Installing Search Engines

Solr

Official Download Location: http://www.apache.org/dyn/closer.cgi/lucene/solr/

Solr is Java but comes in a pre=packaged form that requires very little other than the JRE and Jetty. It’s very performant and has an advanced featureset. Haystack requires Solr 1.3+. Installation is relatively simple:

curl -O http://apache.mirrors.tds.net/lucene/solr/1.4.1/apache-solr-1.4.1.tgz
tar xvzf apache-solr-1.4.1.tgz
cd apache-solr-1.4.1
cd example
java -jar start.jar

You’ll need to revise your schema. You can generate this from your application (once Haystack is installed and setup) by running ./manage.py build_solr_schema. Take the output from that command and place it in apache-solr-1.4.1/example/solr/conf/schema.xml. Then restart Solr.

You’ll also need a Solr binding, pysolr. The official pysolr package, distributed via PyPI, is the best version to use (2.0.13+). Place pysolr.py somewhere on your PYTHONPATH.

Note

pysolr has it’s own dependencies that aren’t covered by Haystack. For best results, you should have an ElementTree variant install (preferably the lxml variant), httplib2 for timeouts (though it will fall back to httplib) and either the json module that comes with Python 2.5+ or simplejson.

More Like This

To enable the “More Like This” functionality in Haystack, you’ll need to enable the MoreLikeThisHandler. Add the following line to your solrconfig.xml file within the config tag:

<requestHandler name="/mlt" class="solr.MoreLikeThisHandler" />

Spelling Suggestions

To enable the spelling suggestion functionality in Haystack, you’ll need to enable the SpellCheckComponent.

The first thing to do is create a special field on your SearchIndex class that mirrors the text field, but has indexed=False on it. This disables the post-processing that Solr does, which can mess up your suggestions. Something like the following is suggested:

class MySearchIndex(indexes.SearchIndex):
    text = indexes.CharField(document=True, use_template=True)
    # ... normal fields then...
    suggestions = indexes.CharField()

    def prepare(self, obj):
        prepared_data = super(NoteIndex, self).prepare(object)
        prepared_data['suggestions'] = prepared_data['text']
        return prepared_data

Then, you enable it in Solr by adding the following line to your solrconfig.xml file within the config tag:

<searchComponent name="spellcheck" class="solr.SpellCheckComponent">

    <str name="queryAnalyzerFieldType">textSpell</str>

    <lst name="spellchecker">
      <str name="name">default</str>
      <str name="field">suggestions</str>
      <str name="spellcheckIndexDir">./spellchecker1</str>
      <str name="buildOnCommit">true</str>
    </lst>
</searchComponent>

Then change your default handler from:

<requestHandler name="standard" class="solr.StandardRequestHandler" default="true" />

... to ...:

<requestHandler name="standard" class="solr.StandardRequestHandler" default="true">
    <arr name="last-components">
        <str>spellcheck</str>
    </arr>
</requestHandler>

Be warned that the <str name="field">suggestions</str> portion will be specific to your SearchIndex classes (in this case, assuming the main field is called text).

Whoosh

Official Download Location: http://bitbucket.org/mchaput/whoosh/

Whoosh is pure Python, so it’s a great option for getting started quickly and for development, though it does work for small scale live deployments. The current recommended version is 1.3.1+. You can install via PyPI using:

sudo easy_install whoosh
# ... or ...
sudo pip install whoosh

Note that, while capable otherwise, the Whoosh backend does not currently support “More Like This” or faceting. Support for these features has recently been added to Whoosh itself & may be present in a future release.

Xapian

Official Download Location: http://xapian.org/download

Xapian is written in C++ so it requires compilation (unless your OS has a package for it). Installation looks like:

curl -O http://oligarchy.co.uk/xapian/1.0.11/xapian-core-1.0.11.tar.gz
curl -O http://oligarchy.co.uk/xapian/1.0.11/xapian-bindings-1.0.11.tar.gz

tar xvzf xapian-core-1.0.11.tar.gz
tar xvzf xapian-bindings-1.0.11.tar.gz

cd xapian-core-1.0.11
./configure
make
sudo make install

cd ..
cd xapian-bindings-1.0.11
./configure
make
sudo make install

Xapian is a third-party supported backend. It is not included in Haystack proper due to licensing. To use it, you need both Haystack itself as well as xapian-haystack. You can download the source from http://github.com/notanumber/xapian-haystack/tree/master. Installation instructions can be found on that page as well. The backend, written by David Sauve (notanumber), fully implements the SearchQuerySet API and is an excellent alternative to Solr.

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