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|
# require 'pp'
module Luigi
#
# library version
#
VERSION = '0.4.0'
#
# built-in filters
#
FILTERS = {
# upper-case string
uc: proc { |v, args, row, t|
(v || '').to_s.upcase
},
# lower-case string
lc: proc { |v, args, row, t|
(v || '').to_s.downcase
},
# html-escape string
h: proc { |v, args, row, t|
(v || '').to_s.gsub(/&/, '&').gsub(/</, '<').gsub(/>/, '>').gsub(/'/, '&apos').gsub(/"/, '"')
},
# uri-escape string
u: proc( { |v, args, row, t|
require 'uri'
URI.escape((v || '').to_s)
},
# json-encode value
json: proc { |v, args, row, t|
require 'json'
v.to_json
},
# trim leading and trailing whitespace from string
trim: proc { |v, args, row, t|
(v || '').to_s.strip
},
# base64-encode string
base64: proc { |v, args, row, t|
[(v || '').to_s].pack('m')
},
# hash string
hash: proc { |v, args, row, t|
require 'openssl'
OpenSSL::Digest.new(args[0] || 'md5').hexdigest((v || '').to_s)
},
}
#
# Template parser.
#
module Parser
RES = {
action: %r{
# match opening brace
%\{
# match optional whitespace
\s*
# match key
(?<key>[^\s\|\}]+)
# match filter(s)
(?<filters>(\s*\|(\s*[^\s\|\}]+)+)*)
# match optional whitespace
\s*
# match closing brace
\}
# or match up all non-% chars or a single % char
| (?<text>[^%]* | %)
}mx,
filter: %r{
# match filter name
(?<name>\S+)
# match filter arguments (optional)
(?<args>(\s*\S+)*)
# optional trailing whitespace
\s*
}mx,
delim_filters: %r{
\s*\|\s*
}mx,
delim_args: %r{
\s+
},
}
#
# Parse a (possibly empty) string into an array of actions.
#
def self.parse_template(str)
str.scan(RES[:action]).map { |m|
if m[0] && m[0].length > 0
r = {
type: :action,
key: m[0].intern,
filters: parse_filters(m[1]),
}
else
# literal text
r = { type: :text, text: m[2] }
end
# pp r
# return result
r
}
end
#
# Parse a (possibly empty) string into an array of filters.
#
def self.parse_filters(str)
# strip leading and trailing whitespace
str = (str || '').strip
if str.length > 0
str.strip.split(RES[:delim_filters]).inject([]) do |r, f|
# strip whitespace
f = f.strip
if f.length > 0
md = f.match(RES[:filter])
raise "invalid filter: #{f}" unless md
# pp md
# get args
args = md[:args].strip
# add to result
r << {
name: md[:name].intern,
args: args.length > 0 ? args.split(RES[:delim_args]) : [],
}
end
# return result
r
end
else
# return empty filter set
[]
end
end
end
#
# Template class.
#
class Template
#
# Create a new Template from the given string.
#
def initialize(str, filters = FILTERS)
@str, @filters = str, filters
@actions = Parser.parse_template(str)
end
#
# Run template with given arguments
#
def run(args)
@actions.map { |a|
# pp a
case a[:type]
when :action
# check key and get value
val = if args.key?(a[:key])
args[a[:key]]
elsif args.key?(a[:key].to_s)
args[a[:key].to_s]
else
# invalid key
raise "unknown argument: #{a[:key]}"
end
# filter value
a[:filters].inject(val) do |r, f|
# check filter name
raise "unknown filter: #{f[:name]}" unless @filters.key?(f[:name])
# call filter, return result
@filters[f[:name]].call(r, f[:args], args, self)
end
when :text
# literal text
a[:text]
else
# never reached
raise "unknown action type: #{a[:type]}"
end
}.join
end
end
#
# Simple template cache.
#
class Cache
#
# Create a new template cache with the given templates
#
def initialize(strings, filters = FILTERS)
@templates = Hash.new do |h, k|
# always deal with symbols
k = k.intern
# make sure template exists
raise "unknown template: #{k}" unless strings.key?(k)
# create template
h[k] = Template.new(strings[k], filters)
end
end
#
# Run specified template with given arguments.
#
def run(key, args)
# run template with args and return result
@templates[key].run(args)
end
end
#
# test module
#
module Test
# test template
TEMPLATE = '
basic test: hello %{name}
test filters: hello %{name | uc | base64 | hash sha1}
test custom: hello %{name|custom}
test custom_with_arg: %{name|custom_with_arg asdf}
'
CUSTOM_FILTERS = {
custom: proc {
'custom'
},
custom_with_arg: proc { |v, args|
args.first || 'custom'
},
}
# test template cache
CACHE = {
test: TEMPLATE
}
# test arguments
ARGS = {
name: 'paul',
}
def self.run
# add custom filters
Luigi::FILTERS.update(CUSTOM_FILTERS)
# test individual template
puts Template.new(TEMPLATE).run(ARGS)
# test template cache
puts Cache.new(CACHE).run(:test, ARGS)
end
end
end
Luigi::Test.run if __FILE__ == $0
|
