---
title: HTTP Downloads
pagination_next: demos/net/upload/index
---

<head>
  <script src="https://unpkg.com/axios@1.6.5/dist/axios.min.js"></script>
  <script src="https://unpkg.com/superagent@8.1.2/dist/superagent.min.js"></script>
</head>

import current from '/version.js';
import CodeBlock from '@theme/CodeBlock';

`XMLHttpRequest` and `fetch` browser APIs enable binary data transfer between
web browser clients and web servers.  Since this library works in web browsers,
server conversion work can be offloaded to the client!  This demo shows a few
common scenarios involving browser APIs and popular wrapper libraries.

:::info pass

This demo focuses on downloading files. Other demos cover other HTTP use cases:

- ["HTTP Uploads"](/docs/demos/net/upload) covers uploading files
- ["HTTP Server Processing"](/docs/demos/net/server) covers HTTP servers

:::

:::caution Third-Party Hosts and Binary Data

Third-party cloud platforms such as AWS may corrupt raw binary downloads by
encoding requests and responses in UTF-8 strings.

For AWS, in the "Binary Media Types" section of the API Gateway console, the
`"application/vnd.ms-excel"` type should be added to ensure that AWS Lambda
functions functions can send files to clients.

:::

## Downloading Binary Data

Most interesting spreadsheet files are binary data that contain byte sequences
that represent invalid UTF-8 characters.

APIs generally provide options to control how downloaded data is interpreted.
The `arraybuffer` response type usually forces the data to be presented as an
`ArrayBuffer` object which can be parsed with the SheetJS `read` method[^1].

The following example shows the data flow using `fetch` to download files:

```mermaid
flowchart LR
  server[(Remote\nFile)]
  response(Response\nobject)
  subgraph SheetJS operations
    ab(XLSX Data\nArrayBuffer)
    wb(((SheetJS\nWorkbook)))
  end
  server --> |`fetch`\nGET request| response
  response --> |`arrayBuffer`\n\n| ab
  ab --> |`read`\n\n| wb
```

```js
/* download data into an ArrayBuffer object */
const res = await fetch("https://sheetjs.com/pres.numbers");
const ab = await res.arrayBuffer(); // recover data as ArrayBuffer

/* parse file */
const wb = XLSX.read(ab);
```

## Browser Demos

When the page is accessed, the browser will attempt to download https://sheetjs.com/pres.numbers
and read the workbook.  The old table will be replaced with a table whose
contents match the first worksheet.  The table is generated using the SheetJS
`sheet_to_html` method[^2]

:::note Tested Deployments

Each browser demo was tested in the following environments:

| Browser     | Date       |
|:------------|:-----------|
| Chrome 120  | 2024-01-30 |
| Safari 17.2 | 2024-01-15 |

:::

### XMLHttpRequest

For downloading data, the `arraybuffer` response type generates an `ArrayBuffer`
that can be viewed as an `Uint8Array` and fed to the SheetJS `read` method. For
legacy browsers, the option `type: "array"` should be specified:

```js
/* set up an async GET request */
var req = new XMLHttpRequest();
req.open("GET", url, true);
req.responseType = "arraybuffer";

req.onload = function(e) {
  /* parse the data when it is received */
  var data = new Uint8Array(req.response);
  var workbook = XLSX.read(data, {type:"array"});
  /* DO SOMETHING WITH workbook HERE */
};
req.send();
```

<details>
  <summary><b>Live Download demo</b> (click to show)</summary>

This demo uses `XMLHttpRequest` to download https://sheetjs.com/pres.numbers
and show the data in an HTML table.

```jsx live
function SheetJSXHRDL() {
  const [__html, setHTML] = React.useState("");

  /* Fetch and update HTML */
  React.useEffect(() => { (async() => {
    /* Fetch file */
    const req = new XMLHttpRequest();
    req.open("GET", "https://sheetjs.com/pres.numbers", true);
    req.responseType = "arraybuffer";
    req.onload = e => {
      /* Parse file */
      const wb = XLSX.read(new Uint8Array(req.response));
      const ws = wb.Sheets[wb.SheetNames[0]];

      /* Generate HTML */
      setHTML(XLSX.utils.sheet_to_html(ws));
    };
    req.send();
  })(); }, []);

  return ( <div dangerouslySetInnerHTML={{ __html }}/> );
}
```

