如何通过GitHub Action编辑GitHub Pages内容而不覆盖原有内容？

嘿，我完全懂你的困扰！现在你的Action能自动把主分支的文档发布到GitHub Pages，但你想给每个PR也生成一份文档放到/pulls/[PR编号]/这样的子目录里，又怕新部署会把主分支已经存在的内容给冲掉——毕竟默认的Pages部署是直接替换整个站点内容的对吧？

别担心，咱们可以通过先拉取现有Pages内容，再合并新内容后重新部署的方式解决这个问题，核心思路是操作GitHub Pages背后的gh-pages分支（或者你自定义的Pages源分支），把新内容加到对应的位置，再整体上传部署。

一、调整主分支的文档部署Workflow #

首先，原来的主分支部署会直接覆盖整个站点，咱们得改一改，让它保留/pulls/目录的内容，只更新根目录的主分支文档：

name: Publish Main Branch Docs
on:
  push:
    branches: [main]

permissions:
  pages: write
  id-token: write
  contents: read

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout main branch code
        uses: actions/checkout@v4

      - name: Build docs
        run: cargo doc --no-deps  # 生成主分支文档，根据你的项目调整命令

      - name: Checkout existing gh-pages content
        uses: actions/checkout@v4
        with:
          ref: gh-pages
          path: gh-pages-content
          fetch-depth: 0

      - name: Clear old main docs (keep /pulls/ directory)
        run: |
          # 删除根目录下除了pulls文件夹之外的所有内容
          cd gh-pages-content
          ls -1 | grep -v 'pulls' | xargs rm -rf

      - name: Copy new main docs to root
        run: cp -r target/doc/* gh-pages-content/

      - name: Upload updated Pages artifact
        uses: actions/upload-pages-artifact@v3
        with:
          path: gh-pages-content

  deploy:
    needs: build
    runs-on: ubuntu-latest
    environment:
      name: github-pages
      url: ${{ steps.deployment.outputs.page_url }}
    steps:
      - name: Deploy to GitHub Pages
        id: deployment
        uses: actions/deploy-pages@v4

二、新增PR文档的部署Workflow #

接下来创建一个专门处理PR的Workflow，每个PR触发时，把它的文档放到/pulls/[PR编号]/目录下，同时保留现有所有内容：

name: Publish PR Docs
on:
  pull_request:
    types: [opened, synchronize, reopened]

permissions:
  pages: write
  id-token: write
  contents: read

jobs:
  build-and-deploy-pr-docs:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout PR code
        uses: actions/checkout@v4
        with:
          ref: ${{ github.head_ref }}

      - name: Build PR docs
        run: cargo doc --no-deps  # 同样，根据你的项目调整构建命令

      - name: Checkout existing gh-pages content
        uses: actions/checkout@v4
        with:
          ref: gh-pages
          path: gh-pages-content
          fetch-depth: 0

      - name: Create PR docs directory
        run: mkdir -p gh-pages-content/pulls/${{ github.event.pull_request.number }}

      - name: Copy PR docs to target directory
        run: cp -r target/doc/* gh-pages-content/pulls/${{ github.event.pull_request.number }}/

      - name: Upload updated Pages artifact
        uses: actions/upload-pages-artifact@v3
        with:
          path: gh-pages-content

      - name: Deploy to GitHub Pages
        id: deployment
        uses: actions/deploy-pages@v4

额外小贴士 #

• 如果想在PR关闭后自动删除对应的/pulls/[PR编号]/目录，可以再加一个Workflow，触发条件设为pull_request: types: [closed]，步骤类似：拉取gh-pages内容，删除对应目录，再部署。
• 注意权限设置：两个Workflow都需要pages: write和id-token: write权限才能部署，contents: read用来拉取代码和gh-pages分支。
• 测试的时候可以先开个小PR，看看部署后的Pages站点是不是同时保留了主分支的根目录文档和PR的子目录文档~

备注：内容来源于stack exchange，提问作者joshlf