Get a web page content without freeze in lazarus/freepsacal
lazarus / 38-Networking and Web Programming

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ojZim · 2013-01-26 19:11

Hello 
I have a problem!
I added synapse componet to my project, and it's working very good: 
Code: [Select]uses httpsend;

function GetWebPageContent(const Url: string): String;
var fs: TStringList; HTTP: THTTPSend;
begin
   fs := TStringList.Create;
   HTTP := THTTPSend.Create;
   try
      HTTP.HTTPMethod('GET', Url);
      fs.LoadFromStream(Http.Document);
      Result := fs.Text;
   finally
      fs.Free;
      http.Free;
   end;
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
  Memo1.Lines.Add(GetWebPageContent('http://www.iran.ir/'));
end; 
But i have a small problem! When I click on Button1, the program is
freezing and i can't do action in my program!
I want to use many procedures! like this:
Code: [Select]procedure OnGetWebFinished(Header: String; Document:
String);
begin

end;

My English is very bad, sorry for my bad English
Thanks. I waiting for my Answer!

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wjackson153 · 2013-01-26 20:04

Have you tried

adding the following:

application.processmessages;

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Leledumbo · 2013-01-26 20:05

Synapse is purely object oriented (and mostly synchronous), use lNet
if you want even driven networking library. If you want to stick to
Synapse, use threads and Synchronize() at the end of Execute().
QuoteHave you tried

adding the following:

application.processmessages;
That won't work, it's Synapse that's blocking, not the application
code.

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ojZim · 2013-01-26 20:29

Quote from: wjackson153 on January 26, 2013, 09:04:21 pmHave you tried

adding the following:

application.processmessages;
Thank for your answer! No it's not solve my problem! Thanks.

Quote from: Leledumbo on January 26, 2013, 09:05:44 pmSynapse is
purely object oriented (and mostly synchronous), use lNet if you want
even driven networking library. If you want to stick to Synapse, use
threads and Synchronize() at the end of Execute().
Thanks for your answer! Is lNet componet works on linux? if it's
working on linux i use it!!
But if i want to stock to Synaspe, How can i use threads and
Synchronize() at the end of Execute()?
I waiting for your answers! Thanks!

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wjackson153 · 2013-01-26 20:46

For linux I would use  a simpler method

Combine Tprocess
with wget  

See my example on wiki
http://wiki.lazarus.freepascal.org/Executing_External_Programs#A_Simpl
e_Example

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Silvio Clécio · 2013-01-26 21:28

Try it buddy:

Code: [Select]uses
  fphttpclient;

procedure ProcessContent;
begin
  with TFPHTTPClient.Create(nil) do
  try
    Form1.Memo1.Text := Get(
        'http://www.lazarus.freepascal.org/index.php/topic,19685.msg11
2286.html');
  finally
    Free;
  end;
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
  BeginThread(TThreadFunc(@ProcessContent));
end;

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ojZim · 2013-01-26 21:57

Quote from: silvioprog on January 26, 2013, 10:28:50 pmTry it buddy:

Code: [Select]uses
  fphttpclient;

procedure ProcessContent;
begin
  with TFPHTTPClient.Create(nil) do
  try
    Form1.Memo1.Text := Get(
        'http://www.lazarus.freepascal.org/index.php/topic,19685.msg11
2286.html');
  finally
    Free;
  end;
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
  BeginThread(TThreadFunc(@ProcessContent));
end;

WoW! THanks for your Answer! just
BeginThread(TThreadFunc(@ProcessContent)); working good, my Problem is
solved by your help! the BeginThread(TThreadFunc(@ProcessContent)); is
solved my problem. thank you!

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Leledumbo · 2013-01-27 06:11

QuoteThanks for your answer! Is lNet componet works on linux? if it's
working on linux i use it!!Yes, lNet works on many platforms.
QuoteBut if i want to stock to Synaspe, How can i use threads and
Synchronize() at the end of Execute()?You can use Silvio's answer, but
he uses the built-in (FCL) fphttpclient, which is great as well.
Changing to Synapse should be easy, just change the ProcessContent
method.

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ojZim · 2013-01-29 12:20

Quote from: Leledumbo on January 27, 2013, 07:11:13 amQuoteThanks for
your answer! Is lNet componet works on linux? if it's working on linux
i use it!!Yes, lNet works on many platforms.
QuoteBut if i want to stock to Synaspe, How can i use threads and
Synchronize() at the end of Execute()?You can use Silvio's answer, but
he uses the built-in (FCL) fphttpclient, which is great as well.
Changing to Synapse should be easy, just change the ProcessContent
method.
Yes Thank you! I used from Silvio's answer and i changed fphttpclient
to Synapse. It was easily. And my code is:
Code: [Select]uses httpsend;
function GetWebPageContent(const Url: string): String;
var fs: TStringList; HTTP: THTTPSend;
begin
   fs := TStringList.Create;
   HTTP := THTTPSend.Create;
   try
      HTTP.HTTPMethod('GET', Url);
      fs.LoadFromStream(Http.Document);
      Result := fs.Text;
   finally
      fs.Free;
      HTTP.Free;
   end;
end;

procedure aa();
begin
  Form1.Memo1.Lines.Add(GetWebPageContent('http://www.iran.ir/'));
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
  BeginThread(TThreadFunc(@aa));
end;
Now it's not freezing and working good! Thank from all.