[SOLVED] duplicate route doesn't trigger exception

[Чебурашка]

Hello,
The following code does not show any exception here, but I would expect this to happen.
Any ideas?

me@debian:~/Documents/dev$ fpc -version
[0.004] Free Pascal Compiler version 3.0.4+dfsg-22 [2019/01/24] for x86_64
[0.004] Copyright (c) 1993-2017 by Florian Klaempfl and others

Code: Pascal  [Select][+][-]

1. program project1;
2.  
3.  
4. uses
5.  
6.   Classes, SysUtils
7.  
8.   , HTTPDefs
9.   , httproute;
10.  
11. procedure PostCallback1(req: TRequest; res: TResponse);
12. begin
13.   // Actions on post event
14. end;
15. procedure PostCallback2(req: TRequest; res: TResponse);
16. begin
17.   // Actions on post event
18. end;
19.  
20. begin
21.   try
22.     HTTPRouter.RegisterRoute('/post' , TRouteMethod.rmPost, @PostCallback1, False);
23.     HTTPRouter.RegisterRoute('/post' , TRouteMethod.rmPost, @PostCallback2, False);
24.   except
25.     on E: Exception do begin
26.       Writeln(E.Message);
27.     end;
28.   end;
29. end.
30.  

Thank you

[Thaddy]

Empty procs are removed by default, so try -O-

[Чебурашка]

Same.

Anyway the problem is in RegisterRoute being called twice with same address/routemethod not in the fact that the callbacks are wiped because of optimization.

Btw does really optimization wipe out a method that is referenced?

Code: Pascal  [Select][+][-]

1.  
2. program project2;
3.  
4.  
5. uses
6.  
7.   Classes, SysUtils
8.  
9.   , HTTPDefs
10.   , httproute;
11.  
12. procedure PostCallback1(req: TRequest; res: TResponse);
13. begin
14.   Writeln('hello');
15. end;
16. procedure PostCallback2(req: TRequest; res: TResponse);
17. begin
18.   Writeln('world');
19. end;
20.  
21. begin
22.   try
23.     HTTPRouter.RegisterRoute('/post' , TRouteMethod.rmPost, @PostCallback1, False);
24.     HTTPRouter.RegisterRoute('/post' , TRouteMethod.rmPost, @PostCallback2, False);
25.   except
26.     on E: Exception do begin
27.       Writeln(E.Message);
28.     end;
29.   end;
30. end.
31.  
32.  

[irawan]

PostCallback2 replaces PostCallback1. so there is no exception occured.

[Чебурашка]

So HTTPRouter is intended to be callable twice with the same couple ('/path', rmPost)?

Then what is the meaning of the inner method CheckDuplicates? For what I understand such a method should trigger a exception when '/path', rmPost already exists in the routes set.

Apparently I am wrong can some one explain?

Code: Pascal  [Select][+][-]

1. function THTTPRouter.CreateHTTPRoute(AClass : THTTPRouteClass; const APattern: String;AMethod: TRouteMethod; IsDefault: Boolean) : THTTPRoute;
2.  
3. begin
4.   CheckDuplicate(APattern,AMethod,isDefault);
5.   Result:=AClass.Create(FRoutes);
6.   With Result do
7.     begin
8.     URLPattern:=APattern;
9.     Default:=IsDefault;
10.     Method:=AMethod;
11.     end;
12. end;
13.  
14. procedure THTTPRouter.CheckDuplicate(APattern: String; AMethod: TRouteMethod;
15.   isDefault: Boolean);
16. Var
17.   I,DI : Integer;
18.   R : THTTPRoute;
19.  
20. begin
21.   DI:=-1;
22.   For I:=0 to FRoutes.Count-1 do
23.     begin
24.     R:=FRoutes[I];
25.     if R.Default then
26.       DI:=I;
27.     if R.Matches(APattern,AMethod) then
28.       Raise EHTTPRoute.CreateFmt(EDuplicateRoute,[APattern,RouteMethodToString(AMethod)]);
29.     end;
30.   if isDefault and (DI<>-1) then
31.     Raise EHTTPRoute.CreateFmt(EDuplicateDefaultRoute,[APattern,RouteMethodToString(AMethod)]);
32. end;
33.  
34. function THTTPRoute.Matches(const APattern: String; AMethod: TRouteMethod
35.   ): Boolean;
36. begin
37.   Result:=(CompareText(URLPattern,APattern)=0)
38.           and ((Method=rmAll) or (AMethod=Method))
39. end;
40.  
41.  

