{ ***************************************************************************

  Copyright (c) 2015-2020 Kike Pérez

  Unit        : Quick.Data.Redis
  Description : Redis client
  Author      : Kike Pérez
  Version     : 1.0
  Created     : 22/02/2020
  Modified    : 02/03/2020

  This file is part of QuickLib: https://github.com/exilon/QuickLib

 ***************************************************************************

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

  http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.

 *************************************************************************** }

unit Quick.Data.Redis;

{$i QuickLib.inc}

interface

uses
  System.SysUtils,
  System.DateUtils,
  IdTCPClient,
  Quick.Commons;

type
  IRedisResponse = interface
  ['{21EF7ABF-E678-4F18-AE56-8A7C6B817AE3}']
    function GetIsDone: Boolean;
    function GetResponse: string;
    procedure SetIsDone(const Value: Boolean);
    procedure SetResponse(const Value: string);
    property IsDone : Boolean read GetIsDone write SetIsDone;
    property Response : string read GetResponse write SetResponse;
  end;
  TRedisResponse = class(TInterfacedObject,IRedisResponse)
  private
    fIsDone : Boolean;
    fResponse : string;
    function GetIsDone: Boolean;
    function GetResponse: string;
    procedure SetIsDone(const Value: Boolean);
    procedure SetResponse(const Value: string);
  public
    property IsDone : Boolean read GetIsDone write SetIsDone;
    property Response : string read GetResponse write SetResponse;
  end;

  TRedisClient = class
  private
    fTCPClient : TIdTCPClient;
    fHost : string;
    fPort : Integer;
    fDataBaseNumber : Integer;
    fMaxSize : Int64;
    fPassword : string;
    fConnectionTimeout : Integer;
    fReadTimeout : Integer;
    fConnected : Boolean;
    procedure SetConnectionTimeout(const Value: Integer);
    procedure SetReadTimeout(const Value: Integer);
    function Command(const aCommand : string; const aArguments : string = '') : IRedisResponse; overload;
    function Command(const aCommand, aArgumentsFormat : string; aValues : array of const) : IRedisResponse; overload;
    function EscapeString(const json: string) : string;
    function IsIntegerResult(const aValue : string) : Boolean;
  public
    constructor Create;
    destructor Destroy; override;
    property Host : string read fHost write fHost;
    property Port : Integer read fPort write fPort;
    property DataBaseNumber : Integer read fDataBaseNumber write fDataBaseNumber;
    property MaxSize : Int64 read fMaxSize write fMaxSize;
    property Password : string read fPassword write fPassword;
    property ConnectionTimeout : Integer read fConnectionTimeout write SetConnectionTimeout;
    property ReadTimeout : Integer read fReadTimeout write SetReadTimeout;
    property Connected : Boolean read fConnected;
    function RedisSELECT(dbIndex : Integer) : Boolean;
    function RedisSET(const aKey, aValue : string; aTTLMs : Integer = -1) : Boolean;
    function RedisGET(const aKey : string; var vValue : string) : Boolean;
    function RedisRPUSH(const aKey, aValue : string) : Boolean;
    function RedisLPUSH(const aKey, aValue : string) : Boolean;
    function RedisLTRIM(const aKey : string; aFirstElement, aMaxSize : Int64) : Boolean;
    function RedisEXPIRE(const aKey : string; aTTLMs : Integer) : Boolean; overload;
    function RedisEXPIRE(const aKey : string; aExpireDate : TDateTime) : Boolean; overload;
    function RedisAUTH(const aPassword : string) : Boolean;
    function RedisPING : Boolean;
    function RedisQUIT : Boolean;
    procedure Connect;
    procedure Disconnect;
  end;

  ERedisConnectionError = class(Exception);
  ERedisAuthError = class(Exception);
  ERedisCommandError = class(Exception);

implementation

const

  DEF_REDIS_PORT = 6379;
  CRLF = #10#13;
  DEF_CONNECTIONTIMEOUT = 30000;
  DEF_READTIMETOUT = 10000;


