SPARQL Endpoint interface to Python

SPARQLWrapper is a simple Python wrapper around a SPARQL service to remotelly execute your queries. It helps in creating the query invokation and, possibly, convert the result into a more manageable format.

SPARQL Endpoint interface to Python

• About

• Installation & Distribution

• How to use

• SPARQL Endpoint Implementations

• Development

About

SPARQLWrapper is a simple Python wrapper around a SPARQL service to remotely execute your queries. It helps by creating the query invocation and, optionally, converting the result into a more manageable format.

Installation & Distribution

You can install SPARQLWrapper from PyPI:

$ pip install sparqlwrapper

You can install SPARQLWrapper from GitHub:

$ pip install git+https://github.com/rdflib/sparqlwrapper#egg=sparqlwrapper

You can install SPARQLWrapper from Debian:

$ sudo apt-get install python-sparqlwrapper

Note

Be aware that there could be a gap between the latest version of SPARQLWrapper and the version available as Debian package.

Also, the source code of the package can be downloaded in .zip and .tar.gz formats from GitHub SPARQLWrapper releases. Documentation is included in the distribution.

How to use

You can use SPARQLWrapper either as a Python command line script or as a Python package.

Command Line Script

To use as a command line script, you will need to install SPARQLWrapper and then a command line script called rqw (spaRQl Wrapper) will be available within the Python environment into which it is installed. run $ rql -h to see all the script’s options.

Python package

Here are a series of examples of different queries executed via SPARQLWrapper as a python package.

SELECT examples

Simple use of this module is as follows where a live SPARQL endpoint is given and the JSON return format is used:

from SPARQLWrapper import SPARQLWrapper, JSON

sparql = SPARQLWrapper(
    "http://vocabs.ardc.edu.au/repository/api/sparql/"
    "csiro_international-chronostratigraphic-chart_geologic-time-scale-2020"
)
sparql.setReturnFormat(JSON)

# gets the first 3 geological ages
# from a Geological Timescale database,
# via a SPARQL endpoint
sparql.setQuery("""
    PREFIX gts: <http://resource.geosciml.org/ontology/timescale/gts#>

    SELECT *
    WHERE {
        ?a a gts:Age .
    }
    ORDER BY ?a
    LIMIT 3
    """
)

try:
    ret = sparql.queryAndConvert()

    for r in ret["results"]["bindings"]:
        print(r)
except Exception as e:
    print(e)

This should print out something like this:

{'a': {'type': 'uri', 'value': 'http://resource.geosciml.org/classifier/ics/ischart/Aalenian'}}
{'a': {'type': 'uri', 'value': 'http://resource.geosciml.org/classifier/ics/ischart/Aeronian'}}
{'a': {'type': 'uri', 'value': 'http://resource.geosciml.org/classifier/ics/ischart/Albian'}}

The above result is the response from the given endpoint, retrieved in JSON, and converted to a Python object, ret, which is then iterated over and printed.

ASK example

This query gets a boolean response from DBPedia’s SPARQL endpoint:

from SPARQLWrapper import SPARQLWrapper, XML

sparql = SPARQLWrapper("http://dbpedia.org/sparql")
sparql.setQuery("""
    ASK WHERE {
        <http://dbpedia.org/resource/Asturias> rdfs:label "Asturias"@es
    }
""")
sparql.setReturnFormat(XML)
results = sparql.query().convert()
print(results.toxml())

You should see something like:

<?xml version="1.0" ?>
<sparql
    xmlns="http://www.w3.org/2005/sparql-results#"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.w3.org/2001/sw/DataAccess/rf1/result2.xsd">
<head/>
    <boolean>true</boolean>
</sparql>

CONSTRUCT example

CONSTRUCT queries return RDF, so queryAndConvert() here produces an RDFlib Graph object which is then serialized to the Turtle format for printing:

from SPARQLWrapper import SPARQLWrapper

sparql = SPARQLWrapper("http://dbpedia.org/sparql")

sparql.setQuery("""
    PREFIX dbo: <http://dbpedia.org/ontology/>
    PREFIX sdo: <https://schema.org/>

    CONSTRUCT {
      ?lang a sdo:Language ;
      sdo:alternateName ?iso6391Code .
    }
    WHERE {
      ?lang a dbo:Language ;
      dbo:iso6391Code ?iso6391Code .
      FILTER (STRLEN(?iso6391Code)=2) # to filter out non-valid values
    }
    LIMIT 3
""")

results = sparql.queryAndConvert()
print(results.serialize())

Results from this query should look something like this:

@prefix schema: <https://schema.org/> .

