Automatic file backup - using a timer

Once our file backup utility is running and our window is open we need to be able to use the start and stop buttons to control the activity of program.

Here is the code for the start action. It ties into the [start] label in the Start button.

[start] 'startup the backup timer
#main.start "!disable"
#main.stop "!enable"
gosub [checkInitialFiles]
#main.statusLog "Starting backup"
#main.interval "!contents? interval"
timer interval * 1000, [checkFiles]
wait

When the button is clicked we disable the Start button and enable the Stop button to show which operations are valid. We call [checkInitialFiles] which we haven't written yet (we'll get into that later). We show in the statusLog texteditor that we are starting the backup process. Then we get the contents of the interval textbox and start the timer. The reason we multiply the interval by 1000 is that the timer measures time in milliseconds so if we want 5 a second interval we need to give the timer a value of 5000. Finally we stop and wait for a timer tick or for user interaction.

Once our timer is running we need to be able to stop it. Here is our stop handler:

[stop] 'stop the backup timer
timer 0
#main.start "!enable"
#main.stop "!disable"
#main.statusLog "Stopping backup"
wait

This is real simple. First thing is to stop the timer with timer 0. Then we reverse the enabling of the Start and Stop buttons. Compare this to the way that [start] does it. Then we log to the statusLog texteditor that we are stopping. Finally we wait.

The purpose of the [checkInitialFiles] subroutine is to create a description of the files we are interested in and the time and date they were last modified. Then each time the timer ticks after this we create a new description of these files. If the date and time changes on any of these files then it's time to make a new backup.

Just for now let's just create an empty [checkInitialFiles] subroutine:

[checkInitialFiles] 'snapshot of filenames and timestamps
return

The routine doesn't do anything yet, so we only have a RETURN statement.

Now we'll create a [checkFiles] routine which will be called each time the timer ticks. For now the routine will not do much. We will write the full routine in a later section.

[checkFiles] 'are there new files
#main.statusLog "tick"
'temporarily disable the timer
timer 0
'perform the check here
'reenable the timer
timer interval * 1000, [checkFiles]
wait

The first thing we do is log the word "tick" to the statusLog. This is for instructive purposes only and will be removed later. We do this so that we can see that the timer is working. After this we disable the timer. This might seem like a strange idea, but the reason we do it is because the next thing we do is check the files to see if they changed (we'll write this part later). If they change we don't want the timer to be running because if it takes a while to backup the files and the timer is still running then the timer events can build up. Once the file check and possible backup are finished we reenable the timer.

The entire listing so far is posted below. Try running it. When you click Start it will begin logging its activity. Notice that the word tick gets logged every five seconds. Click the Stop button and change the interval to 1. Start it again and the logging will happen once per second.

dim info$(10,10)
setupPath$ = DefaultDir$+"\backupsetup.ini"

WindowWidth = 560
WindowHeight = 460
statictext #main, "Files to backup:", 5, 5, 94, 20
texteditor #main.listOfFiles, 5, 26, 530, 95
statictext #main, "Destination folder:", 5, 132, 107, 20
textbox #main.destination, 115, 127, 420, 25
statictext #main, "Backup interval in seconds:", 5, 157, 163, 20
textbox #main.interval, 170, 152, 100, 25
button #main.save,"Save",[save], UL, 495, 152, 42, 25
button #main.start,"Start",[start], UL, 5, 187, 75, 25
button #main.stop,"Stop",[stop], UL, 90, 187, 70, 25
statictext #main, "Backup status log", 5, 217, 106, 20
texteditor #main.statusLog, 5, 237, 530, 160
menu #main, "Edit"
open "Backup Utility" for window_nf as #main
#main.stop "!disable"
gosub [loadSetup]
wait

[loadSetup]
#main.listOfFiles "!cls";
if fileExists(setupPath$) then
open setupPath$ for input as #setup
while filename$ <> "end!"
line input #setup, filename$
if filename$ <> "end!" then
#main.listOfFiles filename$
end if
wend
line input #setup, destination$
#main.destination destination$
line input #setup, interval
#main.interval interval
close #setup
end if
return