{ TRedisResponse }

function TRedisResponse.GetIsDone: Boolean;
begin
  Result := fIsDone;
end;

function TRedisResponse.GetResponse: string;
begin
  Result := fResponse;
end;

procedure TRedisResponse.SetIsDone(const Value: Boolean);
begin
  fIsDone := Value;
end;

procedure TRedisResponse.SetResponse(const Value: string);
begin
  fResponse := Value;
end;

{ TRedisClient }

constructor TRedisClient.Create;
begin
  inherited;
  fConnected := False;
  fHost := 'localhost';
  fPort := DEF_REDIS_PORT;
  fDataBaseNumber := 0;
  fMaxSize := 0;
  fPassword := '';
  fConnectionTimeout := DEF_CONNECTIONTIMEOUT;
  fReadTimeout := DEF_READTIMETOUT;
  fTCPClient := TIdTCPClient.Create;
end;

destructor TRedisClient.Destroy;
begin
  try
    if fTCPClient.Connected then RedisQUIT;
    fTCPClient.IOHandler.InputBuffer.Clear;
    fTCPClient.IOHandler.WriteBufferFlush;
    if fTCPClient.Connected then fTCPClient.Disconnect(False);
    fTCPClient.Free;
  except
    //avoid closing errors
  end;
  inherited;
end;

procedure TRedisClient.Disconnect;
begin
  if fConnected then RedisQUIT;
  fConnected := False;
end;

procedure TRedisClient.Connect;
begin
  if not fTCPClient.Connected then
  begin
    fTCPClient.Host := fHost;
    fTCPClient.Port := fPort;
    fTCPClient.ConnectTimeout := fConnectionTimeout;
    fTCPClient.ReadTimeout := fConnectionTimeout;
  end;
  try
    fTCPClient.Connect; //first connection
    //connect password and database
    if not fTCPClient.Connected then
    begin
      fTCPClient.Connect;
      if not fTCPClient.Connected then raise ERedisConnectionError.Create('Can''t connect to Redis Server!');
    end;
    fTCPClient.Socket.Binding.SetKeepAliveValues(True,5000,1000);
    if fPassword <> '' then
    begin
      if not RedisAUTH(fPassword) then raise  ERedisAuthError.Create('Redis authentication error!');
    end;
    if fDataBaseNumber > 0 then
    begin
      if not RedisSELECT(fDataBaseNumber) then raise ERedisConnectionError.CreateFmt('Can''t select Redis Database "%d"',[fDataBaseNumber]);
    end;
    fConnected := True;
  except
    on E : Exception do raise ERedisConnectionError.CreateFmt('Can''t connect to Redis service %s:%d (%s)',[Self.Host,Self.Port,e.Message]);
  end;
end;

function TRedisClient.IsIntegerResult(const aValue: string): Boolean;
begin
  Result := IsInteger(StringReplace(aValue,':','',[]));
end;

function TRedisClient.EscapeString(const json: string): string;
begin
  Result := StringReplace(json,'\','\\',[rfReplaceAll]);
  Result := StringReplace(Result,'"','\"',[rfReplaceAll]);
  //Result := StringReplace(Result,'/','\/"',[rfReplaceAll]);
end;

procedure TRedisClient.SetConnectionTimeout(const Value: Integer);
begin
  if fConnectionTimeout <> Value then
  begin
    fConnectionTimeout := Value;
    if Assigned(fTCPClient) then fTCPClient.ConnectTimeout := fConnectionTimeout;
  end;
end;

procedure TRedisClient.SetReadTimeout(const Value: Integer);
begin
  if fReadTimeout <> Value then
  begin
    fReadTimeout := Value;
    if Assigned(fTCPClient) then fTCPClient.ConnectTimeout := fReadTimeout;
  end;
end;

function TRedisClient.Command(const aCommand, aArgumentsFormat : string; aValues : array of const) : IRedisResponse;
begin
  Result := Command(aCommand,Format(aArgumentsFormat,aValues));
end;

