Filter remote object listings by prefix (#129)

`GET /api/v2/remotes/{name}/objects` dropped the `prefix` query parameter, so a filtered listing returned the first page of every artifact in the remote.

- add a `prefix` argument to `ListArtifacts` that matches path prefixes
- pass the `prefix` query parameter through from the objects list handler

Reviewed-on: #129
Co-authored-by: unkin-agent <unkin-agent@unkin.net>
Co-committed-by: unkin-agent <unkin-agent@unkin.net>

internal/database/artifacts.go

@@ -65,7 +65,8 @@ func (db *DB) TouchArtifactAccess(ctx context.Context, remoteName, path string)
 	return err
 }
 
-func (db *DB) ListArtifacts(ctx context.Context, remoteName string, limit, offset int) ([]models.Artifact, error) {
+// ListArtifacts pages a remote's artifacts whose path starts with prefix ("" lists all).
+func (db *DB) ListArtifacts(ctx context.Context, remoteName, prefix string, limit, offset int) ([]models.Artifact, error) {
 	rows, err := db.Pool.Query(ctx, `
 		SELECT a.id, a.remote_name, a.path, a.content_hash, a.upstream_etag,
 			a.upstream_last_modified, a.first_seen_at, a.last_fetched_at,
@@ -73,10 +74,10 @@ func (db *DB) ListArtifacts(ctx context.Context, remoteName string, limit, offse
 			b.size_bytes, b.content_type
 		FROM artifacts a
 		JOIN blobs b ON a.content_hash = b.content_hash
-		WHERE a.remote_name = $1
+		WHERE a.remote_name = $1 AND left(a.path, length($2)) = $2
 		ORDER BY a.path
-		LIMIT $2 OFFSET $3
-	`, remoteName, limit, offset)
+		LIMIT $3 OFFSET $4
+	`, remoteName, prefix, limit, offset)
 	if err != nil {
 		return nil, err
 	}

internal/database/database_test.go

@@ -168,10 +168,17 @@ func TestArtifactsAndBlobs(t *testing.T) {
 	if err := testDB.TouchArtifactAccess(ctx(), "r-art", "path/a.txt"); err != nil {
 		t.Fatal(err)
 	}
-	arts, err := testDB.ListArtifacts(ctx(), "r-art", 10, 0)
-	if err != nil || len(arts) != 1 {
+	if err := testDB.UpsertArtifact(ctx(), "r-art", "other/b.txt", hash, ""); err != nil {
+		t.Fatal(err)
+	}
+	arts, err := testDB.ListArtifacts(ctx(), "r-art", "", 10, 0)
+	if err != nil || len(arts) != 2 {
 		t.Fatalf("list artifacts: %v %v", len(arts), err)
 	}
+	arts, err = testDB.ListArtifacts(ctx(), "r-art", "path/", 10, 0)
+	if err != nil || len(arts) != 1 || arts[0].Path != "path/a.txt" {
+		t.Fatalf("list artifacts with prefix: %+v %v", arts, err)
+	}
 	if err := testDB.InsertAccessLog(ctx(), "r-art", "path/a.txt", true, 10, 5, "1.2.3.4"); err != nil {
 		t.Fatal(err)
 	}
@@ -188,6 +195,45 @@ func TestArtifactsAndBlobs(t *testing.T) {
 	}
 }
 
+func TestListArtifactsPrefix(t *testing.T) {
+	requireDB(t)
+	seedRemote(t, "r-prefix")
+	seedBlob(t, "prefixhash")
+	for _, p := range []string{"a%b/y", "a1b/y", "a_b/x", "aXb/x", "pkg/1", "pkg/2", "pkg/3", "pkgx/4"} {
+		if err := testDB.UpsertArtifact(ctx(), "r-prefix", p, "sha256:prefixhash", ""); err != nil {
+			t.Fatal(err)
+		}
+	}
+	paths := func(prefix string, limit, offset int) []string {
+		t.Helper()
+		arts, err := testDB.ListArtifacts(ctx(), "r-prefix", prefix, limit, offset)
+		if err != nil {
+			t.Fatalf("list %q: %v", prefix, err)
+		}
+		out := make([]string, len(arts))
+		for i, a := range arts {
+			out[i] = a.Path
+		}
+		return out
+	}
+
+	// LIKE wildcards in the prefix must match literally.
+	if got := paths("a_b/", 10, 0); len(got) != 1 || got[0] != "a_b/x" {
+		t.Fatalf("prefix a_b/ = %v, want [a_b/x]", got)
+	}
+	if got := paths("a%", 10, 0); len(got) != 1 || got[0] != "a%b/y" {
+		t.Fatalf("prefix a%% = %v, want [a%%b/y]", got)
+	}
+
+	// limit/offset page the filtered set, not the whole remote.
+	if got := paths("pkg/", 2, 0); len(got) != 2 || got[0] != "pkg/1" || got[1] != "pkg/2" {
+		t.Fatalf("prefix pkg/ page 1 = %v, want [pkg/1 pkg/2]", got)
+	}
+	if got := paths("pkg/", 2, 2); len(got) != 1 || got[0] != "pkg/3" {
+		t.Fatalf("prefix pkg/ page 2 = %v, want [pkg/3]", got)
+	}
+}
+
 func TestOrphanAndColdCleanup(t *testing.T) {
 	requireDB(t)
 	seedBlob(t, "orphanhash")
@@ -320,7 +366,7 @@ func TestDatabaseErrorPaths(t *testing.T) {
 	if _, err := bad.ListVirtuals(ctx); err == nil {
 		t.Error("ListVirtuals should error")
 	}
-	if _, err := bad.ListArtifacts(ctx, "r", 10, 0); err == nil {
+	if _, err := bad.ListArtifacts(ctx, "r", "", 10, 0); err == nil {
 		t.Error("ListArtifacts should error")
 	}
 	if _, err := bad.ListLocalFiles(ctx, "r", 10, 0); err == nil {