Babylon.js/src/Offline/database.ts

import { Nullable } from "../types";
import { Tools } from "../Misc/tools";
import { Logger } from "../Misc/logger";
import { TGATools } from '../Misc/tga';
import { Engine } from "../Engines/engine";
import { IOfflineProvider } from "./IOfflineProvider";
import { WebRequest } from '../Misc/webRequest';

// Sets the default offline provider to Babylon.js
Engine.OfflineProviderFactory = (urlToScene: string, callbackManifestChecked: (checked: boolean) => any, disableManifestCheck = false) => { return new Database(urlToScene, callbackManifestChecked, disableManifestCheck); };

/**
 * Class used to enable access to IndexedDB
 * @see http://doc.babylonjs.com/how_to/caching_resources_in_indexeddb
 */
export class Database implements IOfflineProvider {
    private _callbackManifestChecked: (check: boolean) => any;
    private _currentSceneUrl: string;
    private _db: Nullable<IDBDatabase>;
    private _enableSceneOffline: boolean;
    private _enableTexturesOffline: boolean;
    private _manifestVersionFound: number;
    private _mustUpdateRessources: boolean;
    private _hasReachedQuota: boolean;
    private _isSupported: boolean;

    // Handling various flavors of prefixed version of IndexedDB
    private _idbFactory = <IDBFactory>(typeof window !== "undefined" ? window.indexedDB || window.mozIndexedDB || window.webkitIndexedDB || window.msIndexedDB : indexedDB);

    /** Gets a boolean indicating if the user agent supports blob storage (this value will be updated after creating the first Database object) */
    private static IsUASupportingBlobStorage = true;

    /**
     * Gets a boolean indicating if Database storate is enabled (off by default)
     */
    static IDBStorageEnabled = false;

    /**
     * Gets a boolean indicating if scene must be saved in the database
     */
    public get enableSceneOffline(): boolean {
        return this._enableSceneOffline;
    }

    /**
     * Gets a boolean indicating if textures must be saved in the database
     */
    public get enableTexturesOffline(): boolean {
        return this._enableTexturesOffline;
    }

    /**
     * Creates a new Database
     * @param urlToScene defines the url to load the scene
     * @param callbackManifestChecked defines the callback to use when manifest is checked
     * @param disableManifestCheck defines a boolean indicating that we want to skip the manifest validation (it will be considered validated and up to date)
     */
    constructor(urlToScene: string, callbackManifestChecked: (checked: boolean) => any, disableManifestCheck = false) {
        this._callbackManifestChecked = callbackManifestChecked;
        this._currentSceneUrl = Database._ReturnFullUrlLocation(urlToScene);
        this._db = null;
        this._enableSceneOffline = false;
        this._enableTexturesOffline = false;
        this._manifestVersionFound = 0;
        this._mustUpdateRessources = false;
        this._hasReachedQuota = false;

        if (!Database.IDBStorageEnabled) {
            this._callbackManifestChecked(true);
        } else {
            if (disableManifestCheck) {
                this._enableSceneOffline = true;
                this._enableTexturesOffline = true;
                this._manifestVersionFound = 1;
                Tools.SetImmediate(() => {
                    this._callbackManifestChecked(true);
                });
            }
            else {
                this._checkManifestFile();
            }
        }
    }

    private static _ParseURL = (url: string) => {
        var a = document.createElement('a');
        a.href = url;
        var urlWithoutHash = url.substring(0, url.lastIndexOf("#"));
        var fileName = url.substring(urlWithoutHash.lastIndexOf("/") + 1, url.length);
        var absLocation = url.substring(0, url.indexOf(fileName, 0));
        return absLocation;
    }

    private static _ReturnFullUrlLocation = (url: string): string => {
        if (url.indexOf("http:/") === -1 && url.indexOf("https:/") === -1) {
            return (Database._ParseURL(window.location.href) + url);
        }
        else {
            return url;
        }
    }

    private _checkManifestFile() {
        var noManifestFile = () => {
            this._enableSceneOffline = false;
            this._enableTexturesOffline = false;
            this._callbackManifestChecked(false);
        };

        var timeStampUsed = false;
        var manifestURL = this._currentSceneUrl + ".manifest";

        var xhr = new WebRequest();

        if (navigator.onLine) {
            // Adding a timestamp to by-pass browsers' cache
            timeStampUsed = true;
            manifestURL = manifestURL + (manifestURL.match(/\?/) == null ? "?" : "&") + Date.now();
        }
        xhr.open("GET", manifestURL);

