Issue 3176 - Keep filter list parameters

abp2blocklist.js

 var readline = require("readline");
 var punycode = require("punycode");
 var tldjs = require("tldjs");
 var filterClasses = require("./adblockplus.js");
 
 var typeMap = filterClasses.RegExpFilter.typeMap;
 
+var params = {};
 var requestFilters = [];
 var requestExceptions = [];
 var elemhideFilters = [];
 var elemhideExceptions = [];
 var elemhideSelectorExceptions = Object.create(null);
 
 function recordException(filter) {
         if (filter.contentType & (typeMap.IMAGE
                                 | typeMap.STYLESHEET
                                 | typeMap.SCRIPT
@@ skipping 44 matching lines @@
         if (filter instanceof filterClasses.BlockingFilter)
                 requestFilters.push(filter);
         if (filter instanceof filterClasses.WhitelistFilter)
                 recordException(filter);
         if (filter instanceof filterClasses.ElemHideFilter)
                 elemhideFilters.push(filter);
         if (filter instanceof filterClasses.ElemHideException)
                 recordSelectorException(filter);
 }
 
+function parseLine(line) {
+        var paramMatch = /^\s*!\s*([\w ]+)\s*:\s*(.*)/.exec(line);

[Sebastian Noack, 2015/10/13 11:25:08]

I think we should leave the parsing to the core code imported from ABP. So
instead using a regex here you could check for CommentFilter objects returned by
Filter.fromText().

+        if (paramMatch) {
+                var key = paramMatch[1];
+                var paramsToKeep = ["version", "title", "last modified", "expires", "homepage", "licence"];
+                if (paramsToKeep.indexOf(key.toLowerCase()) != -1)
+                        params[key] = paramMatch[2];
+                return;
+        }
+        parseFilter(line);
+}
+
 function escapeRegExp(s) {
         return s.replace(/[.*+?^${}()|[\]\\]/g, "\\$&");
 }
 
 function matchDomain(domain) {
         return "^https?://([^/:]*\\.)?" + escapeRegExp(domain) + "[/:]";
 }
 
 function convertElemHideFilter(filter) {
         var included = [];
@@ skipping 176 matching lines @@
 
         for (i = 0; i < elemhideFilters.length; i++)
                 convertElemHideFilter(elemhideFilters[i]).forEach(addRule);
         for (i = 0; i < elemhideExceptions.length; i++)
                 addRule(convertFilter(elemhideExceptions[i], "ignore-previous-rules", false));
         for (i = 0; i < requestFilters.length; i++)
                 addRule(convertFilter(requestFilters[i], "block", true));
         for (i = 0; i < requestExceptions.length; i++)
                 addRule(convertFilter(requestExceptions[i], "ignore-previous-rules", true));
 
+        for (key in params)
+                if (params.hasOwnProperty(key))
+                        console.log("// " + key + ": " + params[key]);

[Sebastian Noack, 2015/10/13 11:25:08]

But anyway, valid JSON cannot have comments. So NOT LGTM.

[Felix Dahlke, 2015/10/13 11:37:26]

Did you read https://issues.adblockplus.org/ticket/3176?

The only alternative I see so far is to return a different JSON structure, i.e.
not an array of content blocking rule objects. Stripping out comments is easy,
stripping out anything else on the client-side is more involved.

[Felix Dahlke, 2015/10/13 11:52:15]

But well, different approaches shouldn't be discussed here, that should go into
https://issues.adblockplus.org/ticket/3176. Please have a look and suggest a
different approach there.

         console.log(JSON.stringify(rules, null, "\t"));
 }
 
 var rl = readline.createInterface({input: process.stdin, terminal: false});
-rl.on("line", parseFilter);
+rl.on("line", parseLine);
 rl.on("close", logRules);