From 8261ef36b577fa91b0e264c4eb4d4afb8ca1b068 Mon Sep 17 00:00:00 2001
From: Sanket17052006 <sanket17052006@gmail.com>
Date: Thu, 21 May 2026 00:08:45 +0530
Subject: [PATCH 1/5] refactor: Convert AffiliateLinks.html.jinja to Jinja

---
 openlibrary/macros/AffiliateLinks.html.jinja  |  33 ++
 openlibrary/plugins/openlibrary/partials.py   |  67 +++-
 .../tests/test_jinja_experiment.py            | 327 ++++++++++++++++++
 requirements.txt                              |   1 +
 4 files changed, 426 insertions(+), 2 deletions(-)
 create mode 100644 openlibrary/macros/AffiliateLinks.html.jinja
 create mode 100644 openlibrary/plugins/openlibrary/tests/test_jinja_experiment.py

diff --git a/openlibrary/macros/AffiliateLinks.html.jinja b/openlibrary/macros/AffiliateLinks.html.jinja
new file mode 100644
index 00000000000..bf780a9e45b
--- /dev/null
+++ b/openlibrary/macros/AffiliateLinks.html.jinja
@@ -0,0 +1,33 @@
+{% macro affiliate_link(store) %}
+  <li class="prices-{{ store.key }}">
+      <a href="{{ store.link }}"
+         title="{{ _('Look for this edition for sale at %(store)s', store=store.name) }}"
+         data-ol-link-track="BuyLink|{{ store.analytics_key }}"
+         target="_blank" rel="noopener noreferrer">{{ store.name }}</a>
+      {% if store.price %}
+        <br>
+        <span name="price">{{ store.price }}{{ store.price_note }}</span>
+      {% endif %}
+  </li>
+{% endmacro %}
+
+<span class="affiliate-links-section">
+  <ul class="buy-options-table">
+      {% for store in primary_stores %}
+        {{ affiliate_link(store) | safe }}
+      {% endfor %}
+      {% if more_stores %}
+        <li class="more">
+          <details>
+            <summary>{{ _('More') }}</summary>
+            <ul>
+              {% for store in more_stores %}
+                {{ affiliate_link(store) | safe }}
+              {% endfor %}
+            </ul>
+          </details>
+        </li>
+      {% endif %}
+  </ul>
+  <small>{{ _('When you buy books using these links the Internet Archive may earn a <a class="nostyle" href="/help/faq/about#selling">small commission</a>.') | safe }}</small>
+</span>
diff --git a/openlibrary/plugins/openlibrary/partials.py b/openlibrary/plugins/openlibrary/partials.py
index 9a5fd963a7e..dc2f0b51920 100644
--- a/openlibrary/plugins/openlibrary/partials.py
+++ b/openlibrary/plugins/openlibrary/partials.py
@@ -1,9 +1,15 @@
+import logging
+import os
+import re
+import time as _time
 from dataclasses import dataclass
 from hashlib import md5
+from pathlib import Path
 from typing import Literal, NotRequired, TypedDict
 from urllib.parse import parse_qs, quote, quote_plus
 
 import web
+from jinja2 import Environment, FileSystemLoader
 from pydantic import BaseModel
 
 from infogami.utils.view import public, render_template
@@ -19,7 +25,6 @@
     get_betterworldbooks_metadata,
 )
 from openlibrary.i18n import gettext as _
-from openlibrary.plugins.openlibrary.code import is_bot
 from openlibrary.plugins.openlibrary.lists import get_lists_async, get_user_lists
 from openlibrary.plugins.upstream.utils import render_macro
 from openlibrary.plugins.upstream.yearly_reading_goals import get_reading_goals
@@ -292,6 +297,38 @@ def build_more_stores(ctx: AffiliateStoreBuildContext) -> list[AffiliateStore]:
     ]
 
