feat: SEO backend output (2/4)

docs/api.md

@@ -10,8 +10,9 @@ The origin that serves the app, for example `https://cms.example`. Every path st
 for example `https://cms.example/v1/article/`.
 
 ## Authentication
-- Public routes need nothing: `GET /v1/article/` and `GET /v1/article/{id}`. They return online
-  articles only.
+- Public routes need nothing: `GET /v1/article/`, `GET /v1/article/{id}`, `GET /v1/article/{id}/seo`
+  and `GET /v1/site/{key}/sitemap`. They return online articles only; the list and the resolved SEO
+  object also answer drafts to a verified session or API key.
 - Everything else needs a signed-in browser session (the `jwt` cookie) or an API key:
   `Authorization: Bearer rcms_...`. Create keys at `/integration/api-keys`. A key acts as its
   creator, with that user's role, and shows in full once.
@@ -21,14 +22,14 @@ for example `https://cms.example/v1/article/`.
   under `/v1/site`) and the author writes (`POST`, `PATCH` and `DELETE` under `/v1/author`, `POST /v1/author/me` included) are session only too.
 - Each key can make 120 requests per minute. Beyond that: 429 with a `Retry-After` header.
 
-## Routes a key can call (26)
+## Routes a key can call (29)
 | 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} |
+| Articles | GET /v1/article/, GET /v1/article/{id}, GET /v1/article/{id}/seo, POST /v1/article/{id}/seo/check, 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), 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 (with the linked `author`) |
 | Settings | GET /v1/settings |
-| Sites | GET /v1/site/ |
+| Sites | GET /v1/site/, GET /v1/site/{key}/sitemap |
 | Authors | GET /v1/author/ |
 
 ## Activity log
@@ -155,6 +156,20 @@ those fields, a `null` value (except on `cover_image_id` and `social_image_id`)
 400 with the validator text and an unknown site is 404 `site_not_found`. Moving an article never
 changes `is_online`. `{"body": ""}` still sets an empty body, but `{}` and `{"body": null}` no longer do: they are 400.
 
+### Resolved SEO, check, list status and sitemap
+
+RenewCMS renders no page and injects no meta tag: it returns the data a frontend needs.
+
+| Route | Who | Purpose |
+| --- | --- | --- |
+| `GET /v1/article/{id}/seo` | public for online articles; a verified session or API key also reads drafts | The resolved object `{ title, description, canonical_url, robots, og, twitter, image, authors, published_at, modified_at, fallbacks, json_ld }`. It never carries the body, the id or `seo_dismissed`, ignores `format`, and writes nothing. An offline article for any other caller, and a missing one, is 404 `Article not found`. |
+| `POST /v1/article/{id}/seo/check` | verified session or API key (401 without credentials, 403 unverified) | Evaluates the article without saving. The body is `{}` or any of the twelve SEO fields of `PATCH` plus `body`; each replaces the saved value for this check only. `site_id`, `author_ids`, unknown fields and `null` (except on `cover_image_id` and `social_image_id`) are 400 with the body-mismatch message. The other validation is the one of `PATCH` (`invalid_slug`, `invalid_url` as 422, `image_not_found`, validator text). Answers `{ status, suggestions, slug }` where `suggestions` is `[{ code, field, params }]` and `slug` is `{ available, suggestion }`. A taken slug is a 200 with `available: false` and the first free `<slug>-N` in `suggestion`, never a 409. |
+| `GET /v1/site/{key}/sitemap` | public | A JSON array `[{ url, modified_at, noindex }]` of the online articles of the site with that key, by id ascending. `url` is `base_url/slug` (never the canonical override). `page` (default 1) and `size` (25, 50, 100 or 500, default 100); an invalid value is 400 with the body-mismatch message. The total is in the `X-Total-Count` header. An unknown key, an id included, is 404 `site_not_found`. |
+
+`GET /v1/article/` also takes `seo=ready|suggestions|hidden` (any other value, an empty one included, is 400 with the body-mismatch message, after the `format` check). It is applied before paging and composes with `q`, `status`, `site`, `sort`, `page` and `size`; `total` follows it and `counts` ignore it. Every item carries `seo_status` (`ready`, `suggestions` or `hidden`) and `seo_suggestions` (the number of suggestions that are not dismissed). The filter is evaluated in memory over every matching article, so its cost grows with the number of articles on the site; without it only the returned page is assessed.
+
+`X-Total-Count` is added to `Access-Control-Expose-Headers` next to `Link`, so a browser on an allowed origin can read it.
+
 ### Article SEO fields
 
