Create NPM package

.gitignore

@@ -1,6 +1,4 @@
 /.vscode/c_cpp_properties.json
-/ui/libapi.*
-!/ui/libapi.mjs.d.ts
 /node_modules
 /deps/*
 !/deps/libgphoto2

README.md

@@ -1,9 +1,124 @@
-This is a [demo app](https://web.dev/porting-libusb-to-webusb/) running gPhoto2 on the Web:
-
-![A picture of DSLR camera connected via a USB cable to a laptop. The laptop is running the Web demo mentioned in the article, which mirrors a live video feed from the camera as well as allows to tweak its settings via form controls.](https://web-dev.imgix.net/image/9oK23mr86lhFOwKaoYZ4EySNFp02/MR4YGRvl0Z9AWT6vv3sQ.jpg?auto=format&w=1600)
+# Web-gPhoto2
+A gPhoto2 implementation using WebAssembly to control DSLR cameras from the browser.
 
 Powered by a [custom fork](https://github.com/RReverser/libgphoto2) of [libgphoto2](https://github.com/gphoto/libgphoto2), the [WebUSB](https://github.com/WICG/webusb) backend of [libusb](https://github.com/libusb/libusb), and WebAssembly via [Emscripten](https://emscripten.org/).
 
+# NPM
+## Installation
+```bash
+npm install web-gphoto2
+// or
+yarn add web-gphoto2
+```
+
+## Usage
+**Note: This package ONLY runs in the browser context**. It will not work in NodeJS. If you are using a build-tool make sure to dynamically import this package so it is only imported in the browser context.
+
+```ts
+let initModule: any;
+
+if (typeof window !== 'undefined') {
+    import('web-gphoto2').then((module) => {
+        initModule = module.default;
+    }).catch((error) => {
+        console.error("Error loading web-gphoto2", error);
+    });
+} else {
+    console.warn("web-gphoto2 is only available in the browser");
+}
+```
+
+A short example on how to use this package to obtain the camera config:
+```ts
+// After importing the initModule from web-gphoto2
+const ModulePromise = initModule();
+
+export function rethrowIfCritical(err) {
+    if (err.constructor !== Error) throw err;
+}
+
+export async function connect() {
+    const Module = await ModulePromise;
+
+    let context = await new Module.Context();
+    let supportedOps = await context.supportedOps();
+
+    let queue = Promise.resolve();
+
+    function schedule(op) {
+        let res = queue.then(() => op(context));
+        queue = res.catch(rethrowIfCritical);
+        return res;
+    }
+
+    return {
+        supportedOps,
+        schedule,
+        disconnect() {
+            context.delete();
+        }
+    };
+}
+
+// Select the camera, connect, and obtain the config. Error handling is omitted for brevity but should be included, check the example for details.
+await navigator.usb.requestDevice({
+    filters: [
+        {
+            classCode: 6, // PTP
+            subclassCode: 1 // MTP
+        }
+    ]
+});
+let connection = await connect();
+let config = await connection.schedule((context: any) => context.configToJS());
+console.log('Obtained config: ', config);
+```
+
+More information can be found in the example included in the Github repository.
+
+## Common Issues
+### SharedArrayBuffer can not be found 
+SharedArrayBuffer has been disabled across all browsers due to the Spectre vulnerability. This package uses SharedArrayBuffer to communicate with the WebAssembly module. To work around this issue, you need to set two response headers for your document:
+```
+Cross-Origin-Opener-Policy: same-origin
+Cross-Origin-Embedder-Policy: require-corp
+```
+
+Information from [Stackoverflow](https://stackoverflow.com/questions/64650119/react-error-sharedarraybuffer-is-not-defined-in-firefox)
+
+### Error: Not found: /node_modules/.vite/deps/libapi.wasm
+Vite tries to optimize the dependencies by default. This causes the WebAssembly module to be moved to a different location. To prevent this, you need to exclude the web-gphoto2 package from the optimization.
+
+In vite, both of the above mentioned issues are solved by adding the following to your vite.config.js:
+```ts
+import { sveltekit } from '@sveltejs/kit/vite';
+import { defineConfig } from 'vite';
+
+/** @type {import('vite').Plugin} */
+const viteServerConfig = {
+	name: 'add headers',
+	configureServer: (server) => {
+		server.middlewares.use((req, res, next) => {
+			res.setHeader("Cross-Origin-Opener-Policy", "same-origin");
+			res.setHeader("Cross-Origin-Embedder-Policy", "require-corp");
+			next();
+		});
+	}
+};
+
+export default defineConfig({
+	plugins: [sveltekit(), viteServerConfig],
+	optimizeDeps: {
+		exclude: ['web-gphoto2']
+	}
+});
+```
+
+
+# Demo
+This repository also contains a [demo app](https://web.dev/porting-libusb-to-webusb/) running gPhoto2 on the Web:
+![A picture of DSLR camera connected via a USB cable to a laptop. The laptop is running the Web demo mentioned in the article, which mirrors a live video feed from the camera as well as allows to tweak its settings via form controls.](https://web-dev.imgix.net/image/9oK23mr86lhFOwKaoYZ4EySNFp02/MR4YGRvl0Z9AWT6vv3sQ.jpg?auto=format&w=1600)
+
 For the detailed technical write-up, see [the official blog post](https://web.dev/porting-libusb-to-webusb/). To see the demo in action, visit the hosted version [here](https://web-gphoto2.rreverser.com/) (but make sure to read the [cross-platform compatibility notes](https://web.dev/porting-libusb-to-webusb/#important-cross-platform-compatibility-notes) first).
 