 
+_JINJA_ENV = Environment(
+    loader=FileSystemLoader(
+        Path(__file__).resolve().parent.parent.parent / "macros"
+    ),
+    autoescape=True,
+)
+_JINJA_ENV.globals["_"] = _
+
+logger = logging.getLogger("openlibrary.partials")
+_EXPERIMENT_LOGGER = logging.getLogger("openlibrary.jinja_experiment")
+_JINJA_EXPERIMENT_ENABLED = os.getenv("OL_JINJA_EXPERIMENT") == "1"
+
+
+def _normalize_html(html: str) -> str:
+    """Collapse all non-semantic whitespace in HTML for comparison between engines."""
+    html = re.sub(r">\s+<", "><", html)
+    html = re.sub(r"\s{2,}", " ", html)
+    return html.strip()
+
+
+def _render_affiliate_links_jinja(
+    primary_stores: list[AffiliateStore],
+    more_stores: list[AffiliateStore],
+) -> str:
+    """Render affiliate links using Jinja2 for experiment comparison."""
+    template = _JINJA_ENV.get_template("AffiliateLinks.html.jinja")
+    return template.render(
+        primary_stores=primary_stores,
+        more_stores=more_stores,
+    )
+
+
 class AffiliateLinksPartial:
     """Handler for affiliate links"""
 
@@ -302,6 +339,8 @@ async def generate_async(
         asin: str | None,
         prices: bool,
     ) -> dict:
+        from openlibrary.plugins.openlibrary.code import is_bot
+
         bwb_metadata = None
         amz_metadata = None
         should_fetch_prices = not is_bot() and prices
@@ -317,8 +356,32 @@ async def generate_async(
 
         primary_stores = build_primary_stores(ctx)
         more_stores = build_more_stores(ctx)
+
+        t0 = _time.perf_counter()
         macro = web.template.Template.globals["macros"].AffiliateLinks(primary_stores, more_stores)
-        return {"partials": str(macro)}
+        templetor_html = str(macro)
+        t1 = _time.perf_counter()
+
+        if _JINJA_EXPERIMENT_ENABLED:
+            t2 = _time.perf_counter()
+            try:
+                jinja2_html = _render_affiliate_links_jinja(primary_stores, more_stores)
+                t3 = _time.perf_counter()
+                match = _normalize_html(templetor_html) == _normalize_html(jinja2_html)
+                _EXPERIMENT_LOGGER.info(
+                    "Jinja2 experiment | match=%s templetor_ms=%.2f jinja2_ms=%.2f | title=%s isbn=%s",
+                    match,
+                    (t1 - t0) * 1000,
+                    (t3 - t2) * 1000,
+                    title,
+                    isbn,
+                )
+            except Exception:
+                _EXPERIMENT_LOGGER.exception(
+                    "Jinja2 experiment failed | title=%s isbn=%s", title, isbn,
+                )
+
+        return {"partials": templetor_html}
 
