How to implement full text search in Django?

Question

I would like to implement a search function in a django blogging application. The status quo is that I have a list of strings supplied by the user and the queryset is narrowed down by each string to include only those objects that match the string.

See:

if request.method == "POST":
    form = SearchForm(request.POST)
    if form.is_valid():
        posts = Post.objects.all()
        for string in form.cleaned_data['query'].split():
            posts = posts.filter(
                    Q(title__icontains=string) | 
                    Q(text__icontains=string) |
                    Q(tags__name__exact=string)
                    )
        return archive_index(request, queryset=posts, date_field='date')

Now, what if I didn't want do concatenate each word that is searched for by a logical AND but with a logical OR? How would I do that? Is there a way to do that with Django's own Queryset methods or does one have to fall back to raw SQL queries?

In general, is it a proper solution to do full text search like this or would you recommend using a search engine like Solr, Whoosh or Xapian. What are their benefits?

Answer 1

I suggest you to adopt a search engine.

We've used Haystack search, a modular search application for django supporting many search engines (Solr, Xapian, Whoosh, etc...)

Advantages:

• Faster
• perform search queries even without querying the database.
• Highlight searched terms
• "More like this" functionality
• Spelling suggestions
• Better ranking
• etc...

Disadvantages:

• Search Indexes can grow in size pretty fast
• One of the best search engines (Solr) run as a Java servlet (Xapian does not)

We're pretty happy with this solution and it's pretty easy to implement.