 If you don't have a DSLR, you can check out a recording of the demo below:

package.json

@@ -1,8 +1,35 @@
 {
+  "name": "web-gphoto2",
+  "version": "0.1.0",
+  "description": "WebAssembly implementation of gphoto2 and libusb to control DSLR cameras over USB on the Web",
+  "main": "ui/camera.js",
+  "types": "ui/libapi.mjs.d.ts",
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/GoogleChromeLabs/web-gphoto2"
+  },
+  "keywords": [
+    "gphoto2",
+    "libusb",
+    "webassembly"
+  ],
+  "author": "Ingvar Stepanyan - RReverser - [email protected]",
+  "license": "LGPLv2.1",
+  "bugs": {
+    "url": "https://github.com/GoogleChromeLabs/web-gphoto2/issues"
+  },
+  "homepage": "https://github.com/GoogleChromeLabs/web-gphoto2#readme",
+  "files": [
+    "ui/libapi.*",
+    "ui/camera.js"
+  ],
   "devDependencies": {
     "@types/emscripten": "^1.39.5",
     "@types/requestidlecallback": "^0.3.4",
     "@types/stats.js": "^0.17.0",
     "preact": "^10.5.14"
   }
-}
+}

ui/camera.js

@@ -0,0 +1,114 @@
+/*
+ * Copyright 2021 Google LLC
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
+ */
+
+
+/** @typedef {import('./libapi.mjs').Context} Context */
+
+// To avoid errors for users who use SSR or Hybrid rendering (e.g. Nuxt.js), we need to check if we're in the browser.
+let initModule;
+
+async function initializeModule() {
+    if (typeof window !== 'undefined') {
+        const module = await import('./libapi.mjs');
+        initModule = module.default;
+        return initModule;
+    } else {
+        console.warn("web-gphoto2 is only available in the browser");
+        return null;
+    }
+}
+
+const ModulePromise = initializeModule().then(initModule => {
+    if (initModule) {
+        return initModule();
+    } else {
+        return null;
+    }
+});
+
+class Camera {
+    constructor() {
+        /** @type {Promise<unknown>} */
+        this.queue = Promise.resolve();
+        this.Module = null;
+        this.context = null;
+    }
+
+    rethrowIfCritical(err) {
+        // If it's precisely Error, it's a custom error; anything else - SyntaxError,
+        // WebAssembly.RuntimeError, TypeError, etc. - is treated as critical here.
+        if (err.constructor !== Error) {
+            throw err;
+        }
+    }
+
+    async connect() {
+        this.Module = await ModulePromise;
+        this.context = await new this.Module.Context();
+    }
+
+    /** Schedules an exclusive async operation on the global context.
+     * @template T
+     * @param {(ctx: Context) => Promise<T>} op
+     * @returns {Promise<T>}
+     */
+    async schedule(op) {
+        let res = this.queue.then(() => op(this.context));
+        this.queue = res.catch(this.rethrowIfCritical);
+        return res;
+    }
+
+    async disconnect() {
+        if (!this.context.isDeleted()) {
+            this.context.delete();
+        }
+    }
+
+    async getConfig() {
+        return this.schedule((context) => context.configToJS());
+    }
+
