Gin: Setting headers in middleware chain

[sosedoff]

Im currently experimenting with various middleware handlers for gin and noticed
that setting response header after calling c.Next() does not work. Here's an example:

func BeforeAfterMiddleware() gin.HandlerFunc {
  return func(c *gin.Context) {
    c.Writer.Header().Set("X-Before", "Foo")
    c.Next()
    c.Writer.Header().Set("X-After", "Bar")
  }
}

Only X-Before header is set when request is complete.
Is it a bug or am i doing something wrong?

[rocwong]

Yep, when you calling c.JSON etc, the headers were already written.

[javierprovecho]

https://github.com/gin-gonic/gin/issues/133 check this out and review your code for correct order of events, this is own nature of http.