docs.sheetjs.com/docz/docs/03-demos/30-cloud/31-dropbox.mdx
2024-05-28 01:20:05 -04:00

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---
title: Spreadsheets in Dropbox
sidebar_label: Dropbox
pagination_prev: demos/local/index
pagination_next: demos/extensions/index
---
<head>
<script type="text/javascript" src="https://www.dropbox.com/static/api/2/dropins.js" id="dropboxjs" data-app-key="v85yuk360zx6nyx"></script>
</head>
[Dropbox](https://www.dropbox.com/) is a file hosting service that offers APIs
for programmatic file access.
[SheetJS](https://sheetjs.com) is a JavaScript library for reading and writing
data from spreadsheets.
This demo uses SheetJS to read and write spreadsheets stored on Dropbox. We'll
explore two Dropbox API workflows:
- A "Chooser"[^1] application allows users to select files from their Dropbox
accounts. This demo will fetch and parse the selected file.
- A "Saver"[^2] application allows users to save a generated spreadsheet to
their Dropbox account. This demo will generate a XLS workbook using SheetJS.
## Integration Details
"Dropbox Apps" are the standard way to interact with the service. The
["Dropbox App"](#dropbox-app) section describes how this demo was configured.
:::info pass
The Dropbox API script is loaded in this page with
```html
<script type="text/javascript" src="https://www.dropbox.com/static/api/2/dropins.js" id="dropboxjs" data-app-key="v85yuk360zx6nyx"></script>
```
The `data-app-key` used in this demo is a "Development" key associated with the
`localhost` and `docs.sheetjs.com` domains. Dropbox API does not require
"Production" approval for the Chooser or Saver.
:::
The live demos require a Dropbox account.
### Reading Files
"Chooser" is a small library that lets users select a file from their account.
`Dropbox.createChooseButton` is a function that accepts an options argument and
returns a DOM element that should be added to the page:
```js
var button = Dropbox.createChooseButton({
/* ... options described below ... */
});
document.appendChild(button);
```
The following options must be set:
- `multiselect: false` ensures only one file can be selected
- `folderselect: false` limits selection to real files
- `linkType: "direct"` ensures the link points to a raw file
- `success` method is called when the user selects a file
The following options are optional:
- `extensions: ['.xlsx', '.xls']` limits the file types for selection
#### Chooser Callback
The `success` callback method receives an array of File objects even if only one
file is selected. This file object has the following properties:
- `name` is the name of the selected file
- `link` is a temporary URL that can be fetched
This demo fetches the link using the `fetch` API, parses the raw data using the
SheetJS `read` function[^3] and generates a HTML table using `sheet_to_html`[^4]
```js
async(files) => {
/* get file entry -- note that dropbox API always passes an array */
var file = files[0];
console.log(`Selected ${file.name} ID=${file.id}`);
/* fetch file and parse */
var wb = XLSX.read(await (await fetch(file.link)).arrayBuffer());
/* convert first sheet to HTML table and add to page */
var html = XLSX.utils.sheet_to_html(wb.Sheets[wb.SheetNames[0]]);
console.log(html);
}
```
#### Chooser Live Demo
:::caution pass
If the live demo shows a message
```
ReferenceError: Dropbox is not defined
```
please refresh the page. This is a known bug in the documentation generator.
:::
```jsx live
function SheetJSChoisissez() {
const [msg, setMsg] = React.useState("Press the button to show a Chooser");
const btn = useRef(), tbl = useRef();
React.useEffect(() => {
if(typeof Dropbox == "undefined") return setMsg("Dropbox is not defined");
/* create button */
var button = Dropbox.createChooseButton({
/* required settings */
multiselect: false,
folderselect: false,
linkType: "direct",
/* optional settings */
extensions: ['.xlsx', '.xls', '.numbers'], // list of extensions
/* event handlers */
cancel: () => setMsg("User Canceled Selection!"),
success: async(files) => {
/* get file entry -- note that dropbox API always passes an array */
var file = files[0];
setMsg(`Selected ${file.name} ID=${file.id}`);
/* fetch file and parse */
var wb = XLSX.read(await (await fetch(file.link)).arrayBuffer());
/* convert first sheet to HTML table and add to page */
tbl.current.innerHTML = XLSX.utils.sheet_to_html(wb.Sheets[wb.SheetNames[0]]);
}
});
/* add button to page */
btn.current.appendChild(button);
}, []);
return ( <><b>{msg}</b><br/><div ref={btn}/><div ref={tbl}/></> );
}
```
### Writing Files
"Saver" is a small library that lets users save files to their account.
`Dropbox.createSaveButton` is a function that accepts three arguments and
returns a DOM element that should be added to the page:
```js
var button = Dropbox.createSaveButton(url, filename, options);
/* add button to page */
btn.current.appendChild(button);
```
`filename` will be the recommended filename in the Save window.
The options object supports two callbacks: `success` (if the save succeeded) and
`cancel` (if the user cancels without saving).
