api

     1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/api.go	Sat Jul 18 03:39:27 2015 -0400
     1.3 @@ -0,0 +1,137 @@
     1.4 +package api
     1.5 +
     1.6 +import (
     1.7 +	"encoding/json"
     1.8 +	"errors"
     1.9 +	"log"
    1.10 +	"net/http"
    1.11 +	"strings"
    1.12 +
    1.13 +	"bitbucket.org/ww/goautoneg"
    1.14 +
    1.15 +	"code.secondbit.org/uuid.hg"
    1.16 +
    1.17 +	"golang.org/x/net/context"
    1.18 +)
    1.19 +
    1.20 +const (
    1.21 +	RequestErrAccessDenied  = "access_denied"
    1.22 +	RequestErrInsufficient  = "insufficient"
    1.23 +	RequestErrOverflow      = "overflow"
    1.24 +	RequestErrInvalidValue  = "invalid_value"
    1.25 +	RequestErrInvalidFormat = "invalid_format"
    1.26 +	RequestErrMissing       = "missing"
    1.27 +	RequestErrNotFound      = "not_found"
    1.28 +	RequestErrConflict      = "conflict"
    1.29 +	RequestErrActOfGod      = "act_of_god"
    1.30 +)
    1.31 +
    1.32 +var (
    1.33 +	ActOfGodError      = []RequestError{{Slug: RequestErrActOfGod}}
    1.34 +	InvalidFormatError = []RequestError{{Slug: RequestErrInvalidFormat, Field: "/"}}
    1.35 +
    1.36 +	Encoders = []string{"application/json"}
    1.37 +
    1.38 +	ErrUserIDNotSet = errors.New("user ID not set")
    1.39 +)
    1.40 +
    1.41 +type RequestError struct {
    1.42 +	Slug   string `json:"error,omitempty"`
    1.43 +	Field  string `json:"field,omitempty"`
    1.44 +	Param  string `json:"param,omitempty"`
    1.45 +	Header string `json:"header,omitempty"`
    1.46 +}
    1.47 +
    1.48 +type ContextHandler func(http.ResponseWriter, *http.Request, context.Context)
    1.49 +
    1.50 +func NegotiateMiddleware(h http.Handler) http.Handler {
    1.51 +	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
    1.52 +		if r.Header.Get("Accept") != "" {
    1.53 +			contentType := goautoneg.Negotiate(r.Header.Get("Accept"), Encoders)
    1.54 +			if contentType == "" {
    1.55 +				w.WriteHeader(http.StatusNotAcceptable)
    1.56 +				w.Write([]byte("Unsupported content type requested: " + r.Header.Get("Accept")))
    1.57 +				return
    1.58 +			}
    1.59 +		}
    1.60 +		h.ServeHTTP(w, r)
    1.61 +	})
    1.62 +}
    1.63 +
    1.64 +func Encode(w http.ResponseWriter, r *http.Request, status int, resp interface{}) {
    1.65 +	contentType := goautoneg.Negotiate(r.Header.Get("Accept"), Encoders)
    1.66 +	w.Header().Set("content-type", contentType)
    1.67 +	w.WriteHeader(status)
    1.68 +	var err error
    1.69 +	switch contentType {
    1.70 +	case "application/json":
    1.71 +		enc := json.NewEncoder(w)
    1.72 +		err = enc.Encode(resp)
    1.73 +	default:
    1.74 +		enc := json.NewEncoder(w)
    1.75 +		err = enc.Encode(resp)
    1.76 +	}
    1.77 +	if err != nil {
    1.78 +		log.Println(err)
    1.79 +	}
    1.80 +}
    1.81 +
    1.82 +func Decode(r *http.Request, target interface{}) error {
    1.83 +	defer r.Body.Close()
    1.84 +	switch r.Header.Get("Content-Type") {
    1.85 +	case "application/json":
    1.86 +		dec := json.NewDecoder(r.Body)
    1.87 +		return dec.Decode(target)
    1.88 +	default:
    1.89 +		dec := json.NewDecoder(r.Body)
    1.90 +		return dec.Decode(target)
    1.91 +	}
    1.92 +}
    1.93 +
    1.94 +func CORSMiddleware(h http.Handler) http.Handler {
    1.95 +	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
    1.96 +		w.Header().Set("Access-Control-Allow-Origin", "*")
    1.97 +		w.Header().Set("Access-Control-Allow-Headers", r.Header.Get("Access-Control-Request-Headers"))
    1.98 +		w.Header().Set("Access-Control-Allow-Credentials", "true")
    1.99 +		if strings.ToLower(r.Method) == "options" {
   1.100 +			methods := strings.Join(r.Header[http.CanonicalHeaderKey("Trout-Methods")], ", ")
   1.101 +			w.Header().Set("Access-Control-Allow-Methods", methods)
   1.102 +			w.Header().Set("Allow", methods)
   1.103 +			w.WriteHeader(http.StatusOK)
   1.104 +			return
   1.105 +		}
   1.106 +		h.ServeHTTP(w, r)
   1.107 +	})
   1.108 +}
   1.109 +
   1.110 +func ContextWrapper(c context.Context, handler ContextHandler) http.Handler {
   1.111 +	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
   1.112 +		handler(w, r, c)
   1.113 +	})
   1.114 +}
   1.115 +
   1.116 +func CheckScopes(r *http.Request, scopes ...string) bool {
   1.117 +	passedStr := r.Header.Get("scopes")
   1.118 +	passed := strings.Split(passedStr, " ")
   1.119 +	for _, scope := range scopes {
   1.120 +		var found bool
   1.121 +		for _, p := range passed {
   1.122 +			if scope == strings.TrimSpace(p) {
   1.123 +				found = true
   1.124 +				break
   1.125 +			}
   1.126 +		}
   1.127 +		if !found {
   1.128 +			return false
   1.129 +		}
   1.130 +	}
   1.131 +	return true
   1.132 +}
   1.133 +
   1.134 +func AuthUser(r *http.Request) (uuid.ID, error) {
   1.135 +	rawID := r.Header.Get("User-ID")
   1.136 +	if rawID == "" {
   1.137 +		return nil, ErrUserIDNotSet
   1.138 +	}
   1.139 +	return uuid.Parse(rawID)
   1.140 +}