api: Read basePath from spec/rest.yaml

This helps to avoid changing the path v1 in several places
if we plan to change the version in spec/rest.yaml.

Signed-off-by: Tatiana Nesterenko <tatiana@nspcc.io>

go.mod

@@ -111,5 +111,5 @@ require (
 	google.golang.org/protobuf v1.31.0 // indirect
 	gopkg.in/ini.v1 v1.66.2 // indirect
 	gopkg.in/yaml.v2 v2.4.0 // indirect
-	gopkg.in/yaml.v3 v3.0.1 // indirect
+	gopkg.in/yaml.v3 v3.0.1
 )

handlers/api.go

@@ -3,7 +3,9 @@ package handlers
 import (
 	"context"
 	"fmt"
+	"gopkg.in/yaml.v3"
 	"net/http"
+	"os"
 	"strings"
 	"time"
 
@@ -62,6 +64,10 @@ type SessionToken struct {
 // ContextKey is used for context.Context value. The value requires a key that is not primitive type.
 type ContextKey string
 
+type swaggerSpec struct {
+	BasePath string `yaml:"basePath"`
+}
+
 const (
 	// BearerPrefix is the prefix for authorization token.
 	BearerPrefix       = "Bearer "
@@ -197,13 +203,35 @@ func (a *API) docMiddleware(handler http.Handler) http.Handler {
 		if strings.HasPrefix(r.URL.Path, docsPrefix) {
 			fh.ServeHTTP(w, r)
 		} else if r.URL.Path == "" || r.URL.Path == "/" {
-			http.Redirect(w, r, "/v1/docs/", http.StatusFound)
+			// Get basePath from spec
+			basePath, err := getBasePath("spec/rest.yaml")
+			if err != nil {
+				a.log.Info("cannot get basePath from spec/rest.yaml", zap.Error(err))
+				handler.ServeHTTP(w, r)
+			}
+			http.Redirect(w, r, basePath+"/docs/", http.StatusFound)
 		} else {
 			handler.ServeHTTP(w, r)
 		}
 	})
 }
 
+func getBasePath(path string) (string, error) {
+	// Read the YAML file
+	yamlFile, err := os.ReadFile(path)
+	if err != nil {
+		return "", err
+	}
+
+	// Unmarshal the YAML into swaggerSpec struct
+	var spec swaggerSpec
+	err = yaml.Unmarshal(yamlFile, &spec)
+	if err != nil {
+		return "", err
+	}
+	return spec.BasePath, nil
+}
+
 func (a *API) logAndGetErrorResponse(msg string, err error, fields ...zap.Field) *models.ErrorResponse {
 	fields = append(fields, zap.Error(err))
 	a.log.Error(msg, fields...)