Google Sheets JSON API Script

This Google Apps Script creates a lightweight API for interacting with a Google Sheet. It allows you to:

Retrieve data from a sheet in JSON format.
Append new rows to the sheet via a GET request (with query parameters) or a POST request (with JSON payload).

Features

GET request to retrieve sheet data as JSON.
POST request to append a new row using JSON data.

Setup Instructions

Open Google Sheets:
- Create a new Google Sheet or use an existing one.
Access Script Editor:
- In your Google Sheet, click on Extensions > Apps Script.
Add the Script:
- Replace any existing code with the provided script below or add it as a new function:

   function json(sheetName) {
     const spreadsheet = SpreadsheetApp.getActiveSpreadsheet();
     const sheet = spreadsheet.getSheetByName(sheetName);
     const data = sheet.getDataRange().getValues();
     const jsonData = convertToJson(data);
     return ContentService
           .createTextOutput(JSON.stringify(jsonData))
           .setMimeType(ContentService.MimeType.JSON);
   }

   function convertToJson(data) {
     const headers = data[0];
     const raw_data = data.slice(1,);
     let json = [];
     raw_data.forEach(d => {
         let object = {};
         for (let i = 0; i < headers.length; i++) {
           object[headers[i]] = d[i];
         }
         json.push(object);
     });
     return json;
   }

   function doGet(e) {
      const path = e.parameter.path;
      return json(path);
   }

   function doPost(e) {
     const sheetName = e.parameter.path;
     const data = JSON.parse(e.postData.contents);
     return appendRowJSON(sheetName, data);
   }



   function appendRowJSON(sheetName, data) {
     const sheet = SpreadsheetApp.getActiveSpreadsheet().getSheetByName(sheetName);

     const headers = sheet.getDataRange().getValues()[0]; // Get headers
     let newRow = [];

     headers.forEach(header => {
       newRow.push(data[header] || ''); // Use empty string if field is missing
     });

     sheet.appendRow(newRow);

     return ContentService.createTextOutput("Row added successfully via POST request");
   }

Deploy the Script:
- Click on Deploy > New deployment.
- You may need to approve this Google App on your Google Account.
- Execute as me (your emaiL)
- Who has access (anyone)
- Follow the prompts to deploy the app and copy the Web App URL.

API Usage

1. Retrieve Data as JSON

You can retrieve the entire sheet’s data as JSON by making a GET request.

URL:

https://script.google.com/macros/s/YOUR_SCRIPT_ID/exec?path=Sheet1

Replace YOUR_SCRIPT_ID with your Google Apps Script deployment ID, and Sheet1 with your sheet's name.

2. Append a Row via GET Request (Query Parameters)

You can append a new row by making a GET request with the field values passed as query parameters.

Example URL:

https://script.google.com/macros/s/YOUR_SCRIPT_ID/exec?path=Sheet1&Name=John&Age=30&addRow=true

Replace YOUR_SCRIPT_ID with your deployment ID.
Replace Sheet1 with the name of your sheet.
Add query parameters for the column headers in your sheet (Name, Age, etc.).

3. Append a Row via POST Request (JSON Payload)

You can append a new row by making a POST request with a JSON payload.

POST URL:

https://script.google.com/macros/s/YOUR_SCRIPT_ID/exec?path=Sheet1

JSON Payload Example:

{
  "Name": "Jane",
  "Age": 25
}

Replace YOUR_SCRIPT_ID with your deployment ID.
Ensure that the keys in the JSON payload match the column headers in your sheet.

4. Response

POST requests for appending rows will return the following message upon success:

Row added successfully via GET request (or POST request)

Example API Calls

GET Request (Retrieve Data)

curl "https://script.google.com/macros/s/YOUR_SCRIPT_ID/exec?path=Sheet1"

POST Request (Append Row)

curl -X POST "https://script.google.com/macros/s/YOUR_SCRIPT_ID/exec?path=Sheet1" \
-H "Content-Type: application/json" \
-d '{"Name": "Jane", "Age": 25}'

Troubleshooting

Make sure your Google Sheet has the correct column headers in the first row.
Ensure the sheet name passed in the path parameter is spelled exactly as it appears in your Google Sheet.
If you encounter any issues with permissions, ensure the app is deployed with the appropriate permissions (Anyone or Anyone, even anonymous).