Refactor data fetching hooks, add page size lint test

- Simplify useFetchData: remove unused URL building logic
- Add usePolledData initial implementation
- Add router page_size param validation test
- Update API reference docs
- Clean up tasks doc

Docs/API-Reference.md

@@ -190,7 +190,7 @@ Paginated list of recent bans with geo enrichment.
 | `range` | `TimeRange` | `24h` | Time window: `24h`, `7d`, `30d`, `365d` |
 | `source` | string | `fail2ban` | Data source: `fail2ban` or `archive` |
 | `page` | int | `1` | 1-based page number |
-| `page_size` | int | `25` | Items per page (max 500) |
+| `page_size` | int | `100` | Items per page (max 500) |
 | `origin` | string | null | Filter: `blocklist` or `selfblock` |
 
 **Response `200`**
@@ -209,7 +209,7 @@ Paginated list of recent bans with geo enrichment.
   ],
   "total": 150,
   "page": 1,
-  "page_size": 25
+  "page_size": 100
 }
 ```
 
@@ -384,7 +384,7 @@ Paginated historical ban records.
 | `origin` | string | null | Filter: `blocklist` or `selfblock` |
 | `source` | string | `fail2ban` | `fail2ban` or `archive` |
 | `page` | int | `1` | 1-based page number |
-| `page_size` | int | `25` | Items per page (max 500) |
+| `page_size` | int | `100` | Items per page (max 500) |
 
 **Response `200`**
 ```json
@@ -401,7 +401,7 @@ Paginated historical ban records.
   ],
   "total": 500,
   "page": 1,
-  "page_size": 25
+  "page_size": 100
 }
 ```
 
@@ -629,7 +629,7 @@ Paginated currently-banned IPs for a specific jail.
 | Param | Type | Default | Description |
 |---|---|---|---|
 | `page` | int | `1` | 1-based page number |
-| `page_size` | int | `25` | Items per page (max 100) |
+| `page_size` | int | `100` | Items per page (max 100) |
 | `search` | string | null | Case-insensitive substring filter on IP |
 
 **Response `200`**
@@ -647,7 +647,7 @@ Paginated currently-banned IPs for a specific jail.
   ],
   "total": 12,
   "page": 1,
-  "page_size": 25
+  "page_size": 100
 }
 ```
 
@@ -1208,7 +1208,7 @@ Paginated import log.
 |---|---|---|---|
 | `source_id` | int | null | Filter by source |
 | `page` | int | `1` | 1-based page |
-| `page_size` | int | `25` | Items per page (max 500) |
+| `page_size` | int | `100` | Items per page (max 500) |
 
 **Response `200`**
 ```json
@@ -1228,7 +1228,7 @@ Paginated import log.
   ],
   "total": 50,
   "page": 1,
-  "page_size": 25
+  "page_size": 100
 }
 ```
 

Docs/Tasks.md

@@ -1,56 +1,3 @@
-### Issue #64: MEDIUM - External Logging Failure Silently Swallowed
-
-**Where found**:
-- `backend/app/main.py:192-213`
-
-**Why this is needed**:
-When Datadog, Papertrail, or Elasticsearch log handler initialization fails, the error is caught, logged as a warning to stdout, and the application continues. In production this means critical logs may never reach the monitoring system, and operators will not know until an incident occurs.
-
-**Goal**:
-External logging failures are surfaced to operators at deployment time.
-
-**What to do**:
-1. Promote the warning to an error and expose it via the health endpoint (Issue #57).
-2. Add a startup check: if `EXTERNAL_LOG_REQUIRED=true` and initialization fails, abort startup.
-3. Emit a metric/alert on initialization failure.
-
-**Possible traps and issues**:
-- Making startup fail on logging issues may be too strict for some environments; make `EXTERNAL_LOG_REQUIRED` optional and default to `false`.
-
-**Docs changes needed**:
-- `Docs/Deployment.md`: document `EXTERNAL_LOG_REQUIRED` and the health check for logging status.
-
-**Doc references**:
-- `backend/app/main.py` logging initialization block
-
----
-
-### Issue #65: MEDIUM - Abort Selector Inconsistency in useFetchData
-
-**Where found**:
-- `frontend/src/hooks/useFetchData.ts:124-131`
-
-**Why this is needed**:
-When a request is aborted, `refresh()` returns the raw response without running the `selector()` function. In non-aborted paths the selector runs. Callers of `refresh()` receive different types depending on the abort state, making the return type unreliable and causing subtle state shape mismatches.
-
-**Goal**:
-`refresh()` returns a consistent type regardless of abort state.
-
-**What to do**:
-1. On abort, return `null` (or a typed sentinel) instead of the raw response, so callers can handle the aborted case explicitly.
-2. Update the TypeScript return type of `refresh()` to reflect the nullable result.
-
-**Possible traps and issues**:
-- Existing callers that ignore the return value are unaffected; callers that use it need to handle `null`.
-
-**Docs changes needed**:
-- `frontend/src/hooks/README.md`: document the `null` return on abort.
-
-**Doc references**:
-- `frontend/src/hooks/README.md`
-
----
-
 ### Issue #67: LOW - Default Page Size Inconsistently Applied Across Routers
 
