Add feature user can change mail address

TODO.md

@@ -12,6 +12,7 @@
 - [x] Add validated post image uploads with an in-article preview and click-to-expand view.
 - [x] Add ordered inline step images with captions for long-form repair and engineering posts.
 - [ ] Add code snippets to long-form stories.
-- [ ] Allow users to change their email addresses.
+- [x] Allow users to change their email addresses.
 - [ ] Add user email verification for registration and email-address changes.
 - [ ] Add user real names and use them as the published-by name.
+- [ ] Add ability to hide posts from unregistered users.

app.py

@@ -406,6 +406,30 @@ def change_password():
     return render_template("password_form.html", mode="change")
 
 
+@app.route("/account/email", methods=("GET", "POST"))
+@login_required
+def change_email():
+    user = get_db().execute("SELECT email, password_hash FROM users WHERE id = ?", (session["user_id"],)).fetchone()
+    if request.method == "POST":
+        email = request.form.get("email", "").strip().lower()
+        current_password = request.form.get("current_password", "")
+        if not check_password_hash(user["password_hash"], current_password):
+            flash("Your current password is incorrect.", "error")
+        elif not valid_email(email):
+            flash("Enter a valid email address.", "error")
+        elif email == user["email"]:
+            flash("That is already your email address.", "notice")
+        else:
+            try:
+                get_db().execute("UPDATE users SET email = ? WHERE id = ?", (email, session["user_id"]))
+                get_db().commit()
+                flash("Email address updated.", "success")
+                return redirect(url_for("index"))
+            except sqlite3.IntegrityError:
+                flash("That email address is already in use.", "error")
+    return render_template("email_form.html", email=user["email"])
+
+
 @app.post("/logout")
 def logout():
     session.clear()

templates/base.html

@@ -21,6 +21,7 @@
       {% if current_user %}
         <a href="{{ url_for('write') }}">Write</a>
         {% if current_user.role == 'admin' %}<a href="{{ url_for('admin_users') }}">Accounts</a>{% endif %}
+        <a href="{{ url_for('change_email') }}">Email</a>
         <a href="{{ url_for('change_password') }}">Password</a>
         <span class="user-chip">{{ current_user.username }}</span>
         <form action="{{ url_for('logout') }}" method="post"><input type="hidden" name="csrf_token" value="{{ csrf_token() }}"><button class="text-button" type="submit">Log out</button></form>

templates/email_form.html

@@ -0,0 +1,14 @@
+{% extends 'base.html' %}
+{% block title %}Email address | Eternity Project{% endblock %}
+{% block content %}
+<section class="auth-layout">
+  <div class="auth-copy"><span class="signal-label">ACCOUNT DETAILS</span><h1>Update your<br>address.</h1><p>Use an email address you control. Confirm your current password before saving the change.</p></div>
+  <form class="auth-form" method="post">
+    <input type="hidden" name="csrf_token" value="{{ csrf_token() }}">
+    <label>Current email<input type="email" value="{{ email or '' }}" readonly></label>
+    <label>New email<input name="email" type="email" autocomplete="email" required placeholder="you@example.com"></label>
+    <label>Current password<input name="current_password" type="password" autocomplete="current-password" required></label>
+    <button class="button" type="submit">Save email <span aria-hidden="true">→</span></button>
+  </form>
+</section>
+{% endblock %}