Fix ZeroDivisionError when total mention count is zero

Guard the percentage calculation so it only renders when total > 0.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

add_links/api.py

@@ -1,4 +1,5 @@
 import re
+import sys
 import typing
 
 import requests
@@ -72,18 +73,33 @@ webpage_error = (
 )
 
 
+def _get_active_session() -> requests.sessions.Session:
+    """Return OAuth session if one is available in Flask context, else plain session."""
+    try:
+        from flask import g
+        if hasattr(g, "oauth_session") and g.oauth_session is not None:
+            return g.oauth_session  # type: ignore[return-value]
+    except RuntimeError:
+        pass
+    print("WARNING: using unauthenticated session", file=sys.stderr)
+    return get_session()
+
+
 def api_get(params: StrDict) -> StrDict:
     """Make call to Wikipedia API."""
-    s = get_session()
+    s = _get_active_session()
 
     r = s.get(get_query_url(), params=params)
     try:
         ret: StrDict = r.json()
     except JSONDecodeError:
+        print(f"API request failed: HTTP {r.status_code}", file=sys.stderr)
+        print(f"Response body: {r.text!r}", file=sys.stderr)
         if webpage_error in r.text:
             raise MediawikiError(webpage_error)
-        else:
-            raise MediawikiError("unknown error")
+        if r.status_code == 429:
+            raise MediawikiError("Wikipedia rate limit exceeded — wait a moment and try again.")
+        raise MediawikiError(f"HTTP {r.status_code}: {r.text[:200]!r}")
     check_for_error(ret)
     return ret
 
@@ -271,7 +287,7 @@ def call_get_diff(title: str, section_num: int, section_text: str) -> str:
         "rvdifftotext": section_text.strip(),
     }
 
-    s = get_session()
+    s = _get_active_session()
     r = s.post(get_query_url(), data=data)
     try:
         ret = r.json()

add_links/match.py

@@ -78,7 +78,7 @@ re_cite = re.compile(
     re.I | re.S,
 )
 
-re_cite_template_start = re.compile(r"\{\{(?:cite|citation|short description|gli|defn|annotated link|excerpt|main|see)\b", re.I)
+re_cite_template_start = re.compile(r"\{\{(?:cite|citation|short description|gli|defn|annotated link|excerpt|main|see|for)\b", re.I)
 re_no_param_template = re.compile(r"\{\{[^|{}]+\}\}")
 re_external_link = re.compile(r"\[https?://[^\]]+\]")
 # Italic text (work titles in bibliographies). Handles apostrophes in content
@@ -252,6 +252,14 @@ def add_link(m: re.Match[str], replacement: str, text: str) -> str:
     if matched_text.startswith("[[") and matched_text.endswith("|"):
         return m.re.sub(lambda m: f"[[{replacement}|", text, count=1)
 
+    split_links = matched_text.find("]] [[")
+    if split_links > 0 and m.start() >= 2 and text[m.start() - 2 : m.start()] == "[[":
+        # Match starts inside one link and continues into the next opening link.
+        # Link only the text from the first link span and leave the second link as-is.
+        link_dest = replacement.split("|")[0] if "|" in replacement else replacement
+        visible = matched_text[:split_links]
+        return text[: m.start() - 2] + f"[[{link_dest}|{visible}]]" + text[m.start() + split_links + 2 :]
+
     inner_bracket = matched_text.find("[[")
     if inner_bracket > 0:
         prefix = matched_text[:inner_bracket].rstrip()
@@ -551,4 +559,6 @@ def get_diff(q: str, title: str, linkto: str | None) -> dict[str, typing.Any]:
     )
 
     found["diff"] = call_get_diff(title, found["section_num"], section_text)
+    if not found["diff"]:
+        raise NoMatch
     return found

add_links/mediawiki_oauth.py

@@ -1,5 +1,6 @@
 """Wikipedia OAuth."""
 
