Using TIdHTTP in Delphi to submit form and retrive data (not the usual)

Question

There exists a web page (www.someurl.co.uk) that, amongst other stuff, has inside it a form containing an input field and an image.

In a browser, when the user enters a string in the input field and clicks the image, the form is submitted and another page is generated (www.someurl.co.uk/results.php) containing, amongst other things, a table containing some results.

I need Delphi to fill in the string in the form on the first page, submit the form and get back the contents of a couple of cells from the table on the results page.

I have used the TIdHTTP component to post data to the form using the code below but the text I see in the memo box afterwards is simply the html of the initial page (www.someurl.co.uk).

Please can somebody help me with the correct code to get the the values BlaBla_A, BlaBla_C, BlaBla_C and BlaBla_D from the results page - and to know which is which?

(Although I'm happy with Delphi, I don't know much about web pages and HTML and this is my first time using the Indy component)

This is the code I am using at the moment

procedure TForm1.Button2Click(Sender: TObject);
var
  Response: TStringStream;
  Params: TStringList;
begin
Params := TStringList.Create;
try
  Params.Add('thedata=' + 'MyString');
  Response := TStringStream.Create('');
  try
     IdHTTP1.Post('www.someurl.co.uk', Params, Response);
     memo1.Text := Response.DataString;
  except
   on E: Exception do
   begin
    showmessage('Error: ' + E.Message);
   end;
  end;

finally
  Params.Free;
  Response.Free;
end;

end;

The important bit of the data entry/submit page (www.someurl.co.uk) looks like this

</div>
<h3>Enter the data you want to look for then click FIND</h3>
<form action="results.php" method="post" name="form1" target="_parent" 
      id="form1" 
      onsubmit="if (document.getElementById('text').value==''  
                   || document.getElementById('text').value=='ENTER DATA') 
                   {alert ('Please enter data first then click FIND'); 
                   return false;} 
            else 
               return true;">

<input name="thedata" type="text" id="text" value="ENTER DATA" 
       onclick="effectClear(this.id);this.value = '';" 
       class="validate[required]"/>

<input type="image" src="../images/find.png" name="image" id="homebutton" />
</form>
</div>  

and the important bit of the results page (www.someurl.co.uk/results.php) looks like this

<div id="results_details">
    <table id="results_details_table" border="0">
        <tr>
          <td class="result_general"><h2>Here are your results</h2><br/></td>
          <td class="result_info">
              <label>Result_A</label><br/>BlaBla_A<br/>
              <label>Result_B</label><br/>BlaBla_B<br/>
          </td>
          <td class="result_info">
              <label>Result_C</label><br/>BlaBla_C<br/><br/>
              <label>Result_D</label><br/>BlaBla_D<br/><br/>
          </td>
        </tr>
        </table>
</div>

Answer 1

You are posting your data to this URL, which is wrong:

IdHTTP1.Post('www.someurl.co.uk', Params, Response);

That is why you are getting the initial page back again - that is what you are actually asking for!

You need to post to this URL instead:

IdHTTP1.Post('http://www.someurl.co.uk/results.php', Params, Response);

And BTW, you do not need the TStringStream at all, Post() can return the string data for you:

procedure TForm1.Button2Click(Sender: TObject);
var
  Params: TStringList;
begin
  Params := TStringList.Create;
  try
    Params.Add('thedata=' + 'MyString');
    try
      memo1.Text := IdHTTP1.Post('www.someurl.co.uk', Params);
    except
      on E: Exception do
      begin
        ShowMessage('Error: ' + E.Message);
      end;
    end;
  finally
    Params.Free;
  end;
end;