains(from, "://") {
from = "http://" + from
}
if !strings.Contains(to, "://") {
to = "http://" + to
}
fromURL, err := url.Parse(from)
if err != nil {
return caddy.ExitCodeFailedStartup, fmt.Errorf("parsing 'from' URL: %v", err)
}
toURL, err := url.Parse(to)
if err != nil {
return caddy.ExitCodeFailedStartup, fmt.Errorf("parsing 'to' URL: %v", err)
}
if toURL.Port() == "" {
toPort := "80"
if toURL.Scheme == "https" {
toPort = "443"
}
toURL.Host = net.JoinHostPort(toURL.Host, toPort)
}
ht := HTTPTransport{}
if toURL.Scheme == "https" {
ht.TLS = new(TLSConfig)
}
handler := Handler{
TransportRaw: caddyconfig.JSONModuleObject(ht, "protocol", "http", nil),
Upstreams: UpstreamPool{{Dial: toURL.Host}},
Headers: &headers.Handler{
Request: &headers.HeaderOps{
Set: http.Header{
"Host": []string{"{http.handlers.reverse_proxy.upstream.host}"},
},
},
},
}
route := caddyhttp.Route{
HandlersRaw: []json.RawMessage{
caddyconfig.JSONModuleObject(handler, "handler", "reverse_proxy", nil),
},
}
urlHost := fromURL.Hostname()
if urlHost != "" {
route.MatcherSetsRaw = []map[string]json.RawMessage{
map[string]json.RawMessage{
"host": caddyconfig.JSON(caddyhttp.MatchHost{urlHost}, nil),
},
}
}
listen := ":80"
if urlPort := fromURL.Port(); urlPort != "" {
listen = ":" + urlPort
} else if certmagic.HostQualifies(urlHost) {
listen = ":443"
}
server := &caddyhttp.Server{
Routes: caddyhttp.RouteList{route},
Listen: []string{listen},
}
httpApp := caddyhttp.App{
Servers: map[string]*caddyhttp.Server{"proxy": server},
}
cfg := &caddy.Config{
Admin: &caddy.AdminConfig{Disabled: true},
AppsRaw: map[string]json.RawMessage{
"http": caddyconfig.JSON(httpApp, nil),
},
}
err = caddy.Run(cfg)
if err != nil {
return caddy.ExitCodeFailedStartup, err
}
fmt.Printf("Caddy 2 proxying from %s to %s\n", fromURL, toURL)
select {}
}
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