#### URL
:::caution pass
The Dropbox API was not designed for writing files that are created in the web
browser. The Data URI approach is a neat workaround but should not be used in
production for larger files. It is better to create the files in the server
using NodeJS and generate a proper URL for Dropbox to fetch.
:::
The Dropbox API is designed to fetch data from a user-specified URL. Files are
not included in the request!
The SheetJS workaround involves the Data URI scheme[^5]. The main steps are:
1) Write a workbook using the SheetJS `write`[^6] method. The `type: "base64"`
option instructs the method to return a Base64-encoded string.
```js
/* write XLS workbook (Base64 string) */
const b64 = XLSX.write(workbook, { type: "base64", bookType: "xls" });
```
2) Construct a Data URL by prepending the `data` header:
```js
/* create data URI */
const url = "data:application/vnd.ms-excel;base64," + b64;
```
3) Create a button and add it to the page:
```js
/* create save button using the concise function call */
var button = Dropbox.createSaveButton( url, "SheetJSDropbox.xls", {
success: () => setMsg("File saved successfully!"),
cancel: () => setMsg("User Canceled Selection!"),
});
document.appendChild(button);
```
:::info pass
The file must be written before the Save button is created.
:::
#### Saver Live Demo
This demo starts with an array of arrays of data. When the page loads, the data
is exported to XLSX and a data URI is generated. When the button is clicked, the
data URI is sent to Dropbox and the service will attempt to save the data to
`SheetJSDropbox.xls` in your Dropbox account.
:::caution pass
If the live demo shows a message
```
ReferenceError: Dropbox is not defined
```
please refresh the page. This is a known bug in the documentation generator.
:::
```jsx live
function SheetJSEnregistrez() {
const [msg, setMsg] = React.useState("Press the button to write XLS file");
const btn = useRef(), tbl = useRef();
React.useEffect(() => { (async() => {
if(typeof Dropbox == "undefined") return setMsg("Dropbox is not defined");
/* fetch data and write table (sample data) */
const f = await(await fetch("https://docs.sheetjs.com/pres.xlsx")).arrayBuffer();
const wb = XLSX.read(f);
tbl.current.innerHTML = XLSX.utils.sheet_to_html(wb.Sheets[wb.SheetNames[0]]);
/* create workbook from table */
const table = tbl.current.getElementsByTagName("TABLE")[0];
const new_wb = XLSX.utils.table_to_book(table);
/* write XLS workbook (Base64 string) */
const b64 = XLSX.write(new_wb, { type: "base64", bookType: "xls" });
/* create data URI */
const url = "data:application/vnd.ms-excel;base64," + b64;
/* create save button using the concise function call */
var button = Dropbox.createSaveButton( url, "SheetJSDropbox.xls", {
success: () => setMsg("File saved successfully!"),
cancel: () => setMsg("User Canceled Selection!"),
});
/* add button to page */
btn.current.appendChild(button);
})(); }, []);
return ( <><b>{msg}</b><br/><div ref={btn}/><div ref={tbl}/></> );
}
```
## Dropbox App
:::note Tested Deployments
This demo was last tested on 2024 May 27.
:::
This demo requires a "Dropbox app":
0) Create a Dropbox account and verify the associated email address. This demo
has been tested with a free Dropbox Basic plan account. The app installation
step can be safely skipped.
1) Create a Dropbox app in the Developer panel.
Click the `᎒᎒᎒` icon > App Center. In the next page, click "Build an App" in the
left sidebar. In the next page, click "Create apps".
In the App creation wizard, select the following options:
- "Choose an API": "Scoped access"
- "Choose the type of access you need": "Full Dropbox"
- "Name": (enter any name)
:::caution pass
The Dropbox API Terms and Conditions should be reviewed before acceptance.
:::
Click "Create App" to create the app.
2) Configure the Dropbox app in the Developer tools.
The following permissions should be selected in the "Permissions" tab
- `files.metadata.write` (View and edit information about your Dropbox files and folders)
- `files.metadata.read` (View information about your Dropbox files and folders)
- `files.content.write` (Edit content of your Dropbox files and folders)
- `files.content.read` (View content of your Dropbox files and folders)
After selecting the permissions, click "Submit".
In the Settings tab, under "Chooser / Saver / Embedder domains", the desired
public domains should be added. `localhost` must also be added for development
use (it is not automatically enabled).
For public use, select "Enable Additional Users".
3) Copy the "App key" and add it to the `data-app-key` attribute of the Dropbox
integration script reference.
[^1]: See ["Chooser"](https://www.dropbox.com/developers/chooser) in the Dropbox Developers Documentation
[^2]: See ["Saver"](https://www.dropbox.com/developers/saver) in the Dropbox Developers Documentation
[^3]: See [`read` in "Reading Files"](/docs/api/parse-options)
[^4]: See [`sheet_to_html` in "Utilities"](/docs/api/utilities/html#html-table-output)
[^5]: See ["Data URLs"](https://developer.mozilla.org/en-US/docs/Web/HTTP/Basics_of_HTTP/Data_URLs) in the "MDN web docs"
[^6]: See [`writeFile` in "Writing Files"](/docs/api/write-options)