feat(web): blueprint-prefilled create-server flow + empty-state CTA

- Per-row "Create server" link on /blueprints navigates to
  /servers?blueprint_id=<id>; that page validates the param against
  the user's owned blueprints, pre-selects the option, and auto-opens
  the create modal.
- /servers empty-blueprint state now shows an actionable
  "Create a blueprint first ->" link (styled like the primary button)
  pointing at /blueprints, replacing the silent disabled "+ Create"
  button + muted hint.
- Drop the "Reassign blueprint" form on the server detail page
  along with the unused POST /servers/<id> form route. The JSON
  PATCH /servers/<id> endpoint is retained.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

l4d2web/routes/page_routes.py

@@ -1,6 +1,6 @@
 import json
 
-from flask import Blueprint, Response, redirect, render_template
+from flask import Blueprint, Response, redirect, render_template, request
 from sqlalchemy import select
 
 from l4d2web.auth import current_user, require_admin, require_login
@@ -70,7 +70,23 @@ def servers_page() -> str:
         blueprints = db.scalars(
             select(BlueprintModel).where(BlueprintModel.user_id == user.id).order_by(BlueprintModel.name)
         ).all()
-    return render_template("servers.html", rows=rows, blueprints=blueprints)
+
+    prefill_blueprint_id: int | None = None
+    raw_prefill = request.args.get("blueprint_id")
+    if raw_prefill:
+        try:
+            candidate = int(raw_prefill)
+        except ValueError:
+            candidate = None
+        if candidate is not None and any(b.id == candidate for b in blueprints):
+            prefill_blueprint_id = candidate
+
+    return render_template(
+        "servers.html",
+        rows=rows,
+        blueprints=blueprints,
+        prefill_blueprint_id=prefill_blueprint_id,
+    )
 
 
 @bp.get("/servers/<int:server_id>")
@@ -84,11 +100,6 @@ def server_detail(server_id: int):
         if server is None:
             return Response(status=404)
         blueprint = db.scalar(select(BlueprintModel).where(BlueprintModel.id == server.blueprint_id))
-        blueprints = db.scalars(
-            select(BlueprintModel)
-            .where(BlueprintModel.user_id == user.id)
-            .order_by(BlueprintModel.name)
-        ).all()
         recent_job_rows = db.execute(
             select(Job, User, Server)
             .join(User, User.id == Job.user_id)
@@ -102,7 +113,6 @@ def server_detail(server_id: int):
         "server_detail.html",
         server=server,
         blueprint=blueprint,
-        blueprints=blueprints,
         recent_job_rows=recent_job_rows,
     )
 

l4d2web/routes/server_routes.py

@@ -119,36 +119,6 @@ def update_server(server_id: int) -> Response:
     return jsonify({"id": server_id}), 200
 
 
-@bp.post("/servers/<int:server_id>")
-@require_login
-def update_server_form(server_id: int) -> Response:
-    user = current_user()
-    assert user is not None
-
-    try:
-        blueprint_id = int(request.form["blueprint_id"])
-    except (KeyError, TypeError, ValueError):
-        return Response("blueprint_id is required", status=400)
-
-    with session_scope() as db:
-        server = db.scalar(select(Server).where(Server.id == server_id, Server.user_id == user.id))
-        if server is None:
-            return Response(status=404)
-
-        blueprint = db.scalar(
-            select(BlueprintModel).where(
-                BlueprintModel.id == blueprint_id,
-                BlueprintModel.user_id == user.id,
-            )
-        )
-        if blueprint is None:
-            return Response("blueprint not found", status=404)
-
-        server.blueprint_id = blueprint.id
-
-    return redirect(f"/servers/{server_id}")
-
-
 LIFECYCLE_OPERATIONS = {"initialize", "start", "stop", "delete"}
 
 

l4d2web/static/css/components.css

@@ -59,16 +59,20 @@ a:focus-visible {
   outline-offset: 2px;
 }
 
-button {
+button,
+a.button {
   background: var(--color-primary);
   border: none;
   border-radius: var(--radius-s);
   color: #fff;
   padding: var(--space-s) var(--space-l);
   cursor: pointer;
+  display: inline-block;
+  text-decoration: none;
 }
 
