Class: RailsAiContext::LiveReload

Inherits:
Object
  • Object
show all
Includes:
CountPhrase
Defined in:
lib/rails_ai_context/live_reload.rb

Overview

Watches for file changes and automatically invalidates MCP tool caches, sending notifications to connected AI clients so they re-query fresh data. Runs a background thread alongside the MCP server (stdio or HTTP).

Constant Summary collapse

WATCH_DIRS = 
(Watcher::WATCH_PATTERNS | Fingerprinter::WATCHED_DIRS).freeze

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from CountPhrase

call

Constructor Details

#initialize(app, mcp_server) ⇒ LiveReload

Returns a new instance of LiveReload.



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# File 'lib/rails_ai_context/live_reload.rb', line 14

def initialize(app, mcp_server)
  @app = app
  @mcp_server = mcp_server
  @last_fingerprint = Fingerprinter.compute(app)
end

Instance Attribute Details

#app ⇒ Object (readonly)

Returns the value of attribute app.



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# File 'lib/rails_ai_context/live_reload.rb', line 12

def app
  @app
end

#mcp_server ⇒ Object (readonly)

Returns the value of attribute mcp_server.



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# File 'lib/rails_ai_context/live_reload.rb', line 12

def mcp_server
  @mcp_server
end

Instance Method Details

#categorize_changes(paths) ⇒ Object

Group changed file paths by category (model, controller, etc.)



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# File 'lib/rails_ai_context/live_reload.rb', line 83

def categorize_changes(paths)
  categories = Hash.new(0)

  paths.each do |path|
    category = case path
    when %r{app/models}          then "model"
    when %r{app/controllers}     then "controller"
    when %r{app/views}           then "view"
    when %r{app/jobs}            then "job"
    when %r{app/mailers}         then "mailer"
    when %r{app/javascript}      then "JavaScript file"
    when %r{config/routes}       then "route"
    when %r{config/}             then "config"
    when %r{db/migrate}          then "migration"
    when %r{db/}                 then "database"
    when %r{lib/tasks}           then "rake task"
    else                              "file"
    end

    categories[category] += 1
  end

  categories
end

#format_change_message(categories) ⇒ Object

Build a readable summary like "Files changed: 2 models, 1 controller."



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# File 'lib/rails_ai_context/live_reload.rb', line 109

def format_change_message(categories)
  parts = categories.map { |cat, count| count_phrase(count, cat) }
  "Files changed: #{parts.join(", ")}."
end

#handle_change(changed_paths = []) ⇒ Object

Process a batch of file changes. Public for testability.



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# File 'lib/rails_ai_context/live_reload.rb', line 53

def handle_change(changed_paths = [])
  return unless Fingerprinter.changed?(app, @last_fingerprint)

  @last_fingerprint = Fingerprinter.compute(app)

  # Order matters: reload the app's code first, then drop the caches built
  # from the old constants. Clearing caches alone left the server answering
  # from whatever Rails autoloaded at boot.
  reloaded = CodeReloader.reload!

  # Invalidate all tool caches (includes AstCache.clear)
  Tools::BaseTool.reset_all_caches!

  # Build a human-readable change summary
  message = format_change_message(categorize_changes(changed_paths))

  # Notify connected MCP clients
  mcp_server.notify_resources_list_changed
  mcp_server.notify_log_message(
    data: "#{message} Tool caches invalidated#{reloaded ? " and app code reloaded" : ""}.",
    level: "info",
    logger: "rails-ai-context"
  )

  $stderr.puts "[rails-ai-context] #{message} Tool caches invalidated#{reloaded ? " and app code reloaded" : ""}."
rescue => e
  $stderr.puts "[rails-ai-context] Live reload error: #{e.message}"
end

#start ⇒ Object

Start the file watcher in a background thread. Non-blocking.



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# File 'lib/rails_ai_context/live_reload.rb', line 21

def start
  require "listen"

  root = app.root.to_s
  debounce = RailsAiContext.configuration.live_reload_debounce
  dirs = WATCH_DIRS.map { |p| File.join(root, p) }.select { |d| Dir.exist?(d) }

  if dirs.empty?
    $stderr.puts "[rails-ai-context] Live reload: no watchable directories found"
    return
  end

  $stderr.puts "[rails-ai-context] Live reload enabled (debounce: #{debounce}s)"
  $stderr.puts "[rails-ai-context] Watching: #{dirs.map { |d| d.sub("#{root}/", "") }.join(", ")}"

  listener = Listen.to(*dirs, wait_for_delay: debounce) do |modified, added, removed|
    all_changes = modified + added + removed
    next if all_changes.empty?

    handle_change(all_changes)
  end

  listener.start
  @listener = listener
end

#stop ⇒ Object

Stop the background listener thread.



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# File 'lib/rails_ai_context/live_reload.rb', line 48

def stop
  @listener&.stop
end