---
title: HTTP Uploads
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---
import current from '/version.js';
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Browsers and other platforms offer solutions for uploading files to servers and
cloud storage solutions. Spreadsheets can be written using SheetJS and uploaded.
This demo explores file uploads using a number of browser APIs and wrapper
libraries. The upload process will generate a sample XLSX workbook, upload the
file to [a test server](#test-server), and display the response.
:::info pass
This demo focuses on uploading files. Other demos cover other HTTP use cases:
- ["HTTP Downloads"](/docs/demos/net/network) covers downloading 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 uploads by
encoding requests and responses in UTF-8 strings.
For AWS, in the "Binary Media Types" section of the API Gateway console, the
`"multipart/form-data"` type should be added to ensure that AWS Lambda functions
can receive uploads from clients.
:::
## Uploading Binary Data
The SheetJS `write` method[^1] generates file data stored in `ArrayBuffer`
objects. The `ArrayBuffer` can be added to a `FormData` object. The `FormData`
object can be passed along to POST requests.
```mermaid
flowchart LR
subgraph SheetJS operations
wb(((SheetJS\nWorkbook)))
ab(XLSX Data\nArrayBuffer)
end
file(File\nobject)
form(FormData\nobject)
server[[Server\nrecipient]]
wb --> |`write`\n\n| ab
ab --> |new\n\n| file
file --> |new\nappend\n| form
form --> |POST\nrequest| server
```
```js
/* create sample SheetJS workbook object */
var aoa = [
["S", "h", "e", "e", "t", "J", "S"],
[ 5, 4, 3, 3, 7, 9, 5]
];
var ws = XLSX.utils.aoa_to_sheet(aoa);
var wb = XLSX.utils.book_new();
XLSX.utils.book_append_sheet(wb, ws, "Sheet1");
/* export SheetJS workbook object to XLSX file bytes */
var data = XLSX.write(wb, {bookType: 'xlsx', type: 'array'});
/* build FormData with the generated file */
var fdata = new FormData();
fdata.append('file', new File([data], 'sheetjs.xlsx'));
// field name ^^^^ file name ^^^^^^^^^^^^
/* send data using XMLHttpRequest */
var req = new XMLHttpRequest();
req.open("POST", "https://s2c.sheetjs.com", true);
req.send(fdata);
```
## Test Server
The service is currently hosted on Deno Deploy. The
["Deno Deploy" demo](/docs/demos/cloud/deno#demo) covers the exact steps for
deploying the service.
The CORS-enabled service handles POST requests by looking for uploaded files in
the `"file"` key. If a file is found, the file will be parsed using the SheetJS
`read` method[^2] and the first worksheet will be converted to HTML using the
`sheet_to_html` method[^3].
## Browser Demos
When the upload button is clicked, the browser will build up a new workbook,
generate a XLSX file, upload it to and show the
response. If the process was successful, a HTML table will be displayed
:::note Tested Deployments
Each browser demo was tested in the following environments:
| Browser | Date |
|:------------|:-----------|
| Chrome 120 | 2024-01-15 |
| Safari 17.3 | 2024-02-21 |
:::
### XMLHttpRequest
This demo uses [the code snippet from the intro](#uploading-binary-data).
Live demo (click to show)
This demo starts from an array of arrays of data. When the button is clicked, a
workbook file will be generated and uploaded to . The
service will return a HTML table.
```jsx live
function SheetJSXHRUL() {
const [__html, setHTML] = React.useState("");
const [sz, setSz] = React.useState(0);
const [csv, setCSV] = React.useState("");
/* raw data */
const aoa = [
["S", "h", "e", "e", "t", "J", "S"],
[ 5, 4, 3, 3, 7, 9, 5]
];
/* target URL */
const url = "https://s2c.sheetjs.com";
/* Fetch and update HTML */
const xport = React.useCallback(async() => { try {
/* Make SheetJS Workbook from data */
const ws = XLSX.utils.aoa_to_sheet(aoa);
const wb = XLSX.utils.book_new();
XLSX.utils.book_append_sheet(wb, ws, "Sheet1");
/* Export to XLSX */
const data = XLSX.write(wb, {bookType: 'xlsx', type: 'array'});
setSz(data.length || data.byteLength);
/* Make FormData */
const fdata = new FormData();
fdata.append('file', new File([data], 'sheetjs.xlsx'));
/* Upload */
/* - create XMLHttpRequest */
const req = new XMLHttpRequest();
req.open("POST", url, true);
/* - on success, display the contents */
req.onload = (e) => setHTML(req.responseText);
/* - on error, display "Request failed" */
req.onerror = (e) => setHTML("Request failed");
/* - send data */
req.send(fdata);
} catch(e) { setHTML(e && e.message || e); } });
/* Display data in CSV form */
React.useEffect(() => {
const ws = XLSX.utils.aoa_to_sheet(aoa);
setCSV(XLSX.utils.sheet_to_csv(ws));
}, []);
return (
);
