Merge branch 'main' into #92

backend/app/controllers/posts_controller.rb

@@ -88,7 +88,7 @@ class PostsController < ApplicationController
     original_created_from = params[:original_created_from]
     original_created_before = params[:original_created_before]
 
-    post = Post.new(title:, url:, thumbnail_base: '', uploaded_user: current_user,
+    post = Post.new(title:, url:, thumbnail_base: nil, uploaded_user: current_user,
                     original_created_from:, original_created_before:)
     post.thumbnail.attach(thumbnail)
     if post.save

backend/app/controllers/wiki_pages_controller.rb

@@ -1,8 +1,8 @@
 class WikiPagesController < ApplicationController
-  def index
+  rescue_from Wiki::Commit::Conflict, with: :render_wiki_conflict
-    wiki_pages = WikiPage.all
 
-    render json: wiki_pages
+  def index
+    render json: WikiPage.all
   end
 
   def show
@@ -31,21 +31,25 @@ class WikiPagesController < ApplicationController
 
   def diff
     id = params[:id]
-    from = params[:from]
+    return head :bad_request if id.blank?
+
+    from = params[:from].presence
     to = params[:to].presence
-    return head :bad_request if id.blank? || from.blank?
 
-    wiki_page_from = WikiPage.find(id)
+    page = WikiPage.find(id)
-    wiki_page_to = WikiPage.find(id)
-    wiki_page_from.sha = from
-    wiki_page_to.sha = to
 
-    diffs = Diff::LCS.sdiff(wiki_page_from.body, wiki_page_to.body)
+    from_rev = from && page.wiki_revisions.find(from)
+    to_rev = to ? page.wiki_revisions.find(to) : page.current_revision
+    if ((from_rev && !(from_rev.content?)) || !(to_rev&.content?))
+      return head :unprocessable_entity
+    end
+
+    diffs = Diff::LCS.sdiff(from_rev&.body&.lines || [], to_rev.body.lines)
     diff_json = diffs.map { |change|
       case change.action
       when ?=
         { type: 'context', content: change.old_element }
-      when ?|
+      when ?!
         [{ type: 'removed', content: change.old_element },
          { type: 'added', content: change.new_element }]
       when ?+
@@ -55,23 +59,32 @@ class WikiPagesController < ApplicationController
       end
     }.flatten.compact
 
-    render json: { wiki_page_id:  wiki_page_from.id,
+    render json: { wiki_page_id:      page.id,
-                   title:         wiki_page_from.title,
+                   title:             page.title,
-                   older_sha:     wiki_page_from.sha,
+                   older_revision_id: from_rev&.id,
-                   newer_sha:     wiki_page_to.sha,
+                   newer_revision_id: to_rev.id,
                    diff:              diff_json }
   end
 
   def create
     return head :unauthorized unless current_user
-    return head :forbidden unless ['admin', 'member'].include?(current_user.role)
+    return head :forbidden unless current_user.member?
 
-    wiki_page = WikiPage.new(title: params[:title], created_user: current_user, updated_user: current_user)
+    title = params[:title]&.strip
-    if wiki_page.save
+    body = params[:body].to_s
-      wiki_page.set_body params[:body], user: current_user
+
-      render json: wiki_page, status: :created
+    return head :unprocessable_entity if title.blank? || body.blank?
+
+    page = WikiPage.new(title:, created_user: current_user, updated_user: current_user)
+
+    if page.save
+      message = params[:message].presence
+      Wiki::Commit.content!(page:, body:, created_user: current_user, message:)
+
+      render json: page, status: :created
     else
-      render json: { errors: wiki_page.errors.full_messages }, status: :unprocessable_entity
+      render json: { errors: page.errors.full_messages },
+             status: :unprocessable_entity
     end
   end
 
@@ -79,16 +92,24 @@ class WikiPagesController < ApplicationController
     return head :unauthorized unless current_user
     return head :forbidden unless current_user.member?
 
-    title = params[:title]
+    title = params[:title]&.strip
-    body = params[:body]
+    body = params[:body].to_s
 
     return head :unprocessable_entity if title.blank? || body.blank?
 
