Edit card

http.go

@@ -2,9 +2,11 @@ package main
 
 import (
 	"bytes"
-	"net/http"
-
+	"context"
+	"encoding/hex"
 	"github.com/gorilla/mux"
+	"net/http"
+	"time"
 )
 
 // GetLoginPage renders the login page to the user.
@@ -203,6 +205,309 @@ func (k *Kasse) GetLogout(res http.ResponseWriter, req *http.Request) {
 	}
 }
 
+// GetAddCard renders the add card dialog. The rendered template contains an instruction for the browser to connect to AddCardEvent and listen for the card UID on the next swipe
+func (k *Kasse) GetAddCard(res http.ResponseWriter, req *http.Request) {
+	session, err := k.sessions.Get(req, "nnev-kasse")
+	if err != nil {
+		http.Redirect(res, req, "/login.html", 302)
+		return
+	}
+	ui, ok := session.Values["user"]
+	if !ok {
+		http.Redirect(res, req, "/login.html", 302)
+		return
+	}
+
+	user := ui.(User)
+	data := struct {
+		User        *User
+		Description string
+		Message     string
+	}{
+		User:        &user,
+		Description: "",
+		Message:     "",
+	}
+
+	if err := ExecuteTemplate(res, TemplateInput{Title: "ccchd Kasse", Body: "add_card.html", Data: &data}); err != nil {
+		k.log.Println("Could not render template:", err)
+		http.Error(res, "Internal error", 500)
+		return
+	}
+}
+
+// AddCardEvent returns a json containing the next swiped card UID. The UID is obtained using a channel which is written by the HandleCard method
+func (k *Kasse) AddCardEvent(res http.ResponseWriter, req *http.Request) {
+	session, err := k.sessions.Get(req, "nnev-kasse")
+	if err != nil {
+		http.Redirect(res, req, "/login.html", 302)
+		return
+	}
+	_, ok := session.Values["user"]
+	if !ok {
+		http.Redirect(res, req, "/login.html", 302)
+		return
+	}
+
+	res.Header().Set("Content-Type", "text/event-stream; charset=utf-8")
+	res.WriteHeader(http.StatusOK)
+
+	// Only one go routine can listen on the next card swipe. Tell the client, when it obtains the lock
+	k.registration.Lock()
+	defer k.registration.Unlock()
+	if _, err := res.Write([]byte("event: lock\ndata: lock\n\n")); err != nil {
+		k.log.Println("Could not write: ", err)
+	}
+	if f, ok := res.(http.Flusher); ok {
+		f.Flush()
+	}
+
+	k.log.Println("Waiting for Card")
+
+	// Read from the channel for one minute. If the timeout is exceeded and the registration window is still open on the client, the browser reconnects anyway
+	var uid []byte
+	ctx, cancel := context.WithTimeout(req.Context(), 1*time.Minute)
+	defer cancel()
+	select {
+	case uid = <-k.card:
+	case <-ctx.Done():
+		http.Error(res, ctx.Err().Error(), http.StatusRequestTimeout)
+		return
+	}
+
+	// Send card UID in hexadecimal to client
+	uidString := hex.EncodeToString(uid)
+	k.log.Println("Card UID obtained! Card uid is", uidString)
+
+	if _, err := res.Write([]byte("event: card\ndata: " + uidString + "\n\n")); err != nil {
+		k.log.Println("Could not write: ", err)
+	}
+
+	if f, ok := res.(http.Flusher); ok {
+		f.Flush()
+	}
+}
+
+// PostAddCard creates a new Card for the POSTing user
+func (k *Kasse) PostAddCard(res http.ResponseWriter, req *http.Request) {
+	session, err := k.sessions.Get(req, "nnev-kasse")
+	if err != nil {
+		http.Redirect(res, req, "/login.html", 302)
+		return
+	}
+	ui, ok := session.Values["user"]
+	if !ok {
+		http.Redirect(res, req, "/login.html", 302)
+		return
+	}
+
+	user := ui.(User)
+
+	description := req.FormValue("description")
+	uidString := req.FormValue("uid")
+
+	renderError := func(message string) {
+		data := struct {
+			User        *User
+			Description string
+			Message     string
+		}{
+			User:        &user,
+			Description: description,
+			Message:     message,
+		}
+
+		if err := ExecuteTemplate(res, TemplateInput{Title: "ccchd Kasse", Body: "add_card.html", Data: &data}); err != nil {
+			k.log.Println("Could not render template:", err)
+			http.Error(res, "Internal error", 500)
+			return
+		}
+	}
+
+	if len(uidString) == 0 {
+		renderError("Please swipe Card to register")
+		return
+	}
+
+	uid, err := hex.DecodeString(uidString)
+	if err != nil {
+		renderError("Hexadecimal UID could not be decoded")
+		return
+	}
+
+	_, err = k.AddCard(uid, &user, description)
+	if err != nil {
+		if err == ErrCardExists {
+			renderError("Card is already registered")
+		} else {
+			renderError("Card could not be added")
+		}
+		return
+	}
+
+	http.Redirect(res, req, "/", 302)
+}
+
+// PostRemoveCard removes a card for the POSTing user
+func (k *Kasse) PostRemoveCard(res http.ResponseWriter, req *http.Request) {
