Updated API to get it working with Admin.

* Added missing items from template which are required
* Returned the file as a JSON string with the file as a base64 encoded
string
* Updated tests to match teh desired format

app/template/rest.py

@@ -1,9 +1,10 @@
+import base64
 from flask import (
     Blueprint,
     current_app,
     jsonify,
-    request
-)
+    request)
+from requests import post as requests_post
 
 from app.dao.notifications_dao import get_notification_by_id
 from app.dao.templates_dao import (
@@ -182,23 +183,24 @@ def redact_template(template, data):
     return 'null', 200
 
 
-@template_blueprint.route('/<uuid:template_id>/pdf-preview/<uuid:notification_id>/<file_type>', methods=['GET'])
-def preview_letter_template_by_notification_id(service_id, template_id, notification_id, file_type):
-
+@template_blueprint.route('/preview/<uuid:notification_id>/<file_type>', methods=['GET'])
+def preview_letter_template_by_notification_id(service_id, notification_id, file_type):
     if file_type not in ('pdf', 'png'):
-        raise InvalidRequest({'content': ["file_type must be pdf or png"]}, status_code=404)
+        raise InvalidRequest({'content': ["file_type must be pdf or png"]}, status_code=400)
 
     page = request.args.get('page')
 
-    template = dao_get_template_by_id(template_id)
+    notification = get_notification_by_id(notification_id)
+
+    template = dao_get_template_by_id(notification.template_id)
 
     template_for_letter_print = {
+        "id": str(notification.template_id),
         "subject": template.subject,
-        "content": template.content
+        "content": template.content,
+        "version": str(template.version)
     }
 
-    notification = get_notification_by_id(notification_id)
-
     service = dao_fetch_service_by_id(service_id)
 
     data = {
@@ -208,7 +210,6 @@ def preview_letter_template_by_notification_id(service_id, template_id, notifica
         'dvla_org_id': service.dvla_organisation_id,
     }
 
-    from requests import (post as requests_post)
     resp = requests_post(
         '{}/preview.{}{}'.format(
             current_app.config['TEMPLATE_PREVIEW_API_HOST'],
@@ -219,4 +220,10 @@ def preview_letter_template_by_notification_id(service_id, template_id, notifica
         headers={'Authorization': 'Token {}'.format(current_app.config['TEMPLATE_PREVIEW_API_KEY'])}
     )
 
-    return resp.content, resp.status_code, resp.headers.items()
+    if resp.status_code != 200:
+        raise InvalidRequest(
+            'Error generating preview for {}'.format(notification_id), status_code=500
+        )
+
+    content = base64.b64encode(resp.content).decode('utf-8')
+    return jsonify({"content": content})

tests/app/celery/test_letters_pdf_tasks.py

@@ -157,7 +157,6 @@ def test_create_letters_pdf_handles_s3_errors(mocker, sample_letter_notification
             'Type': 'Sender'
         }
     }
-
     mock_s3 = mocker.patch('app.letters.utils.s3upload', side_effect=ClientError(error_response, 'operation_name'))
     mock_retry = mocker.patch('app.celery.letters_pdf_tasks.create_letters_pdf.retry')
 

tests/app/celery/test_tasks.py

@@ -1258,7 +1258,6 @@ def test_build_dvla_file_retries_if_s3_err(sample_letter_template, mocker):
             'Type': 'Sender'
         }
     }
-
     mocker.patch('app.celery.tasks.LetterDVLATemplate', return_value='dvla|string')
     mocker.patch('app.celery.tasks.s3upload', side_effect=ClientError(error_response, 'operation_name'))
     retry_mock = mocker.patch('app.celery.tasks.build_dvla_file.retry', side_effect=Retry)

tests/app/template/test_rest.py

@@ -1,3 +1,4 @@
+import base64
 import json
 import random
 import string
@@ -6,7 +7,6 @@ from datetime import datetime, timedelta
 import pytest
 from freezegun import freeze_time
 
-from app.errors import InvalidRequest
 from app.models import Template, SMS_TYPE, EMAIL_TYPE, LETTER_TYPE, TemplateHistory
 from app.dao.templates_dao import dao_get_template_by_id, dao_redact_template
 
@@ -798,25 +798,25 @@ def test_update_redact_template_400s_if_no_created_by(admin_request, sample_temp
 
 
 def test_preview_letter_template_by_id_invalid_file_type(
-        sample_service,
-        sample_letter_template,
-        sample_letter_notification):
+        sample_letter_notification,
+        admin_request):
 
-    with pytest.raises(InvalidRequest) as exc:
-        from app.template.rest import preview_letter_template_by_notification_id
-        preview_letter_template_by_notification_id(
-            sample_service.id,
-            sample_letter_template.id,
-            sample_letter_notification.id,
-            'doc')
-    assert 'file_type must be pdf or png' in str(exc.value)
+    resp = admin_request.get(
+        'template.preview_letter_template_by_notification_id',
+        service_id=sample_letter_notification.service_id,
+        template_id=sample_letter_notification.template_id,
+        notification_id=sample_letter_notification.id,
+        file_type='doc',
+        _expected_status=400
+    )
+
+    assert ['file_type must be pdf or png'] == resp['message']['content']
 
 
 def test_preview_letter_template_by_id_valid_file_type(
         notify_api,
         client,
-        sample_service,
-        sample_letter_template,
+        admin_request,
         sample_letter_notification):
 
     with set_config_values(notify_api, {
@@ -834,25 +834,20 @@ def test_preview_letter_template_by_id_valid_file_type(
                 status_code=200
             )
 
-            from app.template.rest import preview_letter_template_by_notification_id
-            content, status_code, items = preview_letter_template_by_notification_id(
-                sample_service.id,
-                sample_letter_template.id,
-                sample_letter_notification.id,
-                'pdf'
+            resp = admin_request.get(
+                'template.preview_letter_template_by_notification_id',
+                service_id=sample_letter_notification.service_id,
+                notification_id=sample_letter_notification.id,
+                file_type='pdf'
             )
 
-            assert status_code == 200
-            assert content == content
-            assert list(items)[0][0] == 'X-pdf-page-count'
-            assert list(items)[0][1] == '1'
+            assert base64.b64decode(resp['content']) == content
 
 
-def test_preview_letter_template_by_id_template_preview_404(
+def test_preview_letter_template_by_id_template_preview_500(
         notify_api,
         client,
-        sample_service,
-        sample_letter_template,
+        admin_request,
         sample_letter_notification):
 
     with set_config_values(notify_api, {
@@ -870,12 +865,12 @@ def test_preview_letter_template_by_id_template_preview_404(
                 status_code=404
             )
 
-            from app.template.rest import preview_letter_template_by_notification_id
-            content, status_code, items = preview_letter_template_by_notification_id(
-                sample_service.id,
-                sample_letter_template.id,
-                sample_letter_notification.id,
-                'pdf'
+            resp = admin_request.get(
+                'template.preview_letter_template_by_notification_id',
+                service_id=sample_letter_notification.service_id,
+                notification_id=sample_letter_notification.id,
+                file_type='pdf',
+                _expected_status=500
             )
 
-            assert status_code == 404
+            assert resp['message'] == 'Error generating preview for {}'.format(sample_letter_notification.id)