Periodically refresh IMPORTXML() spreadsheet function

I made a couple of adjustments to Mogsdad's answer:

• Fixed the releaseLock() call placement
• Updates (or adds) a querystring parameter to the url in the import function (as opposed to storing, removing, waiting 5 seconds, and then restoring all relevant formulas)
• Works on a specific sheet in your spreadsheet
• Shows time of last update

...

function RefreshImports() {
  var lock = LockService.getScriptLock();
  if (!lock.tryLock(5000)) return;             // Wait up to 5s for previous refresh to end.

  var id = "[YOUR SPREADSHEET ID]";
  var ss = SpreadsheetApp.openById(id);
  var sheet = ss.getSheetByName("[SHEET NAME]");
  var dataRange = sheet.getDataRange();
  var formulas = dataRange.getFormulas();
  var content = "";
  var now = new Date();
  var time = now.getTime();
  var re = /.*[^a-z0-9]import(?:xml|data|feed|html|range)\(.*/gi;
  var re2 = /((\?|&)(update=[0-9]*))/gi;
  var re3 = /(",)/gi;

  for (var row=0; row<formulas.length; row++) {
    for (var col=0; col<formulas[0].length; col++) {
      content = formulas[row][col];
      if (content != "") {
        var match = content.search(re);
        if (match !== -1 ) {
          // import function is used in this cell
          var updatedContent = content.toString().replace(re2,"$2update=" + time);
          if (updatedContent == content) {
            // No querystring exists yet in url
            updatedContent = content.toString().replace(re3,"?update=" + time + "$1");
          }
          // Update url in formula with querystring param
          sheet.getRange(row+1, col+1).setFormula(updatedContent);
        }
      }
    }
  }

  // Done refresh; release the lock.
  lock.releaseLock();

  // Show last updated time on sheet somewhere
  sheet.getRange(7,2).setValue("Rates were last updated at " + now.toLocaleTimeString())
}

The Google Spreadsheet row update question and its answers refer to the "Old Sheets", which had different behaviour than the 2015 version of Google Sheets does. There is no automatic refresh of content with "New Sheets"; changes are only evaluated now in response to edits.

While Sheets no longer provides this capability natively, we can use a script to refresh the "import" formulas (IMPORTXML, IMPORTDATA, IMPORTHTML and IMPORTANGE).

Utility script

For periodic refresh of IMPORT formulas, set this function up as a time-driven trigger.

Caveats:

• Import function Formula changes made to the spreadsheet by other scripts or users during the refresh period COULD BE OVERWRITTEN.
• Overlapping refreshes might make your spreadsheet unstable. To mitigate that, the utility script uses a ScriptLock. This may conflict with other uses of that lock in your script.

 

/**
 * Go through all sheets in a spreadsheet, identify and remove all spreadsheet
 * import functions, then replace them a while later. This causes a "refresh"
 * of the "import" functions. For periodic refresh of these formulas, set this
 * function up as a time-based trigger.
 *
 * Caution: Formula changes made to the spreadsheet by other scripts or users
 * during the refresh period COULD BE OVERWRITTEN.
 *
 * From: https://stackoverflow.com/a/33875957/1677912
 */
function RefreshImports() {
  var lock = LockService.getScriptLock();
  if (!lock.tryLock(5000)) return;             // Wait up to 5s for previous refresh to end.
  // At this point, we are holding the lock.

  var id = "YOUR-SHEET-ID";
  var ss = SpreadsheetApp.openById(id);
  var sheets = ss.getSheets();

  for (var sheetNum=0; sheetNum<sheets.length; sheetNum++) {
    var sheet = sheets[sheetNum];
    var dataRange = sheet.getDataRange();
    var formulas = dataRange.getFormulas();
    var tempFormulas = [];
    for (var row=0; row<formulas.length; row++) {
      for (col=0; col<formulas[0].length; col++) {
        // Blank all formulas containing any "import" function
        // See https://regex101.com/r/bE7fJ6/2
        var re = /.*[^a-z0-9]import(?:xml|data|feed|html|range)\(.*/gi;
        if (formulas[row][col].search(re) !== -1 ) {
          tempFormulas.push({row:row+1,
                             col:col+1,
                             formula:formulas[row][col]});
          sheet.getRange(row+1, col+1).setFormula("");
        }
      }
    }

    // After a pause, replace the import functions
    Utilities.sleep(5000);
    for (var i=0; i<tempFormulas.length; i++) {
      var cell = tempFormulas[i];
      sheet.getRange( cell.row, cell.col ).setFormula(cell.formula)
    }

    // Done refresh; release the lock.
    lock.releaseLock();
  }
}