pomerium/internal/middleware/middleware.go
Bobby DeSimone b3d3159185
httputil : wrap handlers for additional context (#413)
Signed-off-by: Bobby DeSimone <bobbydesimone@gmail.com>
2019-12-06 11:07:45 -08:00

107 lines
3.7 KiB
Go

package middleware // import "github.com/pomerium/pomerium/internal/middleware"
import (
"net/http"
"strings"
"time"
"github.com/pomerium/pomerium/internal/httputil"
"github.com/pomerium/pomerium/internal/telemetry/trace"
"github.com/pomerium/pomerium/internal/urlutil"
)
// SetHeaders sets a map of response headers.
func SetHeaders(headers map[string]string) func(next http.Handler) http.Handler {
return func(next http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
ctx, span := trace.StartSpan(r.Context(), "middleware.SetHeaders")
defer span.End()
for key, val := range headers {
w.Header().Set(key, val)
}
next.ServeHTTP(w, r.WithContext(ctx))
})
}
}
// ValidateSignature ensures the request is valid and has been signed with
// the correspdoning client secret key
func ValidateSignature(sharedSecret string) func(next http.Handler) http.Handler {
return func(next http.Handler) http.Handler {
return httputil.HandlerFunc(func(w http.ResponseWriter, r *http.Request) error {
ctx, span := trace.StartSpan(r.Context(), "middleware.ValidateSignature")
defer span.End()
if err := ValidateRequestURL(r, sharedSecret); err != nil {
return httputil.NewError(http.StatusBadRequest, err)
}
next.ServeHTTP(w, r.WithContext(ctx))
return nil
})
}
}
// ValidateRequestURL validates the current absolute request URL was signed
// by a given shared key.
func ValidateRequestURL(r *http.Request, key string) error {
return urlutil.NewSignedURL(key, urlutil.GetAbsoluteURL(r)).Validate()
}
// Healthcheck endpoint middleware useful to setting up a path like
// `/ping` that load balancers or uptime testing external services
// can make a request before hitting any routes. It's also convenient
// to place this above ACL middlewares as well.
//
// https://www.w3.org/Protocols/rfc2616/rfc2616-sec9.html
func Healthcheck(endpoint, msg string) func(http.Handler) http.Handler {
f := func(next http.Handler) http.Handler {
fn := func(w http.ResponseWriter, r *http.Request) {
ctx, span := trace.StartSpan(r.Context(), "middleware.Healthcheck")
defer span.End()
if strings.EqualFold(r.URL.Path, endpoint) {
if r.Method != http.MethodGet && r.Method != http.MethodHead {
http.Error(w, http.StatusText(http.StatusMethodNotAllowed), http.StatusMethodNotAllowed)
return
}
w.Header().Set("Content-Type", "text/plain")
w.WriteHeader(http.StatusOK)
if r.Method == http.MethodGet {
w.Write([]byte(msg))
}
return
}
next.ServeHTTP(w, r.WithContext(ctx))
}
return http.HandlerFunc(fn)
}
return f
}
// StripCookie strips the cookie from the downstram request.
func StripCookie(cookieName string) func(next http.Handler) http.Handler {
return func(next http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
ctx, span := trace.StartSpan(r.Context(), "middleware.StripCookie")
defer span.End()
headers := make([]string, 0, len(r.Cookies()))
for _, cookie := range r.Cookies() {
if !strings.HasPrefix(cookie.Name, cookieName) {
headers = append(headers, cookie.String())
}
}
r.Header.Set("Cookie", strings.Join(headers, ";"))
next.ServeHTTP(w, r.WithContext(ctx))
})
}
}
// TimeoutHandlerFunc wraps http.TimeoutHandler
func TimeoutHandlerFunc(timeout time.Duration, timeoutError string) func(next http.Handler) http.Handler {
return func(next http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
ctx, span := trace.StartSpan(r.Context(), "middleware.TimeoutHandlerFunc")
defer span.End()
http.TimeoutHandler(next, timeout, timeoutError).ServeHTTP(w, r.WithContext(ctx))
})
}
}