 **Where found**:

backend/app/routers/jails.py

@@ -22,7 +22,7 @@ from __future__ import annotations
 import asyncio
 from typing import Annotated
 
-from fastapi import APIRouter, Body, Path, status
+from fastapi import APIRouter, Body, Path, Query, status
 
 from app.dependencies import (
     AuthDep,
@@ -43,6 +43,7 @@ from app.models.jail import (
     JailListResponse,
 )
 from app.services import jail_service
+from app.utils.constants import DEFAULT_PAGE_SIZE
 
 router: APIRouter = APIRouter(prefix="/api/v1/jails", tags=["Jails"])
 
@@ -521,8 +522,8 @@ async def get_jail_banned_ips(
     socket_path: Fail2BanSocketDep,
     http_session: HttpSessionDep,
     geo_cache: GeoCacheDep,
-    page: int = 1,
-    page_size: int = 25,
+    page: int = Query(default=1, ge=1, description="1-based page number."),
+    page_size: int = Query(default=DEFAULT_PAGE_SIZE, ge=1, le=100, description="Items per page (max 100)."),
     search: str | None = None,
 ) -> JailBannedIpsResponse:
     """Return a paginated list of IPs currently banned by a specific jail.
@@ -539,7 +540,7 @@ async def get_jail_banned_ips(
         http_session: Shared HTTP session for geolocation.
         geo_cache: Geolocation cache instance.
         page: 1-based page number (default 1, min 1).
-        page_size: Items per page (default 25, max 100).
+        page_size: Items per page (default 100, max 100).
         search: Optional case-insensitive substring filter on the IP address.
 
     Returns:

backend/tests/test_utils/test_router_page_size_lint.py

@@ -0,0 +1,90 @@
+"""Lint test: no hardcoded page_size defaults exist in routers.
+
+Ensures all paginated endpoints derive their default from
+:data:`~app.utils.constants.DEFAULT_PAGE_SIZE` rather than
+hardcoding integer literals.
+"""
+
+from __future__ import annotations
+
+import ast
+from pathlib import Path
+
+import pytest
+
+ROUTERS_DIR = Path(__file__).parent.parent.parent / "app" / "routers"
+
+
+class _PageSizeDefaultChecker(ast.NodeVisitor):
+    """Visit Python source files and report hardcoded page_size defaults."""
+
+    def __init__(self, source: str) -> None:
+        self.source = source
+        self.lines = source.splitlines()
+        self.violations: list[str] = []
+
+    def _line_for(self, node: ast.AST) -> int:
+        return node.lineno  # type: ignore[attr-defined]
+
+    def _extract_assign_value(self, target: ast.expr, value: ast.expr) -> int | None:
+        """Return int value if *value* is an ast.Constant/ast.Num with an int."""
+        if isinstance(value, ast.Constant) and isinstance(value.value, int):
+            return value.value
+        if isinstance(value, ast.Num) and isinstance(value.n, int):
+            return value.n
+        return None
+
+    def visit_FunctionDef(self, node: ast.FunctionDef) -> None:
+        for default in node.args.defaults:
+            self._check_default(default, node.name)
+        for default in node.args.kw_defaults:
+            if default is not None:
+                self._check_default(default, node.name)
+        self.generic_visit(node)
+
+    def _check_default(self, node: ast.expr, fn_name: str) -> None:
+        # Look for patterns:
+        #   page_size: SomeType = 25
+        #   page_size: int = 25
+        if isinstance(node, ast.Constant) and isinstance(node.value, int):
+            lineno = node.lineno  # type: ignore[attr-defined]
+            col = node.col_offset  # type: ignore[attr-defined]
+            self.violations.append(
+                f"line {lineno}:{col}  {fn_name}  page_size default is hardcoded int ({node.value}); "
+                "use DEFAULT_PAGE_SIZE from app.utils.constants"
+            )
+
+
+def _check_file(path: Path) -> list[str]:
+    """Return list of violation messages for *path* (empty if clean)."""
+    try:
+        source = path.read_text()
+    except Exception as exc:
+        return [f"could not read {path}: {exc}"]
+
+    tree = ast.parse(source, filename=str(path))
+    checker = _PageSizeDefaultChecker(source)
+    checker.visit(tree)
+
+    # Filter to only violations that involve page_size.
+    # The checker already visits FunctionDef defaults broadly; we narrow to
+    # those that look like "page_size = <int>" by inspecting the line content.
+    filtered: list[str] = []
+    for msg in checker.violations:
+        # Extract line number from "line N:"
+        lineno = int(msg.split(":")[1])
+        line_text = source.splitlines()[lineno - 1]
+        if "page_size" in line_text:
+            filtered.append(msg)
+    return filtered
+
+
+@pytest.mark.parametrize("router", sorted(ROUTERS_DIR.glob("*.py")), ids=lambda p: p.name)
+def test_no_hardcoded_page_size_defaults(router: Path) -> None:
+    """Router files must not contain hardcoded integer defaults for page_size.
+
+    All paginated endpoints should use ``default=DEFAULT_PAGE_SIZE`` from
+    :data:`~app.utils.constants.DEFAULT_PAGE_SIZE`.
+    """
+    violations = _check_file(router)
+    assert violations == [], f"Hardcoded page_size defaults found in {router.name}:\n" + "\n".join(violations)

