Google App Engine(python):搜索API:字符串搜索

Question

我正在使用Google App Engine搜索API(https://developers.google.com/appengine/docs/python/search/).我已将所有实体编入索引,搜索工作正常.但只有当我搜索完全匹配时,它才会返回0结果.例如:

from google.appengine.api import search

_INDEX_NAME = 'searchall'


query_string ="United Kingdom"
query = search.Query(query_string=query_string)
index = search.Index(name=_INDEX_NAME)

print index.search(query)

如果我运行以下脚本,我会得到如下结果:

search.SearchResults(results='[search.ScoredDocument(doc_id='c475fd24-34ba-42bd-a3b5-d9a48d880012', fields='[search.TextField(name='name', value='United Kingdom')]', language='en', order_id='45395666'), search.ScoredDocument(doc_id='5fa757d1-05bf-4012-93ff-79dd4b77a878', fields='[search.TextField(name='name', value='United Kingdom')]', language='en', order_id='45395201')]', number_found='2')

但是,如果我改变query_string对"United Kin"或"United"它返回0结果如下:

search.SearchResults(number_found='0')

我想将此API用于普通搜索和AutoSuggest.实现这一目标的最佳方法是什么？

Answer 1

App Engine的全文搜索API不支持子字符串匹配.

但是,我自己需要这种行为来支持用户输入的搜索建议.这是我的解决方案:

""" 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))])

基本思想是为每个可能的子字符串手动生成单独的关键字.这仅适用于短句,但它对我的目的很有用.