The incident occurred when the victim was approached by a group of teenagers on Gas Street, opposite the Tesco store, at around 5pm on Sunday 7 February 2016.
Following the alleged attack he attended Airedale District Hospital for treatment.
Officers are appealing for people to come forward who possibly witnessed the incident or may have information that could assist the investigation.
If you can help, please call North Yorkshire Police on 101, select option 2, and ask for Lisa Jenkinson. Or email firstname.lastname@example.org
If you would prefer to remain anonymous, please contact Crimestoppers on 0800 555111, quoting reference 12160022681.