299 WPG_DOCLOAD
The WPG_DOCLOAD
package provides an interface to download files, BLOB
s and BFILE
s.
See Also:
For more information about implementation of this package:
The chapter contains the following topics:
299.1 WPG_DOCLOAD Constants
WPG_DOCLOAD
defines several constants to use when specifying parameter values.
The WPG_DOCLOAD
constants are listed below:
-
NAME_COL_LEN
-
MIMET_COL_LEN
-
MAX_DOCTABLE_NAME_LEN
NAME_COL_LEN
The NAME
column in your document table must be the same as the value of name_col_len
.
name_col_len CONSTANT pls_integer := 64;
MIMET_COL_LEN
The MIME_TYPE
column in your document table must be the same as the value of mimet_col_len
.
mimet_col_len CONSTANT pls_integer := 48;
MAX_DOCTABLE_NAME_LEN
The name length of your document table must be less than max_doctable_name_len
.
max_doctable_name_len CONSTANT pls_integer := 256;
299.2 Summary of WPG_DOCLOAD Subprograms
The WPG_DOCLOAD package uses one subprogram, the DOWNLOAD_FILE
procedure.
Table 299-1 WPG_DOCLOAD Package Subprograms
Subprogram | Description |
---|---|
Downloads files, |
299.2.1 DOWNLOAD_FILE Procedures
There are three versions of this download file procedure.
-
The first version downloads files and is invoked from within a document download procedure to signal the PL/SQL Gateway that
p_filename
is to be downloaded from the document table to the client's browser. -
The second version can be called from within any procedure to signal the PL/SQL Gateway that
p_blob
is to be downloaded to the client's browser. -
The third version can be called from within any procedure to signal the PL/SQL Gateway that
p_bfile
is to be downloaded to the client's browser.
Syntax
WPG_DOCLOAD.DOWNLOAD_FILE( p_filename IN VARCHAR2, p_bcaching IN BOOLEAN DEFAULT TRUE);
WPG_DOCLOAD.DOWNLOAD_FILE( p_blob IN OUT NOCOPY BLOB); WPG_DOCLOAD.DOWNLOAD_FILE( p_bfile IN OUT BFILE);
Parameters
Table 299-2 DOWNLOAD_FILE Procedure Parameters
Parameter | Description |
---|---|
|
The file to download from the document table. |
|
The |
|
The |
|
Whether browser caching is enabled (see Usage Notes). |
Usage Notes
-
Normally, a document will be downloaded to the browser unless the browser sends an 'If-Modified-Since' header to the gateway indicating that it has the requested document in its cache. In that case, the gateway will determine if the browser's cached copy is up to date, and if it is, it will send an HTTP 304 status message to the browser indicating that the browser should display the cached copy. However, because a document URL and a document do not necessarily have a one-to-one relationship in the PL/SQL Web Gateway, in some cases it may be undesirable to have the cached copy of a document displayed. In those cases, the
p_bcaching
parameter should be set to FALSE to indicate to the gateway to ignore the 'If-Modified-Since' header, and download the document. -
p_bfile
andp_blob
are declared asIN
OUT
because the locator is initially opened to check for file accessibility and existence. The open operation can only be performed if the locator is writable and readable.