SPARQLWrapper - Connecting RDFLib with Fuseki Server - sparql

Question

I am a newbie of SPARQL and Fuseki. I set up Fuseki Server with
fuseki-server --update --mem /address_act
to create a dataset.
And I have a graph containing many triples and then I want to add these triples into the dataset via SPARQLUPDATE. Here are the code to get triples into graph and try to save it to the dataset via Fuseki Server:
import requests
import rdflib
import re
from rdflib import ConjunctiveGraph, Graph, Literal, URIRef
from rdflib.plugins.stores import sparqlstore
query_endpoint = 'http://localhost:3030/address_act/query'
update_endpoint = 'http://localhost:3030/address_act/update'
store = sparqlstore.SPARQLUpdateStore()
store.open((update_endpoint, update_endpoint))
default_graph = URIRef('http://example.org/default-graph')
ng = Graph(store, identifier=default_graph)
g = Graph()
g1 = Graph()
for i in range(1,2):
url = 'http://gnafld.net/address/?per_page=3&page=' + str(i)
g.parse(url)
page = g.query("""SELECT ?subject
WHERE {
?subject a <http://gnafld.net/def/gnaf#Address>.
}""")
for row in page:
ad_info = requests.get(row.subject).content
g1.parse(data=ad_info, format='turtle')
#print('The number of triples in Graph: {}'.format(len(g1)))
ng.update(
u'INSERT DATA { %s }' % g1.serialize(format='turtle')
)
Besides, I have another way to do this using SPARQLWrapper:
import requests
import rdflib
import re
from rdflib import ConjunctiveGraph, Graph, Literal, URIRef
from rdflib.plugins.stores import sparqlstore
from SPARQLWrapper import SPARQLWrapper
query_endpoint = 'http://localhost:3030/address_act/query'
update_endpoint = 'http://localhost:3030/address_act/update'
store = sparqlstore.SPARQLUpdateStore()
store.open((update_endpoint, update_endpoint))
default_graph = URIRef('http://example.org/default-graph')
g = Graph()
g1 = Graph(identifier=default_graph)
for i in range(1,2):
url = 'http://gnafld.net/address/?per_page=3&page=' + str(i)
g.parse(url)
page = g.query("""SELECT ?subject
WHERE {
?subject a <http://gnafld.net/def/gnaf#Address>.
}""")
for row in page:
ad_info = requests.get(row.subject).content
g1.parse(data=ad_info, format='turtle')
#print('The number of triples in Graph: {}'.format(len(g1)))
for s,p,o in g1:
queryStringUpload = 'INSERT DATA {GRAPH <http://example.org/default-graph> {%s %s %s}}' %(s,p,o)
sparql = SPARQLWrapper('http://localhost:3030/address_act/update')
sparql.setQuery(queryStringUpload)
sparql.method = 'POST'
sparql.query()
When I run the two above, the last sentence ng.update(u'INSERT DATA { %s }' % g1.serialize(format='turtle')) and sparql.query() in the program causes the error. I am sure these triples have existed in the graph, but when do update, both give the error like:
QueryBadFormed: QueryBadFormed: a bad request has been sent to the endpoint, probably the sparql query is bad formed.
Response:
b'Error 400: Lexical error at line 11, column 59. Encountered: "\\\'" (39), after : "b"\n\n\nFuseki - version 3.7.0 (Build date: 2018-04-05T11:04:59+0000)\n'
and error like:
QueryBadFormed: QueryBadFormed: a bad request has been sent to the endpoint, probably the sparql query is bad formed.
Response:
b'Error 400: Line 1, column 56: Unresolved prefixed name: http:\n\n\nFuseki - version 3.7.0 (Build date: 2018-04-05T11:04:59+0000)\n'
It seems that the SPARQL update operation does not work. Is there any grammar mistake so that the triples cannot be inserted? Any idea how to solve this? Grateful for any effort.