+import sys
 import typing
 import urllib
 from typing import cast
@@ -73,9 +74,8 @@ def api_request(params: typing.Mapping[str, str | int]) -> dict[str, typing.Any]
     try:
         return cast(dict[str, typing.Any], r.json())
     except Exception:
-        print("text")
-        print(r.text)
-        print("---")
+        print(f"API request failed: HTTP {r.status_code}", file=sys.stderr)
+        print(f"Response body: {r.text!r}", file=sys.stderr)
         raise
 
 
@@ -99,13 +99,40 @@ def userinfo_call() -> typing.Mapping[str, typing.Any]:
     return api_request(params)
 
 
+def get_oauth_session() -> OAuth1Session | None:
+    """Return an OAuth1Session for the current user, or None if not logged in."""
+    if "owner_key" not in session or "owner_secret" not in session:
+        return None
+    app = current_app
+    client_key = app.config["CLIENT_KEY"]
+    client_secret = app.config["CLIENT_SECRET"]
+    oauth = OAuth1Session(
+        client_key,
+        client_secret=client_secret,
+        resource_owner_key=session["owner_key"],
+        resource_owner_secret=session["owner_secret"],
+    )
+    oauth.headers.update({"User-Agent": ua})
+    oauth.params = typing.cast(
+        dict[str, str | int],
+        {"format": "json", "action": "query", "formatversion": 2},
+    )
+    return oauth
+
+
 def get_username() -> None | str:
     """Get the username or None if not logged in."""
     if "owner_key" not in session:
         return None  # not authorized
 
     if "username" not in session:
-        reply = userinfo_call()
+        try:
+            reply = userinfo_call()
+        except Exception as e:
+            print(f"get_username failed, clearing session: {e}", file=sys.stderr)
+            session.pop("owner_key", None)
+            session.pop("owner_secret", None)
+            return None
         if "query" not in reply:
             return None
         session["username"] = reply["query"]["userinfo"]["name"]

static/css/diff.css

@@ -5,19 +5,16 @@ span.searchmatch { font-weight: bold; }
 
 table.diff,td.diff-otitle,td.diff-ntitle{background-color:white}
 td.diff-otitle,td.diff-ntitle{text-align:center}
-td.diff-marker{text-align:right;font-weight:bold;font-size:1.25em}
+td.diff-marker{width:1.5em;text-align:center;font-weight:bold;font-size:1.25em;padding:0 0.3em}
 td.diff-lineno{font-weight:bold}
 td.diff-addedline,td.diff-deletedline,td.diff-context{font-size:88%;vertical-align:top;white-space:-moz-pre-wrap;white-space:pre-wrap}
-td.diff-addedline,td.diff-deletedline{border-style:solid;border-width:1px 1px 1px 4px;border-radius:0.33em}
-td.diff-addedline{border-color:#a3d3ff}
-td.diff-deletedline{border-color:#ffe49c}
-td.diff-context{background:#f3f3f3;color:#333333;border-style:solid;border-width:1px 1px 1px 4px;border-color:#e6e6e6;border-radius:0.33em}
+td.diff-addedline,td.diff-deletedline{border-left:3px solid}
+td.diff-addedline{border-color:#a3d3ff;background:#f0f8ff}
+td.diff-deletedline{border-color:#ffe49c;background:#fffaf0}
+td.diff-context{color:#555}
 .diffchange{font-weight:bold;text-decoration:none}
-table.diff{border:none;width:98%;border-spacing:4px; table-layout:fixed}
-td.diff-addedline .diffchange,td.diff-deletedline .diffchange{border-radius:0.33em;padding:0.25em 0}
+table.diff{border:none;width:100%;border-spacing:0;border-collapse:collapse;table-layout:auto}
 td.diff-addedline .diffchange{background:#d8ecff}
 td.diff-deletedline .diffchange{background:#feeec8}
-table.diff td{padding:0.33em 0.66em}
-table.diff col.diff-marker{width:2%}
-table.diff col.diff-content{width:48%}
-table.diff td div{ word-wrap:break-word; overflow:auto}
+table.diff td{padding:0.2em 0.5em}
+table.diff td div{word-wrap:break-word;overflow:auto}

static/favicon.svg

@@ -0,0 +1,3 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100">
+  <text y=".9em" font-size="90">🔗</text>
+</svg>

