feat(blog): localized post slugs, and the blog in en and es (21/54 posts)

[rdahis]

Translates the blog into English and Spanish, and adds the slug mapping that makes localized blog URLs possible.

This branch is in progress: 21 of 54 posts are translated. The remaining 33 will land as further commits on this same branch. It is opened now so the routing change can be reviewed before another 66 files come to depend on it.

The slug mapping (the part worth reviewing)

Posts keep one filename across locales — that filename is what ties a post's translations together — and each translation declares its own public slug in frontmatter.

• getAllPosts now returns both slug (the URL segment, from frontmatter when present) and filename (shared across locales).
• getPostBySlug resolves by filename first, then falls back to scanning for the post whose frontmatter declares that slug, so both forms work.
• The post page redirects the filename form to the locale's own slug. This matters because the language switcher does router.push(router.pathname, router.asPath, { locale }), carrying the current slug across locales — without the redirect, switching language on a post would land on the blog index.
• getStaticPaths previously generated paths from the Portuguese filenames only, for every locale. It is now locale-aware.
• The "edit this page" link points at the real file rather than the localized slug.

Resolution was simulated against the real files. For example, with blog/en/curso-qgis.md declaring slug: free-qgis-course:

Request	Result
/blog/curso-qgis (pt)	renders, unchanged
/en/blog/free-qgis-course	renders from blog/en/curso-qgis.md
/en/blog/curso-qgis (what the language switcher produces)	redirects to /en/blog/free-qgis-course
/en/blog/<a pt slug with no en translation>	redirects to the blog index, as before

No redirect loops.

Translations so far

21 posts in both en and es — 9 analyses, 6 institutional, 5 tutorials, 1 uncategorised.

One of them, analisando-atividade-economica-do-rio-de-janeiro, already had en and es files, but both contained the Portuguese body under a translated frontmatter. Those are rewritten properly.

Conventions applied throughout:

• SQL, R and Python blocks are verbatim. They reference real BigQuery tables and columns (id_municipio, sigla_uf, id_pais), which the surrounding prose names, so translating an identifier would silently break the tutorial.
• Brazilian institution and dataset names are kept: IBGE, RAIS, CNAE, INEP, INMET, SINAN, SEBRAE, Comex Stat, geobr, LAI.
• Values in reais are kept as reais.
• DB Pro callouts in the English posts use the English brand and the /dbpro URL from feat(bdpro): brand the Pro page as DB Pro on the English site #1680.
• Portuguese wording is unchanged, including informal usages like "a BD".

Also fixed

The blog table-of-contents heading was hardcoded as "Tabela de conteúdo" in Slug.js, so it rendered in Portuguese on every post in every language. It now reads from a new blog.tableOfContents key, added for all three locales.

Testing

Not built or run — the working tree had no node_modules. Verification was static:

• Every edited JS file parses under Babel.
• A script checks each translated post: slug present, slug resolves, filename form redirects to it, no stray Portuguese in prose, and structural parity with the Portuguese source (same count of code blocks and images). All 42 post files pass.

The routing change needs a real next build before merge. Two specifics to look at:

• getStaticPaths now returns { params, locale } entries rather than bare { params }. That is the documented shape for i18n, but it is the kind of thing worth confirming against an actual build.
• getPostBySlug's fallback reads every file in the locale directory when the fast path misses. That is fine at 54 posts and static build time, but it is a linear scan.

Known gaps

• Screenshots and chart images are shared across locales and show Portuguese interfaces (BigQuery, Power BI, QGIS) and Portuguese ggplot axis labels. The prose is translated; the images are not. Localised images would be a separate piece of work.
• Two translated posts carry published: false in the source (intro-ao-pacote-basedosdados-em-python, como-funciona-o-sistema-de-insercao-de-dados-na-bd). They are translated for parity but stay invisible until that flag changes.
• relembrando-o-datathon-bd-2021 links to /ufrj-analytica/datathon-open-data-day-..., which looks like a Medium URL missing its domain. Broken in the Portuguese original too; copied as-is rather than guessed at.