New: Required/Ignored restrictions now support /pattern/ regular expressions

Co-Authored-By: taloth <taloth@users.noreply.github.com>

src/NzbDrone.Core.Test/DecisionEngineTests/ReleaseRestrictionsSpecificationFixture.cs

@@ -29,6 +29,8 @@ namespace NzbDrone.Core.Test.DecisionEngineTests
                                              Title = "Dexter.S08E01.EDITED.WEBRip.x264-KYR"
                                          }
                            };
+
+            Mocker.SetConstant<ITermMatcher>(Mocker.Resolve<TermMatcher>());
         }
 
         private void GivenRestictions(string required, string ignored)
@@ -123,5 +125,16 @@ namespace NzbDrone.Core.Test.DecisionEngineTests
 
             Subject.IsSatisfiedBy(_remoteMovie, null).Accepted.Should().BeFalse();
         }
+
+        [TestCase("/WEB/", true)]
+        [TestCase("/WEB\b/", false)]
+        [TestCase("/WEb/", false)]
+        [TestCase(@"/\.WEB/", true)]
+        public void should_match_perl_regex(string pattern, bool expected)
+        {
+            GivenRestictions(pattern, null);
+
+            Subject.IsSatisfiedBy(_remoteMovie, null).Accepted.Should().Be(expected);
+        }
     }
 }

src/NzbDrone.Core/DecisionEngine/Specifications/ReleaseRestrictionsSpecification.cs

@@ -11,13 +11,15 @@ namespace NzbDrone.Core.DecisionEngine.Specifications
 {
     public class ReleaseRestrictionsSpecification : IDecisionEngineSpecification
     {
-        private readonly IRestrictionService _restrictionService;
         private readonly Logger _logger;
+        private readonly IRestrictionService _restrictionService;
+        private readonly ITermMatcher _termMatcher;
 
-        public ReleaseRestrictionsSpecification(IRestrictionService restrictionService, Logger logger)
+        public ReleaseRestrictionsSpecification(ITermMatcher termMatcher, IRestrictionService restrictionService, Logger logger)
         {
-            _restrictionService = restrictionService;
             _logger = logger;
+            _restrictionService = restrictionService;
+            _termMatcher = termMatcher;
         }
 
         public SpecificationPriority Priority => SpecificationPriority.Default;
@@ -63,9 +65,9 @@ namespace NzbDrone.Core.DecisionEngine.Specifications
             return Decision.Accept();
         }
 
-        private static List<string> ContainsAny(List<string> terms, string title)
+        private List<string> ContainsAny(List<string> terms, string title)
         {
-            return terms.Where(t => title.ToLowerInvariant().Contains(t.ToLowerInvariant())).ToList();
+            return terms.Where(t => _termMatcher.IsMatch(t, title)).ToList();
         }
     }
 }

src/NzbDrone.Core/NzbDrone.Core.csproj

@@ -1201,9 +1201,11 @@
     <Compile Include="Queue\Queue.cs" />
     <Compile Include="Queue\QueueService.cs" />
     <Compile Include="Queue\QueueUpdatedEvent.cs" />
+    <Compile Include="Restrictions\PerlRegexFactory.cs" />
     <Compile Include="Restrictions\Restriction.cs" />
     <Compile Include="Restrictions\RestrictionRepository.cs" />
     <Compile Include="Restrictions\RestrictionService.cs" />
+    <Compile Include="Restrictions\TermMatcher.cs" />
     <Compile Include="Rest\JsonNetSerializer.cs" />
     <Compile Include="Rest\RestClientFactory.cs" />
     <Compile Include="Rest\RestException.cs" />

src/NzbDrone.Core/Restrictions/PerlRegexFactory.cs

@@ -0,0 +1,72 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Text.RegularExpressions;
+using NzbDrone.Common.Exceptions;
+
+namespace NzbDrone.Core.Restrictions
+{
+    public static class PerlRegexFactory
+    {
+        private static Regex _perlRegexFormat = new Regex(@"/(?<pattern>.*)/(?<modifiers>[a-z]*)", RegexOptions.Compiled);
+
+        public static bool TryCreateRegex(string pattern, out Regex regex)
+        {
+            var match = _perlRegexFormat.Match(pattern);
+
+            if (!match.Success)
+            {
+                regex = null;
+                return false;
+            }
+
+            regex = CreateRegex(match.Groups["pattern"].Value, match.Groups["modifiers"].Value);
+            return true;
+        }
+
+        public static Regex CreateRegex(string pattern, string modifiers)
+        {
+            var options = GetOptions(modifiers);
+
+            // For now we simply expect the pattern to be .net compliant. We should probably check and reject perl-specific constructs.
+            return new Regex(pattern, options | RegexOptions.Compiled);
+        }
+
+        private static RegexOptions GetOptions(string modifiers)
+        {
+            var options = RegexOptions.None;
+
+            foreach (var modifier in modifiers)
+            {
+                switch (modifier)
+                {
+                    case 'm':
+                        options |= RegexOptions.Multiline;
+                        break;
+
+                    case 's':
+                        options |= RegexOptions.Singleline;
+                        break;
+
+                    case 'i':
+                        options |= RegexOptions.IgnoreCase;
+                        break;
+
+                    case 'x':
+                        options |= RegexOptions.IgnorePatternWhitespace;
+                        break;
+
+                    case 'n':
+                        options |= RegexOptions.ExplicitCapture;
+                        break;
+
+                    default:
+                        throw new ArgumentException("Unknown or unsupported perl regex modifier: " + modifier);
+                }
+            }
+
+            return options;
+        }
+    }
+}

src/NzbDrone.Core/Restrictions/TermMatcher.cs

@@ -0,0 +1,63 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Text.RegularExpressions;
+using NzbDrone.Common.Cache;
+
+namespace NzbDrone.Core.Restrictions
+{
+    public interface ITermMatcher
+    {
+        bool IsMatch(string term, string value);
+    }
+
+    public class TermMatcher : ITermMatcher
+    {
+        private ICached<Predicate<string>> _matcherCache;
+
+        public TermMatcher(ICacheManager cacheManager)
+        {
+            _matcherCache = cacheManager.GetCache<Predicate<string>>(GetType());
+        }
+
+        public bool IsMatch(string term, string value)
+        {
+            return GetMatcher(term)(value);
+        }
+
+        public Predicate<string> GetMatcher(string term)
+        {
+            return _matcherCache.Get(term, () => CreateMatcherInternal(term), TimeSpan.FromHours(24));
+        }
+
+        private Predicate<string> CreateMatcherInternal(string term)
+        {
+            Regex regex;
+            if (PerlRegexFactory.TryCreateRegex(term, out regex))
+            {
+                return regex.IsMatch;
+            }
+            else
+            {
+                return new CaseInsensitiveTermMatcher(term).IsMatch;
+
+            }
+        }
+
+        private sealed class CaseInsensitiveTermMatcher
+        {
+            private readonly string _term;
+
+            public CaseInsensitiveTermMatcher(string term)
+            {
+                _term = term.ToLowerInvariant();
+            }
+
+            public bool IsMatch(string value)
+            {
+                return value.ToLowerInvariant().Contains(_term);
+            }
+        }
+    }
+}