[start] 'startup the backup timer
#main.start "!disable"
#main.stop "!enable"
#main.interval "!contents? interval"
gosub [checkInitialFiles]
#main.statusLog "Starting backup"
timer interval * 1000, [checkFiles]
wait

[stop] 'stop the backup timer
timer 0
#main.start "!enable"
#main.stop "!disable"
#main.statusLog "Stopping backup"
wait

[checkInitialFiles] 'snapshot of filenames and timestamps
return

[checkFiles] 'are there new files
#main.statusLog "tick"
'temporarily disable the timer
timer 0
'perform the check here
'reenable the timer
timer interval * 1000, [checkFiles]
wait

'return a true if the file in fullPath$ exists, else return false
function fileExists(fullPath$)
files pathOnly$(fullPath$), filenameOnly$(fullPath$), info$()
fileExists = val(info$(0, 0)) > 0
end function

'return just the directory path from a full file path
function pathOnly$(fullPath$)
pathOnly$ = fullPath$
while right$(pathOnly$, 1) <> "\" and pathOnly$ <> ""
pathOnly$ = left$(pathOnly$, len(pathOnly$)-1)
wend
end function

'return just the filename from a full file path
function filenameOnly$(fullPath$)
pathLength = len(pathOnly$(fullPath$))
filenameOnly$ = right$(fullPath$, len(fullPath$)-pathLength)
end function

Automatic file backup - loading setup

Now that we've got a simple GUI designed, let's write some code which will load the files we want to backup, the destination path, and the interval of our automatic backup.

We need a subroutine to load the setup which we will call using GOSUB. We can call this right after we open the window.

open "Backup Utility" for window_nf as #main
gosub [loadSetup]
wait

We want to know if the setup file exists. There is an example program called fileExists.bas that comes with the functions we need to check for file existence. We'll just grab those. Here they are:

'return a true if the file in fullPath$ exists, else return false
function fileExists(fullPath$)
files pathOnly$(fullPath$), filenameOnly$(fullPath$), info$()
fileExists = val(info$(0, 0)) > 0
end function

'return just the directory path from a full file path
function pathOnly$(fullPath$)
pathOnly$ = fullPath$
while right$(pathOnly$, 1) <> "\" and pathOnly$ <> ""
pathOnly$ = left$(pathOnly$, len(pathOnly$)-1)
wend
end function

'return just the filename from a full file path
function filenameOnly$(fullPath$)
pathLength = len(pathOnly$(fullPath$))
filenameOnly$ = right$(fullPath$, len(fullPath$)-pathLength)
end function

We will call the fileExists( ) function from our [loadSetup] subroutine. A really simple example of the data in our setup file would have a list of file paths, and end! marker for the end of that list of files, a single line with the desired destination path, and another line with the interval in seconds between backup attempts.

Example backupSetup.ini

c:\myfolder\test.txt
c:\myfolder\backMeUp.dat
c:\myfolder\SillyPutty.exe
end!
c:\backupFolder\files
5

Once we know the file exists we can open it up and read it, placing the information into the different fields in our GUI.

[loadSetup]
#main.listOfFiles "!cls";
if fileExists(setupPath$) then
open setupPath$ for input as #setup
while filename$ <> "end!"
line input #setup, filename$
if filename$ <> "" then
#main.listOfFiles filename$
end if
wend
line input #setup, destination$
#main.destination destination$
line input #setup, interval
#main.interval interval
close #setup
end if
return

Here is the complete listing so far:

dim info$(10,10)
setupPath$ = DefaultDir$+"\backupsetup.ini"

