In most cases the file(s) will come from a SQL query, which should look like this:

select file_name    as file_name
     , mime_type    as file_mime_type
     , blob_content as file_content_blob
  from some_table

select 'sample_image.png' as file_name
     , mime_type          as file_mime_type
     , file_content       as file_content_blob
  from apex_application_static_files
 where application_id = :APP_ID
   and file_name = 'images/avatar2.png'

select file_name    as file_name
     , mime_type    as file_mime_type
     , file_content as file_content_blob
  from apex_application_static_files
 where application_id = :APP_ID

Sometimes you have files stored as VARCHAR2 or CLOB, and not as binary data. This plug-in can handle both. Instead of providing a file_content_blob column, provide a file_content_clob column. In such cases you can simply define the mime_type as text/plain.

select 'test.txt'     as file_name
     , 'text/plain'   as file_mime_type
     , 'Hello World!' as file_content_clob
  from dual

select 'sample_image.png' as file_name
     , mime_type          as file_mime_type
     , file_content       as file_content_blob
     , null               as file_content_clob
  from apex_application_static_files
 where application_id = :APP_ID
   and file_name = 'images/avatar2.png'

 union all

select 'test.txt'
     , 'text/plain'
     , null
     , 'Hello World!'
  from dual

The files can also be compiled procedural by adding them to a collection in a PL/SQL code block.

Simply add all files to the UC_DOWNLOAD_FILES collection. This special collection will be created and removed accordingly by the plug-in. Just make sure to provide parameters p_c001 for the file name, p_c002 for the mime type, and p_blob001 or p_clob001 for the content.

apex_collection.add_member
    ( p_collection_name => 'UC_DOWNLOAD_FILES'
    , p_c001            => 'README.md'
    , p_c002            => 'text/plain'
    , p_clob001         => 'This zip contains *all* application files!'
    );

for f in (
    select *
      from apex_application_static_files
     where application_id = :APP_ID
) loop
    apex_collection.add_member
        ( p_collection_name => 'UC_DOWNLOAD_FILES'
        , p_c001            => f.file_name
        , p_c002            => f.mime_type
        , p_blob001         => f.file_content
        );
end loop;

-- pro tip: you can override the zip file name by assigning it to the apex_application.g_x01 global variable
apex_application.g_x01 := 'all_files.zip';

To create subdirectories in your zip structure, prepend them to the file name as follows:

apex_collection.add_member
    ( p_collection_name => 'UC_DOWNLOAD_FILES'
    , p_c001            => 'file1.txt'
    , p_c002            => 'text/plain'
    , p_clob001         => 'I''m in the root.'
    );

apex_collection.add_member
    ( p_collection_name => 'UC_DOWNLOAD_FILES'
    , p_c001            => 'hello/world/file2.txt'
    , p_c002            => 'text/plain'
    , p_clob001         => 'I''m two levels down.'
    );

apex_collection.add_member
    ( p_collection_name => 'UC_DOWNLOAD_FILES'
    , p_c001            => '1/2/3/4/5/6/7/8/9/file3.txt'
    , p_c002            => 'text/plain'
    , p_clob001         => 'Hello? Anybody there?'
    );

This plug-in works great in combination with the apex_export API. In the following example we create on export of all the plug-ins included in this application.

declare
    l_files      apex_t_export_files;
    l_components apex_t_varchar2;
    
    l_set_env varchar2(32767);
    l_end_env varchar2(32767);
    
    CRLF constant varchar2(4) := chr(13) || chr(10);
begin
    select 'PLUGIN:' || id
      bulk collect into l_components
      from apex_appl_export_comps
     where application_id = :APP_ID
       and type_name = 'PLUGIN'
       and name like 'UC - %';

    -- export application
    -- we can speed things up by only exporting the needed components
    l_files := apex_export.get_application
        ( p_application_id => :APP_ID
        , p_split          => true
        , p_components     => l_components
        );
    
    -- individual component files do not contain the necessary start and end environment scripts
    -- so in this case we must fetch, prepend and append them ourselves
    select contents
      into l_set_env
      from table(l_files)
     where name like '%set_environment.sql';

    select contents
      into l_end_env
      from table(l_files)
     where name like '%end_environment.sql';
    
    for idx in 1 .. l_files.count
    loop
        if l_files(idx).name like '%/plugins/%'
        then
            -- file names are in the form application/shared_components/plugins/dynamic_action/...
            -- performing a substr to only use the actual plug-in name. i.e everything after the last slash
            apex_collection.add_member
                ( p_collection_name => 'UC_DOWNLOAD_FILES'
                , p_c001            => substr(l_files(idx).name, instr(l_files(idx).name, '/', -1) + 1)
                , p_c002            => 'text/plain'
                , p_clob001         => l_set_env || CRLF || l_files(idx).contents || CRLF || l_end_env
                );
        end if;
    end loop;
end;

When using a SQL Query to return your file(s) to download you have the option to execute a PL/SQL code block just prior to the download starting. This is to allow you to perform actions like tracking the download count. Your changes will be automatically committed.

update my_table set download_count = nvl(download_count, 0) + 1
where  file_name = 'somefile.zip';

When an exception is raised during download, an error notification will be shown and a plug-in event will be fired. You have the option of suppressing this error notification and performing your own custom error handling. When we trap the error we also ensure that we run it through the page/application error handling routine (if you have defined one).

You can access the error message in dynamic action client side conditions or in execute javascript code actions using the following syntax:

this.data.error

You can choose to download the file to the filesystem or preview the file using an "inline" content-disposition. There are some restrictions to using preview mode i.e. we only support the following file types:

• Text Files
• Image Files
• PDF Files

Note: if you preview a file type in a new window that is not supported the behaviour is based on the browser which in most cases results in a file download and a blank preview window.

You can customize/override the dialog settings using the "Javascript Initialization Code" attribute e.g.

function(options) {
   // you can change any of the settings defined here: https://api.jqueryui.com/dialog/
   options.previewOptions = options.previewOptions || {};
   options.previewOptions.modal = false;
   return options;
}

You can use an interactive grid with it's multi-selection capability to choose which files you wish to download.