mediocre-blog/srv/src/api/csrf.go

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package api
import (
"errors"
"net/http"
"github.com/mediocregopher/blog.mediocregopher.com/srv/api/apiutil"
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)
const (
csrfTokenCookieName = "csrf_token"
csrfTokenHeaderName = "X-CSRF-Token"
)
func setCSRFMiddleware(h http.Handler) http.Handler {
return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
csrfTok, err := apiutil.GetCookie(r, csrfTokenCookieName, "")
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if err != nil {
apiutil.InternalServerError(rw, r, err)
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return
} else if csrfTok == "" {
http.SetCookie(rw, &http.Cookie{
Name: csrfTokenCookieName,
Value: apiutil.RandStr(32),
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Secure: true,
})
}
h.ServeHTTP(rw, r)
})
}
func checkCSRFMiddleware(h http.Handler) http.Handler {
return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
csrfTok, err := apiutil.GetCookie(r, csrfTokenCookieName, "")
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if err != nil {
apiutil.InternalServerError(rw, r, err)
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return
}
givenCSRFTok := r.Header.Get(csrfTokenHeaderName)
if givenCSRFTok == "" {
givenCSRFTok = r.FormValue("csrfToken")
}
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if csrfTok == "" || givenCSRFTok != csrfTok {
apiutil.BadRequest(rw, r, errors.New("invalid CSRF token"))
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return
}
h.ServeHTTP(rw, r)
})
}