feat: image variants per image

docs/api.md

@@ -23,7 +23,7 @@ for example `https://cms.example/v1/article/`.
 | Group | Routes |
 | --- | --- |
 | Articles | GET /v1/article/, GET /v1/article/{id}, POST /v1/article/, PATCH /v1/article/{id}, PATCH /v1/article/{id}/publish, PATCH /v1/article/{id}/unpublish, DELETE /v1/article/{id} |
-| Media | GET /v1/media/, POST /v1/media/, PATCH /v1/media/{id}, DELETE /v1/media/{id}, POST /v1/media/merge, GET /v1/media/{id}/usage, GET /v1/media/purge-settings (owner or admin), PATCH /v1/media/purge-settings (owner or admin), GET /v1/media/purge-preview (owner or admin), POST /v1/media/purge (owner or admin) |
+| Media | GET /v1/media/, POST /v1/media/, PATCH /v1/media/{id}, DELETE /v1/media/{id}, POST /v1/media/merge, GET /v1/media/{id}/usage, GET /v1/media/purge-settings (owner or admin), PATCH /v1/media/purge-settings (owner or admin), GET /v1/media/purge-preview (owner or admin), POST /v1/media/purge (owner or admin), GET /v1/media/{id}/variants (owner or admin, session only), POST /v1/media/{id}/variants (owner or admin, session only), POST /v1/media/{id}/variants/{name} (owner or admin, session only), DELETE /v1/media/{id}/variants/{name} (owner or admin, session only) |
 | Users and invites | GET /v1/user/, PATCH /v1/user/me, POST /v1/user/invite (owner only), DELETE /v1/user/invite/{id} (owner only), POST /v1/user/invite/{id}/renew (owner only), GET /v1/auth/me |
 | Settings | GET /v1/settings |
 
@@ -62,7 +62,7 @@ never changes the response or the change itself.
 | Category | Actions |
 | --- | --- |
 | `articles` | `article.create`, `article.edit`, `article.publish`, `article.unpublish`, `article.delete` |
-| `media` | `media.upload`, `media.rename`, `media.delete`, `media.merge`, `media.purge`, `media.variant_create`, `media.variant_update`, `media.variant_delete`, `media.variant_enable`, `media.variant_disable`, `media.variant_purge` |
+| `media` | `media.upload`, `media.rename`, `media.delete`, `media.merge`, `media.purge`, `media.variant_create`, `media.variant_update`, `media.variant_delete`, `media.variant_enable`, `media.variant_disable`, `media.variant_purge`, `media.variant_generate_all`, `media.variant_purge_image` |
 | `users` | `user.register`, `user.verify`, `user.update_profile`, `invite.create`, `invite.cancel`, `invite.renew`, `invite.accept` |
 | `system` | `system.media_purge` (scheduled), `system.update_checked`, `system.update_downloaded`, `system.restart_requested`, `system.activity_cleanup`, `system.activity_retention_changed` |
 
@@ -73,6 +73,10 @@ kinds `text` and `body`; a body edit carries a signed character count delta and
 change that leaves a value as it was (same body, same publish state, same file name, same display
 name) records nothing. Params: `media.merge` and `media.purge` and `system.media_purge` carry
 `merged` and `articles_updated`, plus `failed_groups` when a group failed (still outcome `success`);
+`media.variant_generate_all` carries `generated`, `failed` and `causes` (a list of `too_large`,
+`unsupported_format` or `failed`) and is `failed` only when nothing was generated and something failed;
+`media.variant_purge_image` carries `purged_files` and `purged_bytes`; both have an `image` target
+and are recorded only when files were generated or removed;
 `system.update_checked` carries `update_available`; `system.restart_requested` carries `kind` and,
 for an update, `tag` (it has no target). `system.update_downloaded` is recorded when the job reaches
 `ready` or `failed`, with the origin captured at request time; a refusal at the start is recorded
@@ -88,7 +92,10 @@ try again."; the text of the error never reaches the event, the API or the CSV.
 codes, article bodies, file bytes, storage paths and asset urls are never recorded.
 
 Article routes accept `?format=markdown|html|json` (default `markdown`). `GET /v1/media/` accepts
-`q`, `hash`, `cursor`, `filter`, `sort` and `limit`.
+`q`, `hash`, `cursor`, `filter`, `sort` (`newest`, `oldest`, `name`, `largest` or `total_size`, the
+original plus its generated variants), `variants` (`with` or `without` generated variant files) and
+`limit`. Every item carries `variant_count` and `variant_size` (the index rows of the image and
+their bytes, 0 when none); `counts` stays library-wide. Any other `variants` or `sort` value is 400.
 
 ## Image variants
 Owners and admins manage named variants of the stored images. These routes are session only (no API
@@ -115,6 +122,30 @@ Errors are plain text: 400 for a body that is not valid JSON, 404 "Variant not f
 named “thumb” already exists. Choose another name." and 422 with one sentence for the first invalid
 field (name, width and height, fit, format, quality).
 
+### Variants of one image
+Owners and admins only, session only: a request with an API key is 401. All ids are image ids.
+
+| Route | Purpose |
+| --- | --- |
+| `GET /v1/media/{id}/variants` | `{ "unsupported": null, "items": [...] }` for the enabled variants in name order. `unsupported` is `"svg"` (with `items: []`) for an SVG. |
+| `POST /v1/media/{id}/variants` | Generates every enabled variant that is missing. `{ "generated", "failed", "failures": [{ "name", "cause" }], "items": [...] }`, 200 even when some fail. |
+| `POST /v1/media/{id}/variants/{name}` | Generates one enabled variant. 200 with the item. |
+| `DELETE /v1/media/{id}/variants/{name}` | Removes the generated file. `{ "purged_files", "purged_bytes" }`, also for a disabled variant. |
+
+An item is `{ name, width, height, fit, format, output_width, output_height, output_format,
+generated, size, url }`: `width` and `height` are the settings (`null` when auto), `output_*` the
+size and format the file has or will have (never above the source), `generated` is true only when
+the file exists with the variant's current settings, `size` is its bytes or `null`, and `url` is
+`/static/uploadedImages/<stored name>?v=<name>`. A `cause` is `too_large`, `unsupported_format` or
+`failed`. A file generated here is the same file the public url serves, and the other way round.
+Uploads generate the variants flagged `generate_on_upload` (enabled ones, raster sources only)
+before answering; a failure there is logged and never fails the upload.
+
+Errors are plain text: 400 for a malformed id, 404 "Image not found" or "Variant not found" (also for a
+disabled variant on `POST`), 413 "The source image is too large to generate this variant.", 415 "The
+source image can't be read, so this variant can't be generated.", 422 "Variants aren't generated for
+this format." and 500 "Internal server error".
+
 ## Errors
 Every error is a plain-text body with one sentence; the status is in the HTTP status line. The
 statuses are 400, 401, 403, 404, 409, 429 and 500. Messages are listed on the Integration page.