 
 class SearchFacetsPartial:
diff --git a/openlibrary/plugins/openlibrary/tests/test_jinja_experiment.py b/openlibrary/plugins/openlibrary/tests/test_jinja_experiment.py
new file mode 100644
index 00000000000..62399731f17
--- /dev/null
+++ b/openlibrary/plugins/openlibrary/tests/test_jinja_experiment.py
@@ -0,0 +1,327 @@
+"""Tests for the Phase 3 Jinja2 template experiment.
+
+Validates that the Jinja2 AffiliateLinks template renders correctly
+and produces semantically equivalent HTML to the Templetor template.
+
+Uses Jinja2 directly (not via partials.py) to avoid web.py dependency
+which is unavailable on Python 3.14+.
+"""
+
+from dataclasses import dataclass
+from pathlib import Path
+
+import pytest
+
+JINJA2_AVAILABLE = False
+try:
+    import jinja2  # noqa: F401
+except ImportError:
+    pass
+else:
+    JINJA2_AVAILABLE = True
+
+WEBPY_AVAILABLE = False
+WEBPY_GETTEXT = None
+try:
+    import web
+
+    WEBPY_AVAILABLE = True
+except ImportError:
+    pass
+
+if WEBPY_AVAILABLE:
+    def _gettext_stub(message, *args, **kwargs):
+        if kwargs:
+            return message % kwargs
+        return message
+
+    WEBPY_GETTEXT = _gettext_stub
+
+
+PROJECT_ROOT = Path(__file__).resolve().parent.parent.parent.parent
+MACROS_DIR = PROJECT_ROOT / "macros"
+
+
+def _make_jinja_env():
+    """Create a Jinja2 environment configured like the production experiment."""
+    from jinja2 import Environment, FileSystemLoader
+
+    env = Environment(
+        loader=FileSystemLoader(str(MACROS_DIR)),
+        autoescape=True,
+    )
+
+    def fake_gettext(message: str, **kwargs) -> str:
+        if kwargs:
+            return message % kwargs
+        return message
+
+    env.globals["_"] = fake_gettext
+    return env
+
+
+def _normalize_html(html: str) -> str:
+    """Collapse all non-semantic whitespace in HTML for comparison between engines."""
+    import re
+
+    html = re.sub(r">\s+<", "><", html)
+    html = re.sub(r"\s{2,}", " ", html)
+    return html.strip()
+
+
+@pytest.fixture(scope="module")
+def jinja_env():
+    return _make_jinja_env()
+
+
+@pytest.fixture(scope="module")
+def affiliate_links_template(jinja_env):
+    return jinja_env.get_template("AffiliateLinks.html.jinja")
+
+
+# --- Test data objects ---
+
+
+@dataclass
+class _AffiliateStore:
+    key: str
+    analytics_key: str
+    name: str
+    link: str
+    price: str | None = None
+    price_note: str = ""
+
+
+# --- _normalize_html tests ---
+
+
+class TestNormalizeHtml:
+    def test_collapses_whitespace_between_tags(self):
+        assert _normalize_html("<div>  <span>a</span>  </div>") == "<div><span>a</span></div>"
+
+    def test_preserves_inner_text_whitespace(self):
+        assert _normalize_html("<span>hello world</span>") == "<span>hello world</span>"
+
+    def test_empty_string(self):
+        assert _normalize_html("") == ""
+
+    def test_strips_outer_whitespace(self):
+        assert _normalize_html("  <div>text</div>  ") == "<div>text</div>"
+
+
+# --- Jinja2 rendering tests ---
+
+
+class TestJinja2TemplateRendering:
+    """Tests that the Jinja2 template renders without errors and produces expected output."""
+
+    def test_renders_empty_stores(self, affiliate_links_template):
+        result = affiliate_links_template.render(primary_stores=[], more_stores=[])
+        assert '<span class="affiliate-links-section">' in result
+        assert '<ul class="buy-options-table">' in result
+
+    def test_contains_small_commission_text(self, affiliate_links_template):
+        result = affiliate_links_template.render(primary_stores=[], more_stores=[])
+        assert "small commission" in result
+        assert "help/faq/about" in result
+
+    def test_renders_single_primary_store(self, affiliate_links_template):
+        stores = [
+            _AffiliateStore(
+                key="amazon",
+                analytics_key="Amazon",
+                name="Amazon",
+                link="https://amazon.com/dp/123",
+                price="$10.00",
+                price_note="",
+            ),
+        ]
+        result = affiliate_links_template.render(primary_stores=stores, more_stores=[])
+        assert 'prices-amazon' in result
+        assert "Amazon" in result
+        assert "$10.00" in result
+
+    def test_renders_store_without_price(self, affiliate_links_template):
+        stores = [
+            _AffiliateStore(
+                key="bookshop-org",
+                analytics_key="BookshopOrg",
+                name="Bookshop.org",
+                link="https://bookshop.org/a/test/123",
+            ),
+        ]
+        result = affiliate_links_template.render(primary_stores=stores, more_stores=[])
+        assert "Bookshop.org" in result
+        assert "price" not in result or result.count('<span name="price">') == 0
+
+    def test_renders_more_stores_section(self, affiliate_links_template):
+        stores = [
+            _AffiliateStore(
+                key="amazon", analytics_key="Amazon", name="Amazon", link="https://amazon.com/dp/123"
+            ),
+        ]
+        more = [
+            _AffiliateStore(
+                key="bookshop-org",
+                analytics_key="BookshopOrg",
+                name="Bookshop.org",
+                link="https://bookshop.org/a/test/123",
+            ),
+        ]
+        result = affiliate_links_template.render(primary_stores=stores, more_stores=more)
+        assert "<summary>" in result
+        assert "Bookshop.org" in result
+
+    def test_no_more_stores_section_when_empty(self, affiliate_links_template):
+        stores = [
+            _AffiliateStore(
+                key="amazon", analytics_key="Amazon", name="Amazon", link="https://amazon.com/dp/123"
+            ),
+        ]
+        result = affiliate_links_template.render(primary_stores=stores, more_stores=[])
+        assert "<summary>" not in result
+
+    def test_special_characters_escaped(self, affiliate_links_template):
+        stores = [
+            _AffiliateStore(
