micro/api/resolver/subdomain/subdomain.go

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// Package subdomain is a resolver which uses the subdomain to determine the domain to route to. It
// offloads the endpoint resolution to a child resolver which is provided in New.
package subdomain
import (
"net"
"net/http"
"strings"
"github.com/micro/go-micro/v3/api/resolver"
"github.com/micro/go-micro/v3/logger"
"golang.org/x/net/publicsuffix"
)
func NewResolver(parent resolver.Resolver, opts ...resolver.Option) resolver.Resolver {
options := resolver.NewOptions(opts...)
return &Resolver{options, parent}
}
type Resolver struct {
opts resolver.Options
resolver.Resolver
}
func (r *Resolver) Resolve(req *http.Request, opts ...resolver.ResolveOption) (*resolver.Endpoint, error) {
if dom := r.Domain(req); len(dom) > 0 {
opts = append(opts, resolver.Domain(dom))
}
return r.Resolver.Resolve(req, opts...)
}
func (r *Resolver) Domain(req *http.Request) string {
// determine the host, e.g. foobar.m3o.app
host := req.URL.Hostname()
if len(host) == 0 {
if h, _, err := net.SplitHostPort(req.Host); err == nil {
host = h // host does contain a port
} else if strings.Contains(err.Error(), "missing port in address") {
host = req.Host // host does not contain a port
}
}
// check for an ip address
if net.ParseIP(host) != nil {
return ""
}
// check for dev enviroment
if host == "localhost" || host == "127.0.0.1" {
return ""
}
// extract the top level domain plus one (e.g. 'myapp.com')
domain, err := publicsuffix.EffectiveTLDPlusOne(host)
if err != nil {
logger.Debugf("Unable to extract domain from %v", host)
return ""
}
// there was no subdomain
if host == domain {
return ""
}
// remove the domain from the host, leaving the subdomain, e.g. "staging.foo.myapp.com" => "staging.foo"
subdomain := strings.TrimSuffix(host, "."+domain)
// ignore the API subdomain
if subdomain == "api" {
return ""
}
// return the reversed subdomain as the namespace, e.g. "staging.foo" => "foo-staging"
comps := strings.Split(subdomain, ".")
for i := len(comps)/2 - 1; i >= 0; i-- {
opp := len(comps) - 1 - i
comps[i], comps[opp] = comps[opp], comps[i]
}
return strings.Join(comps, "-")
}
func (r *Resolver) String() string {
return "subdomain"
}