我尝试一个小的python脚本来测试我的SPARQL请求。但是，仅下一个简单的代码不起作用。
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冻结了很长时间，然后给了我一个URLError。
当我停止脚本时，请参见下一条消息：
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
对于2.7和3.4，我的情况相同。
编辑：我将我的连接从Wifi更改为Intranet。我的脚本与DBpedia Sparql端点配合得很好，但是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的本地服务器的问题。
在此先感谢您的帮助。
最佳答案
对于2019年来到这里的用户，由于访问Wikidata sparql端点时出错，Wikidata强制执行严格的User-Agent策略，请参见此Wikidata Project chat，该规则表示发送信息性标头的应用程序指示行为良好的非机器人脚本，另请参见Wikimedia的user-agent policy。
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标头在MDN web docs中描述。
最后，您可以将class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")
希望这可以帮助！
关于python - sparql.query()。convert()处带有SPARQLWrapper的URLError，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/30755625/