+	session, err := k.sessions.Get(req, "nnev-kasse")
+	if err != nil {
+		http.Redirect(res, req, "/login.html", 302)
+		return
+	}
+	ui, ok := session.Values["user"]
+	if !ok {
+		http.Redirect(res, req, "/login.html", 302)
+		return
+	}
+
+	user := ui.(User)
+
+	err = req.ParseForm()
+	if err != nil {
+		http.Error(res, "Internal error", http.StatusBadRequest)
+	}
+	uidString := req.Form.Get("uid")
+
+	uid, err := hex.DecodeString(uidString)
+	if err != nil {
+		http.Redirect(res, req, "/", http.StatusNotFound)
+		return
+	}
+
+	card, err := k.GetCard(uid, user)
+	if err != nil {
+		http.Redirect(res, req, "/", http.StatusNotFound)
+		return
+	}
+
+	err = k.RemoveCard(uid, &user)
+	if err != nil {
+		data := struct {
+			Card    *Card
+			Message string
+		}{
+			Card:    card,
+			Message: err.Error(),
+		}
+
+		if err := ExecuteTemplate(res, TemplateInput{Title: "ccchd Kasse", Body: "edit_card.html", Data: &data}); err != nil {
+			k.log.Println("Could not render template:", err)
+			http.Error(res, "Internal error", 500)
+			return
+		}
+	} else {
+		http.Redirect(res, req, "/", http.StatusFound)
+		return
+	}
+
+	http.Redirect(res, req, "/", 302)
+}
+
+// PostEditCard renders an edit dialog for a given card
+func (k *Kasse) PostEditCard(res http.ResponseWriter, req *http.Request) {
+	session, err := k.sessions.Get(req, "nnev-kasse")
+	if err != nil {
+		http.Redirect(res, req, "/login.html", 302)
+		return
+	}
+	ui, ok := session.Values["user"]
+	if !ok {
+		http.Redirect(res, req, "/login.html", 302)
+		return
+	}
+
+	user := ui.(User)
+
+	uids, ok := req.URL.Query()["uid"]
+	if !ok || len(uids[0]) < 1 {
+		http.Error(res, "No uid given", http.StatusBadRequest)
+		return
+	}
+	uidString := uids[0]
+
+	uid, err := hex.DecodeString(uidString)
+	if err != nil {
+		http.Redirect(res, req, "/", http.StatusNotFound)
+		return
+	}
+
+	card, err := k.GetCard(uid, user)
+	if err != nil {
+		http.Redirect(res, req, "/", http.StatusNotFound)
+		return
+	}
+
+	data := struct {
+		Card    *Card
+		Message string
+	}{
+		Card:    card,
+		Message: "",
+	}
+
+	if err := ExecuteTemplate(res, TemplateInput{Title: "ccchd Kasse", Body: "edit_card.html", Data: &data}); err != nil {
+		k.log.Println("Could not render template:", err)
+		http.Error(res, "Internal error", 500)
+		return
+	}
+}
+
+// PostUpdateCard saves card changes and redirects to the dashboard
+func (k *Kasse) PostUpdateCard(res http.ResponseWriter, req *http.Request) {
+	session, err := k.sessions.Get(req, "nnev-kasse")
+	if err != nil {
+		http.Redirect(res, req, "/login.html", 302)
+		return
+	}
+	ui, ok := session.Values["user"]
+	if !ok {
+		http.Redirect(res, req, "/login.html", 302)
+		return
+	}
+
+	user := ui.(User)
+
+	err = req.ParseForm()
+	if err != nil {
+		http.Error(res, "Internal error", http.StatusBadRequest)
+	}
+	uidString := req.Form.Get("uid")
+
+	uid, err := hex.DecodeString(uidString)
+	if err != nil {
+		http.Redirect(res, req, "/", http.StatusNotFound)
+	}
+
+	description := req.Form.Get("description")
+
+	err = k.UpdateCard(uid, &user, description)
+	if err != nil {
+		card, err2 := k.GetCard(uid, user)
+		message := err.Error()
+		if err2 != nil {
+			message = err2.Error()
+		}
+
+		data := struct {
+			Card    *Card
+			Message string
+		}{
+			Card:    card,
+			Message: message,
+		}
+
+		if err := ExecuteTemplate(res, TemplateInput{Title: "ccchd Kasse", Body: "edit_card.html", Data: &data}); err != nil {
+			k.log.Println("Could not render template:", err)
+			http.Error(res, "Internal error", 500)
+			return
+		}
+	}
+
+	http.Redirect(res, req, "/", http.StatusFound)
+	return
+}
+
 // Handler returns a http.Handler for the webinterface.
 func (k *Kasse) Handler() http.Handler {
 	r := mux.NewRouter()
@@ -213,5 +518,11 @@ func (k *Kasse) Handler() http.Handler {
 	r.Methods("GET").Path("/logout.html").HandlerFunc(k.GetLogout)
 	r.Methods("GET").Path("/create_user.html").HandlerFunc(k.GetNewUserPage)
 	r.Methods("POST").Path("/create_user.html").HandlerFunc(k.PostNewUserPage)
+	r.Methods("GET").Path("/add_card.html").HandlerFunc(k.GetAddCard)
+	r.Methods("POST").Path("/add_card.html").HandlerFunc(k.PostAddCard)
+	r.Methods("GET").Path("/add_card_event").HandlerFunc(k.AddCardEvent)
+	r.Methods("POST").Path("/remove_card.html").HandlerFunc(k.PostRemoveCard)
+	r.Methods("GET").Path("/edit_card.html").HandlerFunc(k.PostEditCard)
+	r.Methods("POST").Path("/update_card.html").HandlerFunc(k.PostUpdateCard)
 	return r
 }