feat(ui): direct-download links for downloadable local repo files (#106)

## Why

The local-repo object browser renders every file name as inert text, so there is no way to grab a file from the UI even though local rpm repos already serve their contents as real yum repos. Users have to hand-construct URLs. This adds one-click downloads, built as a modular per-repo-type capability so other types can be switched on later with a single map entry.

## Changes

- Adds a `downloadableTypes` capability map (`ui/src/components/downloads.ts`) keyed by `package_type`; each entry builds the direct-download URL for a file.
- Enables `rpm`, pointing at the yum files route `/api/v2/remotes/<repo>/files/<path>` (path-segment-encoded).
- Renders file names in the object browser as `<a href download>` links when the repo's type is downloadable, and as plain text otherwise.
- Fetches the repo's `package_type` on the Objects page as the modularity hook and threads it through the tree rows.

## Notes

Download links are same-origin unauthenticated GETs (the API serves local repos with no token on reads, matching how yum clients fetch), so a bare `href` carries no credentials. Adding a future type is one entry in `downloadableTypes`.

---------

Co-authored-by: Ben Vin <neotheo@gmail.com>
Reviewed-on: #106
Co-authored-by: Ben Vincent <ben@unkin.net>
Co-committed-by: Ben Vincent <ben@unkin.net>

ui/src/components/downloads.ts

@@ -0,0 +1,36 @@
+// Per-repo-type "downloadable" capability map.
+//
+// When a repo's package_type has an entry here, file entries in the object
+// browser render as direct-download links pointing at the URL the entry
+// builds. Types absent from the map render as plain text. Enabling a new
+// type is a one-line addition below.
+//
+// Download routes are same-origin, unauthenticated GETs (the API serves local
+// repos as real registries with no token on reads), so a bare <a href download>
+// works and carries no credentials.
+
+// buildUrl receives the repo name and the artifact's full path (may contain
+// slashes) and returns the direct-download URL for that file.
+type DownloadUrlBuilder = (repo: string, path: string) => string;
+
+export const downloadableTypes: Record<string, DownloadUrlBuilder> = {
+  // rpm locals are real yum repos; files are served at
+  // /api/v2/remotes/<repo>/files/<path>.
+  rpm: (repo, path) =>
+    `/api/v2/remotes/${encodeURIComponent(repo)}/files/${path
+      .split('/')
+      .map(encodeURIComponent)
+      .join('/')}`,
+};
+
+// downloadUrlFor returns the direct-download URL for a file when its repo type
+// is downloadable, or null otherwise (render as plain text).
+export function downloadUrlFor(
+  packageType: string | undefined,
+  repo: string,
+  path: string,
+): string | null {
+  if (!packageType) return null;
+  const build = downloadableTypes[packageType];
+  return build ? build(repo, path) : null;
+}

ui/src/pages/Objects.css

@@ -37,6 +37,15 @@
   word-break: break-all;
 }
 
+.tree-file-link {
+  color: var(--accent, #4c9aff);
+  text-decoration: none;
+}
+
+.tree-file-link:hover {
+  text-decoration: underline;
+}
+
 .tree-dir {
   cursor: pointer;
 }

ui/src/pages/Objects.tsx

@@ -3,6 +3,7 @@ import { useParams, useLocation, Link } from 'react-router-dom';
 import { api } from '../api/client';
 import type { Artifact } from '../api/types';
 import { formatBytes, timeAgo, truncateHash } from '../components/format';
+import { downloadUrlFor } from '../components/downloads';
 import './Objects.css';
 
 interface TreeNode {
@@ -100,11 +101,16 @@ interface TreeRowProps {
   expanded: Set<string>;
   onToggle: (path: string) => void;
   onEvict: (path: string) => void;
+  repo: string;
+  packageType?: string;
 }
 
-function TreeRow({ node, depth, expanded, onToggle, onEvict }: TreeRowProps) {
+function TreeRow({ node, depth, expanded, onToggle, onEvict, repo, packageType }: TreeRowProps) {
   const isDir = node.children.size > 0 && !node.artifact;
   const isExpanded = expanded.has(node.path);
+  const downloadUrl = node.artifact
+    ? downloadUrlFor(packageType, repo, node.artifact.path)
+    : null;
 
   const sortedChildren = useMemo(() => {
     if (!isDir) return [];
@@ -124,9 +130,20 @@ function TreeRow({ node, depth, expanded, onToggle, onEvict }: TreeRowProps) {
             {isDir && (
               <span className="tree-toggle">{isExpanded ? '▾' : '▸'}</span>
             )}
-            <span className={isDir ? 'tree-dir-name' : 'mono tree-file-name'}>
-              {node.name}{isDir ? '/' : ''}
-            </span>
+            {downloadUrl ? (
+              <a
+                className="mono tree-file-name tree-file-link"
+                href={downloadUrl}
+                download
+                onClick={(e) => e.stopPropagation()}
+              >
+                {node.name}
+              </a>
+            ) : (
+              <span className={isDir ? 'tree-dir-name' : 'mono tree-file-name'}>
+                {node.name}{isDir ? '/' : ''}
+              </span>
+            )}
           </span>
         </td>
         <td className="num-cell">{formatBytes(node.totalSize)}</td>
@@ -163,6 +180,8 @@ function TreeRow({ node, depth, expanded, onToggle, onEvict }: TreeRowProps) {
           expanded={expanded}
           onToggle={onToggle}
           onEvict={onEvict}
+          repo={repo}
+          packageType={packageType}
         />
       ))}
     </>
@@ -175,6 +194,7 @@ export function Objects() {
   const isLocal = location.pathname.startsWith('/locals/');
   const backLink = isLocal ? `/locals/${name}` : `/remotes/${name}`;
   const [artifacts, setArtifacts] = useState<Artifact[]>([]);
+  const [packageType, setPackageType] = useState<string | undefined>(undefined);
   const [loading, setLoading] = useState(true);
   const [filter, setFilter] = useState('');
   const [expanded, setExpanded] = useState<Set<string>>(new Set());
@@ -190,6 +210,15 @@ export function Objects() {
 
   useEffect(() => { load(); }, [load]);
 
+  // The repo's package_type is the modularity hook: it decides whether file
+  // names render as direct-download links (see downloadableTypes).
+  useEffect(() => {
+    if (!name) return;
+    api.getRemote(name)
+      .then(r => setPackageType(r.package_type))
+      .catch(() => setPackageType(undefined));
+  }, [name]);
+
   const handleEvict = async (path: string) => {
     if (!name || !confirm(`Evict ${path}?`)) return;
     await (isLocal ? api.evictLocalObject(name, path) : api.evictObject(name, path));
@@ -287,6 +316,8 @@ export function Objects() {
                     expanded={expanded}
                     onToggle={toggleExpand}
                     onEvict={handleEvict}
+                    repo={name!}
+                    packageType={packageType}
                   />
                 ))
               )}