mysql encode&decode

MySQL urlencode 函数、urldecode函数 、multiurldecode 函数

DELIMITER ;

DROP FUNCTION IF EXISTS urlencode;

DELIMITER |

CREATE FUNCTION urlencode (s VARCHAR (4096)) RETURNS VARCHAR (4096)
DETERMINISTIC
CONTAINS SQL
BEGIN
       DECLARE c VARCHAR (4096) DEFAULT '' ;
       DECLARE pointer INT DEFAULT 1;
       DECLARE s2 VARCHAR (4096) DEFAULT '' ;

       IF ISNULL (s) THEN
           RETURN NULL ;
       ELSE
       SET s2 = '' ;
       WHILE pointer <= length(s) DO
          SET c = MID(s,pointer,1);
          IF c = ' ' THEN
             SET c = '+' ;
          ELSEIF NOT (ASCII(c) BETWEEN 48 AND 57 OR
                ASCII(c) BETWEEN 65 AND 90 OR
                ASCII(c) BETWEEN 97 AND 122) THEN
             SET c = concat( "%" ,LPAD(CONV(ASCII(c),10,16),2,0));
          END IF;
          SET s2 = CONCAT(s2,c);
          SET pointer = pointer + 1;
       END while;
       END IF;
       RETURN s2;
END ;
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DELIMITER ;

DROP FUNCTION IF EXISTS urldecode;

DELIMITER |

CREATE FUNCTION urldecode (s VARCHAR (4096)) RETURNS VARCHAR (4096)
DETERMINISTIC
CONTAINS SQL
BEGIN
       DECLARE c VARCHAR (4096) DEFAULT '' ;
       DECLARE pointer INT DEFAULT 1;
       DECLARE h CHAR (2);
       DECLARE h1 CHAR (1);
       DECLARE h2 CHAR (1);
       DECLARE s2 VARCHAR (4096) DEFAULT '' ;

       IF ISNULL (s) THEN
          RETURN NULL ;
       ELSE
       SET s2 = '' ;
       WHILE pointer <= LENGTH(s) DO
          SET c = MID(s,pointer,1);
          IF c = '+' THEN
             SET c = ' ' ;
          ELSEIF c = '%' AND pointer + 2 <= LENGTH(s) THEN
             SET h1 = LOWER (MID(s,pointer+1,1));
             SET h2 = LOWER (MID(s,pointer+2,1));
             IF (h1 BETWEEN '0' AND '9' OR h1 BETWEEN 'a' AND 'f' )
                 AND
                 (h2 BETWEEN '0' AND '9' OR h2 BETWEEN 'a' AND 'f' )
                 THEN
                   SET h = CONCAT(h1,h2);
                   SET pointer = pointer + 2;
                   SET c = CHAR (CONV(h,16,10));
              END IF;
          END IF;
          SET s2 = CONCAT(s2,c);
          SET pointer = pointer + 1;
       END while;
       END IF;
       RETURN s2;
END ;

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DELIMITER ;

当一个字符串经过多次 urlencode 处理之后，可以使用 multiurldecode来解码，它将多次调用 urldecode来解码，直到没有需要解码的字符

DELIMITER ;

DROP FUNCTION IF EXISTS multiurldecode;

DELIMITER |

CREATE FUNCTION multiurldecode (s VARCHAR (4096)) RETURNS VARCHAR (4096)
DETERMINISTIC
CONTAINS SQL
BEGIN
       DECLARE pr VARCHAR (4096) DEFAULT '' ;
       IF ISNULL (s) THEN
          RETURN NULL ;
       END IF;
       REPEAT
          SET pr = s;
          SELECT urldecode(s) INTO s;
       UNTIL pr = s END REPEAT;
       RETURN s;
END ;

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DELIMITER ;