        xhr.addEventListener("load", () => {
            if (xhr.status === 200 || Database._ValidateXHRData(xhr, 1)) {
                try {
                    var manifestFile = JSON.parse(xhr.response);
                    this._enableSceneOffline = manifestFile.enableSceneOffline;
                    this._enableTexturesOffline = manifestFile.enableTexturesOffline && Database.IsUASupportingBlobStorage;
                    if (manifestFile.version && !isNaN(parseInt(manifestFile.version))) {
                        this._manifestVersionFound = manifestFile.version;
                    }
                    if (this._callbackManifestChecked) {
                        this._callbackManifestChecked(true);
                    }
                }
                catch (ex) {
                    noManifestFile();
                }
            }
            else {
                noManifestFile();
            }
        }, false);

        xhr.addEventListener("error", () => {
            if (timeStampUsed) {
                timeStampUsed = false;
                // Let's retry without the timeStamp
                // It could fail when coupled with HTML5 Offline API
                var retryManifestURL = this._currentSceneUrl + ".manifest";
                xhr.open("GET", retryManifestURL);
                xhr.send();
            }
            else {
                noManifestFile();
            }
        }, false);

        try {
            xhr.send();
        }
        catch (ex) {
            Logger.Error("Error on XHR send request.");
            this._callbackManifestChecked(false);
        }
    }

    /**
     * Open the database and make it available
     * @param successCallback defines the callback to call on success
     * @param errorCallback defines the callback to call on error
     */
    public open(successCallback: () => void, errorCallback: () => void): void {
        let handleError = () => {
            this._isSupported = false;
            if (errorCallback) { errorCallback(); }
        };

        if (!this._idbFactory || !(this._enableSceneOffline || this._enableTexturesOffline)) {
            // Your browser doesn't support IndexedDB
            this._isSupported = false;
            if (errorCallback) { errorCallback(); }
        }
        else {
            // If the DB hasn't been opened or created yet
            if (!this._db) {
                this._hasReachedQuota = false;
                this._isSupported = true;

                var request: IDBOpenDBRequest = this._idbFactory.open("babylonjs", 1);

                // Could occur if user is blocking the quota for the DB and/or doesn't grant access to IndexedDB
                request.onerror = () => {
                    handleError();
                };

                // executes when a version change transaction cannot complete due to other active transactions
                request.onblocked = () => {
                    Logger.Error("IDB request blocked. Please reload the page.");
                    handleError();
                };

                // DB has been opened successfully
                request.onsuccess = () => {
                    this._db = request.result;
                    successCallback();
                };

                // Initialization of the DB. Creating Scenes & Textures stores
                request.onupgradeneeded = (event: IDBVersionChangeEvent) => {
                    this._db = (<any>(event.target)).result;
                    if (this._db) {
                        try {
                            this._db.createObjectStore("scenes", { keyPath: "sceneUrl" });
                            this._db.createObjectStore("versions", { keyPath: "sceneUrl" });
                            this._db.createObjectStore("textures", { keyPath: "textureUrl" });
                        }
                        catch (ex) {
                            Logger.Error("Error while creating object stores. Exception: " + ex.message);
                            handleError();
                        }
                    }
                };
            }
            // DB has already been created and opened
            else {
                if (successCallback) { successCallback(); }
            }
        }
    }

    /**
     * Loads an image from the database
     * @param url defines the url to load from
     * @param image defines the target DOM image
     */
    public loadImage(url: string, image: HTMLImageElement) {
        var completeURL = Database._ReturnFullUrlLocation(url);

        var saveAndLoadImage = () => {
            if (!this._hasReachedQuota && this._db !== null) {
                // the texture is not yet in the DB, let's try to save it
                this._saveImageIntoDBAsync(completeURL, image);
            }
            // If the texture is not in the DB and we've reached the DB quota limit
            // let's load it directly from the web
            else {
                image.src = url;
            }
        };

        if (!this._mustUpdateRessources) {
            this._loadImageFromDBAsync(completeURL, image, saveAndLoadImage);
        }
        // First time we're download the images or update requested in the manifest file by a version change
        else {
            saveAndLoadImage();
        }
    }

    private _loadImageFromDBAsync(url: string, image: HTMLImageElement, notInDBCallback: () => any) {
        if (this._isSupported && this._db !== null) {
            var texture: any;
            var transaction: IDBTransaction = this._db.transaction(["textures"]);