 An article carries twelve search and sharing fields, all edited through `PATCH /v1/article/{id}` and returned by

docs/api/articles.md

@@ -36,12 +36,14 @@ Visibility is unchanged: anonymous and unverified callers only see online articl
 | `q` | up to 200 characters, matched anywhere in the title, ignoring case and accents | none |
 | `status` | `online` or `draft` | none |
 | `site` | the `key` of a site; an unknown key gives an empty page, an empty value is `400` | none |
+| `seo` | `ready`, `suggestions` or `hidden`; any other value, an empty one included, is `400` | none |
 | `sort` | `title`, `status`, `created_at` or `updated_at`, then `:asc` or `:desc` (lowercase, for example `title:asc`) | `updated_at:desc` |
 
 - `items` is `[]` when empty, never `null`. Each item is the article object below.
 - Items follow `sort` (default `updated_at:desc`) across the whole list before paging. `title` ignores case, `status` orders on online state (`status:asc` puts drafts first), and every ordering ends with `id` descending so pages never overlap.
 - `total` is the number of visible articles matching `q` and `status`, before paging. `page` and `size` echo the values applied.
 - `counts` ignores `q` and `status`, so tab counts do not move while searching. For anonymous and unverified callers `all` equals `online` and `draft` is `0`, and `status=draft` answers `items: []` and `total: 0`.
+- Each item also carries `seo_status` and `seo_suggestions` (see [SEO status and suggestions](#seo-status-and-suggestions)). `seo` filters on the status before paging, so `total` follows it while `counts` do not.
 - A page beyond the last answers `200` with `items: []` and the real `total`.
 - An invalid `page`, `size`, `status`, `sort` or an over-long `q` answers `400` with the plain-text message `The request cannot be processed due to a mismatch in the format of the body.` An invalid `format` is reported first.
 
@@ -117,6 +119,45 @@ Editing a slug that another article of the target site already uses (the new sit
 
 Publishing, unpublishing and `noindex` never change a slug. A deleted article frees its slug.
 