+                key="amazon",
+                analytics_key="Amazon",
+                name="Amazon & Co.",
+                link="https://amazon.com/dp/123?tag=a&b=c",
+                price="$10 & up",
+                price_note=" + tax",
+            ),
+        ]
+        result = affiliate_links_template.render(primary_stores=stores, more_stores=[])
+        assert 'href="https://amazon.com/dp/123?tag=a&amp;b=c"' in result
+        assert "Amazon &amp; Co." in result
+        assert "$10 &amp; up" in result
+
+    def test_all_fields_present_in_output(self, affiliate_links_template):
+        stores = [
+            _AffiliateStore(
+                key="test-key",
+                analytics_key="TestAnalytics",
+                name="Test Store",
+                link="https://example.com/book",
+                price="$19.99",
+                price_note=" - note",
+            ),
+        ]
+        result = affiliate_links_template.render(primary_stores=stores, more_stores=[])
+        assert "prices-test-key" in result
+        assert "TestAnalytics" in result
+        assert "Test Store" in result
+        assert "https://example.com/book" in result
+        assert "$19.99" in result
+        assert " - note" in result
+
+    def test_output_analytics_tracking_attr(self, affiliate_links_template):
+        stores = [
+            _AffiliateStore(
+                key="amazon",
+                analytics_key="Amazon",
+                name="Amazon",
+                link="https://amazon.com/dp/123",
+            ),
+        ]
+        result = affiliate_links_template.render(primary_stores=stores, more_stores=[])
+        assert 'data-ol-link-track="BuyLink|Amazon"' in result
+
+
+# --- Equivalence tests (need web.py for Templetor) ---
+
+
+@pytest.mark.skipif(not WEBPY_AVAILABLE or WEBPY_GETTEXT is None, reason="web.py or gettext not available")
+class TestTempletorEquivalence:
+    """Compares Jinja2 output against Templetor output for the same inputs.
+
+    Requires web.py (web-py) to be installed, which is only available
+    on Python 3.12 or earlier.
+    """
+
+    @pytest.fixture(scope="class")
+    def templetor_template(self):
+        web.template.Template.globals["_"] = WEBPY_GETTEXT
+        source = (MACROS_DIR / "AffiliateLinks.html").read_text()
+        return web.template.Template(source)
+
+    def _render_both(self, templetor_template, affiliate_links_template, stores, more):
+        templetor_html = str(templetor_template(stores, more))
+        jinja2_html = affiliate_links_template.render(
+            primary_stores=stores, more_stores=more
+        )
+        return templetor_html, jinja2_html
+
+    def test_empty_stores_match(self, templetor_template, affiliate_links_template):
+        t, j = self._render_both(templetor_template, affiliate_links_template, [], [])
+        assert _normalize_html(t) == _normalize_html(j)
+
+    def test_primary_stores_only_match(self, templetor_template, affiliate_links_template):
+        stores = [
+            _AffiliateStore(
+                key="betterworldbooks",
+                analytics_key="BetterWorldBooks",
+                name="Better World Books",
+                link="https://www.betterworldbooks.com/product/detail/123",
+                price="$9.99",
+                price_note=" - includes shipping",
+            ),
+            _AffiliateStore(
+                key="amazon",
+                analytics_key="Amazon",
+                name="Amazon",
+                link="https://www.amazon.com/dp/123/?tag=test",
+                price="$14.99",
+                price_note="",
+            ),
+        ]
+        t, j = self._render_both(templetor_template, affiliate_links_template, stores, [])
+        assert _normalize_html(t) == _normalize_html(j)
+
+    def test_primary_and_more_stores_match(self, templetor_template, affiliate_links_template):
+        stores = [
+            _AffiliateStore(
+                key="amazon", analytics_key="Amazon", name="Amazon", link="https://amazon.com/dp/123"
+            ),
+        ]
+        more = [
+            _AffiliateStore(
+                key="bookshop-org",
+                analytics_key="BookshopOrg",
+                name="Bookshop.org",
+                link="https://bookshop.org/a/test/123",
+            ),
+        ]
+        t, j = self._render_both(templetor_template, affiliate_links_template, stores, more)
+        assert _normalize_html(t) == _normalize_html(j)
+
+    def test_multiple_stores_detailed_match(self, templetor_template, affiliate_links_template):
+        stores = [
+            _AffiliateStore(
+                key="betterworldbooks",
+                analytics_key="BetterWorldBooks",
+                name="Better World Books",
+                link="https://www.betterworldbooks.com/product/detail/9781234567890",
+                price="$4.99",
+                price_note=" - includes shipping",
+            ),
+            _AffiliateStore(
+                key="amazon",
+                analytics_key="Amazon",
+                name="Amazon.com",
+                link="https://www.amazon.com/dp/9781234567890/?tag=ol-20",
+                price="$12.50",
+                price_note="",
+            ),
+        ]
+        more = [
+            _AffiliateStore(
+                key="bookshop-org",
+                analytics_key="BookshopOrg",
+                name="Bookshop.org",
+                link="https://bookshop.org/a/1234/9781234567890",
+            ),
+        ]
+        t, j = self._render_both(templetor_template, affiliate_links_template, stores, more)
+        assert _normalize_html(t) == _normalize_html(j)
diff --git a/requirements.txt b/requirements.txt
index c3867b86b3a..a73c1d7273d 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -14,6 +14,7 @@ git+https://github.com/webpy/webpy.git@d3649322b85777b291ac2b7b3699fb6fc839e382
 gunicorn==23.0.0
 httpx==0.28.1
 ijson==3.5.0
+Jinja2>=3.1.6
 internetarchive==5.8.0
 isbnlib==3.10.14
 luqum==0.11.0