templates/all_done.html

@@ -1,10 +1,11 @@
 {% extends "base.html" %}
 
-{% block title %}Index{% endblock %}
+{% block title %}All done{% endblock %}
 
 {% block content %}
-  <div class="container">
-    <h1>All done</h1>
-    <div><a href="{{ url_for('index') }}">back to index </a></div>
-  </div>
+<div class="container text-center mt-5">
+  <h1 class="mb-3">All done</h1>
+  <p class="text-muted mb-4">No more candidates found for this article.</p>
+  <a href="{{ url_for('index') }}" class="btn btn-primary">Search another article</a>
+</div>
 {% endblock %}

templates/article.html

@@ -1,48 +1,152 @@
 {% extends "base.html" %}
 
-{% block title %}Link '{{ title }}' in '{{ hit_title }}'{% endblock %}
+{% block title %}{{ title }}{% endblock %}
 
 {% block style %}
 <link href="{{ url_for("static", filename="css/diff.css") }}" rel="stylesheet"/>
 {% endblock %}
 
 {% block content %}
-  <div class="container">
-    <h1>Link '{{ title }}' in '{{ hit_title }}'</h1>
-    <form action="{{ url_for("index") }}">
-      <input name="q">
-      <input type="submit" value="search">
-    </form>
+<div class="container">
+  <nav aria-label="breadcrumb" class="mb-3">
+    <ol class="breadcrumb">
+      <li class="breadcrumb-item"><a href="{{ url_for('index') }}">Home</a></li>
+      <li class="breadcrumb-item active">{{ title }}</li>
+    </ol>
+  </nav>
 
-    <div>Username: {{ g.user }}</div>
+  <div class="d-flex flex-wrap align-items-baseline gap-3 mb-1">
+    <h1 class="h4 mb-0">Find links to "{{ title }}"</h1>
+    <a href="https://en.wikipedia.org/wiki/{{ title }}" target="_blank" class="text-muted small">{{ title }} ↗</a>
+    {% if redirect_to %}
+    <span class="text-muted small">→ redirects to <a href="https://en.wikipedia.org/wiki/{{ redirect_to }}" target="_blank">{{ redirect_to }} ↗</a></span>
+    {% endif %}
+  </div>
 
-    <div><a href="https://en.wikipedia.org/wiki/{{ title }}" target="_blank">view article</a></div>
+  <div class="d-flex gap-3 mb-3 text-muted small">
+    <span>{{ total }} mentions total</span>
+    <span>{{ with_link }} already linked{% if total > 0 %} ({{ "{:.0%}".format(with_link / total) }}){% endif %}</span>
+    {% if saves_this_session %}
+    <span class="text-success">{{ saves_this_session }} added this session</span>
+    {% endif %}
+  </div>
 
-    <div><a href="{{ url_for('index') }}">back to index </a></div>
+  <div id="search-progress" class="my-4">
+    <div class="d-flex align-items-center gap-2 text-muted">
+      <div class="spinner-border spinner-border-sm" role="status">
+        <span class="visually-hidden">Searching…</span>
+      </div>
+      <span id="search-status">Searching…</span>
+    </div>
+  </div>
 
-    <div>total: {{ total }}</div>
-    <div>with link: {{ with_link }}</div>
-    <div>ratio: {{ "{:.1%}".format(with_link / total) }}</div>
-    {# <div>hit: {{ hit }}</div> #}
-    <div>replacement: {{ found.replacement }}</div>
-    <div>section: {{ found.section }}</div>
-    <table>
-      {{ diff | safe }}
-    </table>
-    <form method="POST">
-      <input type="hidden" name="hit" value="{{ hit_title }}">
-      <div class="my-3">
-        <input type="submit" class="btn btn-primary" value="save"/>
-        <a href="{{url_for("article_page", url_title=url_title, after=hit_title)}}" class="btn btn-primary">skip</a>
+  <div id="result" hidden>
+    <div class="d-flex flex-wrap align-items-baseline gap-2 mb-3">
+      <span class="text-muted small">Adding link in</span>
+      <a id="result-hit-link" href="#" target="_blank" class="small"><span id="result-hit-title"></span> ↗</a>
+    </div>
+    <div class="mb-4">
+      <table class="diff" id="diff-table"></table>
+    </div>
+    <form method="POST" class="mb-4">
+      <input type="hidden" name="hit" id="hit-input">
+      <div class="d-flex gap-2">
+        <button type="submit" class="btn btn-success">Save edit</button>
+        <a id="skip-link" href="#" class="btn btn-outline-secondary">Skip</a>
       </div>
     </form>
+  </div>
 