            transaction.onabort = () => {
                image.src = url;
            };

            transaction.oncomplete = () => {
                var blobTextureURL: string;
                if (texture) {
                    var URL = window.URL || window.webkitURL;
                    blobTextureURL = URL.createObjectURL(texture.data);
                    image.onerror = () => {
                        Logger.Error("Error loading image from blob URL: " + blobTextureURL + " switching back to web url: " + url);
                        image.src = url;
                    };
                    image.src = blobTextureURL;
                }
                else {
                    notInDBCallback();
                }
            };

            var getRequest: IDBRequest = transaction.objectStore("textures").get(url);

            getRequest.onsuccess = (event) => {
                texture = (<any>(event.target)).result;
            };
            getRequest.onerror = () => {
                Logger.Error("Error loading texture " + url + " from DB.");
                image.src = url;
            };
        }
        else {
            Logger.Error("Error: IndexedDB not supported by your browser or BabylonJS Database is not open.");
            image.src = url;
        }
    }

    private _saveImageIntoDBAsync(url: string, image: HTMLImageElement) {
        if (this._isSupported) {
            // In case of error (type not supported or quota exceeded), we're at least sending back XHR data to allow texture loading later on
            var generateBlobUrl = () => {
                var blobTextureURL;

                if (blob) {
                    var URL = window.URL || window.webkitURL;
                    try {
                        blobTextureURL = URL.createObjectURL(blob);
                    }
                    // Chrome is raising a type error if we're setting the oneTimeOnly parameter
                    catch (ex) {
                        blobTextureURL = URL.createObjectURL(blob);
                    }
                }

                if (blobTextureURL) {
                    image.src = blobTextureURL;
                }
            };

            if (Database.IsUASupportingBlobStorage) { // Create XHR
                var xhr = new WebRequest(),
                    blob: Blob;

                xhr.open("GET", url);
                xhr.responseType = "blob";

                xhr.addEventListener("load", () => {
                    if (xhr.status === 200 && this._db) {
                        // Blob as response (XHR2)
                        blob = xhr.response;

                        var transaction = this._db.transaction(["textures"], "readwrite");

                        // the transaction could abort because of a QuotaExceededError error
                        transaction.onabort = (event) => {
                            try {
                                //backwards compatibility with ts 1.0, srcElement doesn't have an "error" according to ts 1.3
                                let srcElement = <any>(event.srcElement || event.target);
                                var error = srcElement.error;
                                if (error && error.name === "QuotaExceededError") {
                                    this._hasReachedQuota = true;
                                }
                            }
                            catch (ex) { }
                            generateBlobUrl();
                        };

                        transaction.oncomplete = () => {
                            generateBlobUrl();
                        };

                        var newTexture = { textureUrl: url, data: blob };

                        try {
                            // Put the blob into the dabase
                            var addRequest = transaction.objectStore("textures").put(newTexture);
                            addRequest.onsuccess = () => {
                            };
                            addRequest.onerror = () => {
                                generateBlobUrl();
                            };
                        }
                        catch (ex) {
                            // "DataCloneError" generated by Chrome when you try to inject blob into IndexedDB
                            if (ex.code === 25) {
                                Database.IsUASupportingBlobStorage = false;
                                this._enableTexturesOffline = false;
                            }
                            image.src = url;
                        }
                    }
                    else {
                        image.src = url;
                    }
                }, false);

                xhr.addEventListener("error", () => {
                    Logger.Error("Error in XHR request in BABYLON.Database.");
                    image.src = url;
                }, false);

                xhr.send();
            }
            else {
                image.src = url;
            }
        }
        else {
            Logger.Error("Error: IndexedDB not supported by your browser or BabylonJS Database is not open.");
            image.src = url;
        }
    }

    private _checkVersionFromDB(url: string, versionLoaded: (version: number) => void) {
        var updateVersion = () => {
            // the version is not yet in the DB or we need to update it
            this._saveVersionIntoDBAsync(url, versionLoaded);
        };
        this._loadVersionFromDBAsync(url, versionLoaded, updateVersion);
    }

    private _loadVersionFromDBAsync(url: string, callback: (version: number) => void, updateInDBCallback: () => void) {
        if (this._isSupported && this._db) {
            var version: any;
            try {
                var transaction = this._db.transaction(["versions"]);