}
```
### 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.
Uploading form data is nearly identical to the `fetch` example:
```js
/* create sample SheetJS workbook object */
var aoa = [
["S", "h", "e", "e", "t", "J", "S"],
[ 5, 4, 3, 3, 7, 9, 5]
];
const ws = XLSX.utils.aoa_to_sheet(aoa);
const wb = XLSX.utils.book_new();
XLSX.utils.book_append_sheet(wb, ws, "Sheet1");
/* export SheetJS workbook object to XLSX file bytes */
var data = XLSX.write(wb, {bookType: 'xlsx', type: 'array'});
/* build FormData with the generated file */
var fdata = new FormData();
fdata.append('file', new File([data], 'sheetjs.xlsx'));
// field name ^^^^ file name ^^^^^^^^^^^^
/* send data using axios */
axios("https://s2c.sheetjs.com", { method: "POST", data: fdata });
```
Live demo (click to show)
This demo uses `axios` to upload data to . It will parse
the workbook and return 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 SheetJSAxiosUL() {
const [__html, setHTML] = React.useState("");
const [sz, setSz] = React.useState(0);
const [csv, setCSV] = React.useState("");
/* raw data */
const aoa = [
["S", "h", "e", "e", "t", "J", "S"],
[ 5, 4, 3, 3, 7, 9, 5]
];
/* target URL */
const url = "https://s2c.sheetjs.com";
/* Fetch and update HTML */
const xport = React.useCallback(async() => { try {
/* Make SheetJS Workbook from data */
const ws = XLSX.utils.aoa_to_sheet(aoa);
const wb = XLSX.utils.book_new();
XLSX.utils.book_append_sheet(wb, ws, "Sheet1");
/* Export to XLSX */
const data = XLSX.write(wb, {bookType: 'xlsx', type: 'array'});
setSz(data.length || data.byteLength);
/* Make FormData */
const fdata = new FormData();
fdata.append('file', new File([data], 'sheetjs.xlsx'));
/* Upload */
const res = await axios(url, {method:"POST", data: fdata});
/* Show Server Response */
setHTML(res.data);
} catch(e) { setHTML(e && e.message || e); }});
/* Display data in CSV form */
React.useEffect(() => {
const ws = XLSX.utils.aoa_to_sheet(aoa);
setCSV(XLSX.utils.sheet_to_csv(ws));
}, []);
return (
);
}
```
#### superagent
[`superagent`](https://ladjs.github.io/superagent/) is a network request library
with a "Fluent Interface".