From 9559a8d2a83f320d8826980a05f03db69cda3ab1 Mon Sep 17 00:00:00 2001
From: "pre-commit-ci[bot]"
 <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Date: Wed, 20 May 2026 19:02:59 +0000
Subject: [PATCH 2/5] [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci
---
 openlibrary/plugins/openlibrary/partials.py   |  8 ++++----
 .../tests/test_jinja_experiment.py            | 19 ++++++-------------
 requirements.txt                              |  2 +-
 3 files changed, 11 insertions(+), 18 deletions(-)

diff --git a/openlibrary/plugins/openlibrary/partials.py b/openlibrary/plugins/openlibrary/partials.py
index dc2f0b51920..453c5977e13 100644
--- a/openlibrary/plugins/openlibrary/partials.py
+++ b/openlibrary/plugins/openlibrary/partials.py
@@ -298,9 +298,7 @@ def build_more_stores(ctx: AffiliateStoreBuildContext) -> list[AffiliateStore]:
 
 
 _JINJA_ENV = Environment(
-    loader=FileSystemLoader(
-        Path(__file__).resolve().parent.parent.parent / "macros"
-    ),
+    loader=FileSystemLoader(Path(__file__).resolve().parent.parent.parent / "macros"),
     autoescape=True,
 )
 _JINJA_ENV.globals["_"] = _
@@ -378,7 +376,9 @@ async def generate_async(
                 )
             except Exception:
                 _EXPERIMENT_LOGGER.exception(
-                    "Jinja2 experiment failed | title=%s isbn=%s", title, isbn,
+                    "Jinja2 experiment failed | title=%s isbn=%s",
+                    title,
+                    isbn,
                 )
 
         return {"partials": templetor_html}
diff --git a/openlibrary/plugins/openlibrary/tests/test_jinja_experiment.py b/openlibrary/plugins/openlibrary/tests/test_jinja_experiment.py
index 62399731f17..37913945b9a 100644
--- a/openlibrary/plugins/openlibrary/tests/test_jinja_experiment.py
+++ b/openlibrary/plugins/openlibrary/tests/test_jinja_experiment.py
@@ -30,6 +30,7 @@
     pass
 
 if WEBPY_AVAILABLE:
+
     def _gettext_stub(message, *args, **kwargs):
         if kwargs:
             return message % kwargs
@@ -137,7 +138,7 @@ def test_renders_single_primary_store(self, affiliate_links_template):
             ),
         ]
         result = affiliate_links_template.render(primary_stores=stores, more_stores=[])
-        assert 'prices-amazon' in result
+        assert "prices-amazon" in result
         assert "Amazon" in result
         assert "$10.00" in result
 
