Best way connecting to a server
lazarus / 38-Networking and Web Programming

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GannTrader · 2015-08-03 10:38

Hi

I need to connect to a server and wonder what is the best way of doing
this.
At the moment im using unit sockets with fpsocket, fpconnect and so
on.

I wonder if there is a more efficient way to connect to a server or if
using sockets still is the best and fastest way to connect to a
server?

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Graeme · 2015-08-03 11:13

What does your server do?

Existing communication protocols have already been implement via the
likes of the Indy or Synapse components - both free and open source.
For a higher level, projects like tiOPF has a client/server and 3-tier
implementation where you can save or load objects or list of objects
with very little effort. All open source too.

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Thaddy · 2015-08-03 11:27

These higher level libraries are more convenient for the programmer,
yes, but both - especially Indy! with its completely inapt use of
exceptions for all and nothing, synapse less so - have a throughput
penalty.
If I understand your question it is: what gives me best performance?
In that case, YES, sockets give you the best performance, especially
near real-time performance if you know what you are doing. There
aren't really any alternatives to sockets. All high level libs also
use them. So from a throughput perspective: yes, sockets are still the
way to go.

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GannTrader · 2015-08-03 11:29

I dont have a server. I want to connect to a server. My program is a
client.

I have tested Indy but when using readln to read what the server sends
it dont funktion that well.
Readln in other words contain bugs.
Using sockets i dont get those errors i get with readln.

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GannTrader · 2015-08-03 11:30

Quote from: Thaddy on August 03, 2015, 01:27:57 pmThese higher level
libraries are more convenient for the programmer, yes, but both -
especially Indy! with its completely inapt use of exceptions for all
and nothing, synapse less so - have a throughput penalty.
If I understand your question it is: what gives me best performance?
In that case, YES, sockets give you the best performance, especially
near real-time performance if you know what you are doing. There
aren't really any alternatives to sockets. All high level libs also
use them. So from a throughput perspective: yes, sockets are still the
way to go.
I thought so just wondered if there were any newer/better way.

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Graeme · 2015-08-06 09:00

Quote from: GannTrader on August 03, 2015, 01:29:31 pmI have tested
Indy but when using readln to read what the server sends it dont
funktion that well.
Readln in other words contain bugs.
Or maybe your usage of it is wrong? I have used Indy for years under
Delphi and FPC - using many of the existing protocols supplied. They
tend to work very well.

Have you asked this question in the Indy support lists?

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derek.john.evans · 2015-08-06 10:06

Quote from: Graeme on August 06, 2015, 11:00:31 amQuote from:
GannTrader on August 03, 2015, 01:29:31 pmI have tested Indy but when
using readln to read what the server sends it dont funktion that well.
Readln in other words contain bugs.
Or maybe your usage of it is wrong? I have used Indy for years under
Delphi and FPC - using many of the existing protocols supplied. They
tend to work very well.

Major Ditto! Indy all the way! Used it for at least 12 years since
Delphi 7. Used it in C# apps, Linux (Kylix) and Lazarus. Just forget
about trying to "install" it. Its not required or recommend IMHO. Just
use the unit name for the client/server you want and create components
as need be. Most of the time I found I inherited from a Indy class
anyway and overrided methods.

Just my 2 cents.

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GannTrader · 2015-08-10 18:55

Im not saying that Indy is buggy but i am saying that the funktion
ReadLn is.
It happens that ReadLn missis what the server sends, very rare but it
happends from time to time.
Since i change to unit Sockets and using fprecv to catch what the
server sends such missis has never happend.
Below is the code i used when using ReadLn, i connected first.
I didnt change any other code when going from ReadLn to fprecv and
that indicates to me that theres something wrong with ReadLn.
I dont remember if the thread locked on the ReadLn row or if it just
missed a string send by the server.

procedure Somethread.Execute;
var message:string;
begin
while not terminated do
   begin
   message:=TCPClient.IOHandler.ReadLn;
   //Do something with message;
   end;
end;