diff options
author | Martin Polden <martin.polden@gmail.com> | 2015-09-18 18:13:14 +0300 |
---|---|---|
committer | Martin Polden <martin.polden@gmail.com> | 2015-09-18 18:36:17 +0300 |
commit | 255826db99d1621648dadb3e92902a3d7caaa5fa (patch) | |
tree | 1cf05b31f170569b27a153a89559ee8c611a83c5 /api/api.go | |
parent | 891312f1f82e5f6bf58d73a979bb5e4094227d70 (diff) |
Improve error handling
Diffstat (limited to 'api/api.go')
-rw-r--r-- | api/api.go | 124 |
1 files changed, 71 insertions, 53 deletions
@@ -19,8 +19,10 @@ import ( ) const ( - IP_HEADER = "x-ifconfig-ip" - COUNTRY_HEADER = "x-ifconfig-country" + IP_HEADER = "x-ifconfig-ip" + COUNTRY_HEADER = "x-ifconfig-country" + TEXT_PLAIN = "text/plain; charset=utf-8" + APPLICATION_JSON = "application/json" ) var cliUserAgentExp = regexp.MustCompile("^(?i)(curl|wget|fetch\\slibfetch)\\/.*$") @@ -29,7 +31,6 @@ type API struct { db *geoip2.Reader CORS bool Template string - Logger *log.Logger } func New() *API { return &API{} } @@ -84,13 +85,17 @@ func ipFromRequest(r *http.Request) (net.IP, error) { return ip, nil } -func headerKeyFromRequest(r *http.Request) string { +func headerPairFromRequest(r *http.Request) (string, string, error) { vars := mux.Vars(r) - key, ok := vars["key"] + header, ok := vars["header"] if !ok { - return "" + header = IP_HEADER } - return key + value := r.Header.Get(header) + if value == "" { + return "", "", fmt.Errorf("no value found for: %s", header) + } + return header, value, nil } func (a *API) lookupCountry(ip net.IP) (string, error) { @@ -110,29 +115,16 @@ func (a *API) lookupCountry(ip net.IP) (string, error) { return "", fmt.Errorf("could not determine country for IP: %s", ip) } -func (a *API) handleError(w http.ResponseWriter, err error) { - a.Logger.Print(err) - w.WriteHeader(http.StatusInternalServerError) - io.WriteString(w, "Internal server error") -} - -func handleUnknownHeader(w http.ResponseWriter, key string) { - w.WriteHeader(http.StatusBadRequest) - io.WriteString(w, "Bad request: Unknown header: "+key) -} - -func (a *API) DefaultHandler(w http.ResponseWriter, r *http.Request) { +func (a *API) DefaultHandler(w http.ResponseWriter, r *http.Request) *appError { cmd := cmdFromQueryParams(r.URL.Query()) funcMap := template.FuncMap{"ToLower": strings.ToLower} t, err := template.New(filepath.Base(a.Template)).Funcs(funcMap).ParseFiles(a.Template) if err != nil { - a.handleError(w, err) - return + return internalServerError(err) } b, err := json.MarshalIndent(r.Header, "", " ") if err != nil { - a.handleError(w, err) - return + return internalServerError(err) } var data = struct { @@ -143,42 +135,37 @@ func (a *API) DefaultHandler(w http.ResponseWriter, r *http.Request) { }{r.Header.Get(IP_HEADER), string(b), r.Header, cmd} if err := t.Execute(w, &data); err != nil { - a.handleError(w, err) + return internalServerError(err) } + return nil } -func (a *API) JSONHandler(w http.ResponseWriter, r *http.Request) { - key := headerKeyFromRequest(r) - if key == "" { - key = IP_HEADER - } - value := map[string]string{key: r.Header.Get(key)} - if value[key] == "" { - handleUnknownHeader(w, key) - return +func (a *API) JSONHandler(w http.ResponseWriter, r *http.Request) *appError { + k, v, err := headerPairFromRequest(r) + contentType := APPLICATION_JSON + if err != nil { + return notFound(err).WithContentType(contentType) } + value := map[string]string{k: v} b, err := json.MarshalIndent(value, "", " ") if err != nil { - a.handleError(w, err) - return + return internalServerError(err).WithContentType(contentType) } + w.Header().Set("Content-Type", contentType) w.Write(b) + return nil } -func (a *API) CLIHandler(w http.ResponseWriter, r *http.Request) { - key := headerKeyFromRequest(r) - if key == "" { - key = IP_HEADER - } - value := r.Header.Get(key) - if value == "" { - handleUnknownHeader(w, key) - return +func (a *API) CLIHandler(w http.ResponseWriter, r *http.Request) *appError { + _, v, err := headerPairFromRequest(r) + if err != nil { + return notFound(err) } - if !strings.HasSuffix(value, "\n") { - value += "\n" + if !strings.HasSuffix(v, "\n") { + v += "\n" } - io.WriteString(w, value) + io.WriteString(w, v) + return nil } func cliMatcher(r *http.Request, rm *mux.RouteMatch) bool { @@ -207,20 +194,51 @@ func (a *API) requestFilter(next http.Handler) http.Handler { }) } +type appHandler func(http.ResponseWriter, *http.Request) *appError + +func (fn appHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) { + if e := fn(w, r); e != nil { // e is *appError + if e.Error != nil { + log.Print(e.Error) + } + contentType := e.ContentType + if contentType == "" { + contentType = TEXT_PLAIN + } + response := e.Response + if response == "" { + response = e.Error.Error() + } + if e.IsJSON() { + var data = struct { + Error string `json:"error"` + }{response} + b, err := json.MarshalIndent(data, "", " ") + if err != nil { + panic(err) + } + response = string(b) + } + w.Header().Set("Content-Type", contentType) + w.WriteHeader(e.Code) + io.WriteString(w, response) + } +} + func (a *API) Handlers() http.Handler { r := mux.NewRouter() // JSON - r.HandleFunc("/", a.JSONHandler).Methods("GET").Headers("Accept", "application/json") - r.HandleFunc("/{key}", a.JSONHandler).Methods("GET").Headers("Accept", "application/json") - r.HandleFunc("/{key}.json", a.JSONHandler).Methods("GET") + r.Handle("/", appHandler(a.JSONHandler)).Methods("GET").Headers("Accept", APPLICATION_JSON) + r.Handle("/{header}", appHandler(a.JSONHandler)).Methods("GET").Headers("Accept", APPLICATION_JSON) + r.Handle("/{header}.json", appHandler(a.JSONHandler)).Methods("GET") // CLI - r.HandleFunc("/", a.CLIHandler).Methods("GET").MatcherFunc(cliMatcher) - r.HandleFunc("/{key}", a.CLIHandler).Methods("GET").MatcherFunc(cliMatcher) + r.Handle("/", appHandler(a.CLIHandler)).Methods("GET").MatcherFunc(cliMatcher) + r.Handle("/{header}", appHandler(a.CLIHandler)).Methods("GET").MatcherFunc(cliMatcher) // Default - r.HandleFunc("/", a.DefaultHandler).Methods("GET") + r.Handle("/", appHandler(a.DefaultHandler)).Methods("GET") // Pass all requests through the request filter return a.requestFilter(r) |