# Getting Started This is a guide to writing your first dropbox.js application. ## Library Setup This section describes how to get the library hooked up into your application. ### Browser Applications To get started right away, place this snippet in your page's ``. ```html ``` The snippet is not a typo. [cdnjs](https://cdnjs.com) recommends using [protocol-relative URLs](http://paulirish.com/2010/the-protocol-relative-url/). The cdnjs build of dropbox.js includes [source maps](http://www.html5rocks.com/en/tutorials/developertools/sourcemaps/), which can greatly help with debugging. To get the latest development build of dropbox.js, follow the steps in the [development guide](./development.md). #### "Powered by Dropbox" Static Web Apps Before writing any source code, use the [console app](https://dl-web.dropbox.com/spa/pjlfdak1tmznswp/powered_by.js/public/index.html) to set up your Dropbox. After adding an application, place the source code at `/Apps/Static Web Apps/my_awesome_app/public`. You should find a pre-generated `index.html` file in there. ### node.js Applications First, install the `dropbox` [npm](https://npmjs.org/) package. ```bash npm install dropbox ``` Once the npm package is installed, the following `require` statement lets you access the same API as browser applications ```javascript var Dropbox = require("dropbox"); ``` ## Initialization [Register your application](https://www.dropbox.com/developers/apps) to obtain an API key. Read the brief [API core concepts intro](https://www.dropbox.com/developers/core/start). Once you have an API key, use it to create a [Dropbox.Client](http://coffeedoc.info/github/dropbox/dropbox-js/master/classes/Dropbox/Client.html). If your JavaScript code runs on users' computers, do NOT expose your API secret in the code. ```javascript // Browser-side applications do not use the API secret. var client = new Dropbox.Client({ key: "your-key-here" }); ``` if your application runs in node.js or in another server environment that you control, include both your API key and API secret in the `Dropbox.Client` constructor call. ```javascript // Server-side applications use both the API key and secret. var client = new Dropbox.Client({ key: "your-key-here", secret: "your-secret-here" }); ``` ## Authentication Before you can make any API calls, your users must authorize your application to access their Dropbox. This process follows the [OAuth 2.0](http://tools.ietf.org/html/rfc6749) protocol, which entails sending the user to a Web page on `www.dropbox.com`, and then having them redirected back to your application. Web applications can use different methods and UI to drive the user through this process, so `dropbox.js` lets application code hook into the authorization process by implementing an [auth driver](../src/auth_driver.coffee). dropbox.js ships with a couple of [built-in auth drivers](./builtin_drivers.md), which are great way to jump-start application development. When your application's needs outgrow the built-in drivers, read the [auth driver guide](./auth_drivers.md) for further information about implementing a custom auth driver. ### Browser Setup The recommended driver will be automatically set up for you. The [built-in auth drivers guide](./builtin_drivers.md) describes some useful options if the recommended setup isn't suitable for your application. ### node.js Setup Single-process node.js applications should create one driver to authenticate all the clients. ```javascript client.authDriver(new Dropbox.AuthDriver.NodeServer(8191)); ``` The [built-in OAuth drivers guide](./builtin_drivers.md) has useful tips on using the `NodeServer` driver. ### Chrome App / Extension Setup At this time, the setup for Chrome applications and extensions is a bit more involved. The `Dropbox.AuthDriver.Chrome` section in the [built-in auth drivers guide](./builtin_drivers.md) has a step-by-step process for setting up the [Chrome auth driver](http://coffeedoc.info/github/dropbox/dropbox-js/master/classes/Dropbox/AuthDriver/Chrome.html). ### Shared Code After setting up an auth driver, authenticating the user is one method call away. ```javascript client.authenticate(function(error, client) { if (error) { // Replace with a call to your own error-handling code. // // Don't forget to return from the callback, so you don't execute the code // that assumes everything went well. return showError(error); } // Replace with a call to your own application code. // // The user authorized your app, and everything went well. // client is a Dropbox.Client instance that you can use to make API calls. doSomethingCool(client); }); ``` ## Error Handling When Dropbox API calls fail, dropbox.js methods pass a `Dropbox.ApiError` instance as the first parameter in their callbacks. This parameter is named `error` in all the code snippets on this page. If `error` is a truthy value, you should either recover from the error, or notify the user that an error occurred. The `status` field in the `Dropbox.ApiError` instance contains the HTTP error code, which should be one of the [error codes in the REST API](https://www.dropbox.com/developers/reference/api#error-handling). The snippet below is a template for an extensive error handler. ```javascript var showError = function(error) { switch (error.status) { case Dropbox.ApiError.INVALID_TOKEN: // If you're using dropbox.js, the only cause behind this error is that // the user token expired. // Get the user through the authentication flow again. break; case Dropbox.ApiError.NOT_FOUND: // The file or folder you tried to access is not in the user's Dropbox. // Handling this error is specific to your application. break; case Dropbox.ApiError.OVER_QUOTA: // The user is over their Dropbox quota. // Tell them their Dropbox is full. Refreshing the page won't help. break; case Dropbox.ApiError.RATE_LIMITED: // Too many API requests. Tell the user to try again later. // Long-term, optimize your code to use fewer API calls. break; case Dropbox.ApiError.NETWORK_ERROR: // An error occurred at the XMLHttpRequest layer. // Most likely, the user's network connection is down. // API calls will not succeed until the user gets back online. break; case Dropbox.ApiError.INVALID_PARAM: case Dropbox.ApiError.OAUTH_ERROR: case Dropbox.ApiError.INVALID_METHOD: default: // Caused by a bug in dropbox.js, in your application, or in Dropbox. // Tell the user an error occurred, ask them to refresh the page. } }; ``` `Dropbox.Client` also supports a DOM event-like API for receiving all errors. This can be used to log API errors, or to upload them to your server for further analysis. ```javascript client.onError.addListener(function(error) { if (window.console) { // Skip the "if" in node.js code. console.error(error); } }); ``` ## The Fun Part Authentication was the hard part of the API integration, and error handling was the most boring part. Now that these are both behind us, you can interact with the user's Dropbox and focus on coding up your application! The following sections have some commonly used code snippets. The [Dropbox.Client API reference](http://coffeedoc.info/github/dropbox/dropbox-js/master/classes/Dropbox/Client.html) will help you navigate less common scenarios, and the [Dropbox REST API reference](https://www.dropbox.com/developers/reference/api) describes the underlying HTTP protocol, and can come in handy when debugging your application, or if you want to extend dropbox.js. ### User Info ```javascript client.getAccountInfo(function(error, accountInfo) { if (error) { return showError(error); // Something went wrong. } alert("Hello, " + accountInfo.name + "!"); }); ``` ### Write a File ```javascript client.writeFile("hello_world.txt", "Hello, world!\n", function(error, stat) { if (error) { return showError(error); // Something went wrong. } alert("File saved as revision " + stat.versionTag); }); ``` ### Read a File ```javascript client.readFile("hello_world.txt", function(error, data) { if (error) { return showError(error); // Something went wrong. } alert(data); // data has the file's contents }); ``` ### List a Directory's Contents ```javascript client.readdir("/", function(error, entries) { if (error) { return showError(error); // Something went wrong. } alert("Your Dropbox contains " + entries.join(", ")); }); ``` ### More Code Snippets The [collection of code snippets](./snippets.md) contains some JavaScript fragments that may be useful in the latter stages of application development. ### Sample Applications Check out the [sample applications](../samples/) to see how all these concepts play out together.