The `send` method accepts a `FormData` object as the first argument:
```js
/* create sample SheetJS workbook object */
var aoa = [
["S", "h", "e", "e", "t", "J", "S"],
[ 5, 4, 3, 3, 7, 9, 5]
];
const ws = XLSX.utils.aoa_to_sheet(aoa);
const wb = XLSX.utils.book_new();
XLSX.utils.book_append_sheet(wb, ws, "Sheet1");
/* export SheetJS workbook object to XLSX file bytes */
var data = XLSX.write(wb, {bookType: 'xlsx', type: 'array'});
/* build FormData with the generated file */
var fdata = new FormData();
fdata.append('file', new File([data], 'sheetjs.xlsx'));
// field name ^^^^ file name ^^^^^^^^^^^^
/* send data (fd is the FormData object) */
superagent.post("https://s2c.sheetjs.com").send(fd);
```
Live demo (click to show)
This demo uses `superagent` to upload data to . It will
parse the workbook and return 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 SheetJSSuperAgentUL() {
const [__html, setHTML] = React.useState("");
const [sz, setSz] = React.useState(0);
const [csv, setCSV] = React.useState("");
/* raw data */
const aoa = [
["S", "h", "e", "e", "t", "J", "S"],
[ 5, 4, 3, 3, 7, 9, 5]
];
/* target URL */
const url = "https://s2c.sheetjs.com";
/* Fetch and update HTML */
const xport = React.useCallback(async() => { try {
/* Make SheetJS Workbook from data */
const ws = XLSX.utils.aoa_to_sheet(aoa);
const wb = XLSX.utils.book_new();
XLSX.utils.book_append_sheet(wb, ws, "Sheet1");
/* Export to XLSX */
const data = XLSX.write(wb, {bookType: 'xlsx', type: 'array'});
setSz(data.length || data.byteLength);
/* Make FormData */
const fdata = new FormData();
fdata.append('file', new File([data], 'sheetjs.xlsx'));
/* Upload */
superagent.post(url).send(fdata).end((err, res) => {
/* Show Server Response */
setHTML(res.text);
});
} catch(e) { setHTML(e && e.message || e); }});
/* Display data in CSV form */
React.useEffect(() => {
const ws = XLSX.utils.aoa_to_sheet(aoa);
setCSV(XLSX.utils.sheet_to_csv(ws));
}, []);
return (
);
}
```
## NodeJS Demos
These examples show how to upload data in NodeJS.
### fetch
The `fetch` implementation mirrors the [browser `fetch`](#fetch).
:::note Tested Deployments
This demo was last tested on 2023 November 19 against NodeJS `20.9.0`
:::
Complete Example (click to show)
This demo uses `fetch` to upload data to . It will parse
the workbook and return data in CSV rows.
1) Install the [SheetJS NodeJS module](/docs/getting-started/installation/nodejs):
{`\
npm i --save https://cdn.sheetjs.com/xlsx-${current}/xlsx-${current}.tgz`}
2) Save the following to `SheetJSFetch.js`:
```js title="SheetJSFetch.js"
const XLSX = require("xlsx");
/* create sample SheetJS workbook object */
var aoa = [
["S", "h", "e", "e", "t", "J", "S"],
[ 5, 4, 3, 3, 7, 9, 5]
];
const ws = XLSX.utils.aoa_to_sheet(aoa);
const wb = XLSX.utils.book_new();
XLSX.utils.book_append_sheet(wb, ws, "Sheet1");
/* export SheetJS workbook object to XLSX file bytes */
var data = XLSX.write(wb, {bookType: 'xlsx', type: 'array'});
/* build FormData with the generated file */
var fdata = new FormData();
fdata.append('file', new File([data], 'sheetjs.xlsx'));
// field name ^^^^ file name ^^^^^^^^^^^^
fdata.append('type', 'csv');
(async() => {
/* send data using fetch */
const res = await fetch("https://s2c.sheetjs.com", { method: "POST", body: fdata });
const txt = await res.text();
console.log(txt);
})();
```
3) Run the script:
```bash
node SheetJSFetch.js
```
It will print CSV contents of the test file.
## Troubleshooting
Some SheetJS users have reported corrupted files. To diagnose the error, it is
strongly recommended to write local files.
For example, using `fetch` in the browser, the bytes can be downloaded using the
[HTML5 Download Attribute](/docs/demos/local/file#html5-download-attribute). The
highlighted lines should be added immediately after `write`:
```js title="Diagnosing issues in a fetch upload"
/* Generate XLSX file */
const data = XLSX.write(wb, {bookType: 'xlsx', type: 'array'});
// highlight-start
/* Write to Local File */
const blob = new Blob([data]);
const url = URL.createObjectURL(blob);
const a = document.createElement("a");
a.download = "SheetJS.xlsx";
a.href = url;
document.body.appendChild(a);
a.click();
document.body.removeChild(a);
// highlight-end
/* Make FormData */
const fdata = new FormData();
fdata.append('file', new File([data], 'sheetjs.xlsx'));
/* Upload */
const url = "https://s2c.sheetjs.com";
const res = await fetch(url, {method:"POST", body: fdata});
```
If the generated file is valid, then the issue is in the server infrastructure.
[^1]: See [`write` in "Writing Files"](/docs/api/write-options)
[^2]: See [`read` in "Reading Files"](/docs/api/parse-options)
[^3]: See [`sheet_to_html` in "Utilities"](/docs/api/utilities/html#html-table-output)