function TRedisclient.Command(const aCommand : string; const aArguments : string = '') : IRedisResponse;
  function TrimResponse(const aResponse : string) : string;
  begin
    Result := Copy(aResponse,Low(aResponse) + 1, aResponse.Length);
  end;
var
  res : string;
begin
  Result := TRedisResponse.Create;
  try
    if not fTCPClient.Connected then Connect;
    fTCPClient.IOHandler.Write(aCommand + ' ' + aArguments + CRLF);
    if fTCPClient.IOHandler.CheckForDataOnSource(fReadTimeout) then
    begin
      res := fTCPClient.IOHandler.ReadLn;
      if not res.IsEmpty then
      case res[Low(res)] of
        '+' :
          begin
            if res.Contains('+OK') then
            begin
              Result.IsDone := True;
            end
            else Result.Response := TrimResponse(res);
          end;
        '-' : Result.Response := TrimResponse(res);
        ':' :
          begin
            Result.Response := TrimResponse(res);
            Result.IsDone := Result.Response.ToInteger > -1;
          end;
        '$' :
          begin
            Result.Response := TrimResponse(res);
            if IsInteger(Result.Response) then
            begin
              if Result.Response.ToInteger > -1 then Result.IsDone := True;
            end
            else Result.IsDone := True;
          end;
        '*' : Result.Response := TrimResponse(res);
      end;
    end;
  except
    on E : Exception do raise ERedisCommandError.CreateFmt('%s error: %s',[aCommand,e.message]);
  end;
end;

function TRedisClient.RedisRPUSH(const aKey, aValue : string) : Boolean;
begin
  Result := Command('RPUSH','%s "%s"',[aKey,EscapeString(aValue)]).IsDone;
end;

function TRedisClient.RedisSELECT(dbIndex: Integer): Boolean;
begin
  Result := Command('SELECT',dbIndex.ToString).IsDone;
end;

function TRedisClient.RedisSET(const aKey, aValue: string; aTTLMs: Integer = -1): Boolean;
begin
  Result := Command('SET','%s "%s" PX %d',[aKey,EscapeString(aValue),aTTLMs]).IsDone;
end;

function TRedisClient.RedisLPUSH(const aKey, aValue : string) : Boolean;
begin
  Result := Command('LPUSH','%s "%s"',[aKey,EscapeString(aValue)]).IsDone;
end;

function TRedisClient.RedisLTRIM(const aKey : string; aFirstElement, aMaxSize : Int64) : Boolean;
begin
  Result := Command('LTRIM','%s %d %d',[aKey,aFirstElement,fMaxSize]).IsDone;
end;

function TRedisClient.RedisAUTH(const aPassword : string) : Boolean;
begin
  Result := Command('AUTH',fPassword).IsDone;
end;

function TRedisClient.RedisEXPIRE(const aKey: string; aExpireDate: TDateTime): Boolean;
begin
  Result := RedisEXPIRE(aKey,MilliSecondsBetween(Now(),aExpireDate));
end;

function TRedisClient.RedisEXPIRE(const aKey: string; aTTLMs: Integer): Boolean;
begin
  Result := Command('PEXPIRE','%s %d',[aKey,aTTLMs]).IsDone;
end;

function TRedisClient.RedisGET(const aKey: string; var vValue: string): Boolean;
begin
  if Command('GET','%s',[aKey]).IsDone then
  begin
    vValue := fTCPClient.IOHandler.ReadLn;
    Result := True;
  end;
end;

function TRedisClient.RedisPING : Boolean;
begin
  Result := False;
  if Command('PING').IsDone then
  begin
    Result := fTCPClient.IOHandler.ReadLn = 'PONG';
  end;
end;

function TRedisClient.RedisQUIT : Boolean;
begin
  try
    Result := Command('QUIT').IsDone;
  except
    Result := False;
  end;
end;

end.