python - sparql.query().convert() 中 SPARQLWrapper 的 URLError

Question

我尝试使用一个小的 Python 脚本来测试我的 SPARQL 请求。然而，只是下一个简单的代码是行不通的。

from SPARQLWrapper import SPARQLWrapper, JSON
import rdflib
#connect to the sparql point
sparql = SPARQLWrapper("http://localhost:3030/sparql")
#SPARQL request
sparql.setQuery("""
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX owl: <http://www.w3.org/2002/07/owl#>
PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>
PREFIX rme: <http://www.semanticweb.org/reminer/>

SELECT ?o
WHERE { ?s ?p ?o }
LIMIT 1
""")
sparql.setReturnFormat(JSON)
results = sparql.query().convert()

for result in results["results"]["bindings"]:
     print(result["o"]["value"])

我的代码在转换步骤卡住了很长时间，然后给我一个 URLError。当我停止脚本时，看到下一条消息:

HTTPError                                 Traceback (most recent call last)
<ipython-input-6-2ab63307a418> in <module>()
     18 """)
     19 sparql.setReturnFormat(JSON)
---> 20 results = sparql.query().convert()
     21 
     22 for result in results["results"]["bindings"]:

/Users/francocy/anaconda/lib/python3.4/site-packages/SPARQLWrapper/Wrapper.py in query(self)
    533             @rtype: L{QueryResult} instance
    534         """
--> 535         return QueryResult(self._query())
    536 
    537     def queryAndConvert(self):

/Users/francocy/anaconda/lib/python3.4/site-packages/SPARQLWrapper/Wrapper.py in _query(self)
    513                 raise EndPointInternalError(e.read())
    514             else:
--> 515                 raise e
    516 
    517     def query(self):

/Users/francocy/anaconda/lib/python3.4/site-packages/SPARQLWrapper/Wrapper.py in _query(self)
    503 
    504         try:
--> 505             response = urlopener(request)
    506             return response, self.returnFormat
    507         except urllib.error.HTTPError as e:

/Users/francocy/anaconda/lib/python3.4/urllib/request.py in urlopen(url, data, timeout, cafile, capath, cadefault, context)
    159     else:
    160         opener = _opener
--> 161     return opener.open(url, data, timeout)
    162 
    163 def install_opener(opener):

/Users/francocy/anaconda/lib/python3.4/urllib/request.py in open(self, fullurl, data, timeout)
    467         for processor in self.process_response.get(protocol, []):
    468             meth = getattr(processor, meth_name)
--> 469             response = meth(req, response)
    470 
    471         return response

/Users/francocy/anaconda/lib/python3.4/urllib/request.py in http_response(self, request, response)
    577         if not (200 <= code < 300):
    578             response = self.parent.error(
--> 579                 'http', request, response, code, msg, hdrs)
    580 
    581         return response

/Users/francocy/anaconda/lib/python3.4/urllib/request.py in error(self, proto, *args)
    505         if http_err:
    506             args = (dict, 'default', 'http_error_default') + orig_args
--> 507             return self._call_chain(*args)
    508 
    509 # XXX probably also want an abstract factory that knows when it makes

/Users/francocy/anaconda/lib/python3.4/urllib/request.py in _call_chain(self, chain, kind, meth_name, *args)
    439         for handler in handlers:
    440             func = getattr(handler, meth_name)
--> 441             result = func(*args)
    442             if result is not None:
    443                 return result

/Users/francocy/anaconda/lib/python3.4/urllib/request.py in http_error_default(self, req, fp, code, msg, hdrs)
    585 class HTTPDefaultErrorHandler(BaseHandler):
    586     def http_error_default(self, req, fp, code, msg, hdrs):
--> 587         raise HTTPError(req.full_url, code, msg, hdrs, fp)
    588 
    589 class HTTPRedirectHandler(BaseHandler):

HTTPError: HTTP Error 403: Forbidden

我在 2.7 和 3.4 中遇到了同样的情况。编辑:我将连接从 Wifi 更改为 Intranet。我的脚本适用于 DBpedia Sparql 端点，但是当我在本地服务器上请求时出现 Http 错误。这似乎是代理或访问我本地服务器的问题。

预先感谢您的帮助。

Answer 1

对于 2019 年来到这里的用户，对于访问维基数据 sparql 端点的错误，维基数据执行严格的用户代理策略，请参阅此存档(感谢 Pere)Wikidata Project chat ，它表示应用程序发送信息性 header 表示行为良好的非机器人脚本，另请参阅 user-agent policy维基媒体。

根据documentation ，我们可以使用 agent 实例变量设置用户代理。用户代理 HTTP header 在 MDN web docs 中描述。 .最后，您可以将类对象初始化为，

sparql = SPARQLWrapper("https://query.wikidata.org/sparql", agent="Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.11 (KHTML, like Gecko) Chrome/23.0.1271.64 Safari/537.11")

希望这对您有所帮助!