Merge pull request #1756 from alphagov/rc_send_template_preview_one_page

Updated the notification template endpoint to extract the pdf page

app/template/rest.py

@@ -1,14 +1,19 @@
 import base64
+from io import BytesIO
 
 import botocore
+from PyPDF2.utils import PdfReadError
 from flask import (
     Blueprint,
     current_app,
     jsonify,
     request)
+from notifications_utils.pdf import extract_page_from_pdf
+from notifications_utils.template import SMSMessageTemplate
 from requests import post as requests_post
 
 from app.dao.notifications_dao import get_notification_by_id
+from app.dao.services_dao import dao_fetch_service_by_id
 from app.dao.templates_dao import (
     dao_update_template,
     dao_create_template,
@@ -18,16 +23,14 @@ from app.dao.templates_dao import (
     dao_get_template_versions,
     dao_update_template_reply_to,
     dao_get_template_by_id)
-from notifications_utils.template import SMSMessageTemplate
-from app.dao.services_dao import dao_fetch_service_by_id
-from app.letters.utils import get_letter_pdf
-from app.models import SMS_TYPE
-from app.notifications.validators import service_has_permission, check_reply_to
-from app.schemas import (template_schema, template_history_schema)
 from app.errors import (
     register_errors,
     InvalidRequest
 )
+from app.letters.utils import get_letter_pdf
+from app.models import SMS_TYPE
+from app.notifications.validators import service_has_permission, check_reply_to
+from app.schemas import (template_schema, template_history_schema)
 from app.utils import get_template_instance, get_public_notify_type_text
 
 template_blueprint = Blueprint('template', __name__, url_prefix='/service/<uuid:service_id>/template')
@@ -202,18 +205,30 @@ def preview_letter_template_by_notification_id(service_id, notification_id, file
 
             pdf_file = get_letter_pdf(notification)
 
-        except botocore.exceptions.ClientError:
+        except botocore.exceptions.ClientError as e:
-            current_app.logger.exception(
+            raise InvalidRequest(
-                'Error getting letter file from S3 notification id {}'.format(notification_id))
+                'Error extracting requested page from PDF file for notification_id {} type {} {}'.format(
-            raise InvalidRequest('Error getting letter file from S3 notification id {}'.format(notification_id),
+                    notification_id, type(e), e),
-                                 status_code=500)
+                status_code=500
+            )
 
         content = base64.b64encode(pdf_file).decode('utf-8')
 
         if file_type == 'png':
-            url = '{}/precompiled-preview.png{}'.format(
+
-                current_app.config['TEMPLATE_PREVIEW_API_HOST'],
+            try:
-                '?page={}'.format(page) if page else ''
+                page_number = page if page else "0"
+                pdf_page = extract_page_from_pdf(BytesIO(pdf_file), int(page_number) - 1)
+                content = base64.b64encode(pdf_page).decode('utf-8')
+            except PdfReadError as e:
+                raise InvalidRequest(
+                    'Error extracting requested page from PDF file for notification_id {} type {} {}'.format(
+                        notification_id, type(e), e),
+                    status_code=500
+                )
+
+            url = '{}/precompiled-preview.png'.format(
+                current_app.config['TEMPLATE_PREVIEW_API_HOST']
             )
 
             content = _get_png_preview(url, content, notification.id, json=False)
@@ -262,14 +277,8 @@ def _get_png_preview(url, data, notification_id, json=True):
         )
 
     if resp.status_code != 200:
-        current_app.logger.exception(
-            'Error generating preview letter for {} \nStatus code: {}\n{}'.format(
-                notification_id,
-                resp.status_code,
-                resp.content
-            ))
         raise InvalidRequest(
-            'Error generating preview letter for {}\nStatus code: {}\n{}'.format(
+            'Error generating preview letter for {} Status code: {} {}'.format(
                 notification_id,
                 resp.status_code,
                 resp.content

requirements.txt

@@ -23,6 +23,6 @@ notifications-python-client==4.7.2
 # PaaS
 awscli-cwlogs>=1.4,<1.5
 