<http://dbpedia.org/resource/Arabic> a schema:Language ;
    schema:alternateName "ar" .

<http://dbpedia.org/resource/Aragonese_language> a schema:Language ;
    schema:alternateName "an" .

<http://dbpedia.org/resource/Uruguayan_Spanish> a schema:Language ;
    schema:alternateName "es" .

DESCRIBE example

Like CONSTRUCT queries, DESCRIBE queries also produce RDF results, so this example produces an RDFlib Graph object which is then serialized into the JSON-LD format and printed:

from SPARQLWrapper import SPARQLWrapper

sparql = SPARQLWrapper("http://dbpedia.org/sparql")
sparql.setQuery("DESCRIBE <http://dbpedia.org/resource/Asturias>")

results = sparql.queryAndConvert()
print(results.serialize(format="json-ld"))

The result for this example is large but starts something like this:

[
    {
        "@id": "http://dbpedia.org/resource/Mazonovo",
        "http://dbpedia.org/ontology/subdivision": [
            {
                "@id": "http://dbpedia.org/resource/Asturias"
            }
    ],
...

SPARQL UPDATE example

UPDATE queries write changes to a SPARQL endpoint, so we can’t easily show a working example here. However, if https://example.org/sparql really was a working SPARQL endpoint that allowed updates, the following code might work:

from SPARQLWrapper import SPARQLWrapper, POST, DIGEST

sparql = SPARQLWrapper("https://example.org/sparql")
sparql.setHTTPAuth(DIGEST)
sparql.setCredentials("some-login", "some-password")
sparql.setMethod(POST)

sparql.setQuery("""
    PREFIX dbp:  <http://dbpedia.org/resource/>
    PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>

    WITH <http://example.graph>
    DELETE {
       dbo:Asturias rdfs:label "Asturies"@ast
    }
    """
)

results = sparql.query()
print results.response.read()

If the above code really worked, it would delete the triple dbo:Asturias rdfs:label "Asturies"@ast from the graph http://example.graph.

SPARQLWrapper2 example

There is also a SPARQLWrapper2 class that works with JSON SELECT results only and wraps the results to make processing of average queries even simpler.

from SPARQLWrapper import SPARQLWrapper2

sparql = SPARQLWrapper2("http://dbpedia.org/sparql")
sparql.setQuery("""
    PREFIX dbp:  <http://dbpedia.org/resource/>
    PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>

    SELECT ?label
    WHERE {
        dbp:Asturias rdfs:label ?label
    }
    LIMIT 3
    """
                )

for result in sparql.query().bindings:
    print(f"{result['label'].lang}, {result['label'].value}")

The above should print out something like:

en, Asturias
ar, أشتورية
ca, Astúries

Return formats

The expected return formats differs per query type (SELECT, ASK, CONSTRUCT, DESCRIBE…).

Note

From the SPARQL specification, The response body of a successful query operation with a 2XX response is either:

• SELECT and ASK: a SPARQL Results Document in XML, JSON, or CSV/TSV format.

• DESCRIBE and CONSTRUCT: an RDF graph serialized, for example, in the RDF/XML syntax, or an equivalent RDF graph serialization.

The package, though it does not contain a full SPARQL parser, makes an attempt to determine the query type when the query is set. This should work in most of the cases, but there is a possibility to set this manually, in case something goes wrong.

Automatic conversion of the results

To make processing somewhat easier, the package can do some conversions automatically from the return result. These are:

• for XML, the xml.dom.minidom is used to convert the result stream into a Python representation of a DOM tree.

• for JSON, the json package to generate a Python dictionary.

• for CSV or TSV, a simple string.

• For RDF/XML and JSON-LD, the RDFLib package is used to convert the result into a Graph instance.

• For RDF Turtle/N3, a simple string.

There are two ways to generate this conversion:

• use ret.convert() in the return result from sparql.query() in the code above

• use sparql.queryAndConvert() to get the converted result right away, if the intermediate stream is not used

For example, in the code below:

try :
    sparql.setReturnFormat(SPARQLWrapper.JSON)
    ret = sparql.query()
    d = ret.convert()
except Exception as e:
    print(e)

the value of d is a Python dictionary of the query result, based on the SPARQL Query Results JSON Format.

