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How to: Limit instances of your app being run on a network (ie: 3 user license) |
Wed, May 10 2006 6:05 AM | Permanent Link |
Graham Wood | I probably got this from here in the first place but I can't remember, so in case I
didn't, here's some damn handy code. Great for limiting the instances of your app being run on a network. Would work just as effectively for File Server and Client/Server, so long as the exe is being run from a shared server folder. It gives your users incentive to purchase extra licenses. Only issue is that if one user is 'goofy' enough to run extra instances of your exe on their machine, they'll be considered as extra users. You can get around this by educating your users, or by putting in instance limiting code. Here's the handy stuff: {** Function to count the number of users on a given EXE } unit u_LimitUsers; interface uses Messages, SysUtils, Windows; {** Function to count the number of users on a given EXE | Adds the user and returns his user number, or -1 if all slots are taken. You don't have to remove him. That will happen automatically when he exits the program. fn is a legal file name in an existing directory that will control access. The file need not exist, or have any contents. max is the Maximum number of users allowed. } function AddUser(fn: string; max: integer): integer; var FileMustExist: boolean; BIGNUMBER: dword; implementation var h: integer; function AddUser(fn: string; max: integer): integer; var n, i: integer; FoundOne: boolean; begin Result := -1; // The magic file must be open for this to work. // if it doesn't exist, create it. Then open it, // making sure access is shared so other instances of // the app can also open it. if h <= 0 then begin if not FileExists(fn) then begin if FileMustExist then begin exit; end; begin h := FileCreate(fn); FileClose(h); end; end; h := FileOpen(fn, fmShareDenyNone); if h <= 0 then begin exit; end; end; n := 0; FoundOne := False; for i := 0 to max - 1 do begin if LockFile(h, i{ BIGNUMBER}, 0, 1, 0) then begin if not FoundOne then begin FoundOne := True; end else begin UnlockFile(h, i{ BIGNUMBER}, 0, 1, 0); end; // continue to loop after finding a slot, to count users. // Just be sure to unlock the bytes we locked solely // for counting purposes. end else begin Inc(n); end; // Current user count is the number of bytes we can't lock. end; if FoundOne then begin Result := n; end{ 1}; end; initialization h := -1; FileMustExist := False; BIGNUMBER := 0; end. USE THE ABOVE UNIT LIKE THIS: ___________________________________________________________________________________ var iUserCount: Integer; sTheAppPath: String; begin sTheAppPath := ExtractFilePath(Application.ExeName); iUserCount := 3; // 3 user license as an example, usually we set it up with $IF DEFS; if not (iUserCount = 0) then begin // Check for license conditions. if (AddUser(TheAppPath + 'your_app.lic', iUserCount) = -1) then begin // Exceeded the user limit. MessageDlg('There are too many people currently logged in to this program.' + #13 + #10 + 'You have a ' + IntToStr(iUserCount) + ' user license and the limit has been exceeded.' + #13 + #10 + #13 + #10 + 'This program will now close.', mtInformation, [mbOK], 0); end else begin // Logged on within the limit. Close; end; end else begin // Unlimited user. Close; end; end; ___________________________________________________________________________________ |
Wed, May 10 2006 11:25 AM | Permanent Link |
Jon Lloyd Duerdoth | and into "Knowledgebase" it goes...
