From c4d0c0e9daa49a9c742a6000cfe231965b247444 Mon Sep 17 00:00:00 2001
From: Julian Stirling <julian@julianstirling.co.uk>
Date: Tue, 10 Mar 2026 15:25:04 +0000
Subject: [PATCH] Explicit header, text and bullet blocks rather than one HTML
 block in ui spec

---
 .../things/scan_workflows.py                  |  9 ++-
 src/openflexure_microscope_server/ui.py       | 60 +++++++++++--------
 .../data/html_sanitisation_test_cases.md      | 13 +++-
 tests/unit_tests/test_scan_workflows.py       | 29 +++++----
 .../serverSpecifiedInterface.vue              | 12 +++-
 5 files changed, 82 insertions(+), 41 deletions(-)

diff --git a/src/openflexure_microscope_server/things/scan_workflows.py b/src/openflexure_microscope_server/things/scan_workflows.py
index 7679207a..1bf5b826 100644
--- a/src/openflexure_microscope_server/things/scan_workflows.py
+++ b/src/openflexure_microscope_server/things/scan_workflows.py
@@ -42,7 +42,8 @@ from openflexure_microscope_server.things.stage import BaseStage
 from openflexure_microscope_server.ui import (
     UI_ELEMENT_RESPONSE,
     Accordion,
-    HTMLBlock,
+    HeaderBlock,
+    TextBlock,
     UIElementList,
     action_button_for,
     property_control_for,
@@ -642,7 +643,8 @@ class HistoScanWorkflow(RectGridWorkflow[HistoScanSettingsModel]):
 
         return UIElementList(
             [
-                HTMLBlock(html=f"<h4>{self.display_name}</h4><p>{self.ui_blurb}<p>"),
+                HeaderBlock(text=self.display_name, level=4),
+                TextBlock(text=self.ui_blurb),
                 Accordion(title="Background Detect", children=background_ui),
                 Accordion(
                     title="Scan Settings",
@@ -750,7 +752,8 @@ class RegularGridWorkflow(RectGridWorkflow[RegularGridSettingsModel]):
         )
         return UIElementList(
             [
-                HTMLBlock(html=f"<h4>{self.display_name}</h4><p>{self.ui_blurb}<p>"),
+                HeaderBlock(text=self.display_name, level=4),
+                TextBlock(text=self.ui_blurb),
                 Accordion(
                     title="Scan Settings",
                     children=scan_settings,
diff --git a/src/openflexure_microscope_server/ui.py b/src/openflexure_microscope_server/ui.py
index b6692785..2524515e 100644
--- a/src/openflexure_microscope_server/ui.py
+++ b/src/openflexure_microscope_server/ui.py
@@ -5,24 +5,12 @@ from html.parser import HTMLParser
 from typing import Annotated, Any, Literal, Optional
 from urllib.parse import urlparse
 
-from pydantic import BaseModel, BeforeValidator, RootModel
+from pydantic import BaseModel, BeforeValidator, Field, RootModel
 
 import labthings_fastapi as lt
 
-ALLOWED_TAGS = {
-    "p",
-    "i",
-    "b",
-    "h1",
-    "h2",
-    "h3",
-    "h4",
-    "h5",
-    "h6",
-    "ul",
-    "li",
-    "a",
-}
+# Only allowed tags are italic, bold, and link. Also allows self closing br tags.
+ALLOWED_TAGS = {"i", "b", "a"}
 
 ALLOWED_SCHEMES = {"http", "https"}
 
@@ -116,8 +104,7 @@ class SafeHTMLParser(HTMLParser):
 def sanitise_html(html: str) -> str:
     """Santitise HTML to only have a small list of allowed tags.
 
-    Tags allowed without attrs: ``<p>, <i>, <b>, <h1>, <h2>, <h3>, <h4>, <h5>, <h6>,``
-    ``<ul>, <li>``
+    Tags allowed without attrs: ``<i>, <b>,``
 
     Tags allowed with attrs: ``<a>`` is allowed with ``href`` only. This automatically
     appends ``target="_blank" rel="noopener noreferrer"`` so the link opens externally.
@@ -137,14 +124,31 @@ def sanitise_html(html: str) -> str:
 HtmlFragment = Annotated[str, BeforeValidator(sanitise_html)]
 
 
-class HTMLBlock(BaseModel):
-    """The data required for creating a block of HTML for the UI.
+class HeaderBlock(BaseModel):
+    """The data required for header."""
 
-    The HTML is limited to a small number of tags.
-    """
+    element_type: Literal["header_block"] = "header_block"
+    text: HtmlFragment
+    """The header text (can include basic HTML tags)."""
 
