Google Sheets API Tutorial - nvbach91/4IZ268-2021-2022-ZS GitHub Wiki

How to read and write data with Google Sheets API 4

This article will guide you through the process of creating a web application (HTML, JavaScript) that can communicate with a Google Spreadsheet (Read and Write data)

Useful links and documentation

Setup

*Note: You can also follow the QuickStart guide to automatically do the following steps (enable Google Sheets API, Create Consent Screen,Create Client ID, Create API Key)

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  • Create Consent screen

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  • Create OAuth 2.0 Client ID and copy it

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  • Create an API key and copy it

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Example application

The following app will allow users to authenticate to your Google API project and read/write data from/to a specific Google Spreadsheet.

  • Source code:

  • How to run:

    • Download the folder and open it in VS Code
    • Run file index.html with Live Server plugin in VS Code, it will open under http://localhost:5500
    • If the URL is different, you need to put it in the Authorized JavaScript Origins in the Client ID Settings

  • How it works:

    • We'll use GAPI SDK to achieve these functionalities. Import https://apis.google.com/js/api.js to your HTML page.
    • We need the following 4 information to access a public SpreadSheet
      • App.CLIENT_ID = '377940326267-5t4orjmje65mu9eflp7mpdgp646rke3j.apps.googleusercontent.com'; - You created this during the Setup process
      • App.API_KEY = 'AIzaSyAY5zq1-HwkZyARqLD7FzSRLrajuR7XGl0'; - You created this during the Setup process
      • App.spreadsheetId = '1OZwvAfh0q0hQkCwh34iVBBW24mnMyJh5OuEMXYbu8vg'; - This ID is taken from the link to an existing spreadsheet. Go ahead and create a new spreadsheet, make it public for read and write. Copy its ID from its URL.
      • App.SCOPES = 'https://www.googleapis.com/auth/spreadsheets'; - This is the permissions you need to grant users so they can access your spreadsheet. For orther type of permissions, visit https://developers.google.com/identity/protocols/googlescopes
    • When the page is ready, call gapi.load('client:auth2', () => { ... });
    • In this call back, initialize the gapi client.
gapi.client.init({
  apiKey: App.API_KEY,
  clientId: App.CLIENT_ID,
  discoveryDocs: App.DISCOVERY_DOCS,
  scope: App.SCOPES
}).then(() => {
  // manipulate the DOM to notify users that they have logged in successfully

  // Listen for sign-in state changes.
  gapi.auth2.getAuthInstance().isSignedIn.listen(App.updateSigninStatus);

  // Handle the initial sign-in state.
  App.updateSigninStatus(gapi.auth2.getAuthInstance().isSignedIn.get());

  // you can now start making Google Sheets API calls to retrieve data from a spreadsheet
  App.listData();
}, (error) => {
  // if there is any error, notify the users
  console.log(JSON.stringify(error, null, 2));
});
  • This is an example function to fetch data from a spreadsheet and show them on the page
App.listData = () => {
  // select the HTML table for displaying data
  const tableBody = document.querySelector('#table-body');
  const rows = [];
  // call the method to fetch data
  gapi.client.sheets.spreadsheets.values.get({
    spreadsheetId: App.spreadsheetId, // this is the ID of your spreadsheet that contains data
    range: 'Sheet1!A1:D101', // this is the cell range to be fetched from the spreadsheet
  }).then((response) => {
    const range = response.result; // the result contains arrays of data, you'll have to process it
    if (range.values.length > 0) {
      for (i = 0; i < range.values.length; i++) {
        const row = range.values[i];
        rows.push(row);
      }
      // display the rows of data in the table on the page
      tableBody.innerHTML = rows.map((row) => `<tr>${row.map((value) => `<td>${value}</td>`).join('')}</tr>`).join('');
    } else {
        console.log('No data found.');
    }
  }, (response) => {
    console.log('Error: ' + response.result.error.message);
  });
};
  • This is an example function that will append a new row to a spreadsheet
// the .append method will append a new row to a table whose cell is the specified range
gapi.client.sheets.spreadsheets.values.append({
  spreadsheetId: App.spreadsheetId,
  range: 'Sheet1!A1',
  valueInputOption: 'RAW',
  insertDataOption: 'INSERT_ROWS',
  resource: {
    values: [
      ['123', 'Dave', '2019-11-19', 175] // this is a row
    ]
  }
}).then((response) => {
  var result = response.result;
  console.log(`${result.updates.updatedCells} cells appended.`);
  // refresh the table to verify the newly appended data
  App.listData();
});
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