thanks Graham... thanks Steve Jon Graham Wood wrote: > I probably got this from here in the first place but I can't remember, so in case I > didn't, here's some damn handy code. > Great for limiting the instances of your app being run on a network. Would work just as > effectively for File Server and Client/Server, so long as the exe is being run from a > shared server folder. It gives your users incentive to purchase extra licenses. > > Only issue is that if one user is 'goofy' enough to run extra instances of your exe on > their machine, they'll be considered as extra users. You can get around this by educating > your users, or by putting in instance limiting code. > > > Here's the handy stuff: > > > {** Function to count the number of users on a given EXE } > > unit u_LimitUsers; > > interface > > uses > Messages, > SysUtils, > Windows; > > {** Function to count the number of users on a given EXE | > Adds the user and returns his user number, or -1 if all > slots are taken. You don't have to remove him. That will > happen automatically when he exits the program. > > fn is a legal file name in an existing directory that will > control access. The file need not exist, or have any > contents. > > max is the Maximum number of users allowed. > } > > function AddUser(fn: string; max: integer): integer; > > var > FileMustExist: boolean; > BIGNUMBER: dword; > > implementation > > var > h: integer; > > function AddUser(fn: string; max: integer): integer; > var > n, i: integer; > FoundOne: boolean; > begin > Result := -1; > > // The magic file must be open for this to work. > // if it doesn't exist, create it. Then open it, > // making sure access is shared so other instances of > // the app can also open it. > > if h <= 0 then > begin > if not FileExists(fn) then > begin > if FileMustExist then > begin > exit; > end; > begin > h := FileCreate(fn); > FileClose(h); > end; > end; > h := FileOpen(fn, fmShareDenyNone); > if h <= 0 then > begin > exit; > end; > end; > > n := 0; > FoundOne := False; > > for i := 0 to max - 1 do > begin > if LockFile(h, i{ BIGNUMBER}, 0, 1, 0) then > begin > if not FoundOne then > begin > FoundOne := True; > end > else > begin > UnlockFile(h, i{ BIGNUMBER}, 0, 1, 0); > end; > // continue to loop after finding a slot, to count users. > // Just be sure to unlock the bytes we locked solely > // for counting purposes. > end > else > begin > Inc(n); > end; > // Current user count is the number of bytes we can't lock. > end; > > if FoundOne then > begin > Result := n; > end{ 1}; > end; > > initialization > h := -1; > FileMustExist := False; > BIGNUMBER := 0; > end. > > > USE THE ABOVE UNIT LIKE THIS: > ___________________________________________________________________________________ > var > iUserCount: Integer; > sTheAppPath: String; > begin > sTheAppPath := ExtractFilePath(Application.ExeName); > iUserCount := 3; // 3 user license as an example, usually we set it up with $IF DEFS; > > if not (iUserCount = 0) then > begin > // Check for license conditions. > if (AddUser(TheAppPath + 'your_app.lic', iUserCount) = -1) then > begin > // Exceeded the user limit. > MessageDlg('There are too many people currently logged in to this program.' + > #13 + #10 + 'You have a ' + IntToStr(iUserCount) + > ' user license and the limit has been exceeded.' + > #13 + #10 + #13 + #10 + 'This program will now close.', mtInformation, [mbOK], 0); > end > else > begin > // Logged on within the limit. > Close; > end; > end > else > begin > // Unlimited user. > Close; > end; > end; > ___________________________________________________________________________________ > > > > |
Wed, May 10 2006 5:21 PM | Permanent Link |
Steve Forbes Team Elevate | Hi Jon,
Nice tip Graham! thanks. And thanks for the eplug, Jon <bg> -- Best regards Steve "Jon Lloyd Duerdoth" <jld@welshdragoncomputing.ca> wrote in message news:0D03BBB0-34AC-462B-96DF-54AA11EB0A8A@news.elevatesoft.com... > and into "Knowledgebase" it goes... > thanks Graham... thanks Steve |
Wed, May 10 2006 8:57 PM | Permanent Link |
Jon Lloyd Duerdoth | Well (of course) I should have mentioned the
Knowledgebase web site http://www.ozmosys.net.au/ while I was at it, seeing as Steve would not want to do that himself. BTW: I am just a happy user and not associated in anyway with ozmosys. Steve Forbes wrote: > Hi Jon, > > Nice tip Graham! thanks. > > And thanks for the eplug, Jon <bg> |
Wed, May 10 2006 9:20 PM | Permanent Link |
"Walter Matte" | It had been loaded into my KnowledgeBase too!!