WindowWidth = 560
WindowHeight = 460
statictext #main, "Files to backup:", 5, 5, 94, 20
texteditor #main.listOfFiles, 5, 26, 530, 95
statictext #main, "Destination folder:", 5, 132, 107, 20
textbox #main.destination, 115, 127, 420, 25
statictext #main, "Backup interval in seconds:", 5, 157, 163, 20
textbox #main.interval, 170, 152, 100, 25
button #main.save,"Save",[save], UL, 495, 152, 42, 25
button #main.start,"Start",[start], UL, 5, 187, 75, 25
button #main.stop,"Stop",[stop], UL, 90, 187, 70, 25
statictext #main, "Backup status log", 5, 217, 106, 20
texteditor #main.statusLog, 5, 237, 530, 160
menu #main, "Edit"
open "Backup Utility" for window_nf as #main
gosub [loadSetup]
wait

[loadSetup]
#main.listOfFiles "!cls";
if fileExists(setupPath$) then
open setupPath$ for input as #setup
while filename$ <> ""
line input #setup, filename$
if filename$ <> "end!" then
#main.listOfFiles filename$
end if
wend
line input #setup, destination$
#main.destination destination$
line input #setup, interval
#main.interval interval
close #setup
end if
return

'return a true if the file in fullPath$ exists, else return false
function fileExists(fullPath$)
files pathOnly$(fullPath$), filenameOnly$(fullPath$), info$()
fileExists = val(info$(0, 0)) > 0
end function

'return just the directory path from a full file path
function pathOnly$(fullPath$)
pathOnly$ = fullPath$
while right$(pathOnly$, 1) <> "\" and pathOnly$ <> ""
pathOnly$ = left$(pathOnly$, len(pathOnly$)-1)
wend
end function

'return just the filename from a full file path
function filenameOnly$(fullPath$)
pathLength = len(pathOnly$(fullPath$))
filenameOnly$ = right$(fullPath$, len(fullPath$)-pathLength)
end function

Automatic file backup UI design

Here's what I'm thinking. The back utility GUI will be a simple window with a text area that contains a list of file paths. There will be start and stop buttons, an interval for a timer in seconds, and a field with a destination path.

When the timer is started the backup utility will examine each file that is specified in the text area and collect modification date and time. Later when the timer ticks we will check them again to see if any of them has changed. If even one of the files is different we will back them up as a set.

To perform the backup the program will take the destination path and use it to create a unique folder by adding a number to it. Then it will copy all the files into newly created folder.

There will also be a status area in the window where the user will be kept informed about backup activities.

The configuration for the backup utility will be stored in a file. When the program is started it will be loaded and displayed in the GUI, and there will be a save button to save the configuration back to the configuration file.

More than likely this design will evolve as we actually build the program code.

Here is the beginning of our program, just the GUI code to start.

WindowWidth = 560
WindowHeight = 460
statictext #main, "Files to backup:", 5, 5, 94, 20
texteditor #main.listOfFiles, 5, 26, 530, 95
statictext #main, "Destination folder:", 5, 132, 107, 20
textbox #main.destination, 115, 127, 420, 25
statictext #main, "Backup interval in seconds:", 5, 157, 163, 20
textbox #main.interval, 170, 152, 100, 25
button #main.save,"Save",[save], UL, 495, 152, 42, 25
button #main.start,"Start",[start], UL, 5, 187, 75, 25
button #main.stop,"Stop",[stop], UL, 90, 187, 70, 25
statictext #main, "Backup status log", 5, 217, 106, 20
texteditor #main.statusLog, 5, 237, 530, 160
menu #main, "Edit"
open "Backup Utility" for window as #main
wait

Automatic file backup

I'm inspired by a real world need I have to create utility in Liberty BASIC which will do the following:

1) Periodically examine a list of files in a folder to see if they have changed
2) Make a new folder with a unique name somewhere else to contain the updated files
3) Copy the changed files to the new folder

We can keep a list of paths and files in a file, create a simple gui for maintaining this list and starting and stopping the timer, and for displaying a log of activity.

In our next installment we will write the GUI code.

Projects

I've decided to start some small projects which show how to do various things in Liberty BASIC. This will be a good way to demonstrate how easy programming in BASIC can be, and it will help people to learn specific programming techniques.