docs.sheetjs.com/docz/docs/03-demos/03-net/03-server/04-drash.md
2023-11-19 21:51:44 -05:00

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Drash is a Deno server-side framework. The body parser works in memory and can handle file uploads on hosted services.

SheetJS is a JavaScript library for reading and writing data from spreadsheets.

This demo uses Drash and SheetJS to read and write data. We'll explore how to parse uploaded files in a POST request handler and respond to GET requests with downloadable spreadsheets.

The "Complete Example" section includes a complete server.

:::note

This demo was last tested on 2023 October 16 against Drash 2.8.1 and Deno 1.37.2.

:::

Integration Details

The SheetJS Deno module can be imported from Drash server scripts.

Reading Data

Request#bodyParam reads body parameters. For uploaded files, the content property is a Uint8Array which can be parsed with the SheetJS read method1.

This example server responds to POST requests. The server will look for a file in the request body under the "upload" key. If a file is present, the server will parse the file, generate an HTML table using the sheet_to_html method2 and respond with the HTML code:

{\ // @deno-types="https://cdn.sheetjs.com/xlsx-${current}/package/types/index.d.ts" import { read, utils } from 'https://cdn.sheetjs.com/xlsx-${current}/package/xlsx.mjs'; \n\ import * as Drash from "https://cdn.jsdelivr.net/gh/drashland/drash@v2.8.1/mod.ts"; \n\ class ParseResource extends Drash.Resource { public paths = ["/"]; \n\ public POST(request: Drash.Request, response: Drash.Response) { // assume a form upload like <input type="file" id="upload" name="upload"> // highlight-next-line const file = request.bodyParam<Drash.Types.BodyFile>("upload"); if (!file) throw new Error("File is required!"); \n\ // read file // highlight-next-line var wb = read(file.content); \n\ // respond with HTML from first worksheet var ws = wb.Sheets[wb.SheetNames[0]]; var html = utils.sheet_to_html(html) return response.html(html); } }}

Writing Data

Headers are manually set with Response#headers.set while the raw body is set with Response#send. The raw body can be Uint8Array or ArrayBuffer objects.

Given a SheetJS workbook object, the write method using type: "buffer"3 generates data objects compatible with Drash.

This example server responds to GET requests. The server will generate a SheetJS worksheet object from an array of arrays4, build up a new workbook using the book_new5 and book_append_sheet6 utility methods, generate a XLSX file using write, and send the file with appropriate headers to initiate a download with file name "SheetJSDrash.xlsx":

{\ // @deno-types="https://cdn.sheetjs.com/xlsx-${current}/package/types/index.d.ts" import { utils, write } from 'https://cdn.sheetjs.com/xlsx-${current}/package/xlsx.mjs'; \n\ import * as Drash from "https://cdn.jsdelivr.net/gh/drashland/drash@v2.8.1/mod.ts"; \n\ class WriteResource extends Drash.Resource { public paths = ["/export"]; \n\ public GET(request: Drash.Request, response: Drash.Response): void { // create some fixed workbook const data = ["SheetJS".split(""), [5,4,3,3,7,9,5]]; const ws = utils.aoa_to_sheet(data); const wb = utils.book_new(); utils.book_append_sheet(wb, ws, "data"); \n\ // write the workbook to XLSX as a Uint8Array // highlight-next-line const file = write(wb, { bookType: "xlsx", type: "buffer"}); // set headers response.headers.set("Content-Disposition", 'attachment; filename="SheetJSDrash.xlsx"'); // send data // highlight-next-line return response.send("application/vnd.ms-excel", file); } }}

Complete Example

  1. Download SheetJSDrash.ts:
curl -LO https://docs.sheetjs.com/drash/SheetJSDrash.ts
  1. Run the server:
deno run --allow-net SheetJSDrash.ts
  1. Download the test file https://sheetjs.com/pres.numbers

  2. Open http://localhost:7262/ in your browser.

Click "Choose File" and select pres.numbers. Then click "Submit"

The page should show the contents of the file as an HTML table.

  1. Open http://localhost:7262/export in your browser.

The page should attempt to download SheetJSDrash.xlsx . Open the new file.