bouncer/internal/proxy/director/director.go

package director

import (
	"context"
	"net/http"

	"forge.cadoles.com/Cadoles/go-proxy"
	"forge.cadoles.com/Cadoles/go-proxy/wildcard"
	"forge.cadoles.com/cadoles/bouncer/internal/store"
	"github.com/davecgh/go-spew/spew"
	"github.com/pkg/errors"
	"gitlab.com/wpetit/goweb/logger"
)

type Director struct {
	proxyRepository store.ProxyRepository
	layerRegistry   *LayerRegistry
}

func (d *Director) rewriteRequest(r *http.Request) (*http.Request, error) {
	ctx := r.Context()

	proxies, err := d.getProxies(ctx)
	if err != nil {
		return r, errors.WithStack(err)
	}

	var match *store.Proxy

MAIN:
	for _, p := range proxies {
		for _, from := range p.From {
			if matches := wildcard.Match(r.Host, from); !matches {
				continue
			}

			match = p
			break MAIN
		}
	}

	if match == nil {
		return r, nil
	}

	r.URL.Host = match.To.Host
	r.URL.Scheme = match.To.Scheme

	ctx = withProxy(ctx, match)
	r = r.WithContext(ctx)

	return r, nil
}

func (d *Director) getProxies(ctx context.Context) ([]*store.Proxy, error) {
	headers, err := d.proxyRepository.QueryProxy(ctx)
	if err != nil {
		return nil, errors.WithStack(err)
	}

	proxies := make([]*store.Proxy, len(headers))

	for i, h := range headers {
		proxy, err := d.proxyRepository.GetProxy(ctx, h.Name)
		if err != nil {
			return nil, errors.WithStack(err)
		}

		proxies[i] = proxy
	}

	return proxies, nil
}

func (d *Director) RequestTransformer() proxy.RequestTransformer {
	return func(r *http.Request) {
		ctx := r.Context()
		_, err := ctxProxy(ctx)
		if err != nil {
			if errors.Is(err, errContextKeyNotFound) {
				return
			}

			logger.Error(ctx, "could not retrieve proxy from context", logger.E(errors.WithStack(err)))

			return
		}

		// spew.Dump(proxy)
	}
}

func (d *Director) ResponseTransformer() proxy.ResponseTransformer {
	return func(r *http.Response) error {
		ctx := r.Request.Context()
		proxy, err := ctxProxy(ctx)
		if err != nil {
			if errors.Is(err, errContextKeyNotFound) {
				return nil
			}

			logger.Error(ctx, "could not retrieve proxy from context", logger.E(errors.WithStack(err)))

			return nil
		}

		spew.Dump(proxy)

		return nil
	}
}

func (d *Director) Middleware() proxy.Middleware {
	return func(next http.Handler) http.Handler {
		fn := func(w http.ResponseWriter, r *http.Request) {
			r, err := d.rewriteRequest(r)
			if err != nil {
				logger.Error(r.Context(), "could not rewrite request", logger.E(errors.WithStack(err)))
				http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)

				return
			}

			next.ServeHTTP(w, r)
		}

		return http.HandlerFunc(fn)
	}
}

func New(repo store.ProxyRepository, layers ...Layer) *Director {
	registry := NewLayerRegistry(layers...)

	return &Director{repo, registry}
}