Partial interpretation of the results

Further help is to offer an extra, partial interpretation of the results, again to cover most of the practical use cases. Based on the SPARQL Query Results JSON Format, the SPARQLWrapper.SmartWrapper.Bindings class can perform some simple steps in decoding the JSON return results. If SPARQLWrapper.SmartWrapper.SPARQLWrapper2 is used instead of SPARQLWrapper.Wrapper.SPARQLWrapper, this result format is generated. Note that this relies on a JSON format only, ie, it has to be checked whether the SPARQL service can return JSON or not.

Here is a simple code that makes use of this feature:

from SPARQLWrapper import SPARQLWrapper2

sparql = SPARQLWrapper2("http://example.org/sparql")
sparql.setQuery("""
    SELECT ?subj ?prop
    WHERE {
        ?subj ?prop ?obj
    }
    """
)

try:
    ret = sparql.query()
    print(ret.variables)  # this is an array consisting of "subj" and "prop"
    for binding in ret.bindings:
        # each binding is a dictionary. Let us just print the results
        print(f"{binding['subj'].value}, {binding['subj'].type}")
        print(f"{binding['prop'].value}, {binding['prop'].type}")
except Exception as e:
    print(e)

To make this type of code even easier to realize, the [] and in operators are also implemented on the result of SPARQLWrapper.SmartWrapper.Bindings. This can be used to check and find a particular binding (ie, particular row in the return value). This features becomes particularly useful when the OPTIONAL feature of SPARQL is used. For example:

from SPARQLWrapper import SPARQLWrapper2

sparql = SPARQLWrapper2("http://example.org/sparql")
sparql.setQuery("""
    SELECT ?subj ?obj ?opt
    WHERE {
        ?subj <http://a.b.c> ?obj .
        OPTIONAL {
            ?subj <http://d.e.f> ?opt
        }
    }
    """
)

try:
    ret = sparql.query()
    print(ret.variables)  # this is an array consisting of "subj", "obj", "opt"
    if ("subj", "prop", "opt") in ret:
        # there is at least one binding covering the optional "opt", too
        bindings = ret["subj", "obj", "opt"]
        # bindings is an array of dictionaries with the full bindings
        for b in bindings:
            subj = b["subj"].value
            o = b["obj"].value
            opt = b["opt"].value
            # do something nice with subj, o, and opt

    # another way of accessing to values for a single variable:
    # take all the bindings of the "subj"
    subjbind = ret.getValues("subj")  # an array of Value instances
    ...
except Exception as e:
    print(e)

GET or POST

By default, all SPARQL services are invoked using HTTP GET verb. However, POST might be useful if the size of the query extends a reasonable size; this can be set in the query instance.

Note that some combinations may not work yet with all SPARQL processors (e.g., there are implementations where POST + JSON return does not work). Hopefully, this problem will eventually disappear.

SPARQL Endpoint Implementations

Introduction

From SPARQL 1.1 Specification:

The response body of a successful query operation with a 2XX response is either:

• SELECT and ASK: a SPARQL Results Document in XML, JSON, or CSV/TSV format.

• DESCRIBE and CONSTRUCT: an RDF graph serialized, for example, in the RDF/XML syntax, or an equivalent RDF graph serialization.

The fact is that the parameter key for the choice of the output format is not defined. Virtuoso uses format, Fuseki uses output, rasqual seems to use results, etc… Also, in some cases HTTP Content Negotiation can/must be used.

ClioPatria

Website

The SWI-Prolog Semantic Web Server

Documentation

Search ‘sparql’ in http://cliopatria.swi-prolog.org/help/http.

Uses

Parameters and Content Negotiation.

Parameter key

format.

Parameter value

MUST be one of these values: rdf+xml, json, csv, application/sparql-results+xml or application/sparql-results+json.

OpenLink Virtuoso

Website

OpenLink Virtuoso

Parameter key

format or output.

JSON-LD (application/ld+json)

supported (in CONSTRUCT and DESCRIBE).

