Initial gallery implementation

By appending `/gallery`, you can view the list of all past drawings from
the lobby. The link will work after the lobby dies, if the data is still
in your session storage. We try to avoid sending requests multiple times
by caching.

In order to do this, we've refactored parts of the lobby, moving shared
drawing / color code into draw.js (previously floodfill.js).

internal/api/http.go

@@ -19,6 +19,8 @@ func (handler *V1Handler) SetupRoutes(rootPath string, router chi.Router) {
 	router.Get(routePrefix+"/lobby", handler.getLobbies)
 	router.Post(routePrefix+"/lobby", handler.postLobby)
 
+	router.Get(routePrefix+"/lobby/{lobby_id}/gallery", handler.getGallery)
+
 	router.Patch(routePrefix+"/lobby/{lobby_id}", handler.patchLobby)
 	// The websocket is shared between the public API and the official client
 	router.Get(routePrefix+"/lobby/{lobby_id}/ws", handler.websocketUpgrade)

internal/api/v1.go

@@ -51,6 +51,27 @@ type LobbyEntry struct {
 	CustomWords     bool       `json:"customWords"`
 }
 
+//easyjson:json
+type Gallery [][]any
+
+func (handler *V1Handler) getGallery(writer http.ResponseWriter, request *http.Request) {
+	lobby := state.GetLobby(chi.URLParam(request, "lobby_id"))
+	if lobby == nil {
+		http.Error(writer, ErrLobbyNotExistent.Error(), http.StatusNotFound)
+		return
+	}
+
+	// FIXME Synchronise access to lobby.Drawings.
+	// The drawings should also be available in an unstarted game.
+
+	if started, _, err := easyjson.MarshalToHTTPResponseWriter(Gallery(lobby.Drawings), writer); err != nil {
+		if !started {
+			http.Error(writer, err.Error(), http.StatusInternalServerError)
+		}
+		return
+	}
+}
+
 func (handler *V1Handler) getLobbies(writer http.ResponseWriter, _ *http.Request) {
 	// REMARK: If paging is ever implemented, we might want to maintain order
 	// when deleting lobbies from state in the state package.

internal/frontend/create.go

@@ -197,5 +197,5 @@ func (handler *SSRHandler) ssrCreateLobby(writer http.ResponseWriter, request *h
 	// We only add the lobby if we could do all necessary pre-steps successfully.
 	state.AddLobby(lobby)
 
-	http.Redirect(writer, request, handler.basePageConfig.RootPath+"/ssrEnterLobby/"+lobby.LobbyID, http.StatusFound)
+	http.Redirect(writer, request, handler.basePageConfig.RootPath+"/lobby/"+lobby.LobbyID, http.StatusFound)
 }

internal/frontend/gallery.go

@@ -0,0 +1,42 @@
+package frontend
+
+import (
+	"log"
+	"net/http"
+	"strings"
+
+	"github.com/go-chi/chi/v5"
+	"github.com/scribble-rs/scribble.rs/internal/translations"
+)
+
+type galleryPageData struct {
+	*BasePageConfig
+
+	LobbyID     string
+	Translation translations.Translation
+	Locale      string
+}
+
+func (handler *SSRHandler) ssrGallery(writer http.ResponseWriter, request *http.Request) {
+	userAgent := strings.ToLower(request.UserAgent())
+	if !isHumanAgent(userAgent) {
+		// FIXME Handle robots
+		return
+	}
+
+	lobbyId := chi.URLParam(request, "lobby_id")
+	translation, locale := determineTranslation(request)
+	pageData := &galleryPageData{
+		BasePageConfig: handler.basePageConfig,
+		LobbyID:        lobbyId,
+		Translation:    translation,
+		Locale:         locale,
+	}
+
+	// If the pagedata isn't initialized, it means the synchronized block has exited.
+	// In this case we don't want to template the lobby, since an error has occurred
+	// and probably already has been handled.
+	if err := pageTemplates.ExecuteTemplate(writer, "gallery-page", pageData); err != nil {
+		log.Printf("Error templating lobby: %s\n", err)
+	}
+}

internal/frontend/http.go

@@ -6,9 +6,11 @@ import (
 	"html/template"
 	"net/http"
 	"path"
+	"strings"
 
