# 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/start/core). Once you have an API key, use it to create a `Dropbox.Client`. ```javascript var client = new Dropbox.Client({ key: "your-key-here", secret: "your-secret-here", sandbox: true }); ``` If your application requires full Dropbox access, leave out the `sandbox: true` parameter. ### Browser and Open-Source Applications The Dropbox API guidelines ask that the API key and secret is never exposed in cleartext. This is an issue for the applications that use dropbox.js on the client side (browser apps and Chrome extensions), as well as all open-source applications. To meet this requirement, [encode your API key](https://dl-web.dropbox.com/spa/pjlfdak1tmznswp/api_keys.js/public/index.html). ```javascript var client = new Dropbox.Client({ key: "encoded-key-string|it-is-really-really-long", sandbox: true }); ``` ## Authentication Before you can make any API calls, you need to authenticate your application's user with Dropbox, and have them authorize your apps to access their Dropbox. This process follows the [OAuth 1.0](http://tools.ietf.org/html/rfc5849) protocol, which entails sending the user to a Web page on `www.dropbox.com`, and then having them redirected back to your application. Each Web application has its requirements, so `dropbox.js` lets you customize the authentication process by implementing an [OAuth driver](../src/auth_driver.coffee). At the same time, dropbox.js ships with a couple of OAuth drivers, and you should take advantage of them as you prototype your application. Read the [authentication doc](./auth_drivers.md) for further information about writing an OAuth driver, and to learn about all the drivers that ship with `dropbox.js`. ### Browser Setup The following snippet will set up the recommended driver. ```javascript client.authDriver(new Dropbox.Drivers.Redirect()); ``` The [authentication doc](./auth_drivers.md) describes some useful options that you can pass to the `Dropbox.Drivers.Redirect` constructor. ### node.js Setup Single-process node.js applications should create one driver to authenticate all the clients. ```javascript client.authDriver(new Dropbox.Drivers.NodeServer(8191)); ``` The [authentication doc](./auth_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 than the one-liners above. The `Dropbox.Drivers.Chrome` section in the [authentication doc](./auth_drivers.md) has a step-by-step process for setting up the Chrome OAuth driver. ### Shared Code After setting up an OAuth 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 Handlng 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.getUserInfo(function(error, userInfo) { if (error) { return showError(error); // Something went wrong. } alert("Hello, " + userInfo.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.revisionTag); }); ``` ### 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 [code snippets doc](./snippets.md) contains some JavaScript fragments that may be useful in the latter stages of application development. ### Sample Applications Check out the [sample apps](../samples/) to see how all these concepts play out together.