Solr: Facet one field with two outputs

问题

I'm using Solr for indexing products and organising them into several categories. Each document has a taxon_names multi value field, where the categories are stored as human readable strings for a product.

Now I want to fetch all the categories from Solr and display them with clickable links to the user, without hitting the database again. At index time, I get the permalinks for every category from the MySQL database, which is stored as a multi value field taxon_permalinks. For generating the links to the products, I need the human readable format of the category and its permalink (otherwise you would have such ugly URLs in your browser, when just using the plain human readable name of the category, e.g. %20 for space).

When I do a facet search with http://localhost:8982/solr/default/select?q=*%3A*&rows=0&wt=xml&facet=true&facet.field=taxon_names, I get a list of human readable taxons with its counts. Based on this list, I want to create the links, so that I don't have to hit the database again.

So, is it possible to retrieve the matching permalinks from Solr for the different categories? For example, I get a XML like this:

<response>
<lst name="responseHeader">
  <int name="status">0</int>
  <int name="QTime">0</int>
</lst>
<result name="response" numFound="6580" start="0"/>
  <lst name="facet_counts">
  <lst name="facet_queries"/>
  <lst name="facet_fields">
  <lst name="taxon_names">
    <int name="Books">2831</int>
    <int name="Music">984</int>
      ...
  </lst>
</result>

And inside the taxon_names array I would need the name of the permalink.

Maybe it's possible by defining a custom field type in the config XMLs. But for this, I don't have enough experience with Solr.

回答1:

Since it appears from your description that you are faceting permalink in the taxon_permalink field and the values in that field should correspond to the same category names in the taxon_names field. Solr allows you to facet on multiple fields, so you can just facet on both fields and walk the two facet results grabbing the display name from the taxon_names facet values and the permalink from the taxon_permalink facet values.

Query:

 http://localhost:8982/solr/default/selectq=*%3A*&rows=0&wt=xml
   &facet=true&facet.field=taxon_names&facet.field=taxon_permalink

Your output should then look like similar to the following:

<response>
<lst name="responseHeader">
  <int name="status">0</int>
  <int name="QTime">0</int>
</lst>
<result name="response" numFound="6580" start="0"/>
  <lst name="facet_counts">
  <lst name="facet_queries"/>
  <lst name="facet_fields">
  <lst name="taxon_names">
    <int name="Books">2831</int>
    <int name="Music">984</int>
      ...
  </lst>
  <lst name="taxon_permalink">
    <int name="permalink1">2831</int>
    <int name="permalink2">984</int>
      ...
  </lst>
</result>

来源：https://stackoverflow.com/questions/18153390/solr-facet-one-field-with-two-outputs