• Parameter value, like directly: “text/html” (HTML), “text/x-html+tr” (HTML (Faceted Browsing Links)), “application/vnd.ms-excel”, “application/sparql-results+xml” (XML), “application/sparql-results+json” (JSON), “application/javascript” (Javascript), “text/turtle” (Turtle), “application/rdf+xml” (RDF/XML), “text/plain” (N-Triples), “text/csv” (CSV), “text/tab-separated-values” (TSV)

• Parameter value, like indirectly: “HTML” (alias text/html), “JSON” (alias application/sparql-results+json), “XML” (alias application/sparql-results+xml), “TURTLE” (alias text/rdf+n3), JavaScript (alias application/javascript) See http://virtuoso.openlinksw.com/dataspace/doc/dav/wiki/Main/VOSSparqlProtocol#AdditionalHTTPResponseFormats–SELECT

• For a SELECT query type, the default return mimetype (if Accept: */* is sent) is application/sparql-results+xml

• For a ASK query type, the default return mimetype (if Accept: */* is sent) is text/html

• For a CONSTRUCT query type, the default return mimetype (if Accept: */* is sent) is text/turtle

• For a DESCRIBE query type, the default return mimetype (if Accept: */* is sent) is text/turtle

Fuseki

Website

Fuseki

Uses

Parameters and Content Negotiation.

Parameter key

format or output (Fuseki 1, Fuseki 2).

JSON-LD (application/ld+json)

supported (in CONSTRUCT and DESCRIBE).

• Fuseki 1 - Short names for “output=” : “json”, “xml”, “sparql”, “text”, “csv”, “tsv”, “thrift”

• Fuseki 2 - Short names for “output=” : “json”, “xml”, “sparql”, “text”, “csv”, “tsv”, “thrift”

• If a non-expected short name is used, the server returns an “Error 400: Can’t determine output serialization”

• Valid alias for SELECT and ASK: “json”, “xml”, csv”, “tsv”

• Valid alias for DESCRIBE and CONSTRUCT: “json” (alias for json-ld ONLY in Fuseki 2), “xml”

• Valid mimetype for DESCRIBE and CONSTRUCT: “application/ld+json”

• Default return mimetypes: For a SELECT and ASK query types, the default return mimetype (if Accept: / is sent) is application/sparql-results+json

• Default return mimetypes: For a DESCRIBE and CONTRUCT query types, the default return mimetype (if Accept: / is sent) is text/turtle

• In case of a bad formed query, Fuseki 1 returns 200 instead of 400.

Eclipse RDF4J

Website

Eclipse RDF4J (formerly known as OpenRDF Sesame)

Documentation

https://rdf4j.eclipse.org/documentation/rest-api/#the-query-operation, https://rdf4j.eclipse.org/documentation/rest-api/#content-types

Uses

Only content negotiation (no URL parameters).

Parameter

If an unexpected parameter is used, the server ignores it.

JSON-LD (application/ld+json)

supported (in CONSTRUCT and DESCRIBE).

• SELECT

  • application/sparql-results+xml (DEFAULT if Accept: */* is sent))

  • application/sparql-results+json (also application/json)

  • text/csv

  • text/tab-separated-values

  • Other values: application/x-binary-rdf-results-table

• ASK

  • application/sparql-results+xml (DEFAULT if Accept: */* is sent))

  • application/sparql-results+json

  • Other values: text/boolean

  • Not supported: text/csv

  • Not supported: text/tab-separated-values

• CONSTRUCT

  • application/rdf+xml

  • application/n-triples (DEFAULT if Accept: */* is sent)

  • text/turtle

  • text/n3

  • application/ld+json

  • Other acceptable values: application/n-quads, application/rdf+json, application/trig, application/trix, application/x-binary-rdf

  • text/plain (returns application/n-triples)

  • text/rdf+n3 (returns text/n3)

  • text/x-nquads (returns application/n-quads)

• DESCRIBE

  • application/rdf+xml

  • application/n-triples (DEFAULT if Accept: */* is sent)

  • text/turtle

  • text/n3

  • application/ld+json

  • Other acceptable values: application/n-quads, application/rdf+json, application/trig, application/trix, application/x-binary-rdf

  • text/plain (returns application/n-triples)

  • text/rdf+n3 (returns text/n3)

  • text/x-nquads (returns application/n-quads)

RASQAL

Website

RASQAL

Documentation

http://librdf.org/rasqal/roqet.html

Parameter key

results.

JSON-LD (application/ld+json)

NOT supported.

Uses roqet as RDF query utility (see http://librdf.org/rasqal/roqet.html) For variable bindings, the values of FORMAT vary upon what Rasqal supports but include simple for a simple text format (default), xml for the SPARQL Query Results XML format, csv for SPARQL CSV, tsv for SPARQL TSV, rdfxml and turtle for RDF syntax formats, and json for a JSON version of the results.

