Gin 307 Temporary Redirect - CORS header ‘Access-Control-Allow-Origin’ missing

Description

How to reproduce

I am sending an AJAX request which has trailing slash redirect but it does not redirects because of CORS issue. I dig the code more and then i found that gin.go file has redirectRequest function github.com/gin-gonic/gin/gin.go if i add the the CORS header then the whole request works fine as you can see the screenshot under EXPECTATION section.

How to resolve the issue without modifying the GIN core file ?

func redirectRequest(c *Context) {

        // CODE INSERTED ==================
    c.Writer.Header().Set("Access-Control-Allow-Origin", c.Request.Header.Get("Origin"))

    req := c.Request
       ....
}

Expectations

Actual result

Environment

• go version: 1.14
• gin version (or commit ref): v1.6.3
• operating system: OSX

Comment From: khanakia

Any update ?

Comment From: unbyte

see https://github.com/gin-contrib/cors

Comment From: khanakia

@unbyte i did already test that git contrib cors. CORS are not working for Temporary Redirects that's why i have to add it manually.

Comment From: GiancarlosIO

Same problem here 😢

Comment From: Thytu

same issue, any update?

Comment From: khanakia

@Thytu do not make the request with trailing slash so your request won't be redirected

Comment From: dungmv

any update

Comment From: alirostami1

I use this workaround to remove trailing slash from URL path before even passing it to gin handler

type Router struct {
  *gin.Engine
}

func (r *Router) ServeHTTP(w http.ResponseWriter, req *http.Request) {
  // remove trailing slash
  if strings.HasSuffix(req.RequestURI, "/") {
    req.URL.Path = filepath.Clean(req.URL.Path)
  }
  r.Engine.ServeHTTP(w, req)
}

func main() {
  g := gin.Default()
  g.RedirectTrailingSlash = false
  g.RedirectFixedPath = false
  g.RemoteIPHeaders = append(g.RemoteIPHeaders, "X-Original-Forwarded-For", "Ar-Real-Ip", "CF-Connecting-IP")

  g.GET("/ping", func(c *gin.Context) {
    c.JSON(http.StatusOK, gin.H{
      "message": "pong",
    })
  })

  skipContextPathRouter := Router{
    Engine: g,
  }

  server := &http.Server{
    Addr:    "0.0.0.0:5050",
    Handler: &skipContextPathRouter,
  }
  err := server.ListenAndServe()
  if err != nil {
    log.Fatalf("server stopped: %v", err)
  }
}