</details>


### fetch

For downloading data, `Response#arrayBuffer` resolves to an `ArrayBuffer` that
can be converted to `Uint8Array` and passed to the SheetJS `read` method:

```js
fetch(url).then(function(res) {
  /* get the data as a Blob */
  if(!res.ok) throw new Error("fetch failed");
  return res.arrayBuffer();
}).then(function(ab) {
  /* parse the data when it is received */
  var data = new Uint8Array(ab);
  var workbook = XLSX.read(data, {type:"array"});

  /* DO SOMETHING WITH workbook HERE */
});
```

<details>
  <summary><b>Live Download demo</b> (click to show)</summary>

This demo uses `fetch` to download https://sheetjs.com/pres.numbers and show
the data in an HTML table.

```jsx live
function SheetJSFetchDL() {
  const [__html, setHTML] = React.useState("");

  /* Fetch and update HTML */
  React.useEffect(() => { (async() => {
    /* Fetch file */
    const res = await fetch("https://sheetjs.com/pres.numbers");
    const ab = await res.arrayBuffer();

    /* Parse file */
    const wb = XLSX.read(ab);
    const ws = wb.Sheets[wb.SheetNames[0]];

    /* Generate HTML */
    setHTML(XLSX.utils.sheet_to_html(ws));
  })(); }, []);

  return ( <div dangerouslySetInnerHTML={{ __html }}/> );
}
```

</details>

### jQuery

[jQuery](https://jquery.com/) is a JavaScript library that includes helpers for
performing "Ajax" network requests. `jQuery.ajax` (`$.ajax`) does not support
binary data out of the box[^3]. A custom `ajaxTransport` can add support.

SheetJS users have reported success with `jquery.binarytransport.js`[^4] in IE10.

After including the main `jquery.js` and `jquery.binarytransport.js` scripts,
`$.ajax` will support `dataType: "binary"` and `processData: false`.

**[Live Download Demo](pathname:///jquery/index.html)**

In a GET request, the default behavior is to return a `Blob` object.  Passing
`responseType: "arraybuffer"` returns a proper `ArrayBuffer` object in IE10:

```js
$.ajax({
  type: "GET", url: "https://sheetjs.com/pres.numbers",

  /* suppress jQuery post-processing */
  // highlight-next-line
  processData: false,

  /* use the binary transport */
  // highlight-next-line
  dataType: "binary",

  /* pass an ArrayBuffer in the callback */
  // highlight-next-line
  responseType: "arraybuffer",

  success: function (ab) {
    /* at this point, ab is an ArrayBuffer */
    // highlight-next-line
    var wb = XLSX.read(ab);

    /* do something with workbook here */
    var ws = wb.Sheets[wb.SheetNames[0]];
    var html = XLSX.utils.sheet_to_html(ws);
    $("#out").html(html);
  }
});
```

### Wrapper Libraries

Before `fetch` shipped with browsers, there were various wrapper libraries to
simplify `XMLHttpRequest`. Due to limitations with `fetch`, these libraries are
still relevant.

#### axios

[`axios`](https://axios-http.com/) presents a Promise based interface. Setting
`responseType` to `arraybuffer` ensures the return type is an ArrayBuffer. The
`data` property of the result can be passed to the SheetJS `read` method:

```js
async function workbook_dl_axios(url) {
  const res = await axios(url, {responseType:'arraybuffer'});
  const workbook = XLSX.read(res.data);
  return workbook;
}
```

<details>
  <summary><b>Live Download demo</b> (click to show)</summary>

This demo uses `axios` to download https://sheetjs.com/pres.numbers and show
the data in an HTML table.

:::caution pass

If the live demo shows a message

```
ReferenceError: axios is not defined
```

please refresh the page.  This is a known bug in the documentation generator.

:::

```jsx live
function SheetJSAxiosDL() {
  const [__html, setHTML] = React.useState("");

  /* Fetch and update HTML */
  React.useEffect(() => { (async() => {
    if(typeof axios != "function") return setHTML("ReferenceError: axios is not defined");
    /* Fetch file */
    const res = await axios("https://sheetjs.com/pres.numbers", {responseType: "arraybuffer"});

    /* Parse file */
    const wb = XLSX.read(res.data);
    const ws = wb.Sheets[wb.SheetNames[0]];

    /* Generate HTML */
    setHTML(XLSX.utils.sheet_to_html(ws));
  })(); }, []);

  return ( <div dangerouslySetInnerHTML={{ __html }}/> );
}
```

</details>

#### superagent

[`superagent`](https://ladjs.github.io/superagent/) is a network request library
with a "Fluent Interface". Calling the `responseType` method with
`"arraybuffer"` will ensure the final response object is an `ArrayBuffer`:

```js
/* set up an async GET request with superagent */
superagent
  .get(url)
  .responseType('arraybuffer')
  .end(function(err, res) {
    /* parse the data when it is received */
    var data = new Uint8Array(res.body);
    var workbook = XLSX.read(data, {type:"array"});

    /* DO SOMETHING WITH workbook HERE */
  });
```

<details>
  <summary><b>Live Download demo</b> (click to show)</summary>

This demo uses `superagent` to download https://sheetjs.com/pres.numbers and
show the data in an HTML table.

