feat(19.3-03): storage.uploads.public_url for direct bucket or CDN file URLs

- OpenBucket validates public_url (absolute http/https, host, no user info, query
  or fragment; the error names the key) and records it next to public_path_prefix
- a set public_url logs one start-up line: the bucket behind it must hold only
  public files, since it bypasses the is_public check
- attach.PublicURLBase; PublicURL, File.URL and thumbnail URLs use the base when
  set and keep the public_path_prefix proxy URLs otherwise
- TestPublicURLSmoke; storage Public URL base section, attachments, configuration
  and lagoon README

modules/lagoon/README.md

@@ -38,7 +38,7 @@ Use cases:
 - Lifecycle and relations: hook interfaces matching GORM's native method names (`lagoon.HasBeforeCreate`, `lagoon.HasBeforeSave`, `lagoon.HasBeforeDelete`, `lagoon.HasAfterDelete`) plus `lagoon.HasBeforeValidate`; `lagoon.WithSoftDeleteCascade` runs a cascade inside the parent delete; `lagoon.RegisterJoinTable` wires pivot models with business columns.
 - Deferred binding: WinterCMS's `deferred_bindings` table holds the uploads and related-record changes of a form whose record is not saved yet. Every operation takes a `lagoon.DeferredKey` (the form's session key, the owning backend admin's id and the master record's morph type from `lagoon.MorphType`) and never reads or changes another admin's rows, since each row stores `backend_user_id`. `lagoon.DeferredBind` and `lagoon.DeferredUnbind` port WinterCMS's duplicate and cancel rules: a repeated bind writes nothing, and an unbind of a slave with a pending bind deletes that bind and returns it so the caller can remove what it created. `lagoon.DeferredBindings` reads and locks a session's bindings for the save that commits them, `lagoon.DeferredForget` deletes them once applied, and `lagoon.DeferredSlaves` is the subquery a list uses to include pending rows. A child created under deferral carries the `lagoon.DeferredEnvelope` (`{"created":true,"pivot":{...},"upload_id":"..."}`) in `pivot_data`. `lagoon.PurgeDeferred` removes expired bindings: it deletes an unattached `system_files` row a bind points at, and its blobs only after the commit, deletes a child only when its binding carries the created envelope, keeps records that were only linked, and locks each batch with `FOR UPDATE SKIP LOCKED`.
 - Imports from Laravel: `lagoon.DecryptLaravelPayload` decrypts Laravel `encrypted` payloads with the old application key, for one-off data imports.
-- Attachments (`attach`): the `attach.File` model for `system_files` rows, WinterCMS-compatible partitioned storage keys (`attach.BlobKey`, `attach.PartitionDirectory`), an S3 bucket option behind the `attach.S3BuildTag` build tag (an untagged binary refuses an `s3://` bucket URL at boot with an error naming the tag), public URLs (`attach.PublicURL` for any key, `attach.File.URL` for an original, matching WinterCMS's `File::getPath()` under the WinterCMS layout), on-demand thumbnails through `attach.File.Thumb` for JPEG, PNG, GIF and WebP originals (a WebP original's thumbnail is JPEG bytes under its `.webp` name, since WebP cannot be encoded; a missing, undecodable or oversized original gets WinterCMS's broken-image picture, `attach.BrokenImagePNG`, as its thumbnail, as `File::makeThumb` does), storing uploads through `attach.Store` (a server-generated disk name whose extension follows the sniffed content through `attach.DiskExtension`, so a PNG named `x.html` is stored as `.png`, an extension allow-list with `attach.DefaultImageExtensions` and `attach.DefaultFileExtensions` as defaults, a MIME filter, a size limit enforced while streaming and, in image mode, the `attach.IsAllowedImage` content guard), attachment relation declarations (`attach.Relation`, `attach.HasRelations`), static serving with an optional `is_public` gate (`attach.StaticHandlerPublic`), and a two-phase delete that removes blobs only after the database transaction commits (`attach.DeleteForOwner`, `attach.DeleteKeys`).
+- Attachments (`attach`): the `attach.File` model for `system_files` rows, WinterCMS-compatible partitioned storage keys (`attach.BlobKey`, `attach.PartitionDirectory`), an S3 bucket option behind the `attach.S3BuildTag` build tag (an untagged binary refuses an `s3://` bucket URL at boot with an error naming the tag), public URLs (`attach.PublicURL` for any key, under `storage.uploads.public_url` when a public bucket or CDN serves the files (`attach.PublicURLBase`), `attach.File.URL` for an original, matching WinterCMS's `File::getPath()` under the WinterCMS layout), on-demand thumbnails through `attach.File.Thumb` for JPEG, PNG, GIF and WebP originals (a WebP original's thumbnail is JPEG bytes under its `.webp` name, since WebP cannot be encoded; a missing, undecodable or oversized original gets WinterCMS's broken-image picture, `attach.BrokenImagePNG`, as its thumbnail, as `File::makeThumb` does), storing uploads through `attach.Store` (a server-generated disk name whose extension follows the sniffed content through `attach.DiskExtension`, so a PNG named `x.html` is stored as `.png`, an extension allow-list with `attach.DefaultImageExtensions` and `attach.DefaultFileExtensions` as defaults, a MIME filter, a size limit enforced while streaming and, in image mode, the `attach.IsAllowedImage` content guard), attachment relation declarations (`attach.Relation`, `attach.HasRelations`), static serving with an optional `is_public` gate (`attach.StaticHandlerPublic`), and a two-phase delete that removes blobs only after the database transaction commits (`attach.DeleteForOwner`, `attach.DeleteKeys`).
 
