xesite/cmd/site/internal/middleware/requestid.go

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2019-03-27 14:18:52 +00:00
package middleware
import (
"net/http"
"github.com/celrenheit/sandflake"
"within.website/ln"
)
// RequestID appends a unique (sandflake) request ID to each request's
// X-Request-Id header field, much like Heroku's router does.
func RequestID(next http.Handler) http.Handler {
var g sandflake.Generator
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
id := g.Next().String()
if rid := r.Header.Get("X-Request-Id"); rid != "" {
id = rid + "," + id
}
ctx := ln.WithF(r.Context(), ln.F{
"request_id": id,
})
r = r.WithContext(ctx)
w.Header().Set("X-Request-Id", id)
r.Header.Set("X-Request-Id", id)
next.ServeHTTP(w, r)
})
}