added real_ip and cloudflare_real_ip middlewares, fixed that some middlewares does not work properly

internal/net/http/middleware/modify_response.go

@@ -0,0 +1,60 @@
+package middleware
+
+import (
+	"net/http"
+
+	D "github.com/yusing/go-proxy/internal/docker"
+	E "github.com/yusing/go-proxy/internal/error"
+)
+
+type (
+	modifyResponse struct {
+		*modifyResponseOpts
+		m *Middleware
+	}
+	// order: set_headers -> add_headers -> hide_headers
+	modifyResponseOpts struct {
+		SetHeaders  map[string]string
+		AddHeaders  map[string]string
+		HideHeaders []string
+	}
+)
+
+var ModifyResponse = func() (mr *modifyResponse) {
+	mr = new(modifyResponse)
+	mr.m = new(Middleware)
+	mr.m.labelParserMap = D.ValueParserMap{
+		"set_headers":  D.YamlLikeMappingParser(true),
+		"add_headers":  D.YamlLikeMappingParser(true),
+		"hide_headers": D.YamlStringListParser,
+	}
+	mr.m.withOptions = NewModifyResponse
+	return
+}()
+
+func NewModifyResponse(optsRaw OptionsRaw, _ *ReverseProxy) (*Middleware, E.NestedError) {
+	mr := new(modifyResponse)
+	mr.m = &Middleware{
+		impl:           mr,
+		modifyResponse: mr.modifyResponse,
+	}
+	mr.modifyResponseOpts = new(modifyResponseOpts)
+	err := Deserialize(optsRaw, mr.modifyResponseOpts)
+	if err != nil {
+		return nil, E.FailWith("set options", err)
+	}
+	return mr.m, nil
+}
+
+func (mr *modifyResponse) modifyResponse(resp *http.Response) error {
+	for k, v := range mr.SetHeaders {
+		resp.Header.Set(k, v)
+	}
+	for k, v := range mr.AddHeaders {
+		resp.Header.Add(k, v)
+	}
+	for _, k := range mr.HideHeaders {
+		resp.Header.Del(k)
+	}
+	return nil
+}