-    <ol>
+  <div id="all-done" hidden class="text-center mt-4">
+    <p class="text-muted mb-4">No more candidates found for this article.</p>
+    <a href="{{ url_for('index') }}" class="btn btn-primary">Search another article</a>
+  </div>
+
+  {% if hits %}
+  <details id="candidates-section" class="border rounded p-3 mt-2">
+    <summary class="text-muted small" style="cursor:pointer"><span id="candidates-count">{{ hits | length }}</span> candidates</summary>
+    <ol class="mt-3 mb-0 small" id="candidates-list">
     {% for hit in hits %}
-      {% set url = url_for("article_page", url_title=url_title, title=hit.title) %}
-      <li><a href="{{ url }}">{{ hit.title }}</a> &ndash; {{ hit.snippet | safe }}</li>
+      <li class="mb-1" data-title="{{ hit.title }}">
+        <a href="{{ url_for("article_page", url_title=url_title, title=hit.title) }}">{{ hit.title }}</a>
+      </li>
     {% endfor %}
     </ol>
-  </div>
+  </details>
+  {% endif %}
+</div>
 {% endblock %}
 
+{% block script %}
+<script>
+(function () {
+  const hits = {{ hits | map(attribute='title') | list | tojson }};
+  const linkTo = {{ title | tojson }};
+  const redirectTo = {{ redirect_to | tojson }};
+  const apiUrl = {{ url_for('api_valid_hit') | tojson }};
+  const pageUrl = new URL(window.location.href);
+
+  const elProgress = document.getElementById('search-progress');
+  const elStatus   = document.getElementById('search-status');
+  const elResult   = document.getElementById('result');
+  const elAllDone  = document.getElementById('all-done');
+  const elList     = document.getElementById('candidates-list');
+
+  function removeCandidate(title) {
+    if (!elList) return;
+    const li = elList.querySelector(`li[data-title="${CSS.escape(title)}"]`);
+    if (!li) return;
+    li.remove();
+    const elCount = document.getElementById('candidates-count');
+    if (elCount) elCount.textContent = elList.children.length;
+  }
+
+  async function search() {
+    for (const hitTitle of hits) {
+      elStatus.textContent = `Checking "${hitTitle}"…`;
+
+      let data;
+      try {
+        const params = new URLSearchParams({ link_to: linkTo, link_from: hitTitle });
+        if (redirectTo) params.append('redirect_to', redirectTo);
+        const resp = await fetch(apiUrl + '?' + params);
+        if (!resp.ok) continue;
+        data = await resp.json();
+      } catch (e) {
+        continue;
+      }
+
+      if (!data.valid) { removeCandidate(hitTitle); continue; }
+
+      elProgress.hidden = true;
+
+      document.getElementById('result-hit-title').textContent = hitTitle;
+      document.getElementById('result-hit-link').href =
+        'https://en.wikipedia.org/wiki/' + encodeURIComponent(hitTitle.replace(/ /g, '_'));
+      document.getElementById('diff-table').innerHTML = data.diff;
+      document.getElementById('hit-input').value = hitTitle;
+
+      const skipUrl = new URL(pageUrl);
+      skipUrl.searchParams.delete('title');
+      skipUrl.searchParams.set('after', hitTitle);
+      document.getElementById('skip-link').href = skipUrl.toString();
+
+      const currentUrl = new URL(pageUrl);
+      currentUrl.searchParams.delete('after');
+      currentUrl.searchParams.set('title', hitTitle);
+      history.replaceState(null, '', currentUrl.toString());
+
+      elResult.hidden = false;
+      return;
+    }
+
+    elProgress.hidden = true;
+    const elCandidates = document.getElementById('candidates-section');
+    if (elCandidates) elCandidates.hidden = true;
+    elAllDone.hidden = false;
+  }
+
+  search();
+}());
+</script>
+{% endblock %}

