使用Elastic Search后端无法“更像这样”在Haystack中返回任何结果

Question

I don't seem to be able to get the more_like_this tag in Haystack to return any results. Not sure if it's down to the data I've input, but I've tried it with some documents that should very similar.

I've verified it doesn't work even with a fairly simple index like this:

class PaperIndex(indexes.SearchIndex, indexes.Indexable):
    text = indexes.CharField(document=True, use_template=True)

    def get_model(self):
        return Paper

Again the simplified model looks like:

class Paper(Publishable):
    title = models.CharField(max_length=255)
    abstract = models.TextField()

    def __unicode__(self):
        return self.title

The search template looks like:

{% autoescape off %}
{{ object.title }}
{{ object.abstract|striptags }}
{% endautoescape %}

At the moment I'm just looking to see that's in the returned result from the tag like this:

{% more_like_this paper as related_papers limit 1 %}
{{ related_papers }}

Not sure if there is anything else I need to do. The elastic search docs mention "In order to use the mlt feature a mlt_field needs to be either be stored, store term_vector or source needs to be enabled." However I'm not sure what that equates to in Haystack terms.

I should note that I'm not seeing any errors - it's just that I get back an empty list/result set from more_like_this .

Oh and Elastic Search is version 1.1.1.

Answer 1

Old question, but still a recurring problem.

The solution is simple: provide enough information in your search template for Elastic Search to be able to calculate similarities.

If you have tags, full description, genres, languages, or anything else that could serve to find matches, add them to the search template.

To add a list (of tags for instance), you could do something like this in your search template:

{% load search_tags %}
{% render_tags object %}

And in the search_tags add a template tag called render_tags :

from django.template import Library
from django.utils.safestring import mark_safe

register = Library()


@register.simple_tag
def render_tags(obj):
    return mark_safe(' '.join([t.tag for t in obj.tags.all()]))

This assumes you have a ManyToMany relation to tags in your model.