                transaction.oncomplete = () => {
                    if (version) {
                        // If the version in the JSON file is different from the version in DB
                        if (this._manifestVersionFound !== version.data) {
                            this._mustUpdateRessources = true;
                            updateInDBCallback();
                        }
                        else {
                            callback(version.data);
                        }
                    }
                    // version was not found in DB
                    else {
                        this._mustUpdateRessources = true;
                        updateInDBCallback();
                    }
                };

                transaction.onabort = () => {
                    callback(-1);
                };

                var getRequest = transaction.objectStore("versions").get(url);

                getRequest.onsuccess = (event) => {
                    version = (<any>(event.target)).result;
                };
                getRequest.onerror = () => {
                    Logger.Error("Error loading version for scene " + url + " from DB.");
                    callback(-1);
                };
            }
            catch (ex) {
                Logger.Error("Error while accessing 'versions' object store (READ OP). Exception: " + ex.message);
                callback(-1);
            }
        }
        else {
            Logger.Error("Error: IndexedDB not supported by your browser or BabylonJS Database is not open.");
            callback(-1);
        }
    }

    private _saveVersionIntoDBAsync(url: string, callback: (version: number) => void) {
        if (this._isSupported && !this._hasReachedQuota && this._db) {
            try {
                // Open a transaction to the database
                var transaction = this._db.transaction(["versions"], "readwrite");

                // the transaction could abort because of a QuotaExceededError error
                transaction.onabort = (event) => {
                    try {//backwards compatibility with ts 1.0, srcElement doesn't have an "error" according to ts 1.3
                        var error = (<any>event.srcElement)['error'];
                        if (error && error.name === "QuotaExceededError") {
                            this._hasReachedQuota = true;
                        }
                    }
                    catch (ex) { }
                    callback(-1);
                };

                transaction.oncomplete = () => {
                    callback(this._manifestVersionFound);
                };

                var newVersion = { sceneUrl: url, data: this._manifestVersionFound };

                // Put the scene into the database
                var addRequest = transaction.objectStore("versions").put(newVersion);
                addRequest.onsuccess = () => {
                };
                addRequest.onerror = () => {
                    Logger.Error("Error in DB add version request in BABYLON.Database.");
                };
            }
            catch (ex) {
                Logger.Error("Error while accessing 'versions' object store (WRITE OP). Exception: " + ex.message);
                callback(-1);
            }
        }
        else {
            callback(-1);
        }
    }

    /**
     * Loads a file from database
     * @param url defines the URL to load from
     * @param sceneLoaded defines a callback to call on success
     * @param progressCallBack defines a callback to call when progress changed
     * @param errorCallback defines a callback to call on error
     * @param useArrayBuffer defines a boolean to use array buffer instead of text string
     */
    public loadFile(url: string, sceneLoaded: (data: any) => void, progressCallBack?: (data: any) => void, errorCallback?: () => void, useArrayBuffer?: boolean): void {
        var completeUrl = Database._ReturnFullUrlLocation(url);

        var saveAndLoadFile = () => {
            // the scene is not yet in the DB, let's try to save it
            this._saveFileAsync(completeUrl, sceneLoaded, progressCallBack, useArrayBuffer, errorCallback);
        };

        this._checkVersionFromDB(completeUrl, (version) => {
            if (version !== -1) {
                if (!this._mustUpdateRessources) {
                    this._loadFileAsync(completeUrl, sceneLoaded, saveAndLoadFile);
                }
                else {
                    this._saveFileAsync(completeUrl, sceneLoaded, progressCallBack, useArrayBuffer, errorCallback);
                }
            }
            else {
                if (errorCallback) {
                    errorCallback();
                }
            }
        });
    }

    private _loadFileAsync(url: string, callback: (data?: any) => void, notInDBCallback: () => void) {
        if (this._isSupported && this._db) {
            var targetStore: string;
            if (url.indexOf(".babylon") !== -1) {
                targetStore = "scenes";
            }
            else {
                targetStore = "textures";
            }

            var file: any;
            var transaction = this._db.transaction([targetStore]);

            transaction.oncomplete = () => {
                if (file) {
                    callback(file.data);
                }
                // file was not found in DB
                else {
                    notInDBCallback();
                }
            };

            transaction.onabort = () => {
                notInDBCallback();
            };

            var getRequest = transaction.objectStore(targetStore).get(url);