@@ -156,9 +157,7 @@ def test_renders_store_without_price(self, affiliate_links_template):
 
     def test_renders_more_stores_section(self, affiliate_links_template):
         stores = [
-            _AffiliateStore(
-                key="amazon", analytics_key="Amazon", name="Amazon", link="https://amazon.com/dp/123"
-            ),
+            _AffiliateStore(key="amazon", analytics_key="Amazon", name="Amazon", link="https://amazon.com/dp/123"),
         ]
         more = [
             _AffiliateStore(
@@ -174,9 +173,7 @@ def test_renders_more_stores_section(self, affiliate_links_template):
 
     def test_no_more_stores_section_when_empty(self, affiliate_links_template):
         stores = [
-            _AffiliateStore(
-                key="amazon", analytics_key="Amazon", name="Amazon", link="https://amazon.com/dp/123"
-            ),
+            _AffiliateStore(key="amazon", analytics_key="Amazon", name="Amazon", link="https://amazon.com/dp/123"),
         ]
         result = affiliate_links_template.render(primary_stores=stores, more_stores=[])
         assert "<summary>" not in result
@@ -248,9 +245,7 @@ def templetor_template(self):
 
     def _render_both(self, templetor_template, affiliate_links_template, stores, more):
         templetor_html = str(templetor_template(stores, more))
-        jinja2_html = affiliate_links_template.render(
-            primary_stores=stores, more_stores=more
-        )
+        jinja2_html = affiliate_links_template.render(primary_stores=stores, more_stores=more)
         return templetor_html, jinja2_html
 
     def test_empty_stores_match(self, templetor_template, affiliate_links_template):
@@ -281,9 +276,7 @@ def test_primary_stores_only_match(self, templetor_template, affiliate_links_tem
 
     def test_primary_and_more_stores_match(self, templetor_template, affiliate_links_template):
         stores = [
-            _AffiliateStore(
-                key="amazon", analytics_key="Amazon", name="Amazon", link="https://amazon.com/dp/123"
-            ),
+            _AffiliateStore(key="amazon", analytics_key="Amazon", name="Amazon", link="https://amazon.com/dp/123"),
         ]
         more = [
             _AffiliateStore(
diff --git a/requirements.txt b/requirements.txt
index a73c1d7273d..c067ed4fa66 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -14,9 +14,9 @@ git+https://github.com/webpy/webpy.git@d3649322b85777b291ac2b7b3699fb6fc839e382
 gunicorn==23.0.0
 httpx==0.28.1
 ijson==3.5.0
-Jinja2>=3.1.6
 internetarchive==5.8.0
 isbnlib==3.10.14
+Jinja2>=3.1.6
 luqum==0.11.0
 lxml==6.1.0
 multipart==1.3.1

From 4cdaf21d63d69a2663bb72b241409e5d35b52fbd Mon Sep 17 00:00:00 2001
From: Sanket17052006 <sanket17052006@gmail.com>
Date: Sat, 23 May 2026 11:34:29 +0530
Subject: [PATCH 3/5] fix:  remove unused logger and improve test

---
 openlibrary/plugins/openlibrary/partials.py                   | 1 -
 .../plugins/openlibrary/tests/test_jinja_experiment.py        | 4 ++++
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/openlibrary/plugins/openlibrary/partials.py b/openlibrary/plugins/openlibrary/partials.py
index 453c5977e13..4ae90c65de3 100644
--- a/openlibrary/plugins/openlibrary/partials.py
+++ b/openlibrary/plugins/openlibrary/partials.py
@@ -303,7 +303,6 @@ def build_more_stores(ctx: AffiliateStoreBuildContext) -> list[AffiliateStore]:
 )
 _JINJA_ENV.globals["_"] = _
 
-logger = logging.getLogger("openlibrary.partials")
 _EXPERIMENT_LOGGER = logging.getLogger("openlibrary.jinja_experiment")
 _JINJA_EXPERIMENT_ENABLED = os.getenv("OL_JINJA_EXPERIMENT") == "1"
 
diff --git a/openlibrary/plugins/openlibrary/tests/test_jinja_experiment.py b/openlibrary/plugins/openlibrary/tests/test_jinja_experiment.py
index 37913945b9a..63f141dbed3 100644
--- a/openlibrary/plugins/openlibrary/tests/test_jinja_experiment.py
+++ b/openlibrary/plugins/openlibrary/tests/test_jinja_experiment.py
@@ -20,6 +20,10 @@
 else:
     JINJA2_AVAILABLE = True
 
+pytestmark = pytest.mark.skipif(
+    not JINJA2_AVAILABLE, reason="Jinja2 is not installed"
+)
+
 WEBPY_AVAILABLE = False
 WEBPY_GETTEXT = None
 try:

From 01464bf75a37164f1a7070a72087c052aa1cbb61 Mon Sep 17 00:00:00 2001
From: "pre-commit-ci[bot]"
 <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Date: Sat, 23 May 2026 06:12:07 +0000
Subject: [PATCH 4/5] [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci
---
 .../plugins/openlibrary/tests/test_jinja_experiment.py        | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/openlibrary/plugins/openlibrary/tests/test_jinja_experiment.py b/openlibrary/plugins/openlibrary/tests/test_jinja_experiment.py
index 63f141dbed3..6e931fea464 100644
--- a/openlibrary/plugins/openlibrary/tests/test_jinja_experiment.py
+++ b/openlibrary/plugins/openlibrary/tests/test_jinja_experiment.py
@@ -20,9 +20,7 @@
 else:
     JINJA2_AVAILABLE = True
 
-pytestmark = pytest.mark.skipif(
-    not JINJA2_AVAILABLE, reason="Jinja2 is not installed"
-)
+pytestmark = pytest.mark.skipif(not JINJA2_AVAILABLE, reason="Jinja2 is not installed")
 
 WEBPY_AVAILABLE = False
 WEBPY_GETTEXT = None

From f02bc8c5c6af65038588ab5a6e7002bbd98c8a8b Mon Sep 17 00:00:00 2001
From: Sanket17052006 <sanket17052006@gmail.com>
Date: Wed, 27 May 2026 14:15:06 +0530
Subject: [PATCH 5/5] switched to jinja=true query param and lazy Jinja env
 init

---
 openlibrary/fastapi/partials.py               |  4 +
 openlibrary/plugins/openlibrary/partials.py   | 74 +++++++------------
 .../tests/test_jinja_experiment.py            |  5 +-
 3 files changed, 35 insertions(+), 48 deletions(-)

diff --git a/openlibrary/fastapi/partials.py b/openlibrary/fastapi/partials.py
index 71e8f371e43..2718e4ca1f4 100644
--- a/openlibrary/fastapi/partials.py
+++ b/openlibrary/fastapi/partials.py
@@ -54,12 +54,15 @@ async def search_facets_partial(
 @router.get("/partials/AffiliateLinks.json", include_in_schema=SHOW_PARTIALS_IN_SCHEMA)
 async def affiliate_links_partial(
     data: Annotated[str, Query(description="JSON-encoded data with book information")],
+    jinja: Annotated[bool, Query(description="Use Jinja2 template instead of Templetor")] = False,
 ) -> dict:
     """
     Get affiliate links HTML for a book.
 
     The data parameter should contain:
     - args: list with [title, opts] where opts is a dict with optional isbn
+
+    Optionally pass jinja=true to render with the Jinja2 template (for testing).
     """
     try:
         parsed_data = json.loads(data)
@@ -76,6 +79,7 @@ async def affiliate_links_partial(
         isbn=opts.get("isbn", None),
         asin=opts.get("asin", None),
         prices=opts.get("prices", False),
+        jinja=jinja,
     )
 
 
diff --git a/openlibrary/plugins/openlibrary/partials.py b/openlibrary/plugins/openlibrary/partials.py
index 4ae90c65de3..eed56701f30 100644
--- a/openlibrary/plugins/openlibrary/partials.py
+++ b/openlibrary/plugins/openlibrary/partials.py
@@ -1,15 +1,11 @@
-import logging
-import os
-import re
-import time as _time
 from dataclasses import dataclass
+from functools import cache as functools_cache
 from hashlib import md5
 from pathlib import Path
 from typing import Literal, NotRequired, TypedDict
 from urllib.parse import parse_qs, quote, quote_plus
 
 import web
-from jinja2 import Environment, FileSystemLoader
 from pydantic import BaseModel
 
 from infogami.utils.view import public, render_template
@@ -297,29 +293,32 @@ def build_more_stores(ctx: AffiliateStoreBuildContext) -> list[AffiliateStore]:
     ]
 
 
-_JINJA_ENV = Environment(
-    loader=FileSystemLoader(Path(__file__).resolve().parent.parent.parent / "macros"),
-    autoescape=True,
-)
-_JINJA_ENV.globals["_"] = _
-
-_EXPERIMENT_LOGGER = logging.getLogger("openlibrary.jinja_experiment")
-_JINJA_EXPERIMENT_ENABLED = os.getenv("OL_JINJA_EXPERIMENT") == "1"
+@functools_cache
+def _get_jinja_env():
+    """Lazily initialize and return the Jinja2 environment (cached after first call).
 