+    async getSupportedOps() {
+        if (this.context) {
+            return await this.context.supportedOps();
+        }
+        throw new Error("You need to connect to the camera first");
+    }
+
+    async setConfigValue(name, value) {
+        const uiTimeout = new Promise((resolve) => setTimeout(resolve, 800));
+        const setResult = this.schedule((context) => context.setConfigValue(name, value));
+        // wait for both the config set operation and the timeout to complete
+        return Promise.all([setResult, uiTimeout]);
+    }
+
+
+    async capturePreviewAsBlob() {
+        return this.schedule((context) => context.capturePreviewAsBlob());
+    }
+
+    async captureImageAsFile() {
+        return this.schedule((context) => context.captureImageAsFile());
+    }
+
+    async consumeEvents() {
+        return this.schedule((context) => context.consumeEvents());
+    }
+}
+
+export default Camera;

ui/libapi.mjs.d.ts

@@ -22,14 +22,14 @@ export type Config = {
   label: string;
   readonly: boolean;
 } & (
-  | { type: 'range'; value: number; min: number; max: number; step: number }
-  | { type: 'menu' | 'radio'; value: string; choices: string[] }
-  | { type: 'toggle'; value: boolean }
-  | { type: 'text'; value: string }
-  | { type: 'window'; children: Record<string, Config> }
-  | { type: 'section'; children: Record<string, Config> }
-  | { type: 'datetime'; value: number }
-);
+    | { type: 'range'; value: number; min: number; max: number; step: number }
+    | { type: 'menu' | 'radio'; value: string; choices: string[] }
+    | { type: 'toggle'; value: boolean }
+    | { type: 'text'; value: string }
+    | { type: 'window'; children: Record<string, Config> }
+    | { type: 'section'; children: Record<string, Config> }
+    | { type: 'datetime'; value: number }
+  );
 
 declare interface SupportedOps {
   captureImage: boolean;
@@ -41,6 +41,9 @@ declare interface SupportedOps {
 }
 
 declare class Context {
+  context(): Promise<any> {
+    throw new Error('Method not implemented.');
+  }
   configToJS(): Promise<Config & { type: 'window' }>;
   setConfigValue(
     name: string,
@@ -55,6 +58,26 @@ declare class Context {
   isDeleted(): boolean;
 }
 
+export declare class Camera {
+  constructor();
+
+  connect(): Promise<void>;
+  disconnect(): Promise<void>;
+
+  getConfig(): Promise<any>; // replace "any" with the actual type of the config if you have it
+
+  getSupportedOps(): SupportedOps;
+
+  setConfigValue(name: string, value: number | string | boolean): Promise<void>;
+
+  capturePreviewAsBlob(): Promise<Blob>;
+  captureImageAsFile(): Promise<File>;
+  consumeEvents(): Promise<boolean>;
+
+  private rethrowIfCritical(err: any): void;  // any error type can be replaced by more specific if available
+  private schedule<T>(op: (ctx: any) => Promise<T>): Promise<T>;  // ctx and T types can be replaced by more specific if available
+}
+
 export interface Module extends EmscriptenModule {
   Context: typeof Context;
 }