-button.danger {
+button.danger,
+a.button.danger {
   background: var(--color-danger);
 }
 

l4d2web/templates/blueprints.html

@@ -9,16 +9,17 @@
     <button type="button" data-modal-open="create-blueprint-modal">+ Create</button>
   </div>
   <table class="table">
-    <thead><tr><th>Name</th><th>Created</th><th>Updated</th></tr></thead>
+    <thead><tr><th>Name</th><th>Created</th><th>Updated</th><th>Actions</th></tr></thead>
     <tbody>
       {% for blueprint in blueprints %}
       <tr>
         <td><a href="/blueprints/{{ blueprint.id }}">{{ blueprint.name }}</a></td>
         <td>{{ blueprint.created_at }}</td>
         <td>{{ blueprint.updated_at }}</td>
+        <td><a href="/servers?blueprint_id={{ blueprint.id }}">Create server</a></td>
       </tr>
       {% else %}
-      <tr><td colspan="3" class="muted">No blueprints configured.</td></tr>
+      <tr><td colspan="4" class="muted">No blueprints configured.</td></tr>
       {% endfor %}
     </tbody>
   </table>

l4d2web/templates/server_detail.html

@@ -29,24 +29,6 @@
   </table>
 </section>
 
-<section class="panel">
-  <h2>Reassign blueprint</h2>
-  <form method="post" action="/servers/{{ server.id }}" class="stack">
-    <input type="hidden" name="csrf_token" value="{{ session.get('csrf_token', '') }}">
-    <label>Blueprint
-      <select name="blueprint_id" required>
-        {% for option in blueprints %}
-        <option value="{{ option.id }}"{% if option.id == server.blueprint_id %} selected{% endif %}>{{ option.name }}</option>
-        {% endfor %}
-      </select>
-    </label>
-    <p class="field-hint">Changes apply on the next server action.</p>
-    <div>
-      <button type="submit">Save</button>
-    </div>
-  </form>
-</section>
-
 <section class="panel">
   <div class="page-heading">
     <h2>Recent Jobs</h2>

l4d2web/templates/servers.html

@@ -6,11 +6,12 @@
 <section class="panel">
   <div class="page-heading">
     <h1>Servers</h1>
-    <button type="button" data-modal-open="create-server-modal"{% if not blueprints %} disabled{% endif %}>+ Create</button>
+    {% if blueprints %}
+    <button type="button" data-modal-open="create-server-modal">+ Create</button>
+    {% else %}
+    <a class="button" href="/blueprints">Create a blueprint first &rarr;</a>
+    {% endif %}
   </div>
-  {% if not blueprints %}
-  <p class="muted">Create a blueprint before adding servers.</p>
-  {% endif %}
   <table class="table">
     <thead><tr><th>Name</th><th>Port</th><th>Blueprint</th><th>Desired</th><th>Actual</th></tr></thead>
     <tbody>
@@ -46,7 +47,7 @@
       <label>Blueprint
         <select name="blueprint_id" required>
           {% for blueprint in blueprints %}
-          <option value="{{ blueprint.id }}">{{ blueprint.name }}</option>
+          <option value="{{ blueprint.id }}"{% if blueprint.id == prefill_blueprint_id %} selected{% endif %}>{{ blueprint.name }}</option>
           {% endfor %}
         </select>
       </label>
@@ -58,4 +59,15 @@
   </form>
 </dialog>
 {% endif %}
+
+{% if prefill_blueprint_id %}
+<script>
+  document.addEventListener("DOMContentLoaded", () => {
+    const dialog = document.getElementById("create-server-modal");
+    if (dialog && typeof dialog.showModal === "function") {
+      dialog.showModal();
+    }
+  });
+</script>
+{% endif %}
 {% endblock %}

l4d2web/tests/test_servers.py

@@ -37,6 +37,32 @@ def user_client_with_blueprints(tmp_path, monkeypatch):
     return client, payload
 
 
+def test_servers_page_without_blueprints_shows_create_blueprint_cta(tmp_path, monkeypatch) -> None:
+    db_url = f"sqlite:///{tmp_path/'no_blueprints.db'}"
+    monkeypatch.setenv("DATABASE_URL", db_url)
+    app = create_app({"TESTING": True, "DATABASE_URL": db_url, "SECRET_KEY": "test"})
+    init_db()
+
+    with session_scope() as session:
+        user = User(username="solo", password_digest=hash_password("secret"), admin=False)
+        session.add(user)
+        session.flush()
+        user_id = user.id
+
+    client = app.test_client()
+    with client.session_transaction() as sess:
+        sess["user_id"] = user_id
+        sess["csrf_token"] = "test-token"
+
+    response = client.get("/servers")
+    text = response.get_data(as_text=True)
+
+    assert response.status_code == 200
+    assert 'href="/blueprints"' in text
+    assert "Create a blueprint first" in text
+    assert "disabled" not in text
+
+
 def test_create_server_from_blueprint(user_client_with_blueprints) -> None:
     client, data = user_client_with_blueprints
     payload = {"name": "alpha", "port": 27015, "blueprint_id": data["blueprint_id"]}
@@ -213,59 +239,6 @@ def test_create_server_returns_409_when_port_range_exhausted(tmp_path, monkeypat
     assert second.status_code == 409
 
