Replace uri_template gem with regular expression

Gemfile.lock

@@ -5,7 +5,6 @@ PATH
       hana (~> 1.3)
       regexp_parser (~> 2.0)
       simpleidn (~> 0.2)
-      uri_template (~> 0.7)
 
 GEM
   remote: https://rubygems.org/
@@ -27,7 +26,6 @@ GEM
       unf_ext
     unf (0.1.4-java)
     unf_ext (0.0.8.2)
-    uri_template (0.7.0)
 
 PLATFORMS
   java

json_schemer.gemspec

@@ -30,5 +30,4 @@ Gem::Specification.new do |spec|
   spec.add_runtime_dependency "hana", "~> 1.3"
   spec.add_runtime_dependency "regexp_parser", "~> 2.0"
   spec.add_runtime_dependency "simpleidn", "~> 0.2"
-  spec.add_runtime_dependency "uri_template", "~> 0.7"
 end

lib/json_schemer.rb

@@ -12,10 +12,10 @@
 require 'hana'
 require 'regexp_parser'
 require 'simpleidn'
-require 'uri_template'
 
 require 'json_schemer/version'
 require 'json_schemer/format/hostname'
+require 'json_schemer/format/uri_template'
 require 'json_schemer/format'
 require 'json_schemer/errors'
 require 'json_schemer/cached_resolver'

lib/json_schemer/format.rb

@@ -2,6 +2,7 @@
 module JSONSchemer
   module Format
     include Hostname
+    include URITemplate
 
     # this is no good
     EMAIL_REGEX = /\A[^@\s]+@([\p{L}\d-]+\.)+[\p{L}\d\-]{2,}\z/i.freeze
@@ -115,13 +116,6 @@ def iri_escape(data)
       end.force_encoding(Encoding::US_ASCII)
     end
 
-    def valid_uri_template?(data)
-      URITemplate.new(data)
-      true
-    rescue URITemplate::Invalid
-      false
-    end
-
     def valid_json_pointer?(data)
       JSON_POINTER_REGEX.match?(data)
     end

lib/json_schemer/format/uri_template.rb

@@ -0,0 +1,34 @@
+# frozen_string_literal: true
+module JSONSchemer
+  module Format
+    module URITemplate
+      # https://datatracker.ietf.org/doc/html/rfc6570
+      PCT_ENCODED = '%\h{2}'                                         # pct-encoded     =  "%" HEXDIG HEXDIG
+      EXPLODE = '\*'                                                 # explode         =  "*"
+      MAX_LENGTH = '[1-9]\d{0,3}'                                    # max-length      =  %x31-39 0*3DIGIT   ; positive integer < 10000
+      PREFIX = ":#{MAX_LENGTH}"                                      # prefix          =  ":" max-length
+      MODIFIER_LEVEL4 = "#{PREFIX}|#{EXPLODE}"                       # modifier-level4 =  prefix / explode
+      VARCHAR = "(\\w|#{PCT_ENCODED})"                               # varchar         =  ALPHA / DIGIT / "_" / pct-encoded
+      VARNAME = "#{VARCHAR}(\\.?#{VARCHAR})*"                        # varname         =  varchar *( ["."] varchar )
+      VARSPEC = "#{VARNAME}(#{MODIFIER_LEVEL4})?"                    # varspec         =  varname [ modifier-level4 ]
+      VARIABLE_LIST = "#{VARSPEC}(,#{VARSPEC})*"                     # variable-list   =  varspec *( "," varspec )
+      OPERATOR = '[+#./;?&=,!@|]'                                    # operator        =  op-level2 / op-level3 / op-reserve
+                                                                     # op-level2       =  "+" / "#"
+                                                                     # op-level3       =  "." / "/" / ";" / "?" / "&"
+                                                                     # op-reserve      =  "=" / "," / "!" / "@" / "|"
+      EXPRESSION = "{#{OPERATOR}?#{VARIABLE_LIST}}"                  # expression      =  "{" [ operator ] variable-list "}"
+      LITERALS = "[^\\x00-\\x20\\x7F\"%'<>\\\\^`{|}]|#{PCT_ENCODED}" # literals        =  %x21 / %x23-24 / %x26 / %x28-3B / %x3D / %x3F-5B
+                                                                     #                 /  %x5D / %x5F / %x61-7A / %x7E / ucschar / iprivate
+                                                                     #                 /  pct-encoded
+                                                                     #                      ; any Unicode character except: CTL, SP,
+                                                                     #                      ;  DQUOTE, "'", "%" (aside from pct-encoded),
+                                                                     #                      ;  "<", ">", "\", "^", "`", "{", "|", "}"
+      URI_TEMPLATE = "(#{LITERALS}|#{EXPRESSION})*"                  # URI-Template    = *( literals / expression )
+      URI_TEMPLATE_REGEX = /\A#{URI_TEMPLATE}\z/
+
+      def valid_uri_template?(data)
+        URI_TEMPLATE_REGEX.match?(data)
+      end
+    end
+  end
+end