For RDF graph results, the values of FORMAT are ntriples (N-Triples, default), rdfxml-abbrev (RDF/XML Abbreviated), rdfxml (RDF/XML), turtle (Turtle), json (RDF/JSON resource centric), json-triples (RDF/JSON triples) or rss-1.0 (RSS 1.0, also an RDF/XML syntax).

Marklogic

Website

Marklogic

Uses

Only content negotiation (no URL parameters).

JSON-LD (application/ld+json)

NOT supported.

You can use following methods to query triples:

• SPARQL mode in Query Console. For details, see Querying Triples with SPARQL

• XQuery using the semantics functions, and Search API, or a combination of XQuery and SPARQL. For details, see Querying Triples with XQuery or JavaScript.

• HTTP via a SPARQL endpoint. For details, see Using Semantics with the REST Client API.

Formats are specified as part of the HTTP Accept headers of the REST request. When you query the SPARQL endpoint with REST Client APIs, you can specify the result output format (See https://docs.marklogic.com/guide/semantics/REST#id_54258. The response type format depends on the type of query and the MIME type in the HTTP Accept header.

This table describes the MIME types and Accept Header/Output formats (MIME type) for different types of SPARQL queries. (See https://docs.marklogic.com/guide/semantics/REST#id_54258 and https://docs.marklogic.com/guide/semantics/loading#id_70682)

• SELECT

  • application/sparql-results+xml

  • application/sparql-results+json

  • text/html

  • text/csv

• ASK queries return a boolean (true or false).

• CONSTRUCT or DESCRIBE

  • application/n-triples

  • application/rdf+json

  • application/rdf+xml

  • text/turtle

  • text/n3

  • application/n-quads

  • application/trig

AllegroGraph

Website

AllegroGraph

Documentation

https://franz.com/agraph/support/documentation/current/http-protocol.html

Uses

Only content negotiation (no URL parameters).

Parameter

The server always looks at the Accept header of a request, and tries to generate a response in the format that the client asks for. If this fails, a 406 response is returned. When no Accept, or an Accept of / is specified, the server prefers text/plain, in order to make it easy to explore the interface from a web browser.

JSON-LD (application/ld+json)

NOT supported.

• SELECT

  • application/sparql-results+xml (DEFAULT if Accept: / is sent)

  • application/sparql-results+json (and application/json)

  • text/csv

  • text/tab-separated-values

  • OTHERS: application/sparql-results+ttl, text/integer, application/x-lisp-structured-expression, text/table, application/processed-csv, text/simple-csv, application/x-direct-upis

• ASK

  • application/sparql-results+xml (DEFAULT if Accept: / is sent)

  • application/sparql-results+json (and application/json)

  • Not supported: text/csv

  • Not supported: text/tab-separated-values

• CONSTRUCT

  • application/rdf+xml (DEFAULT if Accept: / is sent)

  • text/rdf+n3

  • OTHERS: text/integer, application/json, text/plain, text/x-nquads, application/trix, text/table, application/x-direct-upis

• DESCRIBE

  • application/rdf+xml (DEFAULT if Accept: / is sent)

  • text/rdf+n3

4store

Website

4store

Documentation

https://4store.danielknoell.de/trac/wiki/SparqlServer/

Uses

Parameters and Content Negotiation.

Parameter key

output.

Parameter value

alias. If an unexpected alias is used, the server is not working properly.

JSON-LD (application/ld+json)

NOT supported.

• SELECT

  • application/sparql-results+xml (alias xml) (DEFAULT if Accept: / is sent))

  • application/sparql-results+json or application/json (alias json)

  • text/csv (alias csv)

  • text/tab-separated-values (alias tsv). Returns “text/plain” in GET.

  • Other values: text/plain, application/n-triples

• ASK

  • application/sparql-results+xml (alias xml) (DEFAULT if Accept: / is sent))

  • application/sparql-results+json or application/json (alias json)

  • text/csv (alias csv)

  • text/tab-separated-values (alias tsv). Returns “text/plain” in GET.

