WebUtil Package For WebUtil Configuration

CREATE OR REPLACE PACKAGE WEBUTIL_DB AUTHID CURRENT_USER AS

/*********************************************************************************\
* WebUtil_DB - Database functions used by the WebUtil_File_Transfer
* Package. These functions allow reading and writing direct
* to the specified BLOB in the database.
* The functions should not be called externally from WebUtil
*********************************************************************************
* Version 1.0.0
*********************************************************************************
* Change History
* DRMILLS 11/JAN/2003 - Creation
*
\*********************************************************************************/

FUNCTION OpenBlob(blobTable in VARCHAR2,
blobColumn in VARCHAR2,
blobWhere in VARCHAR2,
openMode in VARCHAR2,
chunkSize in PLS_INTEGER default null) return BOOLEAN;

FUNCTION CloseBlob(checksum in PLS_INTEGER) return BOOLEAN;

PROCEDURE WriteData(data in VARCHAR2);

FUNCTION ReadData return VARCHAR;

FUNCTION GetLastError return PLS_INTEGER;

FUNCTION GetSourceLength return PLS_INTEGER;

FUNCTION GetSourceChunks return PLS_INTEGER;

END WEBUTIL_DB;
/



CREATE OR REPLACE PACKAGE BODY WEBUTIL_DB AS
m_binaryData BLOB;
m_blobTable VARCHAR2(60);
m_blobColumn VARCHAR2(60);
m_blobWhere VARCHAR2(1024);
m_mode CHAR(1);
m_lastError PLS_INTEGER := 0;
m_sourceLength PLS_INTEGER := 0;
m_bytesRead PLS_INTEGER := 0;
MAX_READ_BYTES PLS_INTEGER := 4096;

-- internal Program Units
PROCEDURE Reset;

PROCEDURE Reset is
BEGIN
m_blobTable := null;
m_blobColumn := null;
m_blobWhere := null;
m_mode := null;
m_lastError := 0;
m_sourceLength := 0;
m_bytesRead := 0;
END Reset;


FUNCTION OpenBlob(blobTable in VARCHAR2, blobColumn in VARCHAR2, blobWhere in VARCHAR2, openMode in VARCHAR2, chunkSize PLS_INTEGER default null) return BOOLEAN is
result BOOLEAN := false;
stmtFetch VARCHAR2(2000);
hit PLS_INTEGER;
BEGIN
-- New transaction clean up
reset;

m_blobTable := blobTable;
m_blobColumn := blobColumn;
m_blobWhere := blobWhere;
m_mode := upper(openMode);

if chunkSize is not null then
if chunkSize > 16384 then
MAX_READ_BYTES := 16384;
else
MAX_READ_BYTES := chunkSize;
end if;
end if;

-- check the target row exists
stmtFetch := 'select count(*) from '||m_blobTable||' where '||m_blobWhere;
EXECUTE IMMEDIATE stmtFetch into hit;

if hit = 1 then
if m_mode = 'W' then
DBMS_LOB.CREATETEMPORARY(m_binaryData,false);
DBMS_LOB.OPEN(m_binaryData,DBMS_LOB.LOB_READWRITE);
m_sourceLength := 0;
result := true;
elsif m_mode = 'R' then
stmtFetch := 'select '||m_blobColumn||' from '||m_blobTable||' where '||m_blobWhere;
EXECUTE IMMEDIATE stmtFetch into m_binaryData;
if m_binaryData is not null then
m_sourceLength := dbms_lob.getlength(m_binaryData);
if m_sourceLength > 0 then
result := true;
else
m_lastError := 110;
end if;
else
m_lastError := 111;
end if;
else
m_lastError := 112;
end if; -- mode
else
-- too many rows
m_lastError := 113;
end if; -- Hit
return result;
END OpenBlob;

FUNCTION CloseBlob(checksum in PLS_INTEGER) return BOOLEAN is
sourceBlob BLOB;
stmtFetch VARCHAR2(2000);
stmtInit VARCHAR2(2000);
result BOOLEAN := false;
BEGIN
if m_mode = 'W' then
m_sourceLength := DBMS_LOB.GETLENGTH(m_binaryData);
end if;

-- checksum
if checksum = m_sourceLength then
if m_mode = 'W' then
-- get the locator to the table blob
stmtFetch := 'select '||m_blobColumn||' from '||m_blobTable||' where '||m_blobWhere||' for update';
EXECUTE IMMEDIATE stmtFetch into sourceBlob;

-- Check the blob has been initialised
-- and if it's not empty clear it out
if sourceBlob is null then
stmtInit := 'update '||m_blobTable||' set '||m_blobColumn||'=EMPTY_BLOB() where '||m_blobWhere;
EXECUTE IMMEDIATE stmtInit;
EXECUTE IMMEDIATE stmtFetch into sourceBlob;
elsif dbms_lob.getlength(sourceBlob) > 0 then
dbms_lob.TRIM(sourceBlob,0);
end if;
-- now replace the table data with the temp BLOB
DBMS_LOB.APPEND(sourceBlob,m_binaryData);
DBMS_LOB.CLOSE(m_binaryData);
result := true;
else
-- todo
null;
end if; --mode
else
m_lastError := 115;
end if; --checksum
return result;
END CloseBlob;

PROCEDURE WriteData(data in VARCHAR2) is
rawData raw(16384);
BEGIN
rawData := utl_encode.BASE64_DECODE(utl_raw.CAST_TO_RAW(data));
dbms_lob.WRITEAPPEND(m_binaryData, utl_raw.LENGTH(rawData), rawData);
END WriteData;


FUNCTION ReadData return VARCHAR is
rawData RAW(16384);
bytesToRead PLS_INTEGER;
BEGIN
bytesToRead := (m_sourceLength - m_bytesRead);
if bytesToRead > MAX_READ_BYTES then
bytesToRead := MAX_READ_BYTES;
end if;
DBMS_LOB.READ(m_binaryData, bytesToRead, (m_bytesRead + 1), rawData);
m_bytesRead := m_bytesRead + bytesToRead;
return UTL_RAW.CAST_TO_VARCHAR2(UTL_ENCODE.BASE64_ENCODE(rawData));
END ReadData;

FUNCTION GetLastError return PLS_INTEGER is
BEGIN
return m_lastError;
END GetLastError;


FUNCTION GetSourceLength return PLS_INTEGER is
BEGIN
return m_sourceLength;
END GetSourceLength;

FUNCTION GetSourceChunks return PLS_INTEGER is
chunks PLS_INTEGER;
BEGIN
chunks := floor(m_sourceLength/MAX_READ_BYTES);
if mod(m_sourceLength,MAX_READ_BYTES) > 0 then
chunks := chunks+1;
end if;
return chunks;
END GetSourceChunks;

END;
/