Fixes #39 - adds whitelistDomainPattern option

This option allows users to specify which domains they want to show titles
for

README.md

@@ -164,6 +164,8 @@ titles will be shown in all channels. Default value: `""`
 
 `ignoredDomainPattern` - ignore domains matching this pattern. Default value: `""`
 
+`whitelistDomainPattern` - ignore any link without a domain matching this pattern. Default value: `""`
+
 ### Tip ###
 
 You can ignore domains that you know aren't websites. This prevents a request from being made at all.
@@ -178,6 +180,10 @@ Ignore `*.tk` and `buzzfeed.com`
 
     !config supybot.plugins.SpiffyTitles.ignoredDomainPattern (\.tk|buzzfeed\.com)
 
+Ignore all links except youtube, imgur, and reddit
+
+    !config supybot.plugins.SpiffyTitles.whitelistDomainPattern /(reddit\.com|youtube\.com|youtu\.be|imgur\.com)/
+
 `userAgents` - A comma separated list of strings of user agents randomly chosen when requesting. 
 
 `urlRegularExpression` - A regular expression used to match URLs. You shouldn't need to change this.

config.py

@@ -110,7 +110,7 @@ conf.registerGlobalValue(SpiffyTitles, 'youtubeDeveloperKey',
 
 # Link cache lifetime
 conf.registerGlobalValue(SpiffyTitles, 'linkCacheLifetimeInSeconds',
-                        registry.Integer(60, _("""Link cache lifetime in seconds""")))                           
+                        registry.Integer(60, _("""Link cache lifetime in seconds""")))                    
                         
                         
                         

plugin.py

@@ -116,7 +116,13 @@ class SpiffyTitles(callbacks.Plugin):
                 is_ignored = self.is_ignored_domain(domain)
                 
                 if is_ignored:
-                    self.log.info("SpiffyTitles: ignoring url due to pattern match: %s" % (url))
+                    self.log.info("SpiffyTitles: URL ignored due to domain blacklist match: %s" % url)
+                    return
+                
+                is_whitelisted_domain = self.is_whitelisted_domain(domain)
+                
+                if self.registryValue("whitelistDomainPattern") and not is_whitelisted_domain:
+                    self.log.info("SpiffyTitles: URL ignored due to domain whitelist mismatch: %s" % url)
                     return
                 
                 """
@@ -263,6 +269,25 @@ class SpiffyTitles(callbacks.Plugin):
             except re.Error:
                 self.log.error("SpiffyTitles: invalid regular expression: %s" % (pattern))
     
+    def is_whitelisted_domain(self, domain):
+        """
+        Checks domain against a regular expression
+        """
+        pattern = self.registryValue("whitelistDomainPattern")
+        
+        if pattern:
+            self.log.debug("SpiffyTitles: matching %s against %s" % (domain, str(pattern)))
+            
+            try:
+                pattern_search_result = re.search(pattern, domain)
+                
+                if pattern_search_result is not None:
+                    match = pattern_search_result.group()
+                    
+                    return match
+            except re.Error:
+                self.log.error("SpiffyTitles: invalid regular expression: %s" % (pattern))
+    
     def get_video_id_from_url(self, url, info):
         """
         Get YouTube video ID from URL