[PascalDragon]

Empty procs are removed by default, so try -O-

Not if they are used (either by calling them or referencing them), which is the case here.

[Чебурашка]

Btw does really optimization wipe out a method that is referenced?

Thanks PascalDragon

[engkin]

So HTTPRouter is intended to be callable twice with the same couple ('/path', rmPost)?

Then what is the meaning of the inner method CheckDuplicates? For what I understand such a method should trigger a exception when '/path', rmPost already exists in the routes set.

Apparently I am wrong can some one explain?

Code: Pascal  [Select][+][-]

1. function THTTPRouter.CreateHTTPRoute(AClass : THTTPRouteClass; const APattern: String;AMethod: TRouteMethod; IsDefault: Boolean) : THTTPRoute;
2.  
3. begin
4.   CheckDuplicate(APattern,AMethod,isDefault);
5.   Result:=AClass.Create(FRoutes);
6.   With Result do
7.     begin
8.     URLPattern:=APattern;
9.     Default:=IsDefault;
10.     Method:=AMethod;
11.     end;
12. end;
13.  
14. procedure THTTPRouter.CheckDuplicate(APattern: String; AMethod: TRouteMethod;
15.   isDefault: Boolean);
16. Var
17.   I,DI : Integer;
18.   R : THTTPRoute;
19.  
20. begin
21.   DI:=-1;
22.   For I:=0 to FRoutes.Count-1 do
23.     begin
24.     R:=FRoutes[I];
25.     if R.Default then
26.       DI:=I;
27.     if R.Matches(APattern,AMethod) then
28.       Raise EHTTPRoute.CreateFmt(EDuplicateRoute,[APattern,RouteMethodToString(AMethod)]);
29.     end;
30.   if isDefault and (DI<>-1) then
31.     Raise EHTTPRoute.CreateFmt(EDuplicateDefaultRoute,[APattern,RouteMethodToString(AMethod)]);
32. end;
33.  
34. function THTTPRoute.Matches(const APattern: String; AMethod: TRouteMethod
35.   ): Boolean;
36. begin
37.   Result:=(CompareText(URLPattern,APattern)=0)
38.           and ((Method=rmAll) or (AMethod=Method))
39. end;
40.  
41.  

You are not wrong. The class changes the first pattern from '/post' to 'post/' before saving it. Later when it checks for double, it compares the second pattern with the modified pattern. Of course they don't match.

The change happens inside THTTPRoute.SetURLPattern:

Code: Pascal  [Select][+][-]

1. procedure THTTPRoute.SetURLPattern(AValue: String);
2.  
3. Var
4.   V : String;
5.  
6. begin
7.   V:=IncludeHTTPPathDelimiter(AValue);
8.   if (V<>'') and (V<>'/') and (V[1]='/') then
9.     Delete(V,1,1);
10.   if FURLPattern=V then Exit;
11.   FURLPattern:=V;
12. end;

To trigger the exception, change your code to:

Code: Pascal  [Select][+][-]

1.     HTTPRouter.RegisterRoute('post/' , TRouteMethod.rmPost, @PostCallback1, False);
2.     HTTPRouter.RegisterRoute('post/' , TRouteMethod.rmPost, @PostCallback2, False);

[PascalDragon]

You are not wrong. The class changes the first pattern from '/post' to 'post/' before saving it. Later when it checks for double, it compares the second pattern with the modified pattern. Of course they don't match.

That should be reported as a bug then.

[Чебурашка]

Probably is a small bug then...

in page

https://wiki.freepascal.org/fphttpserver

thers an example telling

Code: Pascal  [Select][+][-]

1. [...]
2.   HTTPRouter.registerRoute('/', @route1);
3.   HTTPRouter.registerRoute('/2', @route2);
4. [...]
5.  

so people thinks / should be normally placed at beginning of path as I did (just taking there code as satring point).

[Чебурашка]

That should be reported as a bug then.

Reported.

[Чебурашка]

https://gitlab.com/freepascal.org/fpc/source/-/commit/7b62186b9c9efddcb0114df889d5830d8634b0bd

by Michael Van Canneyt