lib/json_schemer/schema/base.rb

@@ -32,7 +32,7 @@ def merge(
       end
 
       JSON_POINTER_TOKEN_ESCAPE_CHARS = { '~' => '~0', '/' => '~1' }
-      JSON_POINTER_TOKEN_ESCAPE_REGEXP = Regexp.union(JSON_POINTER_TOKEN_ESCAPE_CHARS.keys)
+      JSON_POINTER_TOKEN_ESCAPE_REGEX = Regexp.union(JSON_POINTER_TOKEN_ESCAPE_CHARS.keys)
 
       class << self
         def draft_name
@@ -624,7 +624,7 @@ def safe_strict_decode64(data)
       end
 
       def escape_json_pointer_token(token)
-        token.gsub(JSON_POINTER_TOKEN_ESCAPE_REGEXP, JSON_POINTER_TOKEN_ESCAPE_CHARS)
+        token.gsub(JSON_POINTER_TOKEN_ESCAPE_REGEX, JSON_POINTER_TOKEN_ESCAPE_CHARS)
       end
 
       def join_uri(a, b)

test/uri_template_test.rb

@@ -0,0 +1,247 @@
+require 'test_helper'
+
+class PrettyErrorsTest < Minitest::Test
+  def test_uri_template_format
+    schema = JSONSchemer.schema({ 'type' => 'string', 'format' => 'uri-template' })
+
+    [
+      '{justright:9999}',
+      '{#has.lots.of.dots}',
+      '{an_underscore}',
+      '{=reserved}',
+      '{,reserved}',
+      '{!reserved}',
+      '{@reserved}',
+      '{|reserved}',
+      '{percent%20encoded}',
+      '{UPCASED}',
+      'literal%20encoded',
+      "literal🖥️unicode"
+    ].each do |data|
+      assert(schema.valid?(data), data)
+    end
+
+    [
+      '{toobig:10000}',
+      '{#.starts.with.dot}',
+      '{#ends.with.dot.}',
+      '{a-dash}',
+      '{doubleexplode**}',
+      '{percent%unencoded}',
+      '{not percent encoded}',
+      '{hangingprefix:}',
+      '{prefixandexplode:3*',
+      '{explodeandprefix*:3',
+      '{varchar🖥️unicode}',
+      '{{double curly}}',
+      '{hanging curlopen',
+      'hanging curlyclose}',
+      'literal space',
+      'literal"dquote',
+      "literal'squote",
+      'literal%percent',
+      'literal<lessthan',
+      'literal>greaterthan',
+      'literal\backslash',
+      'literal^caret',
+      'literal`backtick',
+      'literal{curlyopen',
+      'literal}curlyclose',
+      'literal|bar'
+    ].each do |data|
+      refute(schema.valid?(data), data)
+    end
+
+    # examples from https://datatracker.ietf.org/doc/html/rfc6570
+    [
+      'http://example.com/~{username}/',
+      'http://example.com/dictionary/{term:1}/{term}',
+      'http://example.com/search{?q,lang}',
+      'http://www.example.com/foo{?query,number}',
+      '{var}',
+      '{hello}',
+      '{+var}',
+      '{+hello}',
+      '{+path}/here',
+      'here?ref={+path}',
+      'X{#var}',
+      'X{#hello}',
+      'map?{x,y}',
+      '{x,hello,y}',
+      '{+x,hello,y}',
+      '{#x,hello,y}',
+      '{#path,x}/here',
+      'X{.var}',
+      'X{.x,y}',
+      '{/var}',
+      '{/var,x}/here',
+      '{;x,y}',
+      '{;x,y,empty}',
+      '{?x,y}',
+      '{?x,y,empty}',
+      '?fixed=yes{&x}',
+      '{&x,y,empty}',
+      '{var:3}',
+      '{var:30}',
+      '{list}',
+      '{list*}',
+      '{keys}',
+      '{keys*}',
+      '{+path:6}/here',
+      '{+list}',
+      '{+list*}',
+      '{+keys}',
+      '{+keys*}',
