How to change the Solr request handler with SolrNet and ServiceLocator

by Xavier Comments: 1

I am working in a project that sounds like heaven to me. Big company, hundreds of developers, latest technology all around, totally agile and the search is done with Solr and a REST API in C# which of course uses SolrNet (who would think otherwise?)

In any case, spellcheck was enabled and this wreaked havoc whenever servers were rebooted. It seems like SolrCloud has an issue with spellchecking . The problem is that setting spellcheck in /select request handler makes Solr spin its wheels for a long time while starting, and it has been tracked in The recommended workaround is to have spell check set up in a different request handler.

But here is the problem. In SolrNet you can’t easily explicitly specify the request handler. It basically uses /select.  The request handler is specified via the Handler property in ISolrQueryExecuter. You can see it in action here:

I checked through many forums and threads to try to get to a solution and here are some of the threads I found:

Changing Handler endpoint in SolrQueryExecuter?!searchin/solrnet/handler/solrnet/Kqxn68pU0uo/uG50WSxu_swJ

How can I perform solrnet query in two different request handler?!topic/solrnet/ZA-bv9dkh_0

Different request handler!topic/solrnet/SP14XmifcrY

Calling Custom Request Handler!topic/solrnet/THX-ADS5CLQ

There were many recommendations, among them:

–          Use qt, which the problem is that it is deprecated and I think will not be available in Solr 5. And there is a lot of pushback against qt.

–          Move to CastleWindsor, which is what Eduardo, a friend of mine did last week.  I don’t have enough time to do this. On a really tight schedule.

–          Replace the Handler property in SolrQueryExecuter, which is what was recommended in one of the threads

–          Or Remove() and re Register() the ISolrQueryExecuter

One of the recommendations was modify the Handler this way:

Startup.Init<T>(new SolrConnection("http://localhost:8080/solr"));

var executor = ServiceLocator.Current.GetInstance<ISolrQueryExecuter<T>>() as SolrQueryExecuter<T>;

executor.Handler = "/new";

Which did not work as it did not modify the registered instance. No idea, but if you know how to fix let me know.

So the recommendation from Mauricio Scheffer was to Remove and Reregister, which I did not know how to do but Satish, a very friendly developer, helped me. Here is the solution:

Startup.Init<MyDocument>( “http://localhost:8080/solr”);

var container = ServiceLocator.Current as SolrNet.Utils.Container;


var instance = new SolrQueryExecuter<MyDocument>(container.GetInstance<ISolrAbstractResponseParser<MyDocument>>(), new SolrConnection(“http://localhost:8080/solr”), container.GetInstance<ISolrQuerySerializer>(), container.GetInstance<ISolrFacetQuerySerializer>(), container.GetInstance<ISolrMoreLikeThisHandlerQueryResultsParser<MyDocument>>());

instance.Handler = "/yourhandler";

And this saved my day!