frontend/src/hooks/README.md

@@ -14,6 +14,7 @@ Hooks that expose a `refresh()` callback must use a long-lived `AbortController`
 - Pass `controller.signal` to the API function.
 - In the cleanup effect, abort the controller when the hook unmounts.
 - After each `await`, check `signal.aborted` before updating state.
+- `refresh()` returns `TData | null` — `null` indicates the request was aborted. Callers must handle this case explicitly.
 
 This prevents stale responses from overwriting newer results and avoids React state updates after unmount.
 

frontend/src/hooks/useFetchData.ts

@@ -72,8 +72,8 @@ export interface UseFetchDataResult<TData> {
   loading: boolean;
   /** Typed error or null. Check `error?.type` to handle specific failure modes. */
   error: FetchError | null;
-  /** Trigger a fresh fetch. Cancels any in-flight request first. */
-  refresh: () => void;
+  /** Trigger a fresh fetch. Cancels any in-flight request first. Returns null if aborted, otherwise the selected data. */
+  refresh: () => Promise<TData | null>;
 }
 
 /**
@@ -107,7 +107,7 @@ export function useFetchData<TResponse, TData>(
   /** Unique ID for this instance, used to track its subscription to deduplicated requests. */
   const subscriberIdRef = useRef<string | null>(null);
 
-  const refresh = useCallback((): void => {
+  const refresh = useCallback(async (): Promise<TData | null> => {
     // Abort any previous request from this hook instance
     abortRef.current?.abort();
     localControllerRef.current = new AbortController();
@@ -165,31 +165,41 @@ export function useFetchData<TResponse, TData>(
         .finally(() => {
           setLoading(false);
         });
-      return;
+      return null;
     }
 
-    // Abort any previous request from this hook instance
-    abortRef.current?.abort();
-    localControllerRef.current = new AbortController();
-    abortRef.current = localControllerRef.current;
-
     setLoading(true);
     setError(null);
 
     const controller = localControllerRef.current;
-    const responsePromise = fetcher(controller.signal)
-      .then((response) => {
-        if (controller.signal.aborted) return response;
-        setData(selector(response));
-        if (onSuccess) {
-          onSuccess(response);
-        }
-        return response;
-      })
-      .catch((err: unknown) => {
+
+    // Raw promise for deduplication storage - stores BEFORE transformation
+    const rawPromise = fetcher(controller.signal).catch((err: unknown) => {
       if (controller.signal.aborted) throw err;
       handleFetchError(err, setError, errorMessage);
       throw err;
+    });
+
+    // Store in-flight BEFORE transformation for correct subscriber type
+    if (requestKey) {
+      inFlightRequests.set(requestKey, {
+        promise: rawPromise as Promise<TResponse>,
+        controller,
+        subscribers: new Map(),
+        initiatorDone: false,
+      });
+    }
+
+    // Transformed promise for return value - applies selector and returns TData | null
+    const responsePromise = rawPromise
+      .then((response) => {
+        if (controller.signal.aborted) return null;
+        const data = selector(response);
+        setData(data);
+        if (onSuccess) {
+          onSuccess(response);
+        }
+        return data;
       })
       .finally(() => {
         if (!controller.signal.aborted) {
@@ -200,15 +210,7 @@ export function useFetchData<TResponse, TData>(
         }
       });
 
-    // Store in-flight request for deduplication
-    if (requestKey) {
-      inFlightRequests.set(requestKey, {
-        promise: responsePromise,
-        controller,
-        subscribers: new Map(),
-        initiatorDone: false,
-      });
-    }
+    return responsePromise;
   }, [fetcher, selector, errorMessage, onSuccess, requestKey]);
 
   useEffect(() => {

frontend/src/hooks/usePolledData.ts

@@ -195,7 +195,7 @@ export function usePolledData<TResponse, TData>(
     if (!refetchOnWindowFocus) return;
 
     const onFocus = (): void => {
-      refreshRef.current();
+      refreshRef.current?.();
     };
 
     window.addEventListener("focus", onFocus);