:::caution pass

If the live demo shows a message

```
ReferenceError: superagent is not defined
```

please refresh the page.  This is a known bug in the documentation generator.

:::

```jsx live
function SheetJSSuperAgentDL() {
  const [__html, setHTML] = React.useState("");

  /* Fetch and update HTML */
  React.useEffect(() => { (async() => {
    if(typeof superagent == "undefined" || typeof superagent.get != "function")
      return setHTML("ReferenceError: superagent is not defined");
    /* Fetch file */
    superagent
      .get("https://sheetjs.com/pres.numbers")
      .responseType("arraybuffer")
      .end((err, res) => {
        /* Parse file */
        const wb = XLSX.read(res.body);
        const ws = wb.Sheets[wb.SheetNames[0]];

        /* Generate HTML */
        setHTML(XLSX.utils.sheet_to_html(ws));
      });
  })(); }, []);

  return ( <div dangerouslySetInnerHTML={{ __html }}/> );
}
```

</details>

## NodeJS Demos

These examples show how to download data in NodeJS.

### HTTPS GET

The `https` module provides a low-level `get` method for HTTPS GET requests:

```js title="SheetJSHTTPSGet.js"
var https = require("https"), XLSX = require("xlsx");

https.get('https://sheetjs.com/pres.numbers', function(res) {
  var bufs = [];
  res.on('data', function(chunk) { bufs.push(chunk); });
  res.on('end', function() {
    var buf = Buffer.concat(bufs);
    var wb = XLSX.read(buf);
    /* print the first worksheet to console */
    var ws = wb.Sheets[wb.SheetNames[0]];
    console.log(XLSX.utils.sheet_to_csv(ws));
  });
});
```

<details>
  <summary><b>Complete Example</b> (click to show)</summary>

:::note Tested Environments

This demo was last tested on 2024 January 15 against NodeJS `20.11.0`

:::

1) Install the [NodeJS module](/docs/getting-started/installation/nodejs)

<CodeBlock language="bash">{`\
npm i --save https://cdn.sheetjs.com/xlsx-${current}/xlsx-${current}.tgz`}
</CodeBlock>

2) Copy the `SheetJSHTTPSGet.js` code snippet to a file `SheetJSHTTPSGet.js`

3) Run the script:

```bash
node SheetJSHTTPSGet.js
```

If successful, the script will print CSV contents of the test file.

</details>

### fetch

:::caution pass

Experimental support for `fetch` was introduced in NodeJS `16.15.0`. It will be
considered stable in NodeJS LTS version `22`.

:::

The `fetch` implementation has the same return types as the browser version:

```js
async function parse_from_url(url) {
  const res = await fetch(url);
  if(!res.ok) throw new Error("fetch failed");
  const ab = await res.arrayBuffer();
  const workbook = XLSX.read(ab);
  return workbook;
}
```

<details>
  <summary><b>Complete Example</b> (click to show)</summary>

:::note Tested Environments

This demo was last tested on 2024 January 15 against NodeJS `20.11.0`

:::

1) Install the [NodeJS module](/docs/getting-started/installation/nodejs)

<CodeBlock language="bash">{`\
npm i --save https://cdn.sheetjs.com/xlsx-${current}/xlsx-${current}.tgz`}
</CodeBlock>

2) Save the following to `SheetJSFetch.js`:

```js title="SheetJSFetch.js"
var XLSX = require("xlsx");

async function parse_from_url(url) {
  const res = await fetch(url);
  if(!res.ok) throw new Error("fetch failed");
  const ab = await res.arrayBuffer();
  const workbook = XLSX.read(ab);
  return workbook;
}

(async() => {
  const wb = await parse_from_url('https://sheetjs.com/pres.numbers');
  /* print the first worksheet to console */
  var ws = wb.Sheets[wb.SheetNames[0]];
  console.log(XLSX.utils.sheet_to_csv(ws));
})();
```

3) Run the script:

```bash
node SheetJSFetch.js
```

If successful, the script will print CSV contents of the test file.

