lazarus CRUD

lazarus CRUD

unit Persistence;

{$MODE DELPHI}

interface

uses
  SysUtils,
  Classes,
  BufDataset,
  SQLdb,
  SQLite3Conn;

function ListPersons: TStream;
procedure SavePersons(const ABytes: TBytes);

implementation

const
  SQL_SELECT_PERSONS = 'SELECT * FROM persons';
  SQL_UDPATE_PERSONS = 'UPDATE persons SET name = :name WHERE id = :id';

var
  DBConnection: TSQLConnector;

procedure CreateAndConfigureDBConnection;
begin
  DBConnection := TSQLConnector.Create(nil);
  DBConnection.Transaction := TSQLTransaction.Create(DBConnection);
  DBConnection.ConnectorType := 'SQLite3';
  DBConnection.DatabaseName := '../../../DB/DataBase.sqlite3';
end;

procedure DestroyDBConnection;
begin
  FreeAndNil(DBConnection);
end;

function CreateQuery(const ASQL: string): TSQLQuery;
begin
  Result := TSQLQuery.Create(nil);
  Result.SQLConnection := DBConnection;
  Result.SQLTransaction := DBConnection.Transaction;
  Result.SQL.Text := ASQL;
end;

function ListPersons: TStream;
var
  VQuery: TSQLQuery;
begin
  Result := TBytesStream.Create;
  VQuery := CreateQuery(SQL_SELECT_PERSONS);
  try
    VQuery.Open;
    VQuery.SaveToStream(Result, dfBinary);
    Result.Seek(0, TSeekOrigin.soBeginning);
  finally
    VQuery.Destroy;
  end;
end;

procedure SavePersons(const ABytes: TBytes);
var
  VQuery: TSQLQuery;
  VData: TBytesStream;
begin
  VQuery := CreateQuery(SQL_SELECT_PERSONS);
  VData := TBytesStream.Create(ABytes);
  try
    VQuery.UpdateSQL.Text := SQL_UDPATE_PERSONS;
    VQuery.Prepare;
    VQuery.LoadFromStream(VData, dfBinary);
    VQuery.ApplyUpdates;
    DBConnection.Transaction.Commit;
  finally
    VQuery.Destroy;
    VData.Free;
  end;
end;

initialization
  CreateAndConfigureDBConnection;

finalization
  DestroyDBConnection;

end.

　

uses
  BrookHTTPRequest,
  BrookHTTPResponse,
  BrookHTTPServer,
  Persistence;

type
  THTTPServer = class(TBrookHTTPServer)
  protected
    procedure DoRequest(ASender: TObject; ARequest: TBrookHTTPRequest;
      AResponse: TBrookHTTPResponse); override;
  end;

procedure THTTPServer.DoRequest(ASender: TObject; ARequest: TBrookHTTPRequest;
  AResponse: TBrookHTTPResponse);
begin
  if ARequest.Payload.Length > 0 then
    SavePersons(ARequest.Payload.Content)
  else
    AResponse.SendStream(ListPersons, 200);
end;

begin
  with THTTPServer.Create(nil) do
  try
    Port := 8080;
    Open;
    if not Active then
      Exit;
    WriteLn('Server running at http://localhost:', Port);
    ReadLn;
  finally
    Free;
  end;
end.

　

unit Client;

{$MODE DELPHI}

interface

uses
  SysUtils,
  Classes,
  DB,
  BufDataset,
  FPHTTPClient;

function NewGuid: string;
function ListPersons(const AURL: string): TDataSet;
procedure SavePersons(const AURL: string; ADataSet: TDataSet);
function CreatePersonsDataSet: TDataSet;

implementation

function NewGuid: string;
begin
  Result := TGuid.NewGuid.ToString(True);
end;

function ListPersons(const AURL: string): TDataSet;
var
  VData: TStream;
begin
  Result := TBufDataset.Create(nil);
  VData := TBytesStream.Create;
  try
    TFPHTTPClient.SimpleGet(AURL, VData);
    TBufDataset(Result).LoadFromStream(VData, dfBinary);
  finally
    VData.Free;
  end;
end;

procedure SavePersons(const AURL: string; ADataSet: TDataSet);
var
  VClient: TFPHTTPClient;
begin
  if ADataSet.State in dsEditModes then
    ADataSet.Post;
  try
    VClient := TFPHTTPClient.Create(nil);
    VClient.RequestBody := TBytesStream.Create;
    try
      TBufDataset(ADataSet).SaveToStream(VClient.RequestBody, dfBinary);
      VClient.RequestBody.Seek(0, TSeekOrigin.soBeginning);
      VClient.Post(AURL);
    finally
      VClient.RequestBody.Free;
      VClient.Free;
    end;
  finally
    FreeAndNil(ADataSet);
  end;
end;

function CreatePersonsDataSet: TDataSet;
begin
  Result := TBufDataset.Create(nil);
  Result.FieldDefs.Add('name', ftString, 100);
  TBufDataset(Result).CreateDataSet;
end;

end.