traefik/middlewares/error_pages.go

77 lines
2.3 KiB
Go

package middlewares
import (
"net/http"
"strconv"
"strings"
"github.com/containous/traefik/log"
"github.com/containous/traefik/types"
"github.com/vulcand/oxy/forward"
"github.com/vulcand/oxy/utils"
)
//ErrorPagesHandler is a middleware that provides the custom error pages
type ErrorPagesHandler struct {
HTTPCodeRanges [][2]int
BackendURL string
errorPageForwarder *forward.Forwarder
}
//NewErrorPagesHandler initializes the utils.ErrorHandler for the custom error pages
func NewErrorPagesHandler(errorPage types.ErrorPage, backendURL string) (*ErrorPagesHandler, error) {
fwd, err := forward.New()
if err != nil {
return nil, err
}
//Break out the http status code ranges into a low int and high int
//for ease of use at runtime
var blocks [][2]int
for _, block := range errorPage.Status {
codes := strings.Split(block, "-")
//if only a single HTTP code was configured, assume the best and create the correct configuration on the user's behalf
if len(codes) == 1 {
codes = append(codes, codes[0])
}
lowCode, err := strconv.Atoi(codes[0])
if err != nil {
return nil, err
}
highCode, err := strconv.Atoi(codes[1])
if err != nil {
return nil, err
}
blocks = append(blocks, [2]int{lowCode, highCode})
}
return &ErrorPagesHandler{
HTTPCodeRanges: blocks,
BackendURL: backendURL + errorPage.Query,
errorPageForwarder: fwd},
nil
}
func (ep *ErrorPagesHandler) ServeHTTP(w http.ResponseWriter, req *http.Request, next http.HandlerFunc) {
recorder := newRetryResponseRecorder(w)
next.ServeHTTP(recorder, req)
w.WriteHeader(recorder.GetCode())
//check the recorder code against the configured http status code ranges
for _, block := range ep.HTTPCodeRanges {
if recorder.GetCode() >= block[0] && recorder.GetCode() <= block[1] {
log.Errorf("Caught HTTP Status Code %d, returning error page", recorder.GetCode())
finalURL := strings.Replace(ep.BackendURL, "{status}", strconv.Itoa(recorder.GetCode()), -1)
if newReq, err := http.NewRequest(http.MethodGet, finalURL, nil); err != nil {
w.Write([]byte(http.StatusText(recorder.GetCode())))
} else {
ep.errorPageForwarder.ServeHTTP(w, newReq)
}
return
}
}
//did not catch a configured status code so proceed with the request
utils.CopyHeaders(w.Header(), recorder.Header())
w.Write(recorder.GetBody().Bytes())
}