Canadian in Indonesia, visa for a short visit in Beijing

I am canadian, working in the Indonesian petroleum industry, and expecting to go back to Canada by next Sept.
I aim at making a Singapore-Beijing-Singapore flight on my way back for a (short, unfortunately) three-four days visit in Beijing. I expect to send some 3 days transit in Jakarta before leaving Indonesia. May I apply to the Chinese embassy in Jakarta and expect a visa in such a short notice? I have no letter of invitation and am just by myself. Many thanks for your answer.