Cannot reuse TFPHTTPClient.
lazarus / 38-Networking and Web Programming

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ExSystem · 2017-02-25 07:55

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
project1; Uses  fphttpclient,  Classes,  SysUtils; Var  FHttpClient:
TFPHTTPClient;  FServerUri: String;  Controller: String;  Action:
String;  mResponse: String;Begin  Try    Try      FServerUri :=
'http://www.baidu.com/';      Controller := 'aa';      Action :=
'bb';       FHttpClient := TFPHTTPClient.Create(Nil);     
FHttpClient.RequestBody := TStringStream.Create('{"Revisions":[]}'); 
   FHttpClient.AddHeader('Content-Type', 'text/json');      mResponse
:= FHttpClient.Post(Format('%s%s/%s', [FServerUri, Controller,
Action]));      FHttpClient.RequestBody.Free();     
FHttpClient.RequestBody := Nil;      WriteLn('#1: ', mResponse);     
Action := 'cc';      mResponse :=
FHttpClient.FormPost(Format('%s%s/%s', [FServerUri, Controller,
Action]), 'Page=1');      WriteLn('#2: ', mResponse);    Except     
On e: Exception Do      Begin        WriteLn('######### ',
E.Message);        ReadLn();      End;    End;  Finally   
WriteLn('FINISH!');    ReadLn();    FHttpClient.Free();    FHttpClient
:= Nil;  End;End. 
As the code mentioned above, the second request cannot be finished and
the program hung for a long time and exited. Why? Thanks.

I'm using FPC3.1.1/CodeTyphon 6.0/Windows10 (64bit)

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balazsszekely · 2017-02-25 09:22

Just clear the request headers between the two request:

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  
//... WriteLn('#1: ', mResponse); FHttpClient.RequestHeaders.Clear;
//<-- add this line Action := 'cc';    //...

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ExSystem · 2017-02-25 12:05

Quote from: GetMem on February 25, 2017, 10:22:06 amJust clear the
request headers between the two request:

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  
//... WriteLn('#1: ', mResponse); FHttpClient.RequestHeaders.Clear;
//<-- add this line Action := 'cc';    //...
Quite confused. Header 'Content-Type' should be replaced by FormPost
method, why Clear is required? Will it impact my cookies settings (eg.
the 'login' thing) produced by the first request?
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
TFPCustomHTTPClient.FormPost(const URL, FormData: string;  const
Response: TStream); begin 
RequestBody:=TStringStream.Create(FormData);  try   
AddHeader('Content-Type','application/x-www-form-urlencoded');   
Post(URL,Response);  finally    RequestBody.Free;   
RequestBody:=Nil;  end;end; 
BTW: How to stepping in the source code of TFPHTTPClient when
debugging?...Really recompile it with debug info?

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balazsszekely · 2017-02-25 14:48

QuoteQuite confused. Header 'Content-Type' should be replaced by
FormPost method, why Clear is required? Will it impact my cookies
settings (eg. the 'login' thing) produced by the first request?Well
apparently it does not get replaced by FormPost. I did not study how
FormPost works internally, but you can find out by debugging the code.

QuoteTW: How to stepping in the source code of TFPHTTPClient when
debugging?...Really recompile it with debug info?Ideally you should
recompile FPC with debug info, however in this particular case there
is a shortcut. Just copy fphttpclient.pp from
$(FPCDir)\source\packages\fcl-web\src\base\  to your project folder
and you're good to go.