-    element_type: Literal["html_block"] = "html_block"
-    html: HtmlFragment
+    level: int = Field(default=2, ge=1, le=6)
+    """The header level. A number from 1-6."""
+
+
+class TextBlock(BaseModel):
+    """The data required for creating a block text."""
+
+    element_type: Literal["text_block"] = "text_block"
+    text: HtmlFragment
+    """The text (can include basic HTML tags)."""
+
+
+class BulletBlock(BaseModel):
+    """The data required for creating a block text."""
+
+    element_type: Literal["bullet_block"] = "bullet_block"
+    bullets: list[HtmlFragment]
+    """A list of text elements (can include basic HTML tags)."""
 
 
 class ActionButton(BaseModel):
@@ -304,7 +308,15 @@ class Container(BaseModel):
     children: "UIElementList"
 
 
-UIElementModels = HTMLBlock | PropertyControl | ActionButton | Accordion | Container
+UIElementModels = (
+    HeaderBlock
+    | TextBlock
+    | BulletBlock
+    | PropertyControl
+    | ActionButton
+    | Accordion
+    | Container
+)
 
 
 class UIElementList(RootModel[list[UIElementModels]]):
diff --git a/tests/unit_tests/data/html_sanitisation_test_cases.md b/tests/unit_tests/data/html_sanitisation_test_cases.md
index 2e550d78..f1488883 100644
--- a/tests/unit_tests/data/html_sanitisation_test_cases.md
+++ b/tests/unit_tests/data/html_sanitisation_test_cases.md
@@ -20,7 +20,7 @@ The script is removed but the contents remain.
 ### Result
 ```html
 alert(&quot;x&quot;)
-<p>Hello</p>
+Hello
 ```
 ## Test script in bold tag
 
@@ -81,4 +81,15 @@ Remove the javascript from the links.
 ### Result
 ```html
 <a href="https://openflexure.org" target="_blank" rel="noopener noreferrer">OpenFlexure</a>
+```
+
+## Test basic formatting preserved
+Check basic elements are not changed
+### Input
+```html
+This is <b>bold</b> <i>italic</i> and on a new <br/> line.
+```
+### Result
+```html
+This is <b>bold</b> <i>italic</i> and on a new <br/> line.
 ```
\ No newline at end of file
diff --git a/tests/unit_tests/test_scan_workflows.py b/tests/unit_tests/test_scan_workflows.py
index b9f0fa07..0ffa4a00 100644
--- a/tests/unit_tests/test_scan_workflows.py
+++ b/tests/unit_tests/test_scan_workflows.py
@@ -21,8 +21,9 @@ from openflexure_microscope_server.things.scan_workflows import (
 from openflexure_microscope_server.ui import (
     Accordion,
     ActionButton,
-    HTMLBlock,
+    HeaderBlock,
     PropertyControl,
+    TextBlock,
     UIElementList,
 )
 
@@ -385,20 +386,24 @@ def test_histo_workflow_settings_ui(histo_workflow, mocker):
 
     ui = histo_workflow.settings_ui().root
 
-    # The UI is in 3 blocks
-    assert len(ui) == 3
-    # The top HTML block
-    assert isinstance(ui[0], HTMLBlock)
-    assert "<h4>Histo Scan</h4>" in ui[0].html
+    # The UI is in 4 blocks
+    assert len(ui) == 4
+    # The top is a header
+    assert isinstance(ui[0], HeaderBlock)
+    assert ui[0].text == "Histo Scan"
+    # The then some text (note the & is escaped)
+    assert isinstance(ui[1], TextBlock)
+    fragment = "This scan workflow is optimised for scanning H&amp;E stained biopsies."
+    assert fragment in ui[1].text
     # Followed by a background detect accordion
-    assert isinstance(ui[1], Accordion)
-    assert ui[1].title == "Background Detect"
-    # And a Scan Settings accordion
     assert isinstance(ui[2], Accordion)
-    assert ui[2].title == "Scan Settings"
+    assert ui[2].title == "Background Detect"
+    # And a Scan Settings accordion
+    assert isinstance(ui[3], Accordion)
+    assert ui[3].title == "Scan Settings"
 
     # Background UI is ...
-    background_ui = ui[1].children.root
+    background_ui = ui[2].children.root
     # what the detector specifies as it settings ...
     assert background_ui[0] is mock_prop_control
     # plus 2 action buttons
@@ -409,7 +414,7 @@ def test_histo_workflow_settings_ui(histo_workflow, mocker):
     assert background_ui[2].action == "check_background"
 
     # Finally check the contents of the scan settings accordion
-    scan_settings = ui[2].children.root
+    scan_settings = ui[3].children.root
     assert len(scan_settings) == 8
     for element in scan_settings:
         assert isinstance(element, PropertyControl)
diff --git a/webapp/src/components/labThingsComponents/serverSpecifiedInterface.vue b/webapp/src/components/labThingsComponents/serverSpecifiedInterface.vue
index 10aa5636..f69ae102 100644
--- a/webapp/src/components/labThingsComponents/serverSpecifiedInterface.vue
+++ b/webapp/src/components/labThingsComponents/serverSpecifiedInterface.vue
@@ -1,7 +1,17 @@
 <template>
   <div v-for="(element, index) in elements" :key="index" class="uk-margin">
     <!-- eslint-disable vue/no-v-html -->
-    <div v-if="element.element_type === 'html_block'" v-html="element.html"></div>
+    <component :is="'h' + element.level" v-if="element.element_type === 'header_block'">
+      <span v-html="element.text"></span>
+    </component>
+    <p v-if="element.element_type === 'text_block'" v-html="element.text"></p>
+    <ul v-if="element.element_type === 'bullet_block'">
+      <li
+        v-for="(bulletText, bulletIndex) in element.bullets"
+        :key="'bullet-' + bulletIndex"
+        v-html="bulletText"
+      ></li>
+    </ul>
     <!-- eslint-enable -->
     <server-specified-property-control
       v-else-if="element.element_type === 'property_control'"