            getRequest.onsuccess = (event) => {
                file = (<any>(event.target)).result;
            };
            getRequest.onerror = () => {
                Logger.Error("Error loading file " + url + " from DB.");
                notInDBCallback();
            };
        }
        else {
            Logger.Error("Error: IndexedDB not supported by your browser or BabylonJS Database is not open.");
            callback();
        }
    }

    private _saveFileAsync(url: string, callback: (data?: any) => void, progressCallback?: (this: XMLHttpRequestEventTarget, ev: ProgressEvent) => any, useArrayBuffer?: boolean, errorCallback?: (data?: any) => void) {
        if (this._isSupported) {
            var targetStore: string;
            if (url.indexOf(".babylon") !== -1) {
                targetStore = "scenes";
            }
            else {
                targetStore = "textures";
            }

            // Create XHR
            var xhr = new WebRequest();
            var fileData: any;
            xhr.open("GET", url + "?" + Date.now());

            if (useArrayBuffer) {
                xhr.responseType = "arraybuffer";
            }

            if (progressCallback) {
                xhr.onprogress = progressCallback;
            }

            xhr.addEventListener("load", () => {
                if (xhr.status === 200 || (xhr.status < 400 && Database._ValidateXHRData(xhr, !useArrayBuffer ? 1 : 6))) {
                    // Blob as response (XHR2)
                    fileData = !useArrayBuffer ? xhr.responseText : xhr.response;

                    if (!this._hasReachedQuota && this._db) {
                        // Open a transaction to the database
                        var transaction = this._db.transaction([targetStore], "readwrite");

                        // the transaction could abort because of a QuotaExceededError error
                        transaction.onabort = (event) => {
                            try {
                                //backwards compatibility with ts 1.0, srcElement doesn't have an "error" according to ts 1.3
                                var error = (<any>event.srcElement)['error'];
                                if (error && error.name === "QuotaExceededError") {
                                    this._hasReachedQuota = true;
                                }
                            }
                            catch (ex) { }
                            callback(fileData);
                        };

                        transaction.oncomplete = () => {
                            callback(fileData);
                        };

                        var newFile;
                        if (targetStore === "scenes") {
                            newFile = { sceneUrl: url, data: fileData, version: this._manifestVersionFound };
                        }
                        else {
                            newFile = { textureUrl: url, data: fileData };
                        }

                        try {
                            // Put the scene into the database
                            var addRequest = transaction.objectStore(targetStore).put(newFile);
                            addRequest.onsuccess = () => {
                            };
                            addRequest.onerror = () => {
                                Logger.Error("Error in DB add file request in BABYLON.Database.");
                            };
                        }
                        catch (ex) {
                            callback(fileData);
                        }
                    }
                    else {
                        callback(fileData);
                    }
                }
                else {
                    if (xhr.status >= 400 && errorCallback) {
                        errorCallback(xhr);
                    } else {
                        callback();
                    }
                }
            }, false);

            xhr.addEventListener("error", () => {
                Logger.Error("error on XHR request.");
                callback();
            }, false);

            xhr.send();
        }
        else {
            Logger.Error("Error: IndexedDB not supported by your browser or Babylon.js Database is not open.");
            callback();
        }
    }

    /**
     * Validates if xhr data is correct
     * @param xhr defines the request to validate
     * @param dataType defines the expected data type
     * @returns true if data is correct
     */
    private static _ValidateXHRData(xhr: WebRequest, dataType = 7): boolean {
        // 1 for text (.babylon, manifest and shaders), 2 for TGA, 4 for DDS, 7 for all

        try {
            if (dataType & 1) {
                if (xhr.responseText && xhr.responseText.length > 0) {
                    return true;
                } else if (dataType === 1) {
                    return false;
                }
            }

            if (dataType & 2) {
                // Check header width and height since there is no "TGA" magic number
                var tgaHeader = TGATools.GetTGAHeader(xhr.response);

                if (tgaHeader.width && tgaHeader.height && tgaHeader.width > 0 && tgaHeader.height > 0) {
                    return true;
                } else if (dataType === 2) {
                    return false;
                }
            }

            if (dataType & 4) {
                // Check for the "DDS" magic number
                var ddsHeader = new Uint8Array(xhr.response, 0, 3);

                if (ddsHeader[0] === 68 && ddsHeader[1] === 68 && ddsHeader[2] === 83) {
                    return true;
                } else {
                    return false;
                }
            }

        } catch (e) {
            // Global protection
        }

        return false;
    }
}