Bug? TFPHTTPClient fails on Android when ConnectTimeout<>0
lazarus / 43-Android

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engkin · 2021-06-11 14:54

On Android both in terminal and GUI apps, TFPHTTPClient fails to
connect when ConnectTimeout property has a value bigger than zero.

The following project shows the problem:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i program
test_fphttpclient; {$define UseCThreads}{$mode objfpc}{$H+} uses 
{$IFDEF UNIX}{$IFDEF UseCThreads}  cthreads,  {$ENDIF}{$ENDIF} 
Classes,SysUtils,fphttpclient,opensslsockets,openssl,netdb  { you can
add units after this }; var  c:TFPHTTPClient; 
r:RawByteString='';begin  WriteLn('GetDNSServers:
'+GetDNSServers.ToString);  WriteLn('InitSSLInterface:
'+InitSSLInterface.ToString(TUseBoolStrs.True)); 
WriteLn('IsSSLloaded: '+IsSSLloaded.ToString(TUseBoolStrs.True));  
c:=TFPHTTPClient.Create(nil);  try    c.AllowRedirect:=True;   
c.ConnectTimeout:=0;//<--- Passes    //c.ConnectTimeout:=3000;//<----
Fails    try      r:=c.Get('https://www.google.com');     
WriteLn('Response Length: ',Length(r));    except      on e:exception
do WriteLn(e.ClassName+': '+e.Message);    end;  finally    c.Free; 
end;end. 
Run it using:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i adb push
"$Project()" "/data/local/tmp"adb shell chmod 755
/data/local/tmp/$ProjFile()adb shell
/data/local/tmp/$ProjFile() OR adb push "$Project()" "/data/local/tmp"
&& adb shell chmod 755 /data/local/tmp/$ProjFile() && adb shell
/data/local/tmp/$ProjFile()
When ConnectTimeout>0, it fails with:
QuoteGetDNSServers: 2
InitSSLInterface: True
IsSSLloaded: True
ESocketError: Connect to www.google.com:443 failed.
Tracking the code:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i procedure
TInetSocket.Connect;...  {$ifdef unix}  Err:=ESysEINTR;  While IsError
and (Err in [ESysEINTR, ESysEAGAIN]) do  {$endif}    begin   
IsError:=fpConnect(Handle, @addr, sizeof(addr))<>0;    if IsError
then      Err:=Socketerror;    end;{$IFDEF HAVENONBLOCKING}  if
(ConnectTimeOut>0) then    begin    if IsError and (Err=ErrWouldBlock)
then      begin      TimeOutResult:=CheckSocketConnectTimeout(Handle,
@FDS, @TimeV);      IsError:=(TimeOutResult<>ctrOK);      end;   
SetSocketBlockingMode(Handle, bmBlocking, @FDS);    end;{$ENDIF}  If
Not IsError then    begin    IsError:=Not FHandler.Connect;    if
IsError then      CloseSocket(Handle);    end;  If IsError then    if
TimeoutResult=ctrTimeout then      Raise
ESocketError.Create(seConnectTimeOut, [Format('%s:%d',[FHost,
FPort])])    else      Raise ESocketError.Create(seConnectFailed,
[Format('%s:%d',[FHost, FPort])]);end;
It fails in the call to fpConnect, but the Err is 0!!!
I don't know what that means.

Is it a bug in the way TInetSocket.Connect handles ConnectTimeout?


As a nice outcome, Android is providing openssl libraries for both the
GUI and the terminal apps.


The above test using Laz2.0.10/FPC3.2.0 to cross compile to
Android/ArmV7a

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engkin · 2021-06-13 02:46

Maybe it is not easy for others to test on their devices.

I saw reports indicating a problem in Android 7, my test device. I can
not be sure if the bug is in Android 7, or in TInetSocket.Connect. For
now I changed TInetSocket.Connect to include my case:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i procedure
TInetSocket.Connect;...  if (ConnectTimeOut>0) then    begin    if
IsError and ((Err=ErrWouldBlock) {$ifdef Android}or (Err=0){$endif})
then//<--- is this correct for Android?...
LAMW is not using TFPHTTPClient AFAICT.

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jmpessoa · 2021-06-13 17:05

QuoteLAMW is not using TFPHTTPClient AFAICT.

But, you can use TFPHTTPClient and almost all  FCL (not LCL!) in
LAMW,  just be careful with the paths and the linking process...

This is a great path to be explored!

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engkin · 2021-06-13 17:18

Thank you, jmpessoa.

