Question

The haystack documentation (link below) makes this statement:

Additionally, we’re providing use_template=True on the text field.
This allows us to use a data template (rather than error prone
concatenation) to build the document the search engine will use in
searching.

How would one go about using concatenation to build the document? I couldn’t find an example.

It may have something to do with overriding the prepare method (second link). But in the example given in the documentation the prepare method is used together with a template, so the two might also be orthogonal.

https://github.com/toastdriven/django-haystack/blob/master/docs/tutorial.rst

http://django-haystack.readthedocs.org/en/latest/searchindex_api.html#advanced-data-preparation

Answer 1

You can see how it works in the Haystack source. Basically, the default implementation of the prepare method on SearchField (the base class for Haystack’s fields) calls prepare_template if use_template is True.

If you don’t want to use a template, you can indeed use concatenation – it’s as simple as just joining the data you want together, separated by something (here I’ve used a newline):

def prepare_myfield(self, obj):
    return self.cleaned_data['field1'] + '\n' + self.cleaned_data['field2']

etc.