  • Other values: text/plain, application/n-triples

• CONSTRUCT

  • application/rdf+xml (alias xml) (DEFAULT if Accept: / is sent)

  • text/turtle (alias “text”)

• DESCRIBE

  • application/rdf+xml (alias xml) (DEFAULT if Accept: / is sent)

  • text/turtle (alias “text”)

Valid alias for SELECT and ASK

“json”, “xml”, csv”, “tsv” (also “text” and “ascii”)

Valid alias for DESCRIBE and CONSTRUCT

“xml”, “text” (for turtle)

Blazegraph

Website

Blazegraph (Formerly known as Bigdata) & NanoSparqlServer

Documentation

https://wiki.blazegraph.com/wiki/index.php/REST_API#SPARQL_End_Point

Uses

Parameters and Content Negotiation.

Parameter key

format (available since version 1.4.0). Setting this parameter will override any Accept Header that is present

Parameter value

alias. If an unexpected alias is used, the server is not working properly.

JSON-LD (application/ld+json)

NOT supported.

• SELECT

  • application/sparql-results+xml (alias xml) (DEFAULT if Accept: / is sent))

  • application/sparql-results+json or application/json (alias json)

  • text/csv

  • text/tab-separated-values

  • Other values: application/x-binary-rdf-results-table

• ASK

  • application/sparql-results+xml (alias xml) (DEFAULT if Accept: / is sent))

  • application/sparql-results+json or application/json (alias json)

• CONSTRUCT

  • application/rdf+xml (alias xml) (DEFAULT if Accept: / is sent)

  • text/turtle (returns text/n3)

  • text/n3

• DESCRIBE

  • application/rdf+xml (alias xml) (DEFAULT if Accept: / is sent)

  • text/turtle (returns text/n3)

  • text/n3

Valid alias for SELECT and ASK

“xml”, “json”

Valid alias for DESCRIBE and CONSTRUCT

“xml”, “json” (but it returns unexpected “application/sparql-results+json”)

GraphDB

Website

GraphDB, formerly known as OWLIM (OWLIM-Lite, OWLIM-SE)

Documentation

https://graphdb.ontotext.com/documentation/free/

Uses

Only content negotiation (no URL parameters).

Note

If the Accept value is not within the expected ones, the server returns a 406 “No acceptable file format found.”

JSON-LD (application/ld+json)

supported (in CONSTRUCT and DESCRIBE).

• SELECT

  • application/sparql-results+xml, application/xml (.srx file)

  • application/sparql-results+json, application/json (.srj file)

  • text/csv (DEFAULT if Accept: / is sent)

  • text/tab-separated-values

• ASK

  • application/sparql-results+xml, application/xml (.srx file)

  • application/sparql-results+json (DEFAULT if Accept: / is sent), application/json (.srj file)

  • NOT supported: text/csv, text/tab-separated-values

• CONSTRUCT

  • application/rdf+xml, application/xml (.rdf file)

  • text/turtle (.ttl file)

  • application/n-triples (.nt file) (DEFAULT if Accept: / is sent)

  • text/n3, text/rdf+n3 (.n3 file)

  • application/ld+json (.jsonld file)

• DESCRIBE

  • application/rdf+xml, application/xml (.rdf file)

  • text/turtle (.ttl file)

  • application/n-triples (.nt file) (DEFAULT if Accept: / is sent)

  • text/n3, text/rdf+n3 (.n3 file)

  • application/ld+json (.jsonld file)

Stardog

Website

Stardog

Documentation

https://www.stardog.com/docs/#_http_headers_content_type_accept (looks outdated)

Uses

Only content negotiation (no URL parameters).

Parameter key

If an unexpected parameter is used, the server ignores it.

JSON-LD (application/ld+json)

supported (in CONSTRUCT and DESCRIBE).

• SELECT

  • application/sparql-results+xml (DEFAULT if Accept: / is sent)

  • application/sparql-results+json

  • text/csv

  • text/tab-separated-values

  • Other values: application/x-binary-rdf-results-table

• ASK

  • application/sparql-results+xml (DEFAULT if Accept: / is sent)

  • application/sparql-results+json

  • Other values: text/boolean

  • Not supported: text/csv

  • Not supported: text/tab-separated-values

• CONSTRUCT

  • application/rdf+xml

  • text/turtle (DEFAULT if Accept: / is sent)

  • text/n3

  • application/ld+json

  • Other acceptable values: application/n-triples, application/x-turtle, application/trig, application/trix, application/n-quads

• DESCRIBE

  • application/rdf+xml

  • text/turtle (DEFAULT if Accept: / is sent)

  • text/n3

  • application/ld+json

  • Other acceptable values: application/n-triples, application/x-turtle, application/trig, application/trix, application/n-quads

Development

Requirements

The RDFLib package is used for RDF parsing.

