Specifications of the front hub: 
Brand: Shimano
Model: HB-MT400-B
Color: Black
Number of spoke holes: 32GTS
Type of brake: Disc (Centerlock)
Type of axle: Thru axle Ø 15 MM
Axle included: No
Type of bearings: Ball bearings
Average weight (GR): 167
Intended use: MTB
 
Data for spoke length calculations using the Sapim spoke size calculator: 
Total length of the hub (MM): 110
Non-gear side (MM): 25
Gear side (MM): 15
Hub diameter non-gear side (MM): 43
Hub diameter gear side (MM): 43
 
Link to spoke calculator: www.sapim.be/spoke-calculator