templates/base.html

@@ -2,21 +2,38 @@
 <html lang="en">
 <head>
   <meta charset="utf-8">
-  <link href="{{ url_for("static", filename="bootstrap/css/bootstrap.min.css") }}" rel="stylesheet">
+  <link href="{{ url_for("static", filename="bootstrap5/css/bootstrap.min.css") }}" rel="stylesheet">
   <meta name="viewport" content="width=device-width, initial-scale=1.0" />
-
-  <title>
-    {% block title %}{% endblock %}
-  </title>
-
+  <link rel="icon" type="image/svg+xml" href="{{ url_for('static', filename='favicon.svg') }}">
+  <title>{% block title %}{% endblock %} – Missing Link</title>
   {% block style %}{% endblock %}
 </head>
 
 <body>
+  <nav class="navbar navbar-expand-md navbar-dark bg-dark mb-4">
+    <div class="container">
+      <a class="navbar-brand fw-semibold" href="{{ url_for('index') }}">Missing Link</a>
+      <div class="d-flex align-items-center gap-2">
+        <form class="d-flex" action="{{ url_for('index') }}">
+          <input class="form-control form-control-sm me-2" name="q" placeholder="Article title…" style="width:240px">
+          <button class="btn btn-outline-light btn-sm" type="submit">Go</button>
+        </form>
+        {% if g.user %}
+          <span class="text-light small opacity-75">{{ g.user }}</span>
+          {% if session.get("saves") %}
+          <span class="badge bg-success">{{ session["saves"] }} saved</span>
+          {% endif %}
+          <a class="btn btn-outline-light btn-sm" href="{{ url_for('oauth_disconnect') }}">Log out</a>
+        {% else %}
+          <a class="btn btn-outline-light btn-sm" href="{{ url_for('start_oauth') }}">Log in with Wikipedia</a>
+        {% endif %}
+      </div>
+    </div>
+  </nav>
+
   {% block content %}{% endblock %}
 
-  <script src="{{ url_for("static", filename="bootstrap/js/bootstrap.bundle.min.js")}}></script>
-
+  <script src="{{ url_for("static", filename="bootstrap5/js/bootstrap.bundle.min.js") }}"></script>
   {% block script %}{% endblock %}
 </body>
 </html>

templates/error.html

@@ -0,0 +1,17 @@
+{% extends "base.html" %}
+
+{% block title %}Error{% endblock %}
+
+{% block content %}
+<div class="container mt-5">
+  <div class="row justify-content-center">
+    <div class="col-md-7">
+      <div class="alert alert-danger">
+        <h4 class="alert-heading">Something went wrong</h4>
+        <p class="mb-0"><code>{{ message }}</code></p>
+      </div>
+      <a href="{{ url_for('index') }}" class="btn btn-outline-secondary btn-sm">Back to home</a>
+    </div>
+  </div>
+</div>
+{% endblock %}

templates/index.html

@@ -1,25 +1,44 @@
 {% extends "base.html" %}
 
-{% block title %}Index{% endblock %}
+{% block title %}Missing Link{% endblock %}
 
 {% block content %}
-  <div class="container">
-    <h1>Index</h1>
-    <form>
-      <input name="q">
-      <input type="submit" value="search">
-    </form>
-
-    <div>Username: {{ g.user }}</div>
-
-    <table class="table w-auto">
-      {% for item in examples %}
-      <tr>
-        <td><a href="{{ article_url(item.title) }}">{{ item.title }}</a></td>
-        <td>{{ item.total }}</td>
-        <td>{{ "{:.1%}".format(item.with_links / item.total) }}</td>
-      </tr>
-      {% endfor %}
-    </table>
+<div class="container">
+  <div class="row justify-content-center mt-5">
+    <div class="col-md-6 text-center">
+      <h1 class="mb-2">Missing Link</h1>
+      <p class="text-muted mb-4">Find unlinked mentions of a Wikipedia article and add the links.</p>
+      <form class="d-flex gap-2 justify-content-center" action="{{ url_for('index') }}">
+        <input class="form-control" name="q" placeholder="Article title…" style="max-width:360px" autofocus>
+        <button class="btn btn-primary" type="submit">Search</button>
+      </form>
+    </div>
   </div>
+
+  {% if debug %}
+  <div class="row mt-5">
+    <div class="col">
+      <h2 class="h6 text-muted text-uppercase mb-3">Examples</h2>
+      <table class="table table-sm table-hover w-auto">
+        <thead class="table-light">
+          <tr>
+            <th>Article</th>
+            <th class="text-end">Total</th>
+            <th class="text-end">% linked</th>
+          </tr>
+        </thead>
+        <tbody>
+        {% for item in examples %}
+        <tr>
+          <td><a href="{{ article_url(item.title) }}">{{ item.title }}</a></td>
+          <td class="text-end text-muted">{{ item.total }}</td>
+          <td class="text-end text-muted">{{ "{:.0%}".format(item.with_links / item.total) }}</td>
+        </tr>
+        {% endfor %}
+        </tbody>
+      </table>
+    </div>
+  </div>
+  {% endif %}
+</div>
 {% endblock %}

