[SOLR-7576] Implement RequestHandler in Javascript

• Type: New Feature
• Status: Closed
• Priority: Major
• Resolution: Won't Fix
• Assignee: Unassigned
• Reporter: Noble Paul
• Created: 20/May/15 07:31
• Updated: 30/Dec/19 20:37
• Resolved: 20/Sep/17 15:27

Description

Solr now support dynamic loading (SOLR-7073) of components and it is secured in SOLR-7126

We can extend the same functionality with JS as well

the handler /js is implicitly registered
To make this work

• Solr should be started with -Denable.js.loading=true
• The javascript must be loaded to the .system collection using the blob store API
• Sign the javascript and pass the signature in a param called _sig

The JSRequestHandler is implicitly defined and it can be accessed by hitting /js/<jsname>/<version>

Steps for developing scripts

1. start the cluster with the enable.js.loading . If you are starting using our script it would be bin/solr start -e cloud -a "-Denable.js.loading=true" . You would not need security during development , so don't add the private keys to Solr
2. create .system collection bin/solr create -c .system
3. Write your javascript code . (say test.js )
4. post it to .system collection . curl -X POST -H 'Content-Type: application/octet-stream' --data-binary @test.js http://localhost:8983/solr/.system/blob/test
5. run your script http://host:8983/solr/gettingstarted/js/test/1
6. Edit your script and repeat from step #4 . Keep in mind that the version would be bumped up every time you post a new script . So, the second time the url would be http://host:8983/solr/gettingstarted/js/test/2 . So on and so forth

sample programs
1) writes a val to output

//empty line
$.response().add('testkey','Test Val');

2) manipulate the output to add an extra field to each doc

//empty line
var l = [];
$.query({
              q: '*:*',
              qt: '/select',
              start:0,
          }).forEach('response', function(doc) {
                                         doc.put('script', 'Added this value');
                                         l.push(doc);
          });
 $.response().add('alldocs', l);

3) stream through all the docs

//empty line
$.query({
              q: '*:*',
              qt: '/select',
              start:0,
              distrib:'false'
          }).pipe('response', 'docs', function(doc) { // the pipe function is executed right before the response writer and right after the transformers   
                                         if('IT'== doc.get('genre_s')) return null;
                                         doc.put('script', 'Added this value');
                                         return doc;

          });

Issue Links

• duplicates: SOLR-5005 JavaScriptRequestHandler