add observer

router/plugin/http.go

@@ -0,0 +1,83 @@
+package router
+
+import (
+	"context"
+	"encoding/json"
+	"net"
+	"net/http"
+
+	"github.com/go-gost/core/logger"
+	"github.com/go-gost/core/router"
+	"github.com/go-gost/x/internal/plugin"
+	xrouter "github.com/go-gost/x/router"
+)
+
+type httpPluginGetRouteRequest struct {
+	Dst string `json:"dst"`
+}
+
+type httpPluginGetRouteResponse struct {
+	Net     string `json:"net"`
+	Gateway string `json:"gateway"`
+}
+
+type httpPlugin struct {
+	url    string
+	client *http.Client
+	header http.Header
+	log    logger.Logger
+}
+
+// NewHTTPPlugin creates an Router plugin based on HTTP.
+func NewHTTPPlugin(name string, url string, opts ...plugin.Option) router.Router {
+	var options plugin.Options
+	for _, opt := range opts {
+		opt(&options)
+	}
+
+	return &httpPlugin{
+		url:    url,
+		client: plugin.NewHTTPClient(&options),
+		header: options.Header,
+		log: logger.Default().WithFields(map[string]any{
+			"kind":   "router",
+			"router": name,
+		}),
+	}
+}
+
+func (p *httpPlugin) GetRoute(ctx context.Context, dst net.IP, opts ...router.Option) *router.Route {
+	if p.client == nil {
+		return nil
+	}
+
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, p.url, nil)
+	if err != nil {
+		return nil
+	}
+	if p.header != nil {
+		req.Header = p.header.Clone()
+	}
+	req.Header.Set("Content-Type", "application/json")
+
+	q := req.URL.Query()
+	q.Set("dst", dst.String())
+	req.URL.RawQuery = q.Encode()
+
+	resp, err := p.client.Do(req)
+	if err != nil {
+		return nil
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return nil
+	}
+
+	res := httpPluginGetRouteResponse{}
+	if err := json.NewDecoder(resp.Body).Decode(&res); err != nil {
+		return nil
+	}
+
+	return xrouter.ParseRoute(res.Net, res.Gateway)
+}