templates/save_done.html

@@ -1,10 +1,11 @@
 {% extends "base.html" %}
 
-{% block title %}Index{% endblock %}
+{% block title %}Edit saved{% endblock %}
 
 {% block content %}
-  <div class="container">
-    <h1>Save done</h1>
-    <div>Save is complete.</div>
-  </div>
+<div class="container text-center mt-5">
+  <h1 class="mb-3">Edit saved</h1>
+  <p class="text-muted mb-4">Your edit has been saved to Wikipedia.</p>
+  <a href="{{ url_for('index') }}" class="btn btn-primary">Search another article</a>
+</div>
 {% endblock %}

web_view.py

@@ -4,11 +4,13 @@ import html
 import itertools
 import json
 import re
+import sys
 import typing
 
 import flask
 import werkzeug
 from requests_oauthlib import OAuth1Session
+from requests_oauthlib.oauth1_session import TokenRequestDenied
 from werkzeug.wrappers.response import Response
 
 from add_links import api, core, mediawiki_api, mediawiki_oauth
@@ -94,14 +96,20 @@ def search_count(q: str) -> int:
     return get_hit_count(article_title_to_search_query(q)) - 1
 
 
-def search_count_with_link(q: str) -> int:
+def search_count_with_link(q: str, redirect_to: str | None = None) -> int:
     """Articles in Wikipedia that include this search term and a link."""
-    return get_hit_count(article_title_to_search_query(q) + f' linksto:"{q}"')
+    count = get_hit_count(article_title_to_search_query(q) + f' linksto:"{q}"')
+    if redirect_to:
+        count += get_hit_count(article_title_to_search_query(q) + f' linksto:"{redirect_to}"')
+    return count
 
 
-def search_no_link(q: str) -> tuple[int, list[Hit]]:
+def search_no_link(q: str, redirect_to: str | None = None) -> tuple[int, list[Hit]]:
     """Search for mentions of article title with no link included."""
-    query = run_search(article_title_to_search_query(q) + f' -linksto:"{q}"', "max")
+    exclude = f' -linksto:"{q}"'
+    if redirect_to:
+        exclude += f' -linksto:"{redirect_to}"'
+    query = run_search(article_title_to_search_query(q) + exclude, "max")
     return (query["searchinfo"]["totalhits"], query["search"])
 
 
@@ -109,6 +117,7 @@ def search_no_link(q: str) -> tuple[int, list[Hit]]:
 def global_user() -> None:
     """Make username available everywhere."""
     flask.g.user = mediawiki_oauth.get_username()
+    flask.g.oauth_session = mediawiki_oauth.get_oauth_session()
 
 
 @app.route("/")
@@ -118,17 +127,20 @@ def index() -> str | Response:
         url = flask.url_for("oauth_callback", **flask.request.args)  # type: ignore
         return flask.redirect(url)
 
-    examples = load_examples()
-    examples.sort(
-        key=lambda i: float(i["with_links"]) / float(i["total"]), reverse=True
-    )
-
     if q := flask.request.args.get("q"):
         if q_trimmed := q.strip():
             return flask.redirect(article_url(q_trimmed))
 