-    wiki_page = WikiPage.find(params[:id])
+    page = WikiPage.find(params[:id])
-    wiki_page.title = title
+    base_revision_id = page.current_revision.id
-    wiki_page.updated_user = current_user
+
-    wiki_page.set_body(body, user: current_user)
+    if params[:title].present? && params[:title].strip != page.title
-    wiki_page.save!
+      return head :unprocessable_entity
+    end
+
+    message = params[:message].presence
+    Wiki::Commit.content!(page:,
+                          body:,
+                          created_user: current_user,
+                          message:,
+                          base_revision_id:)
 
     head :ok
   end
@@ -97,55 +118,73 @@ class WikiPagesController < ApplicationController
     title = params[:title]&.strip
 
     q = WikiPage.all
-    q = q.where('title LIKE ?', "%#{ WikiPage.sanitize_sql_like(title) }%") if title.present?
+    if title.present?
+      q = q.where('title LIKE ?', "%#{ WikiPage.sanitize_sql_like(title) }%")
+    end
 
     render json: q.limit(20)
   end
 
   def changes
-    id = params[:id]
+    id = params[:id].presence
-    log = if id.present?
+    q = WikiRevision.includes(:wiki_page, :created_user).order(id: :desc)
-            wiki.page("#{ id }.md")&.versions
+    q = q.where(wiki_page_id: id) if id
-          else
-            wiki.repo.log('main', nil)
-          end
-    return render json: [] unless log
 
-    render json: log.map { |commit|
+    render json: q.limit(200).map { |rev|
-      wiki_page = WikiPage.find(commit.message.split(' ')[1].to_i)
+      { revision_id:  rev.id,
-      wiki_page.sha = commit.id
+        pred:         rev.base_revision_id,
-
+        succ:         nil,
-      next nil if wiki_page.sha.blank?
+        wiki_page:    { id: rev.wiki_page_id, title: rev.wiki_page.title },
-
+        user:         { id: rev.created_user.id, name: rev.created_user.name },
-      user = User.find(commit.author.name.to_i)
+        kind:         rev.kind,
-
+        message:      rev.message,
-      { sha:          wiki_page.sha,
+        timestamp:    rev.created_at }
-        pred:         wiki_page.pred,
-        succ:         wiki_page.succ,
-        wiki_page:    wiki_page && { id: wiki_page.id, title: wiki_page.title },
-        user:         user && { id: user.id, name: user.name },
-        change_type:  commit.message.split(' ')[0].downcase[0...(-1)],
-        timestamp:    commit.authored_date }
     }.compact
   end
 
   private
 
-  WIKI_PATH = Rails.root.join('wiki').to_s
+  def render_wiki_page_or_404 page
+    return head :not_found unless page
 
-  def wiki
+    if params[:version].present?
-    @wiki ||= Gollum::Wiki.new(WIKI_PATH)
+      rev = page.wiki_revisions.find_by(id: params[:version])
+      return head :not_found unless rev
+
+      if rev.redirect?
+        return (
+            redirect_to wiki_page_by_title_path(title: rev.redirect_page.title),
+                        status: :moved_permanently)
       end
 
-  def render_wiki_page_or_404 wiki_page
+      body = rev.body
-    return head :not_found unless wiki_page
+      revision_id = rev.id
+      pred = page.pred_revision_id(revision_id)
+      succ = page.succ_revision_id(revision_id)
 
-    wiki_page.sha = params[:version].presence
+      return render json: page.as_json.merge(body:, revision_id:, pred:, succ:)
+    end
 
-    body = wiki_page.body
+    rev = page.current_revision
-    sha = wiki_page.sha
+    unless rev
-    pred = wiki_page.pred
+      return render json: page.as_json.merge(body: nil, revision_id: nil, pred: nil, succ: nil)
-    succ = wiki_page.succ
+    end
-    render json: wiki_page.as_json.merge(body:, sha:, pred:, succ:)
+
+    if rev.redirect?
+      return (
+          redirect_to wiki_page_by_title_path(title: rev.redirect_page.title),
+                      status: :moved_permanently)
+    end
+
+    body = rev.body
+    revision_id = rev.id
+    pred = page.pred_revision_id(revision_id)
+    succ = page.succ_revision_id(revision_id)
+
+    render json: page.as_json.merge(body:, revision_id:, pred:, succ:)
+  end
+
+  def render_wiki_conflict err
+    render json: { error: 'conflict', message: err.message }, status: :conflict
   end
 end