</details>

### Wrapper Libraries

The latest releases of NodeJS support `fetch` natively.  Before `fetch` support
was added to the platform, third party modules wrapped the native APIs.

#### request

:::danger pass

`request` has been deprecated and should only be used in legacy deployments.

:::

Setting the option `encoding: null` passes raw buffers:

```js title="SheetJSRequest.js"
var XLSX = require('xlsx'), request = require('request');
var url = 'https://sheetjs.com/pres.numbers';

/* call `request` with the option `encoding: null` */
// highlight-next-line
request(url, {encoding: null}, function(err, res, data) {
  if(err || res.statusCode !== 200) return;

  /* if the request was successful, parse the data */
  // highlight-next-line
  var wb = XLSX.read(data);

  /* print the first worksheet to console */
  var ws = wb.Sheets[wb.SheetNames[0]];
  console.log(XLSX.utils.sheet_to_csv(ws));
});
```

<details>
  <summary><b>Complete Example</b> (click to show)</summary>

:::note Tested Environments

This demo was last tested on 2024 January 15 against request `2.88.2`

:::

1) Install the [NodeJS module](/docs/getting-started/installation/nodejs)

<CodeBlock language="bash">{`\
npm i --save https://cdn.sheetjs.com/xlsx-${current}/xlsx-${current}.tgz request@2.88.2`}
</CodeBlock>

2) Copy the `SheetJSRequest.js` code snippet to a file `SheetJSRequest.js`

3) Run the script:

```bash
node SheetJSRequest.js
```

If successful, the script will print CSV contents of the test file.

</details>

#### axios

When the `responseType` is `"arraybuffer"`, `axios` actually captures the data
in a NodeJS Buffer. The SheetJS `read` method handles NodeJS Buffer objects:

```js title="SheetJSAxios.js"
const XLSX = require("xlsx"), axios = require("axios");

async function workbook_dl_axios(url) {
  const res = await axios(url, {responseType:'arraybuffer'});
  /* at this point, res.data is a Buffer */
  const workbook = XLSX.read(res.data);
  return workbook;
}
```

<details>
  <summary><b>Complete Example</b> (click to show)</summary>

:::note Tested Environments

This demo was last tested on 2024 January 15 against Axios `1.6.5`

:::

1) Install the [NodeJS module](/docs/getting-started/installation/nodejs)

<CodeBlock language="bash">{`\
npm i --save https://cdn.sheetjs.com/xlsx-${current}/xlsx-${current}.tgz axios@1.6.5`}
</CodeBlock>

2) Save the following to `SheetJSAxios.js`:

```js title="SheetJSAxios.js"
const XLSX = require("xlsx"), axios = require("axios");

async function workbook_dl_axios(url) {
  const res = await axios(url, {responseType:'arraybuffer'});
  /* at this point, res.data is a Buffer */
  const workbook = XLSX.read(res.data);
  return workbook;
}

(async() => {
  const wb = await workbook_dl_axios('https://sheetjs.com/pres.numbers');
  /* print the first worksheet to console */
  var ws = wb.Sheets[wb.SheetNames[0]];
  console.log(XLSX.utils.sheet_to_csv(ws));
})();
```

3) Run the script:

```bash
node SheetJSAxios.js
```

If successful, the script will print CSV contents of the test file.

</details>

## Other Platforms

Other demos show network operations in special platforms:

- [React Native "Fetching Remote Data"](/docs/demos/mobile/reactnative#fetching-remote-data)
- [NativeScript "Fetching Remote Files"](/docs/demos/mobile/nativescript#fetching-remote-files)
- [AngularJS "Remote Files"](/docs/demos/frontend/angularjs#remote-files)
- [Dojo Toolkit "Parsing Remote Files"](/docs/demos/frontend/dojo#parsing-remote-files)

[^1]: See [`read` in "Reading Files"](/docs/api/parse-options)
[^2]: See [`sheet_to_html` in "Utilities"](/docs/api/utilities/html#html-table-output)
[^3]: See [`dataType` in `jQuery.ajax`](https://api.jquery.com/jQuery.ajax/) in the official jQuery documentation.
[^4]: See [the official `jquery.binarytransport.js` repo](https://github.com/henrya/js-jquery/tree/master/BinaryTransport) for more details.