TY Graham and .... Steve. Walter "Jon Lloyd Duerdoth" <jld@welshdragoncomputing.ca> wrote in message news:26E05270-DA27-438D-A838-6766ABEB9A81@news.elevatesoft.com... > Well (of course) I should have mentioned the > Knowledgebase web site > http://www.ozmosys.net.au/ > while I was at it, seeing as Steve would not want to > do that himself. > > BTW: I am just a happy user and not associated in anyway > with ozmosys. > > Steve Forbes wrote: >> Hi Jon, >> >> Nice tip Graham! thanks. >> >> And thanks for the eplug, Jon <bg> |
Thu, May 11 2006 8:09 PM | Permanent Link |
"Norman W. Clark [Clark-Tech Inc.]" | Like most of you I assume, Knowledgebase is pinned to my Start button - and
always handy there to drop in a hint. Sort of like my own private Google. .... Now, where did I put that code snippet? Thank you Steve. -- .... Norm Norman W. Clark, Clark-Tech Inc. nclark@clark-tech.com www.clark-tech.com www.smbproducts.com "Jon Lloyd Duerdoth" <jld@welshdragoncomputing.ca> wrote in message news:0D03BBB0-34AC-462B-96DF-54AA11EB0A8A@news.elevatesoft.com... > and into "Knowledgebase" it goes... > thanks Graham... thanks Steve > > Jon > > Graham Wood wrote: >> I probably got this from here in the first place but I can't remember, so >> in case I >> didn't, here's some damn handy code. Great for limiting the instances of >> your app being run on a network. Would work just as >> effectively for File Server and Client/Server, so long as the exe is being >> run from a >> shared server folder. It gives your users incentive to purchase extra >> licenses. >> >> Only issue is that if one user is 'goofy' enough to run extra instances of >> your exe on >> their machine, they'll be considered as extra users. You can get around this >> by educating >> your users, or by putting in instance limiting code. >> >> >> Here's the handy stuff: >> >> >> {** Function to count the number of users on a given EXE } >> >> unit u_LimitUsers; >> >> interface >> >> uses >> Messages, >> SysUtils, >> Windows; >> >> {** Function to count the number of users on a given EXE | >> Adds the user and returns his user number, or -1 if all >> slots are taken. You don't have to remove him. That will >> happen automatically when he exits the program. >> >> fn is a legal file name in an existing directory that will >> control access. The file need not exist, or have any >> contents. >> >> max is the Maximum number of users allowed. >> } >> >> function AddUser(fn: string; max: integer): integer; >> >> var >> FileMustExist: boolean; >> BIGNUMBER: dword; >> >> implementation >> >> var >> h: integer; >> >> function AddUser(fn: string; max: integer): integer; >> var >> n, i: integer; >> FoundOne: boolean; >> begin >> Result := -1; >> >> // The magic file must be open for this to work. >> // if it doesn't exist, create it. Then open it, >> // making sure access is shared so other instances of >> // the app can also open it. >> >> if h <= 0 then >> begin >> if not FileExists(fn) then >> begin >> if FileMustExist then >> begin >> exit; >> end; >> begin >> h := FileCreate(fn); >> FileClose(h); >> end; >> end; >> h := FileOpen(fn, fmShareDenyNone); >> if h <= 0 then >> begin >> exit; >> end; >> end; >> >> n := 0; >> FoundOne := False; >> >> for i := 0 to max - 1 do >> begin >> if LockFile(h, i{ BIGNUMBER}, 0, 1, 0) then >> begin >> if not FoundOne then >> begin >> FoundOne := True; >> end >> else >> begin >> UnlockFile(h, i{ BIGNUMBER}, 0, 1, 0); >> end; >> // continue to loop after finding a slot, to count users. >> // Just be sure to unlock the bytes we locked solely >> // for counting purposes. >> end >> else >> begin >> Inc(n); >> end; >> // Current user count is the number of bytes we can't lock. >> end; >> >> if FoundOne then >> begin >> Result := n; >> end{ 1}; >> end; >> >> initialization >> h := -1; >> FileMustExist := False; >> BIGNUMBER := 0; >> end. >> >> >> USE THE ABOVE UNIT LIKE THIS: >> ___________________________________________________________________________________ >> var >> iUserCount: Integer; >> sTheAppPath: String; >> begin >> sTheAppPath := ExtractFilePath(Application.ExeName); >> iUserCount := 3; // 3 user license as an example, usually we set it up with >> $IF DEFS; >> >> if not (iUserCount = 0) then >> begin >> // Check for license conditions. >> if (AddUser(TheAppPath + 'your_app.lic', iUserCount) = -1) then >> begin >> // Exceeded the user limit. >> MessageDlg('There are too many people currently logged in to this >> program.' + >> #13 + #10 + 'You have a ' + IntToStr(iUserCount) + >> ' user license and the limit has been exceeded.' + >> #13 + #10 + #13 + #10 + 'This program will now close.', >> mtInformation, [mbOK], 0); >> end >> else >> begin >> // Logged on within the limit. >> Close; >> end; >> end >> else >> begin >> // Unlimited user. >> Close; >> end; >> end; >> ___________________________________________________________________________________ >> >> >> |
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