93 lines
1.6 KiB
Go
93 lines
1.6 KiB
Go
package auth
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import (
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"crypto/rand"
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"fmt"
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"io"
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"net/http"
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"sync"
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"github.com/evcc-io/evcc/util"
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"github.com/gorilla/mux"
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)
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var instance *Auth
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type Auth struct {
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mu sync.Mutex
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secret []byte
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routes map[string]http.HandlerFunc
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}
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func generateSecret() ([]byte, error) {
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var b [16]byte
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_, err := io.ReadFull(rand.Reader, b[:])
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return b[:], err
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}
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func init() {
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secret, err := generateSecret()
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if err != nil {
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panic(err)
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}
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instance = &Auth{
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secret: secret,
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routes: make(map[string]http.HandlerFunc),
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}
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}
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func Setup(router *mux.Router) {
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router.Methods(http.MethodGet).HandlerFunc(instance.handle)
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}
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func Register(handler http.HandlerFunc) string {
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return instance.register(handler)
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}
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func (a *Auth) register(handler http.HandlerFunc) string {
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a.mu.Lock()
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defer a.mu.Unlock()
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state := util.NewState()
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key := state.Encrypt(a.secret)
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a.routes[key] = handler
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return key
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}
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func (a *Auth) handle(w http.ResponseWriter, r *http.Request) {
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q := r.URL.Query()
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if q.Has("error") {
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w.WriteHeader(http.StatusBadRequest)
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fmt.Fprintf(w, "error: %s: %s\n", q.Get("error"), q.Get("error_description"))
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return
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}
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state, err := util.DecryptState(q.Get("state"), a.secret)
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if err != nil {
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w.WriteHeader(http.StatusBadRequest)
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fmt.Fprintf(w, "failed to decrypt state")
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return
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}
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if err := state.Validate(); err != nil {
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w.WriteHeader(http.StatusBadRequest)
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fmt.Fprintf(w, "invalid state")
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return
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}
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a.mu.Lock()
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handler := a.routes[q.Get("state")]
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a.mu.Unlock()
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if handler == nil {
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w.WriteHeader(http.StatusBadRequest)
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fmt.Fprintf(w, "no handler found")
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return
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}
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handler(w, r)
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}
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