 	"github.com/go-chi/chi/v5"
 	"github.com/scribble-rs/scribble.rs/internal/translations"
+	"golang.org/x/text/language"
 )
 
 var (
@@ -61,8 +63,9 @@ func (handler *SSRHandler) SetupRoutes(router chi.Router) {
 			}),
 		).ServeHTTP,
 	)
-	router.Get("/"+path.Join(handler.cfg.RootPath, "ssrEnterLobby/{lobby_id}"), handler.ssrEnterLobby)
-	router.Post("/"+path.Join(handler.cfg.RootPath, "ssrCreateLobby"), handler.ssrCreateLobby)
+	router.Get("/"+path.Join(handler.cfg.RootPath, "lobby/{lobby_id}/gallery"), handler.ssrGallery)
+	router.Get("/"+path.Join(handler.cfg.RootPath, "lobby/{lobby_id}"), handler.ssrEnterLobby)
+	router.Post("/"+path.Join(handler.cfg.RootPath, "create_lobby"), handler.ssrCreateLobby)
 }
 
 // errorPageData represents the data that error.html requires to be displayed.
@@ -86,3 +89,33 @@ func (handler *SSRHandler) userFacingError(w http.ResponseWriter, errorMessage s
 		panic(err)
 	}
 }
+
+func determineTranslation(r *http.Request) (translations.Translation, string) {
+	languageTags, _, err := language.ParseAcceptLanguage(r.Header.Get("Accept-Language"))
+	if err == nil {
+		for _, languageTag := range languageTags {
+			fullLanguageIdentifier := languageTag.String()
+			fullLanguageIdentifierLowercased := strings.ToLower(fullLanguageIdentifier)
+			translation := translations.GetLanguage(fullLanguageIdentifierLowercased)
+			if translation != nil {
+				return translation, fullLanguageIdentifierLowercased
+			}
+
+			baseLanguageIdentifier, _ := languageTag.Base()
+			baseLanguageIdentifierLowercased := strings.ToLower(baseLanguageIdentifier.String())
+			translation = translations.GetLanguage(baseLanguageIdentifierLowercased)
+			if translation != nil {
+				return translation, baseLanguageIdentifierLowercased
+			}
+		}
+	}
+
+	return translations.DefaultTranslation, "en-us"
+}
+
+func isHumanAgent(userAgent string) bool {
+	return strings.Contains(userAgent, "gecko") ||
+		strings.Contains(userAgent, "chrome") ||
+		strings.Contains(userAgent, "opera") ||
+		strings.Contains(userAgent, "safari")
+}

internal/frontend/lobby.go

@@ -9,7 +9,6 @@ import (
 	"github.com/scribble-rs/scribble.rs/internal/api"
 	"github.com/scribble-rs/scribble.rs/internal/state"
 	"github.com/scribble-rs/scribble.rs/internal/translations"
-	"golang.org/x/text/language"
 )
 
 type lobbyPageData struct {
@@ -34,7 +33,7 @@ func (handler *SSRHandler) ssrEnterLobby(writer http.ResponseWriter, request *ht
 	}
 
 	userAgent := strings.ToLower(request.UserAgent())
-	if !(strings.Contains(userAgent, "gecko") || strings.Contains(userAgent, "chrome") || strings.Contains(userAgent, "opera") || strings.Contains(userAgent, "safari")) {
+	if !isHumanAgent(userAgent) {
 		err := pageTemplates.ExecuteTemplate(writer, "robot-page", &robotPageData{
 			BasePageConfig: handler.basePageConfig,
 			LobbyData:      api.CreateLobbyData(lobby),
@@ -91,26 +90,3 @@ func (handler *SSRHandler) ssrEnterLobby(writer http.ResponseWriter, request *ht
 		}
 	}
 }
-
-func determineTranslation(r *http.Request) (translations.Translation, string) {
-	languageTags, _, err := language.ParseAcceptLanguage(r.Header.Get("Accept-Language"))
-	if err == nil {
-		for _, languageTag := range languageTags {
-			fullLanguageIdentifier := languageTag.String()
-			fullLanguageIdentifierLowercased := strings.ToLower(fullLanguageIdentifier)
-			translation := translations.GetLanguage(fullLanguageIdentifierLowercased)
-			if translation != nil {
-				return translation, fullLanguageIdentifierLowercased
-			}
-
-			baseLanguageIdentifier, _ := languageTag.Base()
-			baseLanguageIdentifierLowercased := strings.ToLower(baseLanguageIdentifier.String())
-			translation = translations.GetLanguage(baseLanguageIdentifierLowercased)
-			if translation != nil {
-				return translation, baseLanguageIdentifierLowercased
-			}
-		}
-	}
-
-	return translations.DefaultTranslation, "en-us"
-}