-
-def _normalize_html(html: str) -> str:
-    """Collapse all non-semantic whitespace in HTML for comparison between engines."""
-    html = re.sub(r">\s+<", "><", html)
-    html = re.sub(r"\s{2,}", " ", html)
-    return html.strip()
+    Per Jinja docs, a single Environment instance should be reused to take
+    advantage of template compilation caching.
+    """
+    from jinja2 import Environment, FileSystemLoader, StrictUndefined
+
+    env = Environment(
+        loader=FileSystemLoader(Path(__file__).resolve().parent.parent.parent / "macros"),
+        autoescape=True,
+        undefined=StrictUndefined,
+        trim_blocks=True,
+        lstrip_blocks=True,
+    )
+    env.globals["_"] = _
+    return env
 
 
 def _render_affiliate_links_jinja(
     primary_stores: list[AffiliateStore],
     more_stores: list[AffiliateStore],
 ) -> str:
-    """Render affiliate links using Jinja2 for experiment comparison."""
-    template = _JINJA_ENV.get_template("AffiliateLinks.html.jinja")
+    """Render affiliate links using Jinja2."""
+    template = _get_jinja_env().get_template("AffiliateLinks.html.jinja")
     return template.render(
         primary_stores=primary_stores,
         more_stores=more_stores,
@@ -335,6 +334,7 @@ async def generate_async(
         isbn: str | None,
         asin: str | None,
         prices: bool,
+        jinja: bool = False,
     ) -> dict:
         from openlibrary.plugins.openlibrary.code import is_bot
 
@@ -354,33 +354,13 @@ async def generate_async(
         primary_stores = build_primary_stores(ctx)
         more_stores = build_more_stores(ctx)
 
-        t0 = _time.perf_counter()
-        macro = web.template.Template.globals["macros"].AffiliateLinks(primary_stores, more_stores)
-        templetor_html = str(macro)
-        t1 = _time.perf_counter()
-
-        if _JINJA_EXPERIMENT_ENABLED:
-            t2 = _time.perf_counter()
-            try:
-                jinja2_html = _render_affiliate_links_jinja(primary_stores, more_stores)
-                t3 = _time.perf_counter()
-                match = _normalize_html(templetor_html) == _normalize_html(jinja2_html)
-                _EXPERIMENT_LOGGER.info(
-                    "Jinja2 experiment | match=%s templetor_ms=%.2f jinja2_ms=%.2f | title=%s isbn=%s",
-                    match,
-                    (t1 - t0) * 1000,
-                    (t3 - t2) * 1000,
-                    title,
-                    isbn,
-                )
-            except Exception:
-                _EXPERIMENT_LOGGER.exception(
-                    "Jinja2 experiment failed | title=%s isbn=%s",
-                    title,
-                    isbn,
-                )
+        if jinja:
+            html = _render_affiliate_links_jinja(primary_stores, more_stores)
+        else:
+            macro = web.template.Template.globals["macros"].AffiliateLinks(primary_stores, more_stores)
+            html = str(macro)
 
-        return {"partials": templetor_html}
+        return {"partials": html}
 
 
 class SearchFacetsPartial:
diff --git a/openlibrary/plugins/openlibrary/tests/test_jinja_experiment.py b/openlibrary/plugins/openlibrary/tests/test_jinja_experiment.py
index 6e931fea464..913e88ab53b 100644
--- a/openlibrary/plugins/openlibrary/tests/test_jinja_experiment.py
+++ b/openlibrary/plugins/openlibrary/tests/test_jinja_experiment.py
@@ -47,11 +47,14 @@ def _gettext_stub(message, *args, **kwargs):
 
 def _make_jinja_env():
     """Create a Jinja2 environment configured like the production experiment."""
-    from jinja2 import Environment, FileSystemLoader
+    from jinja2 import Environment, FileSystemLoader, StrictUndefined
 
     env = Environment(
         loader=FileSystemLoader(str(MACROS_DIR)),
         autoescape=True,
+        undefined=StrictUndefined,
+        trim_blocks=True,
+        lstrip_blocks=True,
     )
 
     def fake_gettext(message: str, **kwargs) -> str: