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/)。我已经索引了所有实体并且搜索工作正常。但只有当我搜索完全匹配时，它才会返回 0 个结果。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')

但如果我将 query_string 更改为 "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键入时的搜索建议。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，但对我的目的非常有用。