+    debug = flask.request.args.get("debug")
+    examples: list[dict[str, str | int]] = []
+    if debug:
+        examples = load_examples()
+        examples.sort(
+            key=lambda i: float(i["with_links"]) / float(i["total"]), reverse=True
+        )
+
     return flask.render_template(
-        "index.html", examples=examples, article_url=article_url
+        "index.html", examples=examples, article_url=article_url, debug=debug
     )
 
 
@@ -187,7 +199,12 @@ def start_oauth() -> Response:
 
     oauth = OAuth1Session(client_key, client_secret=client_secret, callback_uri="oob")
     oauth.headers.update({"User-Agent": api.ua})
-    fetch_response = oauth.fetch_request_token(request_token_url)
+    try:
+        fetch_response = oauth.fetch_request_token(request_token_url)
+    except TokenRequestDenied as e:
+        return flask.make_response(
+            flask.render_template("error.html", message=str(e)), 502
+        )
 
     flask.session["owner_key"] = fetch_response.get("oauth_token")
     flask.session["owner_secret"] = fetch_response.get("oauth_token_secret")
@@ -229,7 +246,8 @@ def oauth_callback() -> werkzeug.wrappers.response.Response:
     flask.session["owner_key"] = oauth_tokens.get("oauth_token")
     flask.session["owner_secret"] = oauth_tokens.get("oauth_token_secret")
 
-    print("login successful")
+    username = mediawiki_oauth.get_username()
+    print(f"login successful: {username}", file=sys.stderr)
 
     next_page = flask.session.get("after_login")
     return flask.redirect(next_page if next_page else flask.url_for("index"))
@@ -281,31 +299,16 @@ def match_type(q: str, snippet: str) -> str | None:
     return match
 
 
-class NoGoodHit(Exception):
-    """No good hit."""
 
 
-def get_best_hit(title: str, hits: list[Hit]) -> tuple[Hit, dict[str, typing.Any]]:
-    """Find the best hit within the search results."""
-    for hit in hits:
-        if hit["title"].lower() == title.lower():
-            continue
-        # if match_type(title, hit["snippet"]) != "exact":
-        #     continue
-
-        try:
-            print(f'get diff: {hit["title"]}, {title}')
-            found = get_diff(title, hit["title"], None)
-        except NoMatch:
-            print("no match")
-            continue
-        except api.MediawikiError as e:
-            print(f"MediawikiError for {hit['title']!r}: {e}")
-            continue
-
-        return (hit, found)
-
-    raise NoGoodHit
+def _record_skip(from_title: str, hit_title: str) -> None:
+    """Record that a candidate was skipped or saved for this article."""
+    skipped: dict[str, list[str]] = flask.session.get("skipped", {})
+    article_skipped = skipped.get(from_title, [])
+    if hit_title not in article_skipped:
+        skipped[from_title] = article_skipped + [hit_title]
+        flask.session["skipped"] = skipped
+        flask.session.modified = True
 
 
 def handle_post(url_title: str) -> Response:
@@ -316,8 +319,16 @@ def handle_post(url_title: str) -> Response:
         do_save(from_title, hit_title)
     except mediawiki_oauth.LoginNeeded:
         return flask.redirect(flask.url_for("start_oauth"))
-    except mediawiki_api.APIError as e:
-        return flask.make_response(f"Save failed: {e}", 502)
+    except (mediawiki_api.APIError, api.MediawikiError) as e:
+        return flask.make_response(
+            flask.render_template("error.html", message=f"Save failed: {e}"), 502
+        )
+    flask.session["saves"] = flask.session.get("saves", 0) + 1
+    saves_by_title: dict[str, int] = flask.session.get("saves_by_title", {})
+    saves_by_title[from_title] = saves_by_title.get(from_title, 0) + 1
+    flask.session["saves_by_title"] = saves_by_title
+    flask.session.modified = True
+    _record_skip(from_title, hit_title)
     return flask.redirect(
         flask.url_for("article_page", url_title=url_title, after=hit_title)
     )
@@ -330,48 +341,55 @@ def article_page(url_title: str) -> str | Response:
         return handle_post(url_title)
 
     from_title = url_title.replace("_", " ").strip()
-    article_title = flask.request.args.get("title")
 
