package http import ( "encoding/json" "errors" "net/http" "net/url" "path" "strconv" "strings" "time" "github.com/coreos/dex/pkg/log" ) func WriteError(w http.ResponseWriter, code int, msg string) { e := struct { Error string `json:"error"` }{ Error: msg, } b, err := json.Marshal(e) if err != nil { log.Errorf("Failed marshaling %#v to JSON: %v", e, err) } w.Header().Set("Content-Type", "application/json") w.WriteHeader(code) w.Write(b) } func cacheControlMaxAge(hdr string) (time.Duration, bool, error) { for _, field := range strings.Split(hdr, ",") { parts := strings.SplitN(strings.TrimSpace(field), "=", 2) k := strings.ToLower(strings.TrimSpace(parts[0])) if k != "max-age" { continue } if len(parts) == 1 { return 0, false, errors.New("max-age has no value") } v := strings.TrimSpace(parts[1]) if v == "" { return 0, false, errors.New("max-age has empty value") } age, err := strconv.Atoi(v) if err != nil { return 0, false, err } if age <= 0 { return 0, false, nil } return time.Duration(age) * time.Second, true, nil } return 0, false, nil } func expires(date, expires string) (time.Duration, bool, error) { if date == "" || expires == "" { return 0, false, nil } te, err := time.Parse(time.RFC1123, expires) if err != nil { return 0, false, err } td, err := time.Parse(time.RFC1123, date) if err != nil { return 0, false, err } ttl := te.Sub(td) // headers indicate data already expired, caller should not // have to care about this case if ttl <= 0 { return 0, false, nil } return ttl, true, nil } func Cacheable(hdr http.Header) (time.Duration, bool, error) { ttl, ok, err := cacheControlMaxAge(hdr.Get("Cache-Control")) if err != nil || ok { return ttl, ok, err } return expires(hdr.Get("Date"), hdr.Get("Expires")) } // MergeQuery appends additional query values to an existing URL. func MergeQuery(u url.URL, q url.Values) url.URL { uv := u.Query() for k, vs := range q { for _, v := range vs { uv.Add(k, v) } } u.RawQuery = uv.Encode() return u } // NewResourceLocation appends a resource id to the end of the requested URL path. func NewResourceLocation(reqURL *url.URL, id string) string { var u url.URL u = *reqURL u.Path = path.Join(u.Path, id) u.RawQuery = "" u.Fragment = "" return u.String() } // CopyRequest returns a clone of the provided *http.Request. // The returned object is a shallow copy of the struct and a // deep copy of its Header field. func CopyRequest(r *http.Request) *http.Request { r2 := *r r2.Header = make(http.Header) for k, s := range r.Header { r2.Header[k] = s } return &r2 }