Can you test this project in LAMW terminal on a real phone?
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i program
test_fphttpclient;         {$define UseCThreads}    {$mode
objfpc}{$H+}         uses      {$IFDEF UNIX}{$IFDEF UseCThreads}     
cthreads,      {$ENDIF}{$ENDIF}     
Classes,SysUtils,fphttpclient,opensslsockets,openssl,netdb      { you
can add units after this };         var      c:TFPHTTPClient;     
r:RawByteString='';    begin      WriteLn('GetDNSServers:
'+GetDNSServers.ToString);      WriteLn('InitSSLInterface:
'+InitSSLInterface.ToString(TUseBoolStrs.True));     
WriteLn('IsSSLloaded: '+IsSSLloaded.ToString(TUseBoolStrs.True));   
     c:=TFPHTTPClient.Create(nil);      try       
c.AllowRedirect:=True;        c.ConnectTimeout:=3000;        try     
   r:=c.Get('https://www.google.com');          WriteLn('Response
Length: ',Length(r));        except          on e:exception do
WriteLn(e.ClassName+': '+e.Message);        end;      finally       
c.Free;      end;    end.

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jmpessoa · 2021-06-13 21:33

My limited test:  (I need update my lazarus/fpc....)

Quote06-13 16:56:34.925 24502-24502/org.lamw.apptfphttpclientdemo1
I/ShowMessage: InitSSLInterface: True
06-13 16:56:34.955 24502-24502/org.lamw.apptfphttpclientdemo1
I/ShowMessage: IsSSLloaded: True
06-13 16:56:34.965 24502-24502/org.lamw.apptfphttpclientdemo1 D/LAMW:
ESocketError: Host name resolution for "www.google.com" failed.

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engkin · 2021-06-14 11:09

Yes, you are having an older bug. Without updating you may be able to
pass this bug by using Google DNS servers:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i begin 
SetLength(DNSServers, 2);  DNSServers[0]:=StrToNetAddr('8.8.8.8'); 
DNSServers[1]:=StrToNetAddr('8.8.4.4');...

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jmpessoa · 2021-06-14 16:38

The same... [Without updating...]
Quote06-14 12:31:37.576 6751-6751/org.lamw.apptfphttpclientdemo1
I/ShowMessage: InitSSLInterface: True
06-14 12:31:37.606 6751-6751/org.lamw.apptfphttpclientdemo1
I/ShowMessage: IsSSLloaded: True
06-14 12:31:47.626 6751-6751/org.lamw.apptfphttpclientdemo1 D/LAMW:
ESocketError:Host name resolution for "www.google.com" failed.

My code:

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i {hint:
Pascal files location: ...\AppTFPHTTPClientDemo1\jni }unit
unit1; {$mode delphi} interface uses  {$IFDEF UNIX}{$IFDEF
UseCThreads}  cthreads,  {$ENDIF}{$ENDIF}   Classes, SysUtils,
AndroidWidget, Laz_And_Controls,  fphttpclient,  httpdefs, 
httpprotocol,  //opensslsockets,  openssl, Sockets,  netdb;  type   {
TAndroidModule1 }   TAndroidModule1 = class(jForm)    jButton1:
jButton;    procedure jButton1Click(Sender: TObject);  private   
{private declarations}  public    {public declarations}  end; var 
AndroidModule1: TAndroidModule1; implementation  {$R *.lfm}   {
TAndroidModule1 } //C:\laz4android2.0.0\fpc\3.0.4\source\packages\fcl-
web\src\base  <--- (-Fu)procedure
TAndroidModule1.jButton1Click(Sender: TObject);var  c:TFPHTTPClient; 
r:RawByteString='';begin    SetLength(DNSServers, 2); 
 DNSServers[0]:=StrToNetAddr('8.8.8.8'); 
 DNSServers[1]:=StrToNetAddr('8.8.4.4');  
 ShowMessage('InitSSLInterface: ' +
InitSSLInterface.ToString(TUseBoolStrs.True)); 
 ShowMessage('IsSSLloaded: ' +    
 IsSSLloaded.ToString(TUseBoolStrs.True));  
c:=TFPHTTPClient.Create(nil);  try    c.AllowRedirect:=True;   
//c.ConnectTimeout:=3000;    try     
r:=c.Get('https://www.google.com');      ShowMessage('Response Length:
'+IntToStr(Length(r))); // NOT CALLED !!!    except      on
e:exception do LogDebug('LAMW',e.ClassName+':'+e.Message);    end; 
finally    c.Free;  end; end; end.

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engkin · 2021-06-14 17:29

I took the relevant files and changed their names so they don't
conflict with the original files in your installation, did some
logging. You can change the procedure in ulog unit if you need to.

Try it with and without -dPossibleFix in the Custom Options.

As the last line when it fails without -dPossibleFix, I expect you to
see:
ESocketError: Connect to www.google.com:443 failed.

With -dPossibleFix it should give you something along:
Response Length: 49123