Israel just wanted to kill the Hamas commander and destroy its weapon storages.Saying that Hamas was firing rockets was just an excuse.
Do you really think,if they hadn't weapons to attack Israeli big cities,Israel would accept truce?Do you remember 2009 war?They killed nearly 1200 palestinians in 22 days,and stopped only after almost the whole world condemned it.
Whether or not Iran gave missiles to Hamas,Israel would still attack them,and they had to defend only with crappy gerad rockets with 10 km range.So,Iran was not the reason for attack,but it was one of the main reasons Israel stopped invasion,to prevent further missile hits to its big cities.