added serializer to show PDF files preview

src/iosanita/contenttypes/restapi/serializers/configure.zcml

@@ -7,7 +7,7 @@
   <adapter factory=".summary.IOSanitaJSONSummarySerializer" />
   <adapter factory=".summary.PuntoDiContattoJSONSummarySerializer" />
   <adapter factory=".modulo.SerializeModuloToJsonSummary" />
-
+  <adapter factory=".dxfields.FileFieldViewModeSerializer" />
 
   <!-- Summary Serializer Metadata -->
   <utility

src/iosanita/contenttypes/restapi/serializers/dxfields.py

@@ -0,0 +1,56 @@
+# -*- coding: utf-8 -*-
+from Acquisition import aq_inner
+from collective.volto.enhancedlinks.interfaces import IEnhancedLinksEnabled
+from iosanita.contenttypes.interfaces import IIosanitaContenttypesLayer
+from plone.base.utils import human_readable_size
+from plone.dexterity.interfaces import IDexterityContent
+from plone.namedfile.interfaces import INamedFileField
+from plone.restapi.serializer.converters import json_compatible
+from plone.restapi.serializer.dxfields import DefaultFieldSerializer
+from zope.component import adapter
+
+
+@adapter(INamedFileField, IDexterityContent, IIosanitaContenttypesLayer)
+class FileFieldViewModeSerializer(DefaultFieldSerializer):
+    """
+    Ovveride the basic DX serializer to:
+        - handle the visualize file functionality
+        - add getObjSize info
+    """
+
+    def __call__(self):
+        namedfile = self.field.get(self.context)
+        if namedfile is None:
+            return
+
+        url = "/".join(
+            (
+                self.context.absolute_url(),
+                self.get_file_view_mode(namedfile.contentType),
+                self.field.__name__,
+            )
+        )
+        size = namedfile.getSize()
+        result = {
+            "filename": namedfile.filename,
+            "content-type": namedfile.contentType,
+            "size": size,
+            "download": url,
+        }
+        if IEnhancedLinksEnabled.providedBy(self.context):
+            result.update(
+                {
+                    "getObjSize": human_readable_size(size),
+                    "enhanced_links_enabled": True,
+                }
+            )
+
+        return json_compatible(result)
+
+    def get_file_view_mode(self, content_type):
+        """Pdf view depends on the anteprima_file property in thq aq_chain"""
+        if self.context and "pdf" in content_type:
+            if getattr(aq_inner(self.context), "anteprima_file", None):
+                return "@@display-file"
+
+        return "@@download"

src/iosanita/contenttypes/tests/test_filefield_custom_serializer.py

@@ -0,0 +1,71 @@
+# -*- coding: utf-8 -*-
+from design.plone.contenttypes.testing import (
+    DESIGN_PLONE_CONTENTTYPES_API_FUNCTIONAL_TESTING,
+)
+from plone import api
+from plone.app.testing import setRoles
+from plone.app.testing import SITE_OWNER_NAME
+from plone.app.testing import SITE_OWNER_PASSWORD
+from plone.app.testing import TEST_USER_ID
+from plone.namedfile.file import NamedBlobFile
+from plone.restapi.testing import RelativeSession
+from transaction import commit
+
+import unittest
+
+
+class FileFieldSerializerTest(unittest.TestCase):
+    layer = DESIGN_PLONE_CONTENTTYPES_API_FUNCTIONAL_TESTING
+
+    def setUp(self):
+        self.app = self.layer["app"]
+        self.portal = self.layer["portal"]
+        self.request = self.layer["request"]
+        self.portal_url = self.portal.absolute_url()
+
+        self.api_session = RelativeSession(self.portal_url)
+        self.api_session.headers.update({"Accept": "application/json"})
+        self.api_session.auth = (SITE_OWNER_NAME, SITE_OWNER_PASSWORD)
+
+        setRoles(self.portal, TEST_USER_ID, ["Manager"])
+
+        self.cartella_modulistica = api.content.create(
+            container=self.portal,
+            type="CartellaModulistica",
+            title="Cartella Modulistica",
+        )
+        self.document = api.content.create(
+            container=self.cartella_modulistica, type="Documento", title="Document"
+        )
+        self.modulo = api.content.create(
+            container=self.document,
+            type="Modulo",
+            title="Modulo",
+            file_principale=NamedBlobFile("some data", filename="file.pdf"),
+        )
+        commit()
+
+    def tearDown(self):
+        self.api_session.close()
+
+    def test_if_anteprima_file_false_so_download(self):
+        response = self.api_session.get(self.modulo.absolute_url()).json()
+
+        self.assertIn("@@download", response["file_principale"]["download"])
+
+    def test_if_anteprima_file_true_so_dsiplay(self):
+        self.cartella_modulistica.anteprima_file = True
+
+        commit()
+
+        response = self.api_session.get(self.modulo.absolute_url()).json()
+        self.assertIn("@@display-file", response["file_principale"]["download"])
+
+    def test_if_enhancedlinks_behavior_active_has_human_readable_obj_size_in_data(self):
+        response = self.api_session.get(self.modulo.absolute_url()).json()
+        self.assertEqual("1 KB", response["file_principale"]["getObjSize"])
+
+    def test_if_enhancedlinks_behavior_active_has_flag_in_data(self):
+        response = self.api_session.get(self.modulo.absolute_url()).json()
+        self.assertIn("enhanced_links_enabled", response["file_principale"])
+        self.assertTrue(response["file_principale"]["enhanced_links_enabled"])