+## Resolved SEO object
+
+`GET /v1/article/{id}/seo` answers the data a frontend renders in its `<head>`. Online articles are public; a draft needs a verified session or API key and is otherwise `404 Article not found`. The query is ignored (no `format`). Keys:
+
+`title`, `description`, `canonical_url`, `robots`, `og` (`type`, `title`, `description`, `image`, `image_alt`, `url`, `site_name`, `locale`), `twitter` (`card`, `title`, `description`, `image`, `image_alt`), `image` (`url`, `alt`, `source`), `authors` (`name`, `url`, `same_as`), `published_at`, `modified_at`, `fallbacks` and `json_ld` (a ready schema.org `Article`).
+
+The fallback chain, first non-empty wins:
+
+| Output | Chain | `fallbacks` value |
+| --- | --- | --- |
+| `title` | `seo_title`, then the article title, then the site `title_template` (`%title%`, `%site%` replaced by `site_name`, result trimmed) | `seo_title`, `title` |
+| `description` | `seo_description`, `excerpt`, the first sentence of the body (tags removed), the site `default_description` | `seo_description`, `excerpt`, `body`, `site`, `none` |
+| `image` | `social_image_id`, `cover_image_id` (with `cover_image_alt`), the site `default_social_image_id`; `url` is the site `base_url` plus the image path, `""` and `none` when there is none | `social`, `cover`, `site`, `none` |
+| `canonical_url` | `canonical_url`, then site `base_url` + `/` + `slug` | `canonical_url`, `site` |
+| `robots` | `noindex, nofollow` when `noindex` is true, otherwise from the site `default_robots` (`index, follow` or `noindex, nofollow`) | none |
+| `og` and `twitter` title and description | `social_title` and `social_description`, then the resolved values | none |
+
+`og.type` is `article`, `og.locale` is the site locale (`""` when none), `twitter.card` is `summary_large_image` with an image and `summary` without. `published_at` is the creation time of an online article and `null` for a draft; `modified_at` is `updated_at`. `authors[].url` is the author website (`""` when none) and `same_as` lists the social link URLs only. `json_ld.headline` is the meta title without the site template, and `author`, `image` and `datePublished` are left out when empty.
+
+## SEO status and suggestions
+
+`POST /v1/article/{id}/seo/check` and the list use one rule set. Soft ranges never block saving or publishing; lengths are counted in characters.
+
+| Code | Field | Fires when | `params` |
+| --- | --- | --- | --- |
+| `title_long` | `seo_title` | the meta title (`seo_title`, else the title) is over 60 characters | `length`, `max` |
+| `title_empty` | `seo_title` | the meta title is empty after trimming | none |
+| `desc_short` | `seo_description` | the resolved description is under 70 characters | `length`, `min` |
+| `desc_long` | `seo_description` | the resolved description is over 160 characters | `length`, `max` |
+| `cover_alt` | `cover_image_alt` | there is a cover and its alt text is empty | none |
+| `cover_none` | `cover_image_id` | there is no cover | none |
+| `slug_long` | `slug` | the slug is over 75 characters | `length`, `max` |
+| `no_au` | `author_ids` | no author is credited | none |
+| `no_h` | `body` | the text has at least 1000 characters and no `h2` to `h6` | none |
+| `body_alt` | `body` | an image of the body has no alt text | `count` |
+| `short` | `body` | the text has fewer than 300 characters | `length`, `min` |
+
+Suggestions come in that order. Codes in `seo_dismissed` are never reported or counted. The status is `hidden` when `noindex` is true, else `suggestions` when at least one suggestion remains, else `ready`. The list items carry `seo_status` and `seo_suggestions` (the count, also for a hidden article).
+
 ## Markdown output
 
 Headings, bold, italic, links, bullet and ordered lists, blockquotes, fenced code blocks, rules, images and inline code are converted. Anything else is reduced to its text. `script` and `style` content is removed, and the source HTML is never passed through; the only HTML in the output is the alignment wrapper described below. List indentation attributes are dropped. Links with a scheme other than http, https, mailto or tel are reduced to their text. Characters that markdown would read as formatting (`*`, `_`, `` ` ``, `[`, `]`, `<`, `\`) and line starts that would read as a heading, list, quote or rule (`#`, `-`, `+`, `>`, `1.`) are backslash-escaped, so plain text stays plain text. A line break becomes a backslash followed by a newline.

docs/release-notes.md

@@ -35,6 +35,13 @@ Articles and sites now store the data a website needs for search and sharing, an
 - Changed: `GET /v1/media/{id}/usage` stays an array, and every item gains `type` and `fields` without losing `id`, `title` and `published`. Authors and sites that use the image are now listed, without a `published` key.
 - Changed: a cover image, a social image, an author avatar and a site default social image all count in `used_in` and in the `unused` filter. Deleting an image clears the covers and social images that use it, and merging or purging repoints them.
 
+### New: SEO output
+
+- `GET /v1/article/{id}/seo` returns the resolved search and sharing data of an article (title with the site template, description, canonical address, robots, Open Graph, Twitter, image, authors and ready JSON-LD), so a frontend can render its meta tags without reimplementing the fallback chain. Drafts answer verified callers only.
+- `POST /v1/article/{id}/seo/check` evaluates an article without saving, with optional overrides, and reports the suggestions, the status and whether the slug is free.
+- `GET /v1/article/` items carry `seo_status` and `seo_suggestions`, and the new `seo` parameter filters on the status.
+- `GET /v1/site/{key}/sitemap` lists the published URLs of a site, paged, with the total in `X-Total-Count`, which is now exposed to browsers through CORS.
+
 ### Upgrading
 
 - The first start after the upgrade adds the new columns, gives every existing article a slug generated from its title (in id order within each site, with `-2`, `-3` on conflicts) and creates the unique `(site_id, slug)` index. Nothing else changes, and a second start changes nothing.