module Shrimp
class Middleware
def initialize(app, options = { }, conditions = { })
@app = app
@options = options
@conditions = conditions
@options[:polling_interval] ||= 1
@options[:polling_offset] ||= 1
@options[:cache_ttl] ||= 1
@options[:request_timeout] ||= @options[:polling_interval] * 10
end
def call(env)
@request = Rack::Request.new(env)
if render_as_pdf? #&& headers['Content-Type'] =~ /text\/html|application\/xhtml\+xml/
if already_rendered? && (up_to_date?(@options[:cache_ttl]) || @options[:cache_ttl] == 0)
if File.size(render_to) == 0
File.delete(render_to)
remove_rendering_flag
return error_response
end
return ready_response if env['HTTP_X_REQUESTED_WITH']
file = File.open(render_to, "rb")
body = file.read
file.close
File.delete(render_to) if @options[:cache_ttl] == 0
remove_rendering_flag
response = [body]
headers = { }
headers["Content-Length"] = (body.respond_to?(:bytesize) ? body.bytesize : body.size).to_s
headers["Content-Type"] = "application/pdf"
[200, headers, response]
else
if rendering_in_progress?
if rendering_timed_out?
remove_rendering_flag
error_response
else
reload_response(@options[:polling_interval])
end
else
File.delete(render_to) if already_rendered?
set_rendering_flag
fire_phantom
reload_response(@options[:polling_offset])
end
end
else
@app.call(env)
end
end
private
# Private: start phantom rendering in a separate process
def fire_phantom
Process::detach fork { Phantom.new(@request.url.sub(%r{\.pdf$}, ''), @options, @request.cookies).to_pdf(render_to) }
end
def render_to
file_name = Digest::MD5.hexdigest(@request.path) + ".pdf"
file_path = @options[:out_path]
"#{file_path}/#{file_name}"
end
def already_rendered?
File.exists?(render_to)
end
def up_to_date?(ttl = 30)
(Time.now - File.new(render_to).mtime) <= ttl
end
def remove_rendering_flag
@request.session["phantom-rendering"] ||={ }
@request.session["phantom-rendering"].delete(render_to)
end
def set_rendering_flag
@request.session["phantom-rendering"] ||={ }
@request.session["phantom-rendering"][render_to] = Time.now
end
def rendering_timed_out?
Time.now - @request.session["phantom-rendering"][render_to] > @options[:request_timeout]
end
def rendering_in_progress?
@request.session["phantom-rendering"]||={ }
@request.session["phantom-rendering"][render_to]
end
def render_as_pdf?
request_path_is_pdf = !!@request.path.match(%r{\.pdf$})
if request_path_is_pdf && @conditions[:only]
rules = [@conditions[:only]].flatten
rules.any? do |pattern|
if pattern.is_a?(Regexp)
@request.path =~ pattern
else
@request.path[0, pattern.length] == pattern
end
end
elsif request_path_is_pdf && @conditions[:except]
rules = [@conditions[:except]].flatten
rules.map do |pattern|
if pattern.is_a?(Regexp)
return false if @request.path =~ pattern
else
return false if @request.path[0, pattern.length] == pattern
end
end
return true
else
request_path_is_pdf
end
end
def concat(accepts, type)
(accepts || '').split(',').unshift(type).compact.join(',')
end
def reload_response(interval=1)
body = <<-HTML.gsub(/[ \n]+/, ' ').strip
Preparing pdf...
HTML
headers = { }
headers["Content-Length"] = body.size.to_s
headers["Content-Type"] = "text/html"
headers["Retry-After"] = interval.to_s
[503, headers, [body]]
end
def ready_response
body = <<-HTML.gsub(/[ \n]+/, ' ').strip
PDF ready here
HTML
headers = { }
headers["Content-Length"] = body.size.to_s
headers["Content-Type"] = "text/html"
[200, headers, [body]]
end
def error_response
body = <<-HTML.gsub(/[ \n]+/, ' ').strip
Sorry request timed out...
HTML
headers = { }
headers["Content-Length"] = body.size.to_s
headers["Content-Type"] = "text/html"
[504, headers, [body]]
end
end
end