This package is imported in a lazy fashion, i.e. only when needed. If the user never intends to use the RDF format, the RDFLib package is not imported and the user does not have to install it.

Source code

The source distribution contains:

• SPARQLWrapper: the Python package. You should copy the directory somewhere into your PYTHONPATH. Alternatively, you can also run the distutils scripts: python setup.py install

• test: some unit and integrations tests. In order to run the tests some packages have to be installed before. So please install the dev packages: pip install '.[dev]'

• scripts: some scripts to run the package against some SPARQL endpoints.

• docs: the documentation.

Community

Community support is available through the RDFlib developer’s discussion group rdflib-dev. The archives. from the old mailing list are still available.

Issues

Please, report any issue to github.

Documentation

The SPARQLWrapper documentation is available online.

Other interesting documents are the latest SPARQL 1.1 Specification (W3C Recommendation 21 March 2013) and the initial SPARQL Specification (W3C Recommendation 15 January 2008).

License

The SPARQLWrapper package is licensed under W3C license.

Acknowledgement

The package was greatly inspired by Lee Feigenbaum’s similar package for Javascript.

Developers involved:

• Ivan Herman <http://www.ivan-herman.net>

• Sergio Fernández <http://www.wikier.org>

• Carlos Tejo Alonso <http://www.dayures.net>

• Alexey Zakhlestin <https://indeyets.ru/>

Organizations involved:

• World Wide Web Consortium

• Salzburg Research

• Foundation CTIC

SPARQLWrapper package

SPARQLWrapper.Wrapper module

SPARQLWrapper.Wrapper.XML = 'xml'

to be used to set the return format to XML (SPARQL Query Results XML format or RDF/XML, depending on the query type). This is the default.

SPARQLWrapper.Wrapper.JSON = 'json'

to be used to set the return format to JSON.

SPARQLWrapper.Wrapper.JSONLD = 'json-ld'

to be used to set the return format to JSON-LD.

SPARQLWrapper.Wrapper.TURTLE = 'turtle'

to be used to set the return format to Turtle.

SPARQLWrapper.Wrapper.N3 = 'n3'

to be used to set the return format to N3 (for most of the SPARQL services this is equivalent to Turtle).

SPARQLWrapper.Wrapper.RDF = 'rdf'

to be used to set the return RDF Graph.

SPARQLWrapper.Wrapper.RDFXML = 'rdf+xml'

to be used to set the return format to RDF/XML explicitly.

SPARQLWrapper.Wrapper.CSV = 'csv'

to be used to set the return format to CSV

SPARQLWrapper.Wrapper.TSV = 'tsv'

to be used to set the return format to TSV

SPARQLWrapper.Wrapper.GET = 'GET'

to be used to set HTTP method GET. This is the default.

SPARQLWrapper.Wrapper.POST = 'POST'

to be used to set HTTP method POST.

SPARQLWrapper.Wrapper.BASIC = 'BASIC'

to be used to set BASIC HTTP Authentication method.

SPARQLWrapper.Wrapper.DIGEST = 'DIGEST'

to be used to set DIGEST HTTP Authentication method.

SPARQLWrapper.Wrapper.SELECT = 'SELECT'

to be used to set the query type to SELECT. This is, usually, determined automatically.

SPARQLWrapper.Wrapper.CONSTRUCT = 'CONSTRUCT'

to be used to set the query type to CONSTRUCT. This is, usually, determined automatically.

SPARQLWrapper.Wrapper.ASK = 'ASK'

to be used to set the query type to ASK. This is, usually, determined automatically.

SPARQLWrapper.Wrapper.DESCRIBE = 'DESCRIBE'

to be used to set the query type to DESCRIBE. This is, usually, determined automatically.

SPARQLWrapper.Wrapper.INSERT = 'INSERT'

to be used to set the query type to INSERT. This is, usually, determined automatically.

SPARQLWrapper.Wrapper.DELETE = 'DELETE'

to be used to set the query type to DELETE. This is, usually, determined automatically.

SPARQLWrapper.Wrapper.CREATE = 'CREATE'

to be used to set the query type to CREATE. This is, usually, determined automatically.

