2 replies to this topic

[OrangeC7]

(I'm reposting this because I didn't know about the "code" and "spoiler" tags, sorry. I'll be more careful next time.)
I've been troubleshooting my FTP_RECEIVER and FTP_SENDER programs for a while, but I'm stuck on a bug that keeps freezing the computer on the initialisation stage. Any help is appreciated, whether it's just to say I have the wrong approach, or if it's a solution to my problem. I'm kind of a beginner to this, although I have some coding experience in other languages including this one.
I start FTP_RECEIVER first, because then it will continue waiting for the next computer, FTP_SENDER to respond. The code is below

FTP_RECEIVER:

Spoiler

-- Open rednet and clear the terminal
rednet.open("top")
term.clear()
term.setCursorPos(1,1)
-- Inform user
print("-------------------------------")
print(" Receiving files	")
print("-------------------------------")
-- While loop to continually perform task until the file has been received
while true do

  -- Fancy loading text =3
  term.setCursorPos(17,2)
  textutils.slowPrint("...")

  -- Broadcasts a "ready" message
  rednet.broadcast("Ready for files! Waiting for a second...")

  -- Waits for initialisation prompt
  id,msg = rednet.receive(1)
  term.setCursorPos(17,2)
  print("   ")

  -- If statement to filter out possible noise
  if msg == "Sending..." then

	-- Informs user that the File Transfer has been initialised
	term.setCursorPos(1,4)
	print(" Initialised...")
	print("-------------------------------")
  
	-- Sends confirmation message in case it was not received"
	rednet.send(id,"Got the initialisation message! Now waiting...")
  
	-- Waits for file name and then prepares file
	id2,msg2 = rednet.receive()

if msg2 == "Sending..." then
   print(" Oh... got an error. Error 04")
   break
else
	  file = fs.open(msg2,"w")
	
	  -- Confirmation message
	  rednet.send(id,"Got file name...")
	
	  -- Waits for file contents
	  id3,msg3 = rednet.receive()
  
	  -- If statement to test for an intercepter
	  if id3 == id and msg3 == "TERMINATE" then
		print("TERMINATING FTP, ASSUMING ATTEMPT AT INTERCEPT")
		-- Deletes file to remove clutter
		fs.delete(msg2)
		rednet.send(id3,"FTP has been terminated by original sender.")
		break
	  else
	  
		-- If there is no intercepter (that the computer knows of), continues file transfer
		file.write(msg3)
		print("Got the file! Now ending FTP...")
		print("-------------------------------")
		break
   end
	end
  else
	-- Don't do anything, just return to the beginning of the loop.
  end
end

FTP_SENDER:

Spoiler

-- Open rednet and clear the terminal
rednet.open("top")
term.clear()
term.setCursorPos(1,1)

repeat
-- Prompt the user
print("--------------------------------------")
print(" Specify the file you want to send... ")
print("--------------------------------------")
term.setCursorPos(2,4)
file = io.read()
print("--------------------------------------")
print(" Who should this be sent to? (ID)")
print("--------------------------------------")
term.setCursorPos(2,8)
ID = io.read()
print("--------------------------------------")
textutils.slowPrint(" Sending file...")
print("--------------------------------------")

-- Make sure that ID is a number
if tonumber(ID) == nil then
  print("The ID you gave is not a number! Please be more careful, try again.")
else
  IDN = tonumber(ID)
end
until IDN

-- Loop until finished
while true do

  -- Waits for ready message
  id,msg = rednet.receive(1)

  -- Make sure the file exists
  if fs.exists(file) == true then

	-- Set variable for the file's contents
	contents = fs.open(file, "r")

	-- Filters out possible noise
	if msg == "Ready for files! Waiting for a second..." then
	  print(" Got ready message! Initialising...")
	  print("--------------------------------------")

	  -- Sends initialisation prompt
	  rednet.send(IDN,"Sending...")

	  -- Waits for confirmation message
	  id2,msg2 = rednet.receive(2)

	  if msg == "Got the initialisation message! Now waiting..." then

		-- Sends file name to recipient
		rednet.send(IDN,file)
		id3,msg3 = rednet.receive(2)

		-- Checks the message and ID
		if msg3 == "Got file name..." and id3 == IDN then

		  -- If all is good, continue and finish
		  rednet.send(IDN,contents)
		  print(" File sent!")
		  print("--------------------------------------")
		  sleep(2)
  print("Finished successfully")
  sleep(2)
  break
		elseif id2 ~= IDN then

		  -- If not all is good, send the "TERMINATE" command and finish
		  rednet.send(IDN,"TERMINATE")
		  print("TERMINATING FTP, ASSUMING ATTEMPT AT INTERCEPT")
		  sleep(2)
  print("Finished with error code 02: TERMINATE")
  break
		else
		end
	  else
		-- Do nothing
	  end
else
	 -- Do nothing
end
  else
	-- If the file doesn't exist, end program.
	print(file.." does not exist, or the wrong computer responded. =(")
sleep(2)
term.setTextColor(colors.red)
print("Finished with error code 01: File does not exist")
	break
  end
end
term.setTextColor(colors.white)

Thank you for reading, and for your patience.

[Bomb Bloke]

OrangeC7, on 14 January 2018 - 07:27 PM, said:

I'm stuck on a bug that keeps freezing the computer on the initialisation stage.

Which script are you talking about? Which block of code within that script?

Taking a quick glance through, your receiver script has a problem in that it makes use of textutils.slowPrint(). This function starts timers, and then continuously pulls events from the front of the event queue until it finds the one it wants. Rednet messages are also "received" via the event queue, but if any are in there while slowPrint is executing, they'll be pulled and discarded: rednet.receive() won't be able to find them later.

[OrangeC7]

Bomb Bloke, on 15 January 2018 - 12:59 AM, said:

Which script are you talking about? Which block of code within that script?

I have no idea what is going wrong, all I know is that both computers output the message that indicates they have done the "initialisation" step, and then never output anything again. I'll try to take your suggestion into consideration, though. The main reason I have all the confirmation messages is because of the slowPrint, both computers keep trying to establish contact, in case the other one missed something. If it means sacrificing good looks for functionality, I'll gladly remove the slowPrint feature and use a regular print. Thank you for replying, though! I appreciate it. =)