idHTTPServer problems
lazarus / 38-Networking and Web Programming

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stargate · 2016-08-25 13:19

Hello,

I am porting an app from Delphi/Windows to Lazarus/Ubuntu. I am having
difficulty with idhttpserver. Initially I couldn't get it to start on
any port (always threw address in use error). Then I added
-dUseCThreads flag to the compiler. Now there is no error but it also
doesn't listen on any set port. This is 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
TForm1.ServerCommandGet(AContext: TIdContext;  ARequestInfo:
TIdHTTPRequestInfo; AResponseInfo: TIdHTTPResponseInfo);begin 
AResponseInfo.ContentText := 'it works!'; 
AResponseInfo.WriteContent;end; procedure TForm1.FormCreate(Sender:
TObject);var Binding: TIdSocketHandle;begin  label1.caption :=
released;  idhttpserver1 := tidhttpserver.create; 
idhttpserver1.OnCommandGet:= @servercommandget;  Binding :=
idhttpserver1.Bindings.Add;  Binding.IPVersion := Id_IPv4;  Binding.IP
:= '127.0.0.1';  Binding.Port := 80;  idhttpserver1.Active :=
True;end;
Id_IPv4 comes as unknown identifier and had to comment that line out
to make it compile, but still it doesn't listen to any port. In this
scenario I already have apache running on port 80 - I was checking to
see that at least it should throw an error about port in use - but the
app runs just fine with no errors.

Any clues?

Thank you.

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balazsszekely · 2016-08-25 13:57

Hi stargate,

Please check out the following thread:
http://forum.lazarus.freepascal.org/index.php/topic,32771.0.html
You will find a nice example implemented by @JD.

regards,
GetMem

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marcov · 2016-08-25 19:05

(afaik on *nix you must be root to bind ports under 1024)

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stargate · 2016-08-26 08:05

Thank you guys for replies,

GetMem, I have already seen that thread and my code is similar. I am
not even concerned at this point by getting an answer on the request -
I just want to see the port opened.

marcov, I am running lazarus-ide as root and I also tried opening
ports higher than 1024.

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JD · 2016-08-26 08:47

@stargate

Please see this post on Stackoverflow. It was my initial try with Indy
on Linux Mint (using TCPServer and Telnet but it should still be OK
since you are try to bind a port to your application).

The problem was with the text encoding.

http://stackoverflow.com/questions/7767616/indy-10-tcpserver-does-not-
communicate-with-connected-clients-on-linux

JD

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stargate · 2016-08-26 09:02

Ok... problem solved but I don't understand how. I have started a new
project with the exact same code. Now it works. Maybe I tinkered too
much with the compiler options to add -dUseCThreads option. I have
added to Project Options - Compiler Options - Custom Options. Now it
seems to work.

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Remy Lebeau · 2016-08-30 01:10

FYI, Id_IPv4 is defined in the IdGlobal unit:

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  
TIdIPVersion = (Id_IPv4, Id_IPv6);
Indy defaults to IPv4 unless you edit IdCompilerDefines.inc to define
IdIPv6 instead of IdIPv4.

As for the code you showed, there are some other problems:

Your OnCommandGet handler is not assigning the
AResponseInfo.ResponseNo or AResponseInfo.ContentType properties.  And
it does not need to call AResponseInfo.WriteContent manually, the
content is written when the handler exits.

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
TForm1.ServerCommandGet(AContext: TIdContext; ARequestInfo:
TIdHTTPRequestInfo; AResponseInfo: TIdHTTPResponseInfo);begin 
AResponseInfo.ResponseNo := 200;  AResponseInfo.ContentType :=
'text/plain';  AResponseInfo.ContentText := 'it works!';end;
And you are leaking the TIdHTTPServer object, as you do not assign an
Owner to it, or Free it in the form's OnDestroy event.

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  
idhttpserver1 := TIdHTTPServer.Create(Self);
Or:

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  
idhttpserver1 := TIdHTTPServer.Create;  ...  idhttpserver1.Free;