Is this the best way to solve the problem I'm getting?

[A Fghtr Pilot]

So, I have a pistol whip for my pistol SWEP's secondary attack, and it works fine. But, in MultiPlayer, I get an error from the client saying that tr.Entity:TakeDamage() is a nil value(it can't be run clientside), because I have my weapon as a shared.lua file. So, here's the whole code:

if SERVER then

AddCSLuaFile("shared.lua")

end

SWEP.PrintName 				= "Pistol"
SWEP.Author 				= ""
SWEP.Contact 				= ""
SWEP.Purpose 				= ""
SWEP.Instructions 			= ""
SWEP.Base 					= "dm_base_hl2"
SWEP.UseHands = true

SWEP.Category           = "The Rebel SWEPs"
SWEP.Spawnable          = true
SWEP.AdminSpawnable 	= true

SWEP.ViewModelFlip 			= false
SWEP.ViewModel                          = "models/weapons/c_pistol.mdl"
SWEP.WorldModel = "models/weapons/w_pistol.mdl"
SWEP.ViewModelFOV = 54

SWEP.AutoSwitchTo			= true		 
SWEP.AutoSwitchFrom			= true

SWEP.Slot 					= 0
SWEP.SlotPos 				= 0

SWEP.HoldType 				= "pistol"
SWEP.FiresUnderwater 		= false
SWEP.Weight 				= 25 
SWEP.ShowViewModel 			= true
SWEP.ShowWorldModel 		= true

SWEP.Primary.ClipSize 		= 18
SWEP.Primary.Ammo 			= "Pistol" 
SWEP.Primary.DefaultClip 	= 72
SWEP.Primary.Automatic 		= false
SWEP.Primary.Force 			= 1
SWEP.Primary.Spread 		= 1
SWEP.Primary.Recoil 		= 4
SWEP.Primary.Delay 			= 0.1
SWEP.Primary.NumberofShots 	= 1
SWEP.Primary.Cone = 0.1

SWEP.Secondary.ClipSize 	= -1 
SWEP.Secondary.Ammo 		= "none" 
SWEP.Secondary.DefaultClip 	= -1     
SWEP.Secondary.Automatic 	= false
SWEP.Damage1 = 20
SWEP.Damage2 = 30

SWEP.RecoilUp = 3
SWEP.RecoilDown = -3

SWEP.RecoilSideLeft = 2
SWEP.RecoilSideRight = -2

SWEP.PrimSpread = 0.50

SWEP.WalkSpread = 1

SWEP.Primary.WalkSpread = 1.25

SWEP.Primary.WepSpread = 0.75

SWEP.Primary.IdleSpread = 0.75

SWEP.SwepSound = "Weapon_Pistol.NPC_Single"

SWEP.FireRate = 0.10

if SERVER then

SWEP.Name = "pistol"

end

if CLIENT then

killicon.AddFont( "dm_pistol", "HL2MPTypeDeath", "-", Color( 255, 80, 0, 255 ) )

end

--pistol whip functionality

function SWEP:SecondaryAttack()

self.Weapon:EmitSound( "WeaponFrag.Throw" )
self.Owner:ViewPunch( Angle( 15, 15, 15 ) )
self.Owner:DoCustomAnimEvent( PLAYERANIMEVENT_ATTACK_GRENADE , 123 )

self.Weapon:SendWeaponAnim( ACT_VM_LOWERED_TO_IDLE )
self:SetNextIdle( CurTime() + self:SequenceDuration() )


	local tracedata = {}

	tracedata.start = self.Owner:GetShootPos()
	tracedata.endpos = self.Owner:GetShootPos() + self.Owner:GetAimVector() * 75
	tracedata.filter = self.Owner
	tracedata.mins = Vector( -8 , -8 , -8 )
	tracedata.maxs = Vector( 8 , 8 , 8 )

	if ( self.Owner:IsPlayer() ) then
		self.Owner:LagCompensation( true )
	end

	local tr = util.TraceHull( tracedata )

	if ( self.Owner:IsPlayer() ) then
		self.Owner:LagCompensation( false )
	end

	if tr.Hit then
		print( tr.Entity )	--your code here
                self.Weapon:EmitSound( "Flesh.ImpactHard" )
                --[[if ( tr.Entity:IsPlayer() ) then
				if SERVER then --this was my method of choice to solve this
                tr.Entity:TakeDamage( 40 )]]--please note that these comment brackets are here to emphasize its importance, in the real code the comment brackets aren't in here
				end
                end
	end

	self:SetNextSecondaryFire( CurTime() + 0.40 )
        self:SetNextPrimaryFire( CurTime() + 0.60 )
end


hook.Add( "DoAnimationEvent" , "AnimEventTest" , function( ply , event , data )
	if event == PLAYERANIMEVENT_ATTACK_GRENADE then
		if data == 123 then
			ply:AnimRestartGesture( GESTURE_SLOT_ATTACK_AND_RELOAD, ACT_HL2MP_GESTURE_RANGE_ATTACK_MELEE, true )
		end

		return ACT_INVALID
	end
end )

As you can see, my method to solve this was to use an

if SERVER then

if statement. Is this the best way to do so? Can anyone tell me what a better way would be if one exists?

[TheKitsune]

Yes, it's the only way to put it server side if it's in a shared file. There are no problems using "if SERVER then".

P.S: I think you should give better titles to your threads, because this gives only little insight on what's your issue.