Node like HTTPServer
lazarus / 38-Networking and Web Programming

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Grahame Grieve · 2025-06-28 21:13

I've been doing a lot of work with Claude writing code in java and
javascript, and so I decided to test Claude out for free pascal, and
it's done a pretty good job. What I asked it to do was write a Node.js
like framework for an HTTP server that would run in either unix or
windows

The outcome is here: https://github.com/HealthIntersections/fhirserver
/tree/master/library/http

I'm wondering whether this is something that other people would find
useful, and I should spin it out into its own space?

btw... why no HTTPS? I would never run my own server native on the web
now - I always run it behind nginx, and let nginx handle basic things
like web security and SSL.

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Gustavo 'Gus' Carreno · 2025-06-28 22:36

Hey Grahame,

I've had a quick look at what you've done and I do like what I see!!
I'm giving it an A+ for effort !! 

Having said that... You've duplicated something that already exists in
Free Pascal.

The fp-web package, in it's latest incarnation, already provides a
router based implementation.

It's no shame to re-invent the wheel when you're trying to learn
stuff!!!
I'm always quite adamant on that!!
But you did re-invent the wheel

Cheers,
Gus

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Gustavo 'Gus' Carreno · 2025-06-28 23:58

Hey Grahame,

I felt I needed to include an example of using the routed version of
fp-web.

Here's a quick example:
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
fpwebserver; {$mode objfpc}{$H+} uses  {$IFDEF UNIX}  cmem, 
cthreads,  BaseUnix,  {$ENDIF}  SysUtils,  fphttpapp,  HTTPDefs, 
httproute; const  cPort = 9191; procedure DefaultRoute(ARequest:
TRequest; AResponse: TResponse);begin  AResponse.Content:=    '<html>'
+    '<head>' +    '<title>FP Web Server</title>' +    '</head>' +   
'<body>' +    '<ul>' +    '<li><a href="/">Default</a></li>' +   
'<li><a href="/about">About</a></li>' +    '</ul>' +    '<h1>FP Web
Server</h1>' +    '<p>Default Route</>' +    '</body>' +    '</html>' 
;end; procedure AboutRoute(ARequest: TRequest; AResponse:
TResponse);begin  AResponse.Content:=    '<html>' +    '<head>' +   
'<title>FP Web Server: About</title>' +    '</head>' +    '<body>' + 
 '<ul>' +    '<li><a href="/">Default</a></li>' +    '<li><a
href="/about">About</a></li>' +    '</ul>' +    '<h1>FP Web Server:
About</h1>' +    '<p>About Route</>' +    '</body>' +    '</html>' 
;end; procedure RegisterRoutes;begin  // Responds to any method 
HTTPRouter.RegisterRoute('/', rmAll, @DefaultRoute, True);  //
Responds only to the GET method  HTTPRouter.RegisterRoute('/about',
rmGet, @AboutRoute);end; {$IFDEF UNIX}procedure CleanUp(ASignal:
LongInt); cdecl;begin  WriteLn;  WriteLn('Cleaning'); 
Application.Terminate;  Halt(0);end;{$ENDIF UNIX} begin 
RegisterRoutes;   {$IFDEF UNIX}  if FpSignal(SIGINT, @CleanUp) =
signalhandler(SIG_ERR) then begin    WriteLn({$I %FILE%}, {$I %LINE%},
Format('Failed to install signal error: %d', [ fpGetErrno ]));   
Halt(1);  end;  if FpSignal(SIGKILL, @CleanUp) =
signalhandler(SIG_ERR) then begin    WriteLn({$I %FILE%}, {$I %LINE%},
Format('Failed to install signal error: %d', [ fpGetErrno ]));   
Halt(1);  end;  {$ENDIF UNIX}   Application.Title:= 'fp-web-
httpserver';  Application.Port:= cPort;  Application.Threaded:= True; 
Application.Initialize;  WriteLn(Format('Serving on
http://localhost:%d', [cPort]));  Application.Run;end. 
Hope that helps compare your effort and what comes with Free Pascal.

Cheers,
Gus

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Grahame Grieve · 2025-06-29 05:35

> But you did re-invent the wheel

interesting - thanks. I did not know about FPWeb - or at least, I
looked long ago and thought it wasn't what it is now, at least

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Gustavo 'Gus' Carreno · 2025-06-29 06:36

Hey Grahame,

Quote from: Grahame Grieve on June 29, 2025, 07:35:23 aminteresting -
thanks.

You're more than welcome !!

Quote from: Grahame Grieve on June 29, 2025, 07:35:23 amI did not know
about FPWeb - or at least, I looked long ago and thought it wasn't
what it is now, at least

And you are correct. In the past we had to deal with WEB Modules and
all that Jazz.
You can still do that, cuz backwards compatibility is a must.

But you can also do it routed, like on the code I provided!!

I'm guessing you haven't looked at it for quite a while

Cheers,
Gus

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Grahame Grieve · 2025-06-29 12:18

The event signature is

Procedure (ARequest: TRequest; AResponse: TResponse) of object

how do I get the client IP?

Also, it looks like the request object parses the body and the URL -
what happens if it's a POST and there are parameters in the both the
URL and the body?

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Gustavo 'Gus' Carreno · 2025-06-30 07:53

Hey Grahame,

Quote from: Grahame Grieve on June 29, 2025, 02:18:48 pmThe event
signature is

Procedure (ARequest: TRequest; AResponse: TResponse) of object

how do I get the client IP?

I've never explored that, but I'm guessing that the ARequest variable
will have something in there that will help.

Looking at 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   {
THTTPHeader }   THTTPHeader = class(TObject)  {...}  public  {...}   
Property RemoteAddress : String Index Ord(hvRemoteAddress) read
GetHTTPVariable Write SetHTTPVariable;    Property RemoteAddr : String
Index Ord(hvRemoteAddress) read GetHTTPVariable Write SetHTTPVariable;
// Alias, Delphi-compat    Property RemoteHost : String Index
Ord(hvRemoteHost) read  GetHTTPVariable Write SetHTTPVariable;  {...} 
end;  { TRequest }   TRequest = class(THttpHeader)  {...}  end;
I would investigate the above properties.

Quote from: Grahame Grieve on June 29, 2025, 02:18:48 pmAlso, it looks
like the request object parses the body and the URL - what happens if
it's a POST and there are parameters in the both the URL and the body?

There's a good wiki post about fp-web:
https://wiki.lazarus.freepascal.org/fpWeb_Tutorial

If you navigate to this section you'll find that those are in
ARequest.QueryFields and .ARequest.ContentFields

These are all good questions. And the programmers that implement it
this way were probably rather thorough. One just has to dig into the
code to try and get some answers when the wiki is short.

Cheers,
Gus