Save smartsheet as .xls on server (curl / php)

The items that need adjusted in your example are the headers and how the response is handled.

First, using curl command line options in the headers will not work. Instead you just need to specify that an XLS file should be returned with headers like the following:

$headers = array("Authorization: Bearer ".$inputToken,    "Accept: application/vnd.ms-excel");

Second, since an XLS file is going to be returned we will not want to parse that response as JSON. Instead, immediately write the response out to a file.

With that in mind the following example should work for you and retrieved the specified sheet as an XLS file. Make sure to replace YOUR_TOKEN and YOUR_SHEET_ID with the appropriate values.

<?php$inputToken = 'YOUR_TOKEN';$baseURL = "https://api.smartsheet.com/1.1";$sheetDetail_url = $baseURL.'/sheet/YOUR_SHEET_ID';$headers = array("Authorization: Bearer ".$inputToken,    "Accept: application/vnd.ms-excel");$curlSession = curl_init($sheetDetail_url);curl_setopt($curlSession, CURLOPT_SSL_VERIFYPEER, false);curl_setopt($curlSession, CURLOPT_HTTPHEADER, $headers);curl_setopt($curlSession, CURLOPT_RETURNTRANSFER, TRUE);$smartsheetData = curl_exec($curlSession);// Check for error or save the fileif (curl_errno($curlSession)){    echo "Oh No! Error: " . curl_error($curlSession);}else{    curl_close($curlSession);    $file1="tmpfile.xls";    if(!(file_put_contents($file1, $smartsheetData))){        echo "file_put error";    }}?>