Add i18n support

.github/workflows/gh-pages.yaml

@@ -1,7 +1,6 @@
 name: GitHub Pages
 
 on:
-  workflow_dispatch: {}
   push:
     branches:
       - master
@@ -11,28 +10,60 @@ on:
     paths:
       - 'book/**'
 
+permissions:
+  contents: read
+  pages: write
+  id-token: write
+
+# Allow one concurrent deployment
+concurrency:
+  group: pages
+  cancel-in-progress: true
+
+env:
+  CARGO_TERM_COLOR: always
+  # Update the language picker in index.hbs to link new languages.
+  LANGUAGES: zh
+
 jobs:
   deploy:
-    runs-on: ubuntu-20.04
-    concurrency:
-      group: ${{ github.workflow }}-${{ github.ref }}
+    environment:
+      name: github-pages
+      url: ${{ steps.deployment.outputs.page_url }}
+    runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - name: Checkout
+        uses: actions/checkout@v3
 
-      # ref https://github.com/peaceiris/actions-mdbook
-      - name: Setup mdBook
-        uses: peaceiris/actions-mdbook@v1
-        with:
-          mdbook-version: 'latest'
-
-      - name: Setup `mdbook-mermaid`
-        run: cargo install mdbook-mermaid
+      - name: Setup Rust cache
+        uses: ./.github/workflows/setup-rust-cache
 
-      - run: mdbook build ./book
+      - name: Install mdbook
+        uses: ./.github/workflows/install-mdbook
 
-      - name: Deploy
-        uses: peaceiris/actions-gh-pages@v3
-        if: ${{ github.ref == 'refs/heads/master' }}
+      - name: Build course in English
+        working-directory: ./book
+        run: mdbook build -d book
+
+      - name: Build all translations
+        working-directory: ./book
+        run: |
+          for po_lang in ${{ env.LANGUAGES }}; do
+              echo "::group::Building $po_lang translation"
+              MDBOOK_BOOK__LANGUAGE=$po_lang \
+              MDBOOK_OUTPUT__HTML__SITE_URL=/flutter-rust-bridge/$po_lang/ \
+              mdbook build -d book/$po_lang
+              echo "::endgroup::"
+          done
+
+      - name: Setup Pages
+        uses: actions/configure-pages@v2
+
+      - name: Upload artifact
+        uses: actions/upload-pages-artifact@v1
         with:
-          github_token: ${{ secrets.GITHUB_TOKEN }}
-          publish_dir: ./book/book
+          path: book/book
+
+      - name: Deploy to GitHub Pages
+        id: deployment
+        uses: actions/deploy-pages@v1

.github/workflows/install-mdbook/action.yaml

@@ -0,0 +1,18 @@
+name: Install mdbook and dependencies
+
+description: Install mdbook with the dependencies we need.
+
+runs:
+  using: composite
+  steps:
+    - name: Install mdbook
+      run: cargo install mdbook --locked --version 0.4.28
+      shell: bash
+
+    - name: Install mdbook-mermaid
+      run: cargo install mdbook-mermaid --locked --version 0.12.6
+      shell: bash
+
+    - name: Install mdbook-i18n-helpers
+      run: cargo install mdbook-i18n-helpers --locked --version 0.1.0
+      shell: bash

.github/workflows/setup-rust-cache/action.yaml

@@ -0,0 +1,9 @@
+name: Setup Rust cache
+
+description: Configure the rust-cache workflow.
+
+runs:
+  using: composite
+  steps:
+    - name: Setup Rust cache
+      uses: Swatinem/rust-cache@v2

book/.gitignore

@@ -1 +1,5 @@
 book
+
+# Translation artifacts
+po/messages.pot
+po/*.mo

book/book.toml

@@ -5,7 +5,19 @@ multilingual = false
 src = "src"
 title = "flutter_rust_bridge"
 
+[build]
+extra-watch-dirs = ["po"]
+
 [preprocessor]
 
 [preprocessor.mermaid]
 command = "mdbook-mermaid"
+
+[preprocessor.gettext]
+after = ["links"]
+
+[output.html]
+curly-quotes = true
+additional-css = ["theme/lang-popup.css"]
+git-repository-url = "https://github.com/fzyzcjy/flutter_rust_bridge"
+edit-url-template = "https://github.com/fzyzcjy/flutter_rust_bridge/edit/master/book/{path}"