 ## Usage
 
@@ -191,7 +191,8 @@ func (p *Plugin) Migrations() []*gormigrate.Migration {
 | `lagoon.RegisterJoinTable` | Registers a custom pivot model for a many-to-many field. |
 | `lagoon.DecryptLaravelPayload` | Decrypts a Laravel AES-256-CBC payload for data imports. |
 | `attach.File` | The `system_files` row model; `attach.File.URL` is the public URL of the original. |
-| `attach.PublicURL` | Public URL of a blob key under `storage.uploads.public_path_prefix`. |
+| `attach.PublicURL` | Public URL of a blob key: under `storage.uploads.public_url` when set, else under `storage.uploads.public_path_prefix`. |
+| `attach.PublicURLBase` | `storage.uploads.public_url` as recorded by `attach.OpenBucket`, empty when unset. |
 | `attach.BrokenImagePNG` | WinterCMS's broken-image picture, stored as the thumbnail of an unusable original. |
 | `attach.Owner` | Implemented by models that own attachments; returns the stored morph type name. |
 | `attach.OpenBucket` | Opens the uploads bucket from config; refuses `s3://` in a binary built without `attach.S3BuildTag`. |
@@ -231,6 +232,7 @@ Keys are read from the compass config; the `SUMMER_` environment overlay maps a
 | `app.previous_keys` | empty | List of earlier base64 keys still accepted when decrypting, for key rotation. |
 | `storage.uploads.bucket_url` | none (required by `attach.OpenBucket`) | Uploads bucket URL, `file://`, `mem://` or `s3://` (with `attach.S3BuildTag`; query parameters such as `region`, `endpoint` and `use_path_style` per gocloud.dev, credentials from the AWS environment). |
 | `storage.uploads.public_path_prefix` | `/storage/uploads` | URL prefix used when building public file and thumbnail URLs. |
+| `storage.uploads.public_url` | empty | Absolute `http` or `https` base of a public bucket or CDN; when set, file and thumbnail URLs are this base plus the partition path. A malformed value fails `attach.OpenBucket`; a set value logs that the bucket must hold only public files. |
 | `database.deferred_bindings.purge_days` | `5` | Age in days after which `deferred:purge` removes a deferred binding, WinterCMS's `cleanUp(5)`; the `--days` flag overrides it. |
 | `database.deferred_bindings.purge_at` | `03:00` | Daily `HH:MM` (in `app.timezone`) at which the scheduler runs `deferred:purge`; an empty value disables the framework entry. |
 

modules/lagoon/attach/bucket.go

@@ -3,6 +3,7 @@ package attach
 import (
 	"context"
 	"fmt"
+	"log/slog"
 	"net/url"
 	"strings"
 	"sync"
@@ -24,6 +25,7 @@ const S3BuildTag = "summercms_s3"
 var (
 	prefixMu         sync.RWMutex
 	publicPathPrefix = defaultPublicPathPrefix
+	publicURLBase    string
 )
 
 func setPublicPathPrefix(prefix string) {
@@ -32,6 +34,38 @@ func setPublicPathPrefix(prefix string) {
 	prefixMu.Unlock()
 }
 
