feat: Add support for convering source document to PDF via Gotenberg

Adds the ability to convert a source document automatically into a PDF.

pdf/pdf.py

@@ -1,12 +1,14 @@
 """ pdfXBlock main Python class"""
 
+from django.conf import settings
 from django.template import Context, Template
 from xblock.core import XBlock
 from xblock.fields import Boolean, Scope, String
 from xblock.fragment import Fragment
 from xblock.utils.resources import ResourceLoader
 
-from .utils import DummyTranslationService, _, bool_from_str, is_all_download_disabled
+
+from .utils import DummyTranslationService, _, bool_from_str, is_all_download_disabled, convert_to_pdf, GOTENBERG_HOST
 
 try:
     import importlib_resources
@@ -71,7 +73,7 @@ def load_resource(self, resource_path):
         """
         Gets the content of a resource
         """
-        resource = importlib_resources.files(__name__).joinpath(resource_path)
+        resource = importlib_resources.files("pdf").joinpath(resource_path)
         return resource.read_text("utf-8")
 
     def render_template(self, template_path, context=None):
@@ -127,7 +129,8 @@ def studio_view(self, context=None):
             'allow_download': self.allow_download,
             'disable_all_download': is_all_download_disabled(),
             'source_text': self.source_text,
-            'source_url': self.source_url
+            'source_url': self.source_url,
+            'enable_conversion': GOTENBERG_HOST is not None,
         }
         html = loader.render_django_template(
             'templates/html/pdf_edit.html',
@@ -151,6 +154,16 @@ def on_download(self, data, suffix=''):  # pylint: disable=unused-argument
         }
         self.runtime.publish(self, event_type, event_data)
 
+    def _generate_pdf_from_source(self):
+        """
+        Uses the Gotenberg API to convert the source document to a PDF.
+        """
+        output_path = "{loc.org}/{loc.course}/{loc.block_type}/{loc.block_id}.pdf".format(loc=self.location)
+        return convert_to_pdf(
+            self.source_url,
+            output_path,
+        )
+
     @XBlock.json_handler
     def save_pdf(self, data, suffix=''):  # pylint: disable=unused-argument
         """
@@ -163,6 +176,9 @@ def save_pdf(self, data, suffix=''):  # pylint: disable=unused-argument
             self.allow_download = bool_from_str(data['allow_download'])
             self.source_text = data['source_text']
             self.source_url = data['source_url']
+            if data['source_url'] and bool_from_str(data['pdf_auto_generate']):
+                pdf_path = self._generate_pdf_from_source()
+                self.url = pdf_path
 
         return {
             'result': 'success',

pdf/static/js/pdf_edit.js

@@ -11,7 +11,8 @@ function pdfXBlockInitEdit(runtime, element) {
             'url': $('#pdf_edit_url').val(),
             'allow_download': $('#pdf_edit_allow_download').val() || '',
             'source_text': $('#pdf_edit_source_text').val() || '',
-            'source_url': $('#pdf_edit_source_url').val() || ''
+            'source_url': $('#pdf_edit_source_url').val() || '',
+            'pdf_auto_generate': $('#pdf_auto_generate').val() || '',
         };
 
         runtime.notify('save', { state: 'start' });

pdf/templates/html/pdf_edit.html

@@ -40,6 +40,18 @@
         <input class="input setting-input" id="pdf_edit_source_url" value="{{ source_url }}" type="text">
       </div>
       <span class="tip setting-help">{% trans "Add a download link for the source file of your PDF. Use it for example to provide the PowerPoint file used to create this PDF." %}</span>
+      {% if enable_conversion %}
+        <div class="wrapper-comp-setting">
+          <label class="label setting-label" for="pdf_auto_generate">{% trans "Generate PDF from source" %}</label>
+          <select class="input setting-input" id="pdf_auto_generate">
+            <option value="True" {% if pdf_auto_generate %}selected{% endif %}>{% trans "True" %}</option>
+            <option value="False" {% if not pdf_auto_generate %}selected{% endif %}>{% trans "False" %}</option>
+          </select>
+        </div>
+        <span class="tip setting-help">
+        {% trans "Automatically generate a PDF from the source document." %}
+      </span>
+      {% endif %}
     </li>
     {% endif %}
 

pdf/utils.py

@@ -1,8 +1,40 @@
 """
 Utility functions for PDF XBlock
 """
+from typing import Optional
+from urllib.parse import urlparse
 
+import requests
 from django.conf import settings
+from django.core.files.base import ContentFile
+from django.core.files.storage import default_storage
+
+GOTENBERG_HOST = getattr(settings, "GOTENBERG_HOST", None)
+GOTENBERG_CONVERSION_URL = f"{GOTENBERG_HOST}/forms/libreoffice/convert"
+
+
+def convert_to_pdf(doc_url: str, pdf_path: str) -> Optional[str]:
+    """
+    Uses the Gotenberg service to convert the document at `doc_url` to a PDF file.
+
+    Parameters:
+        doc_url (str): The path or URL to the document to be converted.
+        pdf_path (str): The path where the converted PDF file will be stored.
+
+    Returns:
+        str | None: Return None if conversation fails, or returns the PDF url.
+    """
+    source_url = urlparse(doc_url)
+    filename = source_url.path.split('/')[-1]
+    source_doc_response = requests.get(doc_url)
+
+    pdf_response = requests.post(GOTENBERG_CONVERSION_URL, files={
+        'file': (filename, source_doc_response.content)
+    })
+    if pdf_response.status_code != 200:
+        return None
+    file_path = default_storage.save(pdf_path, ContentFile(pdf_response.content))
+    return default_storage.url(file_path)
 
 
 def bool_from_str(str_value):