File Download Link On Navigation Bar List

While working on a customized application sometimes we need to create the application documentation or user manual for the end users. We can upload this documentation in the backend table and share a link to download.

This article describes how to create a link to initiate a file download from an APEX application.

Step 1: PL/SQL Code

For this example, I am going to assume you have a table called DOCUMENTS that holds your media in a BLOB column, along with a column for the MIME type. Here is the code I would use to initiate the file download.

CREATE OR REPLACE PROCEDURE get_file (p_doc_id  IN VARCHAR2) IS
  l_blob_content  documents.blob_content%TYPE;
  l_mime_type     documents.mime_type%TYPE;
BEGIN
  SELECT blob_content, mime_type
  INTO   l_blob_content, l_mime_type
  FROM   documents
  WHERE  document_id = p_doc_id;

  sys.HTP.init;
  sys.OWA_UTIL.mime_header(l_mime_type, FALSE);
  sys.HTP.p('Content-Length: ' || DBMS_LOB.getlength(l_blob_content));
  sys.OWA_UTIL.http_header_close;

  sys.WPG_DOCLOAD.download_file(l_blob_content);
  apex_application.stop_apex_engine;
EXCEPTION
  WHEN apex_application.e_stop_apex_engine THEN
    NULL;
  WHEN OTHERS THEN
    HTP.p('Whoops');
END;
/

Here, document_id is the primary key column from documents table.

Step 2: APEX Common Setup (Application Item and Process)

The following APEX setup is required, whether you plan to initiate the download from a link or a button.

Create a new Application Item.

• Shared Components > Application Items

• Click the "Create" button.

• Enter the following details.

  • Name: FILE_ID

  • Scope: Application

  • Session State Protection: Checksum Required - User Level

• Click the "Create Application Item" button.

Create a new Application Process.

• Shared Components > Application Processes

• Click the "Create" button.

• Enter the following details.

  • Name: GET_FILE

  • Sequence: {accept the default}

  • Process Point: Ajax Callback: Run this application process when requested by a page process

• Click the "Next" button.

• Enter the PL/SQL to perform the download

BEGIN
  get_file(:FILE_ID);
END;

• Click the "Next" button.

• Select the "User is Authenticated (not public)" condition type.

• Click the "Create Process" button.

Step 3: APEX URL

Create a new entry in Desktop Navigation Bar List.

• Shared Components > Lists > Desktop Navigation Bar

• Click the "Create Entry" button.

• Enter the following details.

  • Image/Class: fa-download

  • List Entry Label: Download

  • Target Type: URL

  • URL Target:

f?p=&APP_ID.:1:&APP_SESSION.:APPLICATION_PROCESS=get_file:::FILE_ID:2391

Here, we are providing the document id as hard code value.

In this example, I have used a pdf document. When you click on the download link it will open the pdf document.

I hope this example will be helpful.

Thanks for reading !!