refactor: remove forward auth, move module net/http to net/gphttp

internal/net/gphttp/middleware/modify_request.go

@@ -0,0 +1,91 @@
+package middleware
+
+import (
+	"net/http"
+	"path/filepath"
+	"strings"
+)
+
+type (
+	modifyRequest struct {
+		ModifyRequestOpts
+		Tracer
+	}
+	// order: add_prefix -> set_headers -> add_headers -> hide_headers
+	ModifyRequestOpts struct {
+		SetHeaders  map[string]string
+		AddHeaders  map[string]string
+		HideHeaders []string
+		AddPrefix   string
+
+		needVarSubstitution bool
+	}
+)
+
+var ModifyRequest = NewMiddleware[modifyRequest]()
+
+// finalize implements MiddlewareFinalizer.
+func (mr *ModifyRequestOpts) finalize() {
+	mr.checkVarSubstitution()
+}
+
+// before implements RequestModifier.
+func (mr *modifyRequest) before(w http.ResponseWriter, r *http.Request) (proceed bool) {
+	mr.AddTraceRequest("before modify request", r)
+
+	mr.addPrefix(r, nil, r.URL.Path)
+	mr.modifyHeaders(r, nil, r.Header)
+	mr.AddTraceRequest("after modify request", r)
+	return true
+}
+
+func (mr *ModifyRequestOpts) checkVarSubstitution() {
+	for _, m := range []map[string]string{mr.SetHeaders, mr.AddHeaders} {
+		for _, v := range m {
+			if strings.ContainsRune(v, '$') {
+				mr.needVarSubstitution = true
+				return
+			}
+		}
+	}
+}
+
+func (mr *ModifyRequestOpts) modifyHeaders(req *http.Request, resp *http.Response, headers http.Header) {
+	if !mr.needVarSubstitution {
+		for k, v := range mr.SetHeaders {
+			if req != nil && strings.EqualFold(k, "host") {
+				defer func() {
+					req.Host = v
+				}()
+			}
+			headers[k] = []string{v}
+		}
+		for k, v := range mr.AddHeaders {
+			headers[k] = append(headers[k], v)
+		}
+	} else {
+		for k, v := range mr.SetHeaders {
+			if req != nil && strings.EqualFold(k, "host") {
+				defer func() {
+					req.Host = varReplace(req, resp, v)
+				}()
+			}
+			headers[k] = []string{varReplace(req, resp, v)}
+		}
+		for k, v := range mr.AddHeaders {
+			headers[k] = append(headers[k], varReplace(req, resp, v))
+		}
+	}
+
+	for _, k := range mr.HideHeaders {
+		delete(headers, k)
+	}
+}
+
+func (mr *modifyRequest) addPrefix(r *http.Request, _ *http.Response, path string) {
+	if len(mr.AddPrefix) == 0 {
+		return
+	}
+
+	r.URL.Path = filepath.Join(mr.AddPrefix, path)
+}