+func setPublicURLBase(base string) {
+	prefixMu.Lock()
+	publicURLBase = base
+	prefixMu.Unlock()
+}
+
+// PublicURLBase is storage.uploads.public_url as recorded by OpenBucket: an
+// absolute http or https base (a public bucket or a CDN) that file and
+// thumbnail URLs start with instead of PublicPathPrefix. Empty when unset.
+func PublicURLBase() string {
+	prefixMu.RLock()
+	defer prefixMu.RUnlock()
+	return publicURLBase
+}
+
+// parsePublicURL validates storage.uploads.public_url: empty means unset,
+// anything else must be an absolute http or https URL with a host and
+// without user info, query or fragment.
+func parsePublicURL(raw string) (*url.URL, error) {
+	value := strings.TrimSpace(raw)
+	if value == "" {
+		return nil, nil
+	}
+	u, err := url.Parse(value)
+	bad := err != nil || u.Host == "" || u.User != nil || u.RawQuery != "" || u.ForceQuery || u.Fragment != "" ||
+		(!strings.EqualFold(u.Scheme, "http") && !strings.EqualFold(u.Scheme, "https"))
+	if bad {
+		return nil, fmt.Errorf("attach: storage.uploads.public_url must be an absolute http or https URL such as https://cdn.example.com/uploads, without user info, query or fragment (set SUMMER_STORAGE__UPLOADS__PUBLIC_URL)")
+	}
+	return u, nil
+}
+
 // PublicPathPrefix is the URL prefix prepended to partition+filename.
 func PublicPathPrefix() string {
 	prefixMu.RLock()
@@ -79,7 +113,9 @@ func checkS3Driver(bucketURL string) error {
 
 // OpenBucket opens storage.uploads.bucket_url (file://, mem://, or s3:// in a
 // binary built with S3BuildTag) and records
-// storage.uploads.public_path_prefix. An empty bucket_url fails boot.
+// storage.uploads.public_path_prefix and storage.uploads.public_url. An
+// empty bucket_url or a malformed public_url fails boot; a set public_url
+// logs one info line saying the bucket behind it must hold only public files.
 func OpenBucket(ctx context.Context, cfg *compass.Config) (*blob.Bucket, error) {
 	if cfg == nil {
 		return nil, fmt.Errorf("attach: config is nil")
@@ -95,6 +131,10 @@ func OpenBucket(ctx context.Context, cfg *compass.Config) (*blob.Bucket, error)
 	if err := checkS3Driver(bucketURL); err != nil {
 		return nil, err
 	}
+	publicURL, err := parsePublicURL(cfg.String("storage.uploads.public_url"))
+	if err != nil {
+		return nil, err
+	}
 	bucket, err := blob.OpenBucket(ctx, bucketURL)
 	if err != nil {
 		return nil, fmt.Errorf("attach: open bucket %q: %w", raw, err)
@@ -104,6 +144,14 @@ func OpenBucket(ctx context.Context, cfg *compass.Config) (*blob.Bucket, error)
 		prefix = defaultPublicPathPrefix
 	}
 	setPublicPathPrefix(prefix)
+	if publicURL == nil {
+		setPublicURLBase("")
+		return bucket, nil
+	}
+	setPublicURLBase(publicURL.String())
+	slog.Default().InfoContext(ctx, "attach: storage.uploads.public_url is set; every file and thumbnail URL points at this host, "+
+		"which serves any key without the is_public check, so the bucket behind it must hold only public files",
+		slog.String("host", publicURL.Host))
 	return bucket, nil
 }
 

