"[SyntaxError: Unexpected token <]" when I try to add documents to my Solr index with my Node/Express app

Question

I'm trying to integrate Solr into a Node/Express app and while I am using this Node package for the Solr integration. I am able to properly query the index, but following the instructions on the package's GitHub, I am unable to add documents to the index. I keep getting this error:

[SyntaxError: Unexpected token <]

On the Solr console, the error is a little more detailed:

SEVERE: Error processing "legacy" update command:com.ctc.wstx.exc.WstxUnexpectedCharException: Unexpected character '[' (code 91) in prolog; expected '<'

Here is a small test app I'm using to try and get this working:

// set variables for environment
var express = require('express');
var path = require('path');
var solr = require('solr-client');

// Create the Express app
var app = express();
module.exports = app;

// Initialize the Vash view engine
app.set("views", path.join( __dirname, "/views") );
app.set("view engine", "vash");

// set routes
app.get('/', function(req, res) {
    // Create a client
    var client = solr.createClient();

    var query = 'q=fencing';
    client.get('select', query, function(err, obj) {
        if (err) {
            console.log(err);
        } else {
            console.log(obj);
        }
    });

    // Switch on "auto commit", by default `client.autoCommit = false`
    client.autoCommit = true;

    var docs = [];
    for(var i = 0; i <= 10 ; i++){
        var doc = {
            id : 12345 + i,
            title_t : "Title "+ i,
            description_t : "Text"+ i + "Alice"
        };
        docs.push(doc);
    }

    // Add documents
    client.add(docs,function(err,obj){
        if(err){
            console.log(err);
        }else{
            console.log(obj);
        }
    });

    res.render('index');
});

// Set server port
app.listen(4000);
console.log('server is running on localhost:4000');

The specific part that doesn't work is where I attempt to add a document to the index here:

// Add documents
client.add(docs,function(err,obj){
    if(err){
        console.log(err);
    }else{
        console.log(obj);
    }
});

My hunch is that this has something to do with receiving JSON when it's expecting XML, but I cannot for the life of me figure out how to either send XML or to enable Solr to accept JSON. Any advice?

Answer 1

I have seen a little bit the code of the solr-node-client and I see that in order to add a document they use this function Client.prototype.add and this function finally uses this handler

this.UPDATE_JSON_HANDLER = 
(versionUtils.version(this.options.solrVersion) >= versionUtils.Solr4_0) 
? 'update' : 'update/json';

What this means is that if you use Solr version greater or equal to 4 then in the Solrconfig.xml file there exists a request handler named update.

  <requestHandler name="/update" class="solr.UpdateRequestHandler">

  </requestHandler>

A single unified update request handler supports XML, CSV, JSON, and javabin update requests, delegating to the appropriate ContentStreamLoader based on the Content-Type of the ContentStream.

Have a look here https://cwiki.apache.org/confluence/display/solr/Uploading+Data+with+Index+Handlers#UploadingDatawithIndexHandlers-JSONFormattedIndexUpdates

The code in Node package sends json, so Solr would delegate to the appropriate ContentStreamLoader. This is the code in Node package

'content-type' : 'application/json; charset=utf-8',

If you use Solr less than version 4 then in your solrconfig.xml you should have a request handler like this

<requestHandler name="/update/json" class="solr.JsonUpdateRequestHandler">
        <lst name="defaults">
         <str name="stream.contentType">application/json</str>
       </lst>
  </requestHandler> 

So, to make a long story short, make sure that if you use Solr >=4 then in solrconfig.xml you have to have an update request handler

 <requestHandler name="/update" class="solr.UpdateRequestHandler">
      </requestHandler>

and if you use Solr < 4 then make sure you have a update handler like this one

<requestHandler name="/update/json" class="solr.JsonUpdateRequestHandler">
            <lst name="defaults">
             <str name="stream.contentType">application/json</str>
           </lst>
      </requestHandler> 

Hope this helps