Unable to read data from string base64 representing a .xlsx file

[max]

You most likely need to remove the data:;base64, part in xlStr. You can try

xlStr = xlStr.split(',', 1)[1]
xlDecoded = base64.b64decode(xlStr)

You have made my day sir.... that solved the problem and saved my ass :'):

xlStr = xlStr.split(',', 1)[1]
xlDecoded = base64.b64decode(xlStr)
xlsx = xlrd.open_workbook(file_contents=xlDecoded)
firstSheet = xlsx.sheet_by_index(0)

print(firstSheet.cell(1,0).value)

#It printed and worked perfectly as intended....