modules/lagoon/attach/infra_smoke_test.go

@@ -58,3 +58,49 @@ func TestOpenBucketS3Smoke(t *testing.T) {
 		t.Fatalf("close: %v", err)
 	}
 }
+
+// TestPublicURLSmoke checks storage.uploads.public_url (D-12): set, URLs
+// are the base plus the partition path; unset, they keep the proxy prefix;
+// malformed, OpenBucket fails naming the key.
+func TestPublicURLSmoke(t *testing.T) {
+	t.Cleanup(func() {
+		setPublicPathPrefix(defaultPublicPathPrefix)
+		setPublicURLBase("")
+	})
+	key := BlobKey("651a2b3c4d5e61234567.png")
+
+	cfg := openTestConfig(t, "uploads:\n  bucket_url: \"mem://\"\n  public_url: \"https://cdn.example.com/uploads/\"\n")
+	bucket, err := OpenBucket(t.Context(), cfg)
+	if err != nil {
+		t.Fatal(err)
+	}
+	_ = bucket.Close()
+	if got, want := PublicURL(key), "https://cdn.example.com/uploads/"+key; got != want {
+		t.Fatalf("PublicURL with public_url = %q, want %q", got, want)
+	}
+	if got, want := (&File{DiskName: "651a2b3c4d5e61234567.png"}).URL(), "https://cdn.example.com/uploads/651/a2b/3c4/651a2b3c4d5e61234567.png"; got != want {
+		t.Fatalf("File.URL with public_url = %q, want %q", got, want)
+	}
+
+	cfg = openTestConfig(t, "uploads:\n  bucket_url: \"mem://\"\n")
+	bucket, err = OpenBucket(t.Context(), cfg)
+	if err != nil {
+		t.Fatal(err)
+	}
+	_ = bucket.Close()
+	if PublicURLBase() != "" || !strings.HasPrefix(PublicURL(key), "/storage/uploads/") {
+		t.Fatalf("without public_url: base %q, URL %q", PublicURLBase(), PublicURL(key))
+	}
+
+	for _, bad := range []string{"ftp://x", "https://u:p@cdn.example.com", "/storage/uploads", "https://cdn.example.com/?v=1"} {
+		cfg = openTestConfig(t, "uploads:\n  bucket_url: \"mem://\"\n  public_url: \""+bad+"\"\n")
+		bucket, err = OpenBucket(t.Context(), cfg)
+		if err == nil {
+			_ = bucket.Close()
+			t.Fatalf("public_url %q accepted", bad)
+		}
+		if !strings.Contains(err.Error(), "storage.uploads.public_url") || strings.Contains(err.Error(), "u:p") {
+			t.Fatalf("public_url %q: error %q", bad, err)
+		}
+	}
+}

modules/lagoon/attach/thumb.go

@@ -76,13 +76,18 @@ func fileExt(diskName string) string {
 	return strings.ToLower(ext)
 }
 
-// PublicURL returns the public URL of a blob key: storage.uploads.
-// public_path_prefix and the key joined by exactly one slash. With the
-// WinterCMS layout (bucket rooted at storage/app/uploads/public, prefix
-// /storage/app/uploads/public) it is Winter's File::getPath() path.
+// PublicURL returns the public URL of a blob key. With
+// storage.uploads.public_url set (PublicURLBase) it is that base and the key
+// joined by exactly one slash. Otherwise it is
+// storage.uploads.public_path_prefix and the key joined the same way; with
+// the WinterCMS layout (bucket rooted at storage/app/uploads/public, prefix
+// /storage/app/uploads/public) that is Winter's File::getPath() path.
 func PublicURL(key string) string {
-	prefix := strings.TrimRight(PublicPathPrefix(), "/")
 	key = strings.TrimLeft(key, "/")
+	if base := PublicURLBase(); base != "" {
+		return strings.TrimRight(base, "/") + "/" + key
+	}
+	prefix := strings.TrimRight(PublicPathPrefix(), "/")
 	if prefix == "" {
 		return "/" + key
 	}