Read the REST Response Body in Chunks

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Demonstrates Rest.ReadRespChunkBd, which reads the response body one chunk at a time, appending each chunk to a BinData. A return value of 0 signals the body is complete, while -1 indicates a read failure.

var
success: Boolean;
rest: HCkRest;
bTls: Boolean;
bAutoReconnect: Boolean;
statusCode: Integer;
sbError: HCkStringBuilder;
bdBody: HCkBinData;
chunkResult: Integer;

begin
success := False;

rest := CkRest_Create();
bTls := True;
bAutoReconnect := True;
success := CkRest_Connect(rest,'example.com',443,bTls,bAutoReconnect);
if (success = False) then
  begin
    Memo1.Lines.Add(CkRest__lastErrorText(rest));
    Exit;
  end;

success := CkRest_SendReqNoBody(rest,'GET','/api/largefile');
if (success = False) then
  begin
    Memo1.Lines.Add(CkRest__lastErrorText(rest));
    Exit;
  end;

statusCode := CkRest_ReadResponseHeader(rest);
if (statusCode < 0) then
  begin
    Memo1.Lines.Add(CkRest__lastErrorText(rest));
    Exit;
  end;

//  Check for the expected success status code.  If the response is not 200, the body is likely
//  error text formatted as JSON, XML, or HTML rather than the expected content.  In that case read
//  the body as text, report it, and return.
if (statusCode <> 200) then
  begin
    sbError := CkStringBuilder_Create();
    success := CkRest_ReadRespSb(rest,sbError);
    if (success = False) then
      begin
        Memo1.Lines.Add(CkRest__lastErrorText(rest));
        Exit;
      end;
    Memo1.Lines.Add('Request failed with status code ' + IntToStr(statusCode));
    Memo1.Lines.Add(CkStringBuilder__getAsString(sbError));
    Exit;
  end;

//  The status code is 200.  Read the response body in chunks, appending each chunk to the BinData.
//  Each call waits until at least the requested number of bytes is available, unless the response
//  ends first.  A return value of 0 means the final bytes were returned and the body is complete;
//  -1 indicates a read failure.
bdBody := CkBinData_Create();
chunkResult := CkRest_ReadRespChunkBd(rest,8192,bdBody);
while chunkResult > 0 do
  begin
    chunkResult := CkRest_ReadRespChunkBd(rest,8192,bdBody);
  end;

if (chunkResult < 0) then
  begin
    Memo1.Lines.Add(CkRest__lastErrorText(rest));
    Exit;
  end;
Memo1.Lines.Add('Received ' + IntToStr(CkBinData_getNumBytes(bdBody)) + ' bytes.');

CkRest_Dispose(rest);
    CkStringBuilder_Dispose(sbError);
CkBinData_Dispose(bdBody);