 
-def test_update_server_form_reassigns_blueprint(user_client_with_blueprints) -> None:
-    client, data = user_client_with_blueprints
-    create = client.post(
-        "/servers",
-        data={"name": "alpha", "port": "27015", "blueprint_id": str(data["blueprint_id"])},
-        headers={"X-CSRF-Token": "test-token"},
-    )
-    assert create.status_code == 302
-    server_id = int(create.headers["Location"].rsplit("/", 1)[-1])
-
-    response = client.post(
-        f"/servers/{server_id}",
-        data={"blueprint_id": str(data["other_blueprint_id"])},
-        headers={"X-CSRF-Token": "test-token"},
-    )
-    assert response.status_code == 302
-    assert response.headers["Location"] == f"/servers/{server_id}"
-
-    from sqlalchemy import select
-
-    from l4d2web.models import Server
-
-    with session_scope() as session:
-        server = session.scalars(select(Server)).one()
-        assert server.blueprint_id == data["other_blueprint_id"]
-
-
-def test_update_server_form_rejects_foreign_blueprint(user_client_with_blueprints, tmp_path) -> None:
-    client, data = user_client_with_blueprints
-    create = client.post(
-        "/servers",
-        data={"name": "alpha", "port": "27015", "blueprint_id": str(data["blueprint_id"])},
-        headers={"X-CSRF-Token": "test-token"},
-    )
-    server_id = int(create.headers["Location"].rsplit("/", 1)[-1])
-
-    with session_scope() as session:
-        other = User(username="bob", password_digest=hash_password("secret"), admin=False)
-        session.add(other)
-        session.flush()
-        foreign = Blueprint(user_id=other.id, name="foreign", arguments="[]", config="[]")
-        session.add(foreign)
-        session.flush()
-        foreign_id = foreign.id
-
-    response = client.post(
-        f"/servers/{server_id}",
-        data={"blueprint_id": str(foreign_id)},
-        headers={"X-CSRF-Token": "test-token"},
-    )
-    assert response.status_code == 404
-
-
 def test_delete_operation_redirects_to_index(user_client_with_blueprints) -> None:
     client, data = user_client_with_blueprints
     create = client.post(
@@ -285,6 +258,54 @@ def test_delete_operation_redirects_to_index(user_client_with_blueprints) -> Non
     assert response.headers["Location"] == "/servers"
 
 
+def test_servers_page_prefills_blueprint_when_owned(user_client_with_blueprints) -> None:
+    client, data = user_client_with_blueprints
+    response = client.get(f"/servers?blueprint_id={data['other_blueprint_id']}")
+    text = response.get_data(as_text=True)
+
+    assert response.status_code == 200
+    assert f'<option value="{data["other_blueprint_id"]}" selected>' in text
+    assert "showModal" in text
+
+
+def test_servers_page_ignores_foreign_blueprint_id(user_client_with_blueprints) -> None:
+    client, _ = user_client_with_blueprints
+
+    with session_scope() as session:
+        other = User(username="bob", password_digest=hash_password("secret"), admin=False)
+        session.add(other)
+        session.flush()
+        foreign = Blueprint(user_id=other.id, name="foreign", arguments="[]", config="[]")
+        session.add(foreign)
+        session.flush()
+        foreign_id = foreign.id
+
+    response = client.get(f"/servers?blueprint_id={foreign_id}")
+    text = response.get_data(as_text=True)
+
+    assert response.status_code == 200
+    assert "selected" not in text
+    assert "showModal" not in text
+
+
+def test_servers_page_ignores_non_integer_blueprint_id(user_client_with_blueprints) -> None:
+    client, _ = user_client_with_blueprints
+    response = client.get("/servers?blueprint_id=abc")
+    text = response.get_data(as_text=True)
+
+    assert response.status_code == 200
+    assert "showModal" not in text
+
+
+def test_servers_page_without_param_does_not_auto_open(user_client_with_blueprints) -> None:
+    client, _ = user_client_with_blueprints
+    response = client.get("/servers")
+    text = response.get_data(as_text=True)
+
+    assert response.status_code == 200
+    assert "showModal" not in text
+
+
 def test_lifecycle_form_creates_queued_job(user_client_with_blueprints) -> None:
     client, data = user_client_with_blueprints
     create_response = client.post(