{"id":7526,"date":"2021-10-27T15:02:43","date_gmt":"2021-10-27T15:02:43","guid":{"rendered":"https:\/\/max-drake.cc\/?p=7526"},"modified":"2021-10-30T10:48:41","modified_gmt":"2021-10-30T10:48:41","slug":"install-program-files-run-for-set-duration-in-ahk","status":"publish","type":"post","link":"https:\/\/max-drake.cc\/?p=7526","title":{"rendered":"Install program & run for Trial Period for Try before you buy with AHK"},"content":{"rendered":"\n

Previous articles have discussed counter uses for a program and a license check to run. I’m interested in duration, as in, the software will run for 30 days then stop. So how to do? <\/p>\n\n\n\n

On installing a program it has to go and get today’s date and secrete that somewhere. Then each subsequent time the program is run it needs to get the date NOW() and compare it with the start date, if its within bounds then it will allow program to run, if not, it won’t run the program. <\/p>\n\n\n\n

So its really calculating basic subtraction but with dates. <\/p>\n\n\n\n

Jack Dunnings forum post Function Calculating Timespan in Years, Months, and Days<\/strong><\/a> talks about some of the issues. <\/p>\n\n\n\n

In AHK docs there are a couple of topics about time, and comparing time and there is an EnvAdd<\/strong> function that can add\/subract time from date-time. <\/p>\n\n\n\n

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Jack also has this article The HowLongYearsMonthsDays.ahk Script Calculates Time Spans\u2014This New DateCalc() Function Yields New Dates Based on Adding or Subtracting Years, Months, or Days<\/a><\/strong> which raises important issues about year and month variances, but if the program runs for 31 days or 29 its not a massive issue. So there is no need for a high degree of accuracy. If the EnvAdd<\/strong> function is the inbuilt AUTOHOTKEY function then I should give that a crack first. <\/p>\n\n\n\n

Process<\/h3>\n\n\n\n

Get start date<\/strong><\/p>\n\n\n\n

So we need to first grab the time at install, put this somewhere in a readable file (.ini files key\/value pairs are handy for this) and then do something to stop that file being overwritten. <\/p>\n\n\n\n

A couple of things come to mind. 1\/ Rename the file after putting date in it on first run of program, so 2nd time it runs, it looks for the original file and if not there then it does nothing, or 2\/ have a counter in the .ini file set initially at 0, so first time it runs, it checks number, if <1 then write date, otherwise do nothing. <\/p>\n\n\n\n

Calculate time period End date<\/strong><\/p>\n\n\n\n

So we now have original date, we now need to calculate an end date, be it 1, 5, 10, 30 days in the future. <\/p>\n\n\n\n

This can be calculated and sent to the .ini file at the same time as start date is done, we only need to do it once inside the if <1 check above. <\/p>\n\n\n\n

Get current Date\/Time & compare with End date<\/strong><\/p>\n\n\n\n

So after that we just need to get current date and time and put it in a variable and compare that with the End date that we pull from the ini file. <\/p>\n\n\n\n

If End Date – Current Date = ? Positive – run program, negative – trial time ended and you can choose to stop using program or purchase a License. <\/p>\n\n\n\n

License install\/request email. <\/strong><\/p>\n\n\n\n

This process is the same as per this article How to protect final program when distributing? License keys?<\/strong><\/a> where code is available. <\/p>\n\n\n\n

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Unix Epoch time <\/h3>\n\n\n\n

Unix time<\/a><\/strong> (UT) is just a single number, so you could calculate a date-time in the future and then set that number and keep on gathering current date time and converting it into Unix time and seeing if its less than the specified final number. <\/p>\n\n\n\n

An interesting event happening in 2038 with 32 bit computers where the Binary date resets, read Y2k38 Epochalypse<\/strong><\/a> and video :<\/p>\n\n\n\n

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