-git+https://github.com/alphagov/notifications-utils.git@25.0.0#egg=notifications-utils==25.0.0
+git+https://github.com/alphagov/notifications-utils.git@25.1.0#egg=notifications-utils==25.1.0
 
 git+https://github.com/alphagov/boto.git@2.43.0-patch3#egg=boto==2.43.0-patch3

tests/app/template/test_rest.py

@@ -7,6 +7,7 @@ from datetime import datetime, timedelta
 import botocore
 import pytest
 import requests_mock
+from PyPDF2.utils import PdfReadError
 from freezegun import freeze_time
 
 from app.models import Template, SMS_TYPE, EMAIL_TYPE, LETTER_TYPE, TemplateHistory
@@ -945,7 +946,7 @@ def test_preview_letter_template_precompiled_s3_error(
                              'GetObject'
                          ))
 
-            admin_request.get(
+            request = admin_request.get(
                 'template.preview_letter_template_by_notification_id',
                 service_id=notification.service_id,
                 notification_id=notification.id,
@@ -953,6 +954,10 @@ def test_preview_letter_template_precompiled_s3_error(
                 _expected_status=500
             )
 
+            assert request['message'] == "Error extracting requested page from PDF file for notification_id {} type " \
+                                         "<class 'botocore.exceptions.ClientError'> An error occurred (403) " \
+                                         "when calling the GetObject operation: Unauthorized".format(notification.id)
+
 
 def test_preview_letter_template_precompiled_png_file_type(
         notify_api,
@@ -981,6 +986,8 @@ def test_preview_letter_template_precompiled_png_file_type(
 
             mock_get_letter_pdf = mocker.patch('app.template.rest.get_letter_pdf', return_value=pdf_content)
 
+            mocker.patch('app.template.rest.extract_page_from_pdf', return_value=pdf_content)
+
             mock_post = request_mock.post(
                 'http://localhost/notifications-template-preview/precompiled-preview.png',
                 content=png_content,
@@ -1028,6 +1035,8 @@ def test_preview_letter_template_precompiled_png_template_preview_500_error(
 
             mocker.patch('app.template.rest.get_letter_pdf', return_value=pdf_content)
 
+            mocker.patch('app.template.rest.extract_page_from_pdf', return_value=pdf_content)
+
             mock_post = request_mock.post(
                 'http://localhost/notifications-template-preview/precompiled-preview.png',
                 content=png_content,
@@ -1075,6 +1084,8 @@ def test_preview_letter_template_precompiled_png_template_preview_400_error(
 
             mocker.patch('app.template.rest.get_letter_pdf', return_value=pdf_content)
 
+            mocker.patch('app.template.rest.extract_page_from_pdf', return_value=pdf_content)
+
             mock_post = request_mock.post(
                 'http://localhost/notifications-template-preview/precompiled-preview.png',
                 content=png_content,
@@ -1092,3 +1103,52 @@ def test_preview_letter_template_precompiled_png_template_preview_400_error(
 
             with pytest.raises(ValueError):
                 mock_post.last_request.json()
+
+
+def test_preview_letter_template_precompiled_png_template_preview_pdf_error(
+        notify_api,
+        client,
+        admin_request,
+        sample_service,
+        mocker
+):
+
+    template = create_template(sample_service,
+                               template_type='letter',
+                               template_name='Pre-compiled PDF',
+                               subject='Pre-compiled PDF',
+                               hidden=True)
+
+    notification = create_notification(template)
+
+    with set_config_values(notify_api, {
+        'TEMPLATE_PREVIEW_API_HOST': 'http://localhost/notifications-template-preview',
+        'TEMPLATE_PREVIEW_API_KEY': 'test-key'
+    }):
+        with requests_mock.Mocker() as request_mock:
+
+            pdf_content = b'\x00\x01'
+            png_content = b'\x00\x02'
+
+            mocker.patch('app.template.rest.get_letter_pdf', return_value=pdf_content)
+
+            error_message = "PDF Error message"
+            mocker.patch('app.template.rest.extract_page_from_pdf', side_effect=PdfReadError(error_message))
+
+            request_mock.post(
+                'http://localhost/notifications-template-preview/precompiled-preview.png',
+                content=png_content,
+                headers={'X-pdf-page-count': '1'},
+                status_code=404
+            )
+
+            request = admin_request.get(
+                'template.preview_letter_template_by_notification_id',
+                service_id=notification.service_id,
+                notification_id=notification.id,
+                file_type='png',
+                _expected_status=500
+            )
+
+            assert request['message'] == "Error extracting requested page from PDF file for notification_id {} type " \
+                                         "{} {}".format(notification.id, type(PdfReadError()), error_message)