-    total = search_count(from_title)
-    with_link = search_count_with_link(from_title)
+    try:
+        redirect_to = api.get_wiki_info(from_title)
+    except (api.MissingPage, api.MultipleRedirects, api.MediawikiError):
+        redirect_to = None
 
-    no_link_count, hits = search_no_link(from_title)
+    try:
+        total = search_count(from_title)
+        with_link = search_count_with_link(from_title, redirect_to)
+        _no_link_count, hits = search_no_link(from_title, redirect_to)
+    except api.MediawikiError as e:
+        return flask.make_response(
+            flask.render_template("error.html", message=str(e)), 502
+        )
 
-    by_title = {hit["title"]: hit for hit in hits}
+    # Filter out candidates already processed this session
+    session_skipped: set[str] = set(
+        flask.session.get("skipped", {}).get(from_title, [])
+    )
 
-    found = None
-    if article_title in by_title:
-        hit = by_title[article_title]
-        try:
-            found = get_diff(from_title, hit["title"], None)
-        except NoMatch:
-            pass
+    # If a specific candidate was requested, move it to the front
+    title_param = flask.request.args.get("title")
+    if title_param:
+        hits = [h for h in hits if h["title"] == title_param] + \
+               [h for h in hits if h["title"] != title_param]
 
-    if not found:
-        after = flask.request.args.get("after")
-        if after:
-            print(after)
-            hits_iter = itertools.dropwhile(lambda hit: hit["title"] != after, hits)
-            skip = next(hits_iter, None)
-            if skip:
-                hits = list(hits_iter)
+    # Record and apply explicit skip-past
+    after = flask.request.args.get("after")
+    if after:
+        _record_skip(from_title, after)
+        session_skipped.add(after)
 
-        try:
-            hit, found = get_best_hit(from_title, hits)
-        except NoGoodHit:
-            return flask.render_template("all_done.html")
+    hits = [h for h in hits if h["title"] not in session_skipped
+            and h["title"] != from_title and h["title"] != case_flip_first(from_title)]
+
+    if not hits:
+        return flask.render_template("all_done.html")
+
+    saves_this_session = flask.session.get("saves_by_title", {}).get(from_title, 0)
 
     return flask.render_template(
         "article.html",
         title=from_title,
+        redirect_to=redirect_to,
         total=total,
         with_link=with_link,
-        hit_title=hit["title"],
         hits=hits,
-        replacement=found["replacement"],
-        diff=found["diff"],
-        found=found,
         url_title=url_title,
+        saves_this_session=saves_this_session,
     )
 
 
@@ -379,7 +397,12 @@ def do_save(title: str, hit_title: str) -> str:
     """Update page on Wikipedia."""
     token = mediawiki_oauth.get_token()
 
-    found = get_match(title, hit_title, None)
+    try:
+        redirect_to = api.get_wiki_info(title)
+    except (api.MissingPage, api.MultipleRedirects, api.MediawikiError):
+        redirect_to = None
+
+    found = get_match(title, hit_title, redirect_to)
 
     summary = (
         f"link [[{found['replacement']}]] using [[:en:User:Edward/Find link|Find link]]"
@@ -417,16 +440,20 @@ def api_hits() -> werkzeug.wrappers.response.Response:
 
 @app.route("/api/1/valid_hit")
 def api_valid_hit() -> werkzeug.wrappers.response.Response:
-    """Return candidates for the given article title."""
-    link_from = flask.request.args["link_from"]
+    """Check if a candidate article has a valid unlinked mention."""
     link_to = flask.request.args["link_to"]
+    link_from = flask.request.args["link_from"]
+    redirect_to = flask.request.args.get("redirect_to") or None
 
     try:
-        diff, replacement = get_diff(link_to, link_from, None)
+        found = get_diff(link_to, link_from, redirect_to)
     except NoMatch:
+        _record_skip(link_to, link_from)
         return flask.jsonify(valid=False)
+    except api.MediawikiError as e:
+        return flask.jsonify(valid=False, error=str(e))
 
-    return flask.jsonify(valid=True, diff=diff, replacement=replacement)
+    return flask.jsonify(valid=True, diff=found["diff"], replacement=found["replacement"])
 
 
 @app.route("/favicon.ico")