Module: Vehicles::Refresher

Defined in:
lib/vehicles/refresher.rb

Overview

Pulls the latest published dataset from the VehiclesDB data repo (config.data_url) into a local file cache (config.cache_path). This is how data fixes and new makes reach an app WITHOUT a gem upgrade — schedule ‘Vehicles.refresh!` (e.g. a daily job) and loads will prefer the cached data over the bundled snapshot.

Error-isolated by design: a failed/partial download never corrupts the cache and never raises — the gem just keeps serving whatever it already had (cached, or the bundled snapshot). Atomic write so a reader never sees a half-written file.

Constant Summary collapse

MAX_REDIRECTS = 
3

Class Method Summary collapse

Class Method Details

.cached? ⇒ Boolean

True when a refreshed dataset is cached on disk.

Returns:

  • (Boolean) 


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# File 'lib/vehicles/refresher.rb', line 36

def cached?
  path = Vehicles.configuration.cache_path
  !path.to_s.empty? && File.exist?(path)
end

.cached_path ⇒ Object 



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# File 'lib/vehicles/refresher.rb', line 41

def cached_path
  cached? ? Vehicles.configuration.cache_path : nil
end

.clear_cache! ⇒ Object

Remove the cached dataset (the gem falls back to the bundled snapshot).



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# File 'lib/vehicles/refresher.rb', line 46

def clear_cache!
  path = Vehicles.configuration.cache_path
  File.delete(path) if path && File.exist?(path)
  Vehicles.reload!
end

.fetch(url, timeout, redirects_left = MAX_REDIRECTS) ⇒ Object 



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# File 'lib/vehicles/refresher.rb', line 65

def fetch(url, timeout, redirects_left = MAX_REDIRECTS)
  require "net/http"
  require "uri"

  uri = URI(url)
  http = Net::HTTP.new(uri.host, uri.port)
  http.use_ssl = uri.scheme == "https"
  http.open_timeout = timeout
  http.read_timeout = timeout

  response = http.get(uri.request_uri, "Accept" => "application/json")
  case response
  when Net::HTTPSuccess
    # Net::HTTP hands back an ASCII-8BIT body (e.g. after gzip decompression);
    # our datasets are UTF-8 JSON, so label it correctly. Otherwise downstream
    # writes/parses can transcode-raise under Encoding.default_internal = UTF-8.
    response.body&.dup&.force_encoding(Encoding::UTF_8)
  when Net::HTTPRedirection
    return nil if redirects_left <= 0

    fetch(response["location"], timeout, redirects_left - 1)
  end
end

.refresh! ⇒ Object

Download + cache the latest dataset. Returns true on success, false on any failure (network, non-200, unparseable/empty payload). Never raises.



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# File 'lib/vehicles/refresher.rb', line 22

def refresh!
  config = Vehicles.configuration
  body = fetch(config.data_url, config.refresh_timeout)
  return false unless valid_payload?(body)

  write_atomic(config.cache_path, body)
  Vehicles.reload! # drop the in-memory dataset so the next access uses fresh data
  true
rescue StandardError => e
  Vehicles.logger&.warn("[vehicles] refresh failed: #{e.class}: #{e.message}")
  false
end

.valid_payload?(body) ⇒ Boolean

A payload is only accepted if it parses and looks like our dataset, so a CDN error page / truncated download can never replace good data.

Returns:

  • (Boolean) 


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# File 'lib/vehicles/refresher.rb', line 56

def valid_payload?(body)
  return false if body.to_s.empty?

  data = JSON.parse(body)
  data.is_a?(Hash) && data["makes"].is_a?(Array) && !data["makes"].empty?
rescue JSON::ParserError
  false
end

.write_atomic(path, body) ⇒ Object 



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# File 'lib/vehicles/refresher.rb', line 89

def write_atomic(path, body)
  require "fileutils"
  FileUtils.mkdir_p(File.dirname(path))
  tmp = "#{path}.#{Process.pid}.tmp"
  # Binary write: persist the exact bytes, never transcode. Robust regardless
  # of the body's encoding or the app's Encoding.default_internal.
  File.binwrite(tmp, body)
  File.rename(tmp, path) # atomic on the same filesystem
end