backend/app/models/wiki_line.rb

@@ -0,0 +1,15 @@
+class WikiLine < ApplicationRecord
+  has_many :wiki_revision_lines, dependent: :restrict_with_exception
+
+  validates :sha256, presence: true, uniqueness: true, length: { is: 64 }
+  validates :body, presence: true
+
+  def self.upsert_by_body! body
+    sha = Digest::SHA256.hexdigest(body)
+    now = Time.current
+
+    upsert({ sha256: sha, body:, created_at: now, updated_at: now })
+
+    find_by!(sha256: sha)
+  end
+end

backend/app/models/wiki_page.rb

@@ -1,80 +1,50 @@
-require 'gollum-lib'
+require 'set'
 
 
 class WikiPage < ApplicationRecord
-  belongs_to :tag, optional: true
+  has_many :wiki_revisions, dependent: :destroy
-  belongs_to :created_user, class_name: 'User', foreign_key: 'created_user_id'
+  belongs_to :created_user, class_name: 'User'
-  belongs_to :updated_user, class_name: 'User', foreign_key: 'updated_user_id'
+  belongs_to :updated_user, class_name: 'User'
+
+  has_many :redirected_from_revisions,
+           class_name: 'WikiRevision',
+           foreign_key: :redirect_page_id,
+           dependent: :nullify
 
   validates :title, presence: true, length: { maximum: 255 }, uniqueness: true
 
-  def as_json options = { }
+  def current_revision
-    self.sha = nil
+    wiki_revisions.order(id: :desc).first
-    super options
-  end
-
-  def sha= val
-    if val.present?
-      @sha = val
-      @page = wiki.page("#{ id }.md", @sha)
-    else
-      @page = wiki.page("#{ id }.md")
-      @sha = @page.versions.first.id
-    end
-    vers = @page.versions
-    idx = vers.find_index { |ver| ver.id == @sha }
-    if idx
-      @pred = vers[idx + 1]&.id
-      @succ = idx.positive? ? vers[idx - 1].id : nil
-      @updated_at = vers[idx].authored_date
-    else
-      @sha = nil
-      @pred = nil
-      @succ = nil
-      @updated_at = nil
-    end
-    @sha
-  end
-
-  def sha
-    @sha
-  end
-
-  def pred
-    @pred
-  end
-
-  def succ
-    @succ
-  end
-
-  def updated_at
-    @updated_at
   end
 
   def body
-    sha = nil unless @page
+    rev = current_revision
-    @page&.raw_data&.force_encoding('UTF-8')
+    rev.body if rev&.content?
   end
 
-  def set_body content, user:
+  def resolve_redirect limit: 10
-    commit_info = { name:   user.id.to_s,
+    page = self
-                    email:  'dummy@example.com' }
+    visited = Set.new
-    page = wiki.page("#{ id }.md")
+
-    if page
+    limit.times do
-      commit_info[:message] = "Updated #{ id }"
+      return page if visited.include?(page.id)
-      wiki.update_page(page, id.to_s, :markdown, content, commit_info)
+
-    else
+      visited.add(page.id)
-      commit_info[:message] = "Created #{ id }"
+
-      wiki.write_page(id.to_s, :markdown, content, commit_info)
+      rev = page.current_revision
-    end
+      return page if !(rev&.redirect?) || !(rev.redirect_page)
+
+      page = rev.redirect_page
     end
 
-  private
+    page
+  end
 
-  WIKI_PATH = Rails.root.join('wiki').to_s
+  def pred_revision_id revision_id
+    wiki_revisions.where('id < ?', revision_id).order(id: :desc).limit(1).pick(:id)
+  end
 
-  def wiki
+  def succ_revision_id revision_id
-    @wiki ||= Gollum::Wiki.new(WIKI_PATH)
+    wiki_revisions.where('id > ?', revision_id).order(id: :asc).limit(1).pick(:id)
   end
 end

backend/app/models/wiki_revision.rb

@@ -0,0 +1,55 @@
+class WikiRevision < ApplicationRecord
+  belongs_to :wiki_page
+  belongs_to :base_revision, class_name: 'WikiRevision', optional: true
+  belongs_to :created_user, class_name: 'User'
+  belongs_to :redirect_page, class_name: 'WikiPage', optional: true
+
+  has_many :wiki_revision_lines, dependent: :delete_all
+  has_many :wiki_lines, through: :wiki_revision_lines
+
+  enum :kind, { content: 0, redirect: 1 }
+
+  validates :kind, presence: true
+  validates :lines_count, numericality: { only_integer: true, greater_than_or_equal_to: 0 }
+  validates :tree_sha256, length: { is: 64 }, allow_nil: true
+
+  validate :kind_consistency
+
+  def body
+    return unless content?
+
+    wiki_revision_lines
+        .includes(:wiki_line)
+        .order(:position)
+        .map { |rev| rev.wiki_line.body }
+        .join("\n")
+  end
+
+  private
+
+  def kind_consistency
+    if content?
+      if tree_sha256.blank?
+        errors.add(:tree_sha256, '種類がページの場合は必須です．') 
+      end
+
+      if redirect_page_id.present?
+        errors.add(:redirect_page_id, '種類がページの場合は空である必要があります．')
+      end
+    end
+
+    if redirect?
+      if redirect_page_id.blank?
+        errors.add(:redirect_page_id, '種類がリダイレクトの場合は必須です．')
+      end
+
+      if tree_sha256.present?
+        errors.add(:tree_sha256, '種類がリダイレクトの場合は空である必要があります．')
+      end
+
+      if lines_count.to_i > 0
+        errors.add(:lines_count, '種類がリダイレクトの場合は 0 である必要があります．')
+      end
+    end
+  end
+end

backend/app/models/wiki_revision_line.rb

@@ -0,0 +1,8 @@
+class WikiRevisionLine < ApplicationRecord
+  belongs_to :wiki_revision
+  belongs_to :wiki_line
+
+  validates :position, presence: true,
+                       numericality: { only_integer: true, greater_than_or_equal_to: 0 }
+  validates :position, uniqueness: { scope: :wiki_revision_id }
+end

backend/app/services/wiki/commit.rb

@@ -0,0 +1,122 @@
+require 'digest'
+
+
+module Wiki
+  class Commit
+    class Conflict < StandardError
+      ;
+    end
+
+    def self.content! page:, body:, created_user:, message: nil, base_revision_id: nil
+      new(page:, created_user:).content!(body:, message:, base_revision_id:)
+    end
+
+    def self.redirect! page:, redirect_page:, created_user:, message: nil, base_revision_id: nil
+      new(page:, created_user:).redirect!(redirect_page:, message:, base_revision_id:)
+    end
+
+    def initialize page:, created_user:
+      @page = page
+      @created_user = created_user
+    end
+
+    def content! body:, message:, base_revision_id:
+      normalised = normalise_body(body)
+      lines = split_lines(normalised)
+
+      line_shas = lines.map { |line| Digest::SHA256.hexdigest(line) }
+      tree_sha = Digest::SHA256.hexdigest(line_shas.join(','))
+
+      line_id_by_sha = upsert_lines!(lines, line_shas)
+      line_ids = line_shas.map { |sha| line_id_by_sha.fetch(sha) }
+
+      ActiveRecord::Base.transaction do
+        @page.lock!
+
+        if base_revision_id.present?
+          current_id = @page.wiki_revisions.maximum(:id)
+          if current_id && current_id != base_revision_id.to_i
+            raise Conflict,
+                "競合が発生してゐます（現在の Id.：#{ current_id }，ベース Id.：#{ base_revision_id }）．"
+          end
+        end
+
+        rev = WikiRevision.create!(
+            wiki_page:        @page,
+            base_revision_id:,
+            created_user:     @created_user,
+            kind:             :content,
+            redirect_page_id: nil,
+            message:,
+            lines_count:      lines.length,
+            tree_sha256:      tree_sha)
+
+        rows = line_ids.each_with_index.map do |line_id, pos|
+          { wiki_revision_id: rev.id, wiki_line_id: line_id, position: pos }
+        end
+        WikiRevisionLine.insert_all!(rows)
+
+        rev
+      end
+    end
+
+    def redirect! redirect_page:, message:, base_revision_id:
+      ActiveRecord::Base.transaction do
+        @page.lock!
+
+        if base_revision_id.present?
+          current_id = @page.wiki_revisions.maximum(:id)
+          if current_id && current_id != base_revision_id.to_i
+            raise Conflict,
+                "競合が発生してゐます（現在の Id.：#{ current_id }，ベース Id.：#{ base_revision_id }）．"
+          end
+        end
+
+        WikiRevision.create!(
+            wiki_page:        @page,
+            base_revision_id:,
+            created_user:     @created_user,
+            kind:             :redirect,
+            redirect_page:,
+            message:,
+            lines_count:      0,
+            tree_sha256:      nil)
+      end
+    end
+
+    private
+
+    def normalise_body body
+      s = body.to_s
+      s.gsub!("\r\n", "\n")
+      s.encode('UTF-8', invalid: :replace, undef: :replace, replace: '🖕')
+    end
+
+    def split_lines body
+      body.split("\n")
+    end
+
+    def upsert_lines! lines, line_shas
+      now = Time.current
+
+      id_by_sha = WikiLine.where(sha256: line_shas).pluck(:sha256, :id).to_h
+
+      missing_rows = []
+      line_shas.each_with_index do |sha, i|
+        next if id_by_sha.key?(sha)
+
+        missing_rows << { sha256:     sha,
+                          body:       lines[i],
+                          created_at: now,
+                          updated_at: now }
+      end
+
+      if missing_rows.any?
+        WikiLine.upsert_all(missing_rows)
+        id_by_sha = WikiLine.where(sha256: line_shas).pluck(:sha256, :id).to_h
+      end
+
+      id_by_sha
+    end
+  end
+end

backend/db/migrate/20251229012100_remove_tag_from_wiki_pages.rb

@@ -0,0 +1,5 @@
+class RemoveTagFromWikiPages < ActiveRecord::Migration[7.0]
+  def change
+    remove_reference :wiki_pages, :tag, if_exists: true
+  end
+end

backend/db/migrate/20251229020700_create_wiki_lines.rb

@@ -0,0 +1,11 @@
+class CreateWikiLines < ActiveRecord::Migration[7.0]
+  def change
+    create_table :wiki_lines do |t|
+      t.string :sha256, null: false, limit: 64
+      t.text :body, null: false
+      t.timestamps
+    end
+
+    add_index :wiki_lines, :sha256, unique: true
+  end
+end

backend/db/migrate/20251229021000_create_wiki_revisions.rb

@@ -0,0 +1,19 @@
+class CreateWikiRevisions < ActiveRecord::Migration[7.0]
+  def change
+    create_table :wiki_revisions do |t|
+      t.references :wiki_page, null: false, foreign_key: true
+      t.references :base_revision, foreign_key: { to_table: :wiki_revisions }
+      t.references :created_user, null: false, foreign_key: { to_table: :users }
+      t.integer :kind, null: false, default: 0  # 0: content, 1: redirect
+      t.references :redirect_page, foreign_key: { to_table: :wiki_pages }
+      t.string :message
+      t.integer :lines_count, null: false, default: 0
+      t.string :tree_sha256, limit: 64
+      t.timestamps
+    end
+
+    add_index :wiki_revisions, :tree_sha256
+    add_index :wiki_revisions, [:wiki_page_id, :id]
+    add_index :wiki_revisions, :kind
+  end
+end

backend/db/migrate/20251229022100_create_wiki_revision_lines.rb

@@ -0,0 +1,12 @@
+class CreateWikiRevisionLines < ActiveRecord::Migration[7.0]
+  def change
+    create_table :wiki_revision_lines do |t|
+      t.references :wiki_revision, null: false, foreign_key: true
+      t.integer :position, null: false
+      t.references :wiki_line, null: false, foreign_key: true
+    end
+
+    add_index :wiki_revision_lines, [:wiki_revision_id, :position], unique: true
+    add_index :wiki_revision_lines, [:wiki_revision_id, :wiki_line_id]
+  end
+end

backend/db/migrate/20251230143400_make_thumbnail_base_nullable_in_posts.rb

@@ -0,0 +1,27 @@
+class MakeThumbnailBaseNullableInPosts < ActiveRecord::Migration[7.0]
+  def up
+    change_column_null :posts, :thumbnail_base, true
+
+    execute <<~SQL
+      UPDATE
+        posts
+      SET
+        thumbnail_base = NULL
+      WHERE
+        thumbnail_base = ''
+    SQL
+  end
+
+  def down
+    execute <<~SQL
+      UPDATE
+        posts
+      SET
+        thumbnail_base = ''
+      WHERE
+        thumbnail_base IS NULL
+    SQL
+
+    change_column_null :posts, :thumbnail_base, false
+  end
+end

backend/db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[8.0].define(version: 2025_12_10_123200) do
+ActiveRecord::Schema[8.0].define(version: 2025_12_30_143400) do
   create_table "active_storage_attachments", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
     t.string "name", null: false
     t.string "record_type", null: false
@@ -86,7 +86,7 @@ ActiveRecord::Schema[8.0].define(version: 2025_12_10_123200) do
   create_table "posts", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
     t.string "title", null: false
     t.string "url", limit: 2000, null: false
-    t.string "thumbnail_base", limit: 2000, null: false
+    t.string "thumbnail_base", limit: 2000
     t.bigint "parent_id"
     t.bigint "uploaded_user_id"
     t.datetime "created_at", null: false
@@ -167,18 +167,54 @@ ActiveRecord::Schema[8.0].define(version: 2025_12_10_123200) do
     t.datetime "updated_at", null: false
   end
 
+  create_table "wiki_lines", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
+    t.string "sha256", limit: 64, null: false
+    t.text "body", null: false
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+    t.index ["sha256"], name: "index_wiki_lines_on_sha256", unique: true
+  end
+
   create_table "wiki_pages", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
     t.string "title", null: false
-    t.bigint "tag_id"
     t.bigint "created_user_id", null: false
     t.bigint "updated_user_id", null: false
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
     t.index ["created_user_id"], name: "index_wiki_pages_on_created_user_id"
-    t.index ["tag_id"], name: "index_wiki_pages_on_tag_id"
     t.index ["updated_user_id"], name: "index_wiki_pages_on_updated_user_id"
   end
 
+  create_table "wiki_revision_lines", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
+    t.bigint "wiki_revision_id", null: false
+    t.integer "position", null: false
+    t.bigint "wiki_line_id", null: false
+    t.index ["wiki_line_id"], name: "index_wiki_revision_lines_on_wiki_line_id"
+    t.index ["wiki_revision_id", "position"], name: "index_wiki_revision_lines_on_wiki_revision_id_and_position", unique: true
+    t.index ["wiki_revision_id", "wiki_line_id"], name: "index_wiki_revision_lines_on_wiki_revision_id_and_wiki_line_id"
+    t.index ["wiki_revision_id"], name: "index_wiki_revision_lines_on_wiki_revision_id"
+  end
+
+  create_table "wiki_revisions", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
+    t.bigint "wiki_page_id", null: false
+    t.bigint "base_revision_id"
+    t.bigint "created_user_id", null: false
+    t.integer "kind", default: 0, null: false
+    t.bigint "redirect_page_id"
+    t.string "message"
+    t.integer "lines_count", default: 0, null: false
+    t.string "tree_sha256", limit: 64
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+    t.index ["base_revision_id"], name: "index_wiki_revisions_on_base_revision_id"
+    t.index ["created_user_id"], name: "index_wiki_revisions_on_created_user_id"
+    t.index ["kind"], name: "index_wiki_revisions_on_kind"
+    t.index ["redirect_page_id"], name: "index_wiki_revisions_on_redirect_page_id"
+    t.index ["tree_sha256"], name: "index_wiki_revisions_on_tree_sha256"
+    t.index ["wiki_page_id", "id"], name: "index_wiki_revisions_on_wiki_page_id_and_id"
+    t.index ["wiki_page_id"], name: "index_wiki_revisions_on_wiki_page_id"
+  end
+
   add_foreign_key "active_storage_attachments", "active_storage_blobs", column: "blob_id"
   add_foreign_key "active_storage_variant_records", "active_storage_blobs", column: "blob_id"
   add_foreign_key "nico_tag_relations", "tags"
@@ -201,7 +237,12 @@ ActiveRecord::Schema[8.0].define(version: 2025_12_10_123200) do
   add_foreign_key "user_ips", "users"
   add_foreign_key "user_post_views", "posts"
   add_foreign_key "user_post_views", "users"
-  add_foreign_key "wiki_pages", "tags"
   add_foreign_key "wiki_pages", "users", column: "created_user_id"
   add_foreign_key "wiki_pages", "users", column: "updated_user_id"
+  add_foreign_key "wiki_revision_lines", "wiki_lines"
+  add_foreign_key "wiki_revision_lines", "wiki_revisions"
+  add_foreign_key "wiki_revisions", "users", column: "created_user_id"
+  add_foreign_key "wiki_revisions", "wiki_pages"
+  add_foreign_key "wiki_revisions", "wiki_pages", column: "redirect_page_id"
+  add_foreign_key "wiki_revisions", "wiki_revisions", column: "base_revision_id"
 end

backend/lib/tasks/migrate_wiki.rake

@@ -0,0 +1,74 @@
+namespace :wiki do
+  desc 'Wiki 移行'
+  task migrate: :environment do
+    require 'digest'
+    require 'gollum-lib'
+
+    wiki = Gollum::Wiki.new(Rails.root.join('wiki').to_s)
+
+    WikiPage.where.missing(:wiki_revisions).find_each do |wiki_page|
+      page = wiki.page("#{ wiki_page.id }.md")
+      next unless page
+
+      versions = page.versions
+      next if versions.blank?
+
+      base_revision_id = nil
+      versions.reverse_each do |version|
+        pg = wiki.page("#{ wiki_page.id }.md", version.id)
+        raw = pg&.raw_data
+        next unless raw
+
+        lines = raw.force_encoding('UTF-8').split("\n")
+
+        line_shas = lines.map { |l| Digest::SHA256.hexdigest(l) }
+        tree_sha = Digest::SHA256.hexdigest(line_shas.join(','))
+
+        at = version.authored_date
+
+        line_id_by_sha = WikiLine.where(sha256: line_shas).pluck(:sha256, :id).to_h
+
+        missing_rows = []
+        line_shas.each_with_index do |sha, i|
+          next if line_id_by_sha.key?(sha)
+
+          missing_rows << { sha256:     sha,
+                            body:       lines[i],
+                            created_at: at,
+                            updated_at: at }
+        end
+
+        if missing_rows.any?
+          WikiLine.upsert_all(missing_rows)
+          line_id_by_sha = WikiLine.where(sha256: line_shas).pluck(:sha256, :id).to_h
+        end
+        line_ids = line_shas.map { |sha| line_id_by_sha.fetch(sha) }
+
+        rev = nil
+        ActiveRecord::Base.transaction do
+          wiki_page.lock!
+
+          rev = WikiRevision.create!(
+              wiki_page:,
+              base_revision_id:,
+              created_user_id:  (Integer(version.author.name) rescue 2),
+              kind:             :content,
+              redirect_page_id: nil,
+              message:          nil,
+              lines_count:      lines.length,
+              tree_sha256:      tree_sha,
+              created_at:       at,
+              updated_at:       at)
+
+          rows = line_ids.each_with_index.map do |line_id, pos|
+            { wiki_revision_id: rev.id,
+              wiki_line_id:     line_id,
+              position:         pos }
+          end
+          WikiRevisionLine.insert_all!(rows)
+        end
+        base_revision_id = rev.id
+      end
+    end
+  end
+end

backend/lib/tasks/sync_nico.rake

@@ -49,7 +49,7 @@ namespace :nico do
       unless post
         title = datum['title']
         url = "https://www.nicovideo.jp/watch/#{ datum['code'] }"
-        thumbnail_base = fetch_thumbnail.(url) || '' rescue ''
+        thumbnail_base = fetch_thumbnail.(url) rescue nil
         post = Post.new(title:, url:, thumbnail_base:, uploaded_user: nil)
         if thumbnail_base.present?
           post.thumbnail.attach(

frontend/src/components/PostEmbed.tsx

@@ -1,3 +1,4 @@
+import { useState } from 'react'
 import YoutubeEmbed from 'react-youtube'
 
 import NicoViewer from '@/components/NicoViewer'
@@ -39,10 +40,28 @@ export default (({ post }: Props) => {
     }
   }
 
