import bpy

class KnifeProjectOperator(bpy.types.Operator):
    """Knefe project from view selected objects to active"""
    bl_idname = "object.knife_project_operator"
    bl_label = "Knife Project Operator"

    @classmethod
    def poll(cls, context):
        return context.active_object is not None \
            and context.selected_objects > 1

    def execute(self, context):
        if context.mode == 'OBJECT':
            bpy.ops.object.editmode_toggle()
        bpy.ops.mesh.knife_project(cut_through=True)
        bpy.ops.object.editmode_toggle()
        return {'FINISHED'}

def register():
    bpy.utils.register_class(KnifeProjectOperator)

def unregister():
    bpy.utils.unregister_class(KnifeProjectOperator)

if __name__ == "__main__":
    register()