Upload and process a file using Invantive App Online

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The addition of several new procedures in the cloud_http PSQL package enable the processing of binary and text files through a web form. The file(s) can then further be processed for instance parsing it as an XML, JSON, CSV or Excel file.

New cloud_http procedures

The following procedures have been added to the cloud_http package:

  • get_request_form_file_name: Gets the first form file name of the key specified as text value parameter.
  • get_request_form_file_content_type: Gets the first form file content type of the key specified as text value parameter.
  • get_request_form_file_content_disposition: Gets the first form file content disposition of the key specified as text value parameter.
  • get_request_form_file_length: Gets the first form file length of the key specified as text value parameter.
  • get_request_form_file_contents: Gets the first form file contents in binary format of the key specified as text value parameter. Use to_char when UTF-8 to use as varchar2 text.

Sample PSQL-code to process a file

The following sample code allows you to upload a JPEG image file and then display it in a web page.

Place the PSQL-code in a module as shown in the picture and execute it on any database:

image
image1650×930 73.5 KB

PSQL-code:

declare
  p_run       boolean;
  --
  l_binary    blob;
  l_filename  varchar2;
  l_payload   blob;
  l_payload_base64_encoded varchar2;
begin
  --
  -- Get parameters.
  --
  p_run := cast(cloud_http.get_request_form_value('p_run') as boolean);
  --
  if coalesce(p_run, false) = false
  then
    --
    -- Display a form tp upload a file.
    --
    cloud_http.set_use_template(true);
    cloud_http.set_template_step_name(translate_resources('{res:itgen_parameters}'));
    cloud_http.append_line_to_response_body_text('<form method="post" enctype="multipart/form-data">');
    cloud_http.append_line_to_response_body_text('<input type="hidden" id="p_run" name="p_run" value="true"/>');
    cloud_http.append_line_to_response_body_text('<ul>');
    cloud_http.append_line_to_response_body_text('<li><label for="p_file">' || translate_resources('{res:itgen_file}') || '</label></li><li><input type="file" id="p_file" name="p_file" accept=".jpg" required/></li>');
    cloud_http.append_line_to_response_body_text('<li><input type="submit" value="Start"/></li>');
    cloud_http.append_line_to_response_body_text('</ul>');
    cloud_http.append_line_to_response_body_text('</form>');
  else
    --
    -- Process form.
    --
    l_filename := cloud_http.get_request_form_file_name('p_file');
    --
    if l_filename is null
    then
      raise_application_error('sample001', 'The file name is empty.');
    end if;
    --
    l_payload := cloud_http.get_request_form_file_contents('p_file');
    --
    if l_payload is null
    then
      raise_application_error('sample002', 'The file payload is empty.');
    end if;
    --
    l_payload_base64_encoded := base64_encode(l_payload);
    --
    cloud_http.set_use_template(true);
    --
    -- Display file as na image.
    --
    cloud_http.append_line_to_response_body_text
    ( '<img src="data:image/jpg;base64, ' 
      || l_payload_base64_encoded
      || '" />'
    );
  end if;
end;

Execution Sample

xxxDuring execution, first the user is offered the opportunity to specify a file:

image
image764×372 69 KB

Upon selection of the Start-button, the file is uploaded and rendered in a web page:

image