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Solved: Load CSV string from an API to a Stringgrid

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arneolav:
String from API:
I can save the string to a file and then do: Stringgrid:LoadFromCSVStream. Ok!

But to avoid writing file to disk I try this:
HTTPS.Get(URL, Stream);
Error: Writing to Tstream not supported

Are there some other way to load a string to a Stringgrid?

dsiders:

--- Quote from: arneolav on March 06, 2023, 11:29:14 pm ---String from API:
I can save the string to a file and then do: Stringgrid:LoadFromCSVStream. Ok!

But to avoid writing file to disk I try this:
HTTPS.Get(URL, Stream);
Error: Writing to Tstream not supported

Are there some other way to load a string to a Stringgrid?

--- End quote ---

The answer is in the error message - and the source code. TStream.Write is not implemented and raises the exception. you need to use one of the descendants like TMemoryStream, TStringStream, TFileStream, et. al. You'll likely need to reset the stream position to 0 after the HTTP get and before calling LoadFromCSVStream.

arneolav:
Thanks,
it did the trick, I should know but my head was empty...

I put in an example of my solution, may be help for others.

And as a comment in the bottom some example of read a fileStream and
read ReadCSVCells:


--- Code: Pascal  [+][-]window.onload = function(){var x1 = document.getElementById("main_content_section"); if (x1) { var x = document.getElementsByClassName("geshi");for (var i = 0; i < x.length; i++) { x[i].style.maxHeight='none'; x[i].style.height = Math.min(x[i].clientHeight+15,306)+'px'; x[i].style.resize = "vertical";}};} ---unit Unit1;{$mode objfpc}{$H+}interfaceuses  Classes, SysUtils, Forms, Controls, Graphics, Dialogs, StdCtrls, Grids  , LAZFileUtils  , fphttpclient  ; type  { TForm1 }  TForm1 = class(TForm)    Button1: TButton;    CheckBox1: TCheckBox;    Memo1: TMemo;    StringGrid1: TStringGrid;    procedure Button1Click(Sender: TObject);  private    Procedure GetInpAPIcsv;    Function InpAPIstream:TMemoryStream;    procedure WriteMemStream(FFileName:String);  public  end;var  Form1: TForm1;  FFileName  : string;  // if read from fileimplementation{$R *.lfm}{ TForm1 }procedure TForm1.Button1Click(Sender: TObject);begin  GetInpAPIcsv;  with StringGrid1 do  begin    Memo1.Append( Cells[14, 1]);           // col / Row    Memo1.Append( Cells[15, 1]);  endend; Procedure TForm1.GetInpAPIcsv;var  FileStream: TFileStream;   // if read from filebegin  FFileName := 'MyFile.CSV';  try    StringGrid1.BeginUpdate;    StringGrid1.Clear;                                          // Reset the grid     if FileExistsUTF8(FFileName) then                      // May read from file    begin       FileStream := TFileStream.Create(FFileName, fmOpenRead+fmShareDenyWrite);       StringGrid1.LoadFromCSVStream(FileStream, ';', true, 0, true);       FileStream.Free;     end    else    begin                                                         // Read with a memorystream      InpAPIstream.Position:=0;      StringGrid1.LoadFromCSVStream(InpAPIstream, ';', true, 0, true);      if CheckBox1.Checked then WriteMemStream(FFileName);      // We may want to inspect the file      InpAPIstream.Free;    end;  finally    StringGrid1.EndUpdate;  end;end; Function TForm1.InpAPIstream: TMemoryStream;   // The function as a Memorystreamvar HTTPS: TFPHTTPClient;    URL:String;begin  Result := TMemoryStream.Create;  URL:=  'MyUrl.....';  HTTPS := TFPHTTPClient.Create(nil);  try    try      HTTPS.Get(URL, Result);                {<------- HTTPS.Get(URL)----------}      Result.Position:=0;    except      on E: Exception do      begin        Memo1.Append(' Error in HTTPS.Get ' +  E.Message);      end;    end; finally   HTTPS.RequestBody.Free;   HTTPS.Free; end;end;                                                  // We may want to save the file:procedure TForm1.WriteMemStream(FFileName:String);begin  try    InpAPIstream.Position:=0;    InpAPIstream.SaveToFile(FFileName);  except     // on E: Exception do ...  end;end; (*function ReadStream(FFileName: string): string;        //  Read a stream:var  Strm: TFileStream;  n: longint;  txt: string;begin  txt := '';  Strm := TFileStream.Create(FFileName, fmOpenRead or fmShareDenyWrite);  try    n := Strm.Size;    SetLength(txt, n);    Strm.Read(txt[1], n);  finally    Strm.Free;  end;  Result := txt;end;                                                        // Read values from a csv stringfunction TForm2.ReadCSVCell(iText: String; ARow, ACol: Integer): String;// Uses csvdocument     //ReadCSVCellvar  CSVDoc:TCSVDocument;begin  CSVDoc := TCSVDocument.Create;  try    CSVDoc.Delimiter := ';';    CSVDoc.LoadFromFile('Myfile.CSV');    CSVDoc.CSVText:=iText;    Result := CSVDoc.Cells[ACol, ARow];  finally    CSVDoc.Free;  end;end;*) end.

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