Google App Engine (python) : Search API : String Search

Question

i am using the Google App Engine Search API (https://developers.google.com/appengine/docs/python/search/). I have indexed all of the entities and the search is working fine.

Answer 1

App Engine's full text search API does not support substring matching.

However, I needed this behavior myself to support search suggestions as the user types. Here is my solution for that:

""" Takes a sentence and returns the set of all possible prefixes for each word.
    For instance "hello world" becomes "h he hel hell hello w wo wor worl world" """
def build_suggestions(str):
    suggestions = []
    for word in str.split():
        prefix = ""
        for letter in word:
            prefix += letter
            suggestions.append(prefix)
    return ' '.join(suggestions)

# Example use
document = search.Document(
    fields=[search.TextField(name='name', value=object_name),
            search.TextField(name='suggest', value=build_suggestions(object_name))])

The basic idea is to manually generate separate keywords for every possible substring. This is only practical for short sentences, but it works great for my purposes.