+      '{#path:6}/here',
+      '{#list}',
+      '{#list*}',
+      '{#keys}',
+      '{#keys*}',
+      'X{.var:3}',
+      'X{.list}',
+      'X{.list*}',
+      'X{.keys}',
+      'X{.keys*}',
+      '{/var:1,var}',
+      '{/list}',
+      '{/list*}',
+      '{/list*,path:4}',
+      '{/keys}',
+      '{/keys*}',
+      '{;hello:5}',
+      '{;list}',
+      '{;list*}',
+      '{;keys}',
+      '{;keys*}',
+      '{?var:3}',
+      '{?list}',
+      '{?list*}',
+      '{?keys}',
+      '{?keys*}',
+      '{&var:3}',
+      '{&list}',
+      '{&list*}',
+      '{&keys}',
+      '{&keys*}',
+      'find{?year*}',
+      'www{.dom*}',
+      '{count}',
+      '{count*}',
+      '{/count}',
+      '{/count*}',
+      '{;count}',
+      '{;count*}',
+      '{?count}',
+      '{?count*}',
+      '{&count*}',
+      '{var}',
+      '{hello}',
+      '{half}',
+      'O{empty}X',
+      'O{undef}X',
+      '{x,y}',
+      '{x,hello,y}',
+      '?{x,empty}',
+      '?{x,undef}',
+      '?{undef,y}',
+      '{var:3}',
+      '{var:30}',
+      '{list}',
+      '{list*}',
+      '{keys}',
+      '{keys*}',
+      '{+var}',
+      '{+hello}',
+      '{+half}',
+      '{base}index',
+      '{+base}index',
+      'O{+empty}X',
+      'O{+undef}X',
+      '{+path}/here',
+      'here?ref={+path}',
+      'up{+path}{var}/here',
+      '{+x,hello,y}',
+      '{+path,x}/here',
+      '{+path:6}/here',
+      '{+list}',
+      '{+list*}',
+      '{+keys}',
+      '{+keys*}',
+      '{#var}',
+      '{#hello}',
+      '{#half}',
+      'foo{#empty}',
+      'foo{#undef}',
+      '{#x,hello,y}',
+      '{#path,x}/here',
+      '{#path:6}/here',
+      '{#list}',
+      '{#list*}',
+      '{#keys}',
+      '{#keys*}',
+      '{.who}',
+      '{.who,who}',
+      '{.half,who}',
+      'www{.dom*}',
+      'X{.var}',
+      'X{.empty}',
+      'X{.undef}',
+      'X{.var:3}',
+      'X{.list}',
+      'X{.list*}',
+      'X{.keys}',
+      'X{.keys*}',
+      'X{.empty_keys}',
+      'X{.empty_keys*}',
+      '{/who}',
+      '{/who,who}',
+      '{/half,who}',
+      '{/who,dub}',
+      '{/var}',
+      '{/var,empty}',
+      '{/var,undef}',
+      '{/var,x}/here',
+      '{/var:1,var}',
+      '{/list}',
+      '{/list*}',
+      '{/list*,path:4}',
+      '{/keys}',
+      '{/keys*}',
+      '{;who}',
+      '{;half}',
+      '{;empty}',
+      '{;v,empty,who}',
+      '{;v,bar,who}',
+      '{;x,y}',
+      '{;x,y,empty}',
+      '{;x,y,undef}',
+      '{;hello:5}',
+      '{;list}',
+      '{;list*}',
+      '{;keys}',
+      '{;keys*}',
+      '{?who}',
+      '{?half}',
+      '{?x,y}',
+      '{?x,y,empty}',
+      '{?x,y,undef}',
+      '{?var:3}',
+      '{?list}',
+      '{?list*}',
+      '{?keys}',
+      '{?keys*}',
+      '{&who}',
+      '{&half}',
+      '?fixed=yes{&x}',
+      '{&x,y,empty}',
+      '{&x,y,undef}',
+      '{&var:3}',
+      '{&list}',
+      '{&list*}',
+      '{&keys}',
+      '{&keys*}'
+    ].each do |data|
+      assert(schema.valid?(data), data)
+    end
+  end
+end