+  const [framed, setFramed] = useState (false)
+
   return (
-      <a href={post.url} target="_blank">
+      <>
-	<img src={post.thumbnailBase || post.thumbnail}
+	{framed
-	     alt={post.url}
+	 ? (
-	     className="mb-4 w-full"/>
+	    <iframe
-      </a>)
+		src={post.url}
+		title={post.title || post.url}
+		width={640}
+		height={360}/>)
+	 : (
+	    <div>
+	      <a href="#" onClick={e => {
+		e.preventDefault ()
+		setFramed (confirm ('未確認の外部ページを表示します。\n'
+				    + '悪意のあるスクリプトが実行される可能性があります。\n'
+				    + '表示しますか?'))
+		return
+	      }}>
+		外部ページを表示
+	      </a>
+	    </div>)}
+      </>)
 }) satisfies FC<Props>

frontend/src/pages/wiki/WikiDiffPage.tsx

@@ -40,10 +40,10 @@ export default () => {
 	  {diff
 	   ? (
 	      diff.diff.map (d => (
-		  <span className={cn (d.type === 'added' && 'bg-green-200 dark:bg-green-800',
+		  <p className={cn (d.type === 'added' && 'bg-green-200 dark:bg-green-800',
 				    d.type === 'removed' && 'bg-red-200 dark:bg-red-800')}>
-		    {d.content == '\n' ? <br/> : d.content}
+		    {d.content}
-		  </span>)))
+		  </p>)))
 	   : 'Loading...'}
 	</div>
       </MainArea>)

frontend/src/pages/wiki/WikiHistoryPage.tsx

@@ -41,30 +41,20 @@ export default () => {
 	  </thead>
 	  <tbody>
 	    {changes.map (change => (
-		<tr key={change.sha}>
+		<tr key={change.revisionId}>
 		  <td>
-		    {change.changeType === 'update' && (
+		    {change.pred != null && (
-			<Link to={`/wiki/${ change.wikiPage.id }/diff?from=${ change.pred }&to=${ change.sha }`}>
+			<Link to={`/wiki/${ change.wikiPage.id }/diff?from=${ change.pred }&to=${ change.revisionId }`}>
 			  差分
 			</Link>)}
 		  </td>
 		  <td className="p-2">
-		    <Link to={`/wiki/${ encodeURIComponent (change.wikiPage.title) }?version=${ change.sha }`}>
+		    <Link to={`/wiki/${ encodeURIComponent (change.wikiPage.title) }?version=${ change.revisionId }`}>
 		      {change.wikiPage.title}
 		    </Link>
 		  </td>
 		  <td className="p-2">
-		    {(() => {
+		    {change.pred == null ? '新規' : '更新'}
-		      switch (change.changeType)
-		      {
-		      case 'create':
-			return '新規'
-		      case 'update':
-			return '更新'
-		      case 'delete':
-			return '削除'
-		      }
-		    }) ()}
 		  </td>
 		  <td className="p-2">
 		    <Link to={`/users/${ change.user.id }`}>

frontend/src/types.ts

@@ -61,26 +61,30 @@ export type ViewFlagBehavior = typeof ViewFlagBehavior[keyof typeof ViewFlagBeha
 export type WikiPage = {
     id:             number
     title:          string
+    createdUserId:  number
+    updatedUserId:  number
+    createdAt:      string
+    updatedAt:      string
     body:           string
-    sha:        string
+    revisionId:     number
-    pred?:      string
+    pred:           number | null
-    succ?:      string
+    succ:           number | null }
-    updatedAt?: string }
 
 export type WikiPageChange = {
-    sha:        string
+    revisionId: number
-    pred?:      string
+    pred:       number | null
-    succ?:      string
+    succ:       null
-    wikiPage:   WikiPage
+    wikiPage:   Pick<WikiPage, 'id' | 'title'>
-    user:       User
+    user:       Pick<User, 'id' | 'name'>
-    changeType: string
+    kind:       'content' | 'redirect'
+    message:    string | null
     timestamp:  string }
 
 export type WikiPageDiff = {
     wikiPageId:       number
     title:            string
-    olderSha:   string
+    olderRevisionId:  number | null
-    newerSha:   string
+    newerRevisionId:  number
     diff:             WikiPageDiffDiff[] }
 
 export type WikiPageDiffDiff = {