SPARQLWrapper.Wrapper.CLEAR = 'CLEAR'

to be used to set the query type to CLEAR. This is, usually, determined automatically.

SPARQLWrapper.Wrapper.DROP = 'DROP'

to be used to set the query type to DROP. This is, usually, determined automatically.

SPARQLWrapper.Wrapper.LOAD = 'LOAD'

to be used to set the query type to LOAD. This is, usually, determined automatically.

SPARQLWrapper.Wrapper.COPY = 'COPY'

to be used to set the query type to COPY. This is, usually, determined automatically.

SPARQLWrapper.Wrapper.MOVE = 'MOVE'

to be used to set the query type to MOVE. This is, usually, determined automatically.

SPARQLWrapper.Wrapper.ADD = 'ADD'

to be used to set the query type to ADD. This is, usually, determined automatically.

SPARQLWrapper.Wrapper.URLENCODED = 'urlencoded'

to be used to set URL encode as the encoding method for the request. This is, usually, determined automatically.

SPARQLWrapper.Wrapper.POSTDIRECTLY = 'postdirectly'

to be used to set POST directly as the encoding method for the request. This is, usually, determined automatically.

class SPARQLWrapper.Wrapper.SPARQLWrapper(endpoint: str, updateEndpoint: Optional[str] = None, returnFormat: str = 'xml', defaultGraph: Optional[str] = None, agent: str = 'sparqlwrapper 2.0.1a0 (rdflib.github.io/sparqlwrapper)')

Wrapper around an online access to a SPARQL Web entry point.

The same class instance can be reused for subsequent queries. The values of the base Graph URI, return formats, etc, are retained from one query to the next (in other words, only the query string changes). The instance can also be reset to its initial values using the resetQuery() method.

Variables

• endpoint (string) – SPARQL endpoint’s URI.

• updateEndpoint – SPARQL endpoint’s URI for SPARQL Update operations (if it’s a different one).

The default value is None. :vartype updateEndpoint: string :ivar agent: The User-Agent for the HTTP request header. The default value is an autogenerated string using t he SPARQLWrapper version code. :vartype agent: string :ivar _defaultGraph: URI for the default graph. The value can be set either via an explicit call addParameter("default-graph-uri", uri) or as part of the query string. The default value is None. :vartype _defaultGraph: string :ivar user: The username of the credentials for querying the current endpoint. The value can be set an explicit call setCredentials(). The default value is None. :vartype user: string :ivar passwd: The password of the credentials for querying the current endpoint. The value can be set an explicit call setCredentials(). The default value is None. :vartype passwd: string :ivar http_auth: HTTP Authentication type. The default value is BASIC. Possible values are BASIC or DIGEST. It is used only in case the credentials are set. :vartype http_auth: string :ivar onlyConneg: Option for allowing (or not) only HTTP Content Negotiation (so dismiss the use of HTTP parameters). The default value is False. :vartype onlyConneg: boolean :ivar customHttpHeaders: Custom HTTP Headers to be included in the request. It is a dictionary where keys are the header field and values are the header values. Important: These headers override previous values (including Content-Type, User-Agent, Accept and Authorization if they are present). :vartype customHttpHeaders: dict :ivar timeout: The timeout (in seconds) to use for querying the endpoint. :vartype timeout: int :ivar queryString: The SPARQL query text. :vartype queryString: string :ivar queryType: The type of SPARQL query (aka SPARQL query form), like CONSTRUCT, SELECT, ASK, DESCRIBE, INSERT, DELETE, CREATE, CLEAR, DROP, LOAD, COPY, MOVE or ADD (constants in this module). :vartype queryType: string :ivar returnFormat: The return format. No local check is done, so the parameter is simply sent to the endpoint. Eg, if the value is set to JSON and a construct query is issued, it is up to the endpoint to react or not, this wrapper does not check. The possible values are JSON, XML, TURTLE, N3, RDF, RDFXML, CSV, TSV, JSONLD (constants in this module). The default value is XML. :vartype returnFormat: string :ivar requestMethod: The request method for query or update operations. The possibles values are URL-encoded (URLENCODED) or POST directly (POSTDIRECTLY). :vartype requestMethod: string :ivar method: The invocation method (HTTP verb). The default value is GET, but it can be set to POST. :vartype method: string :ivar parameters: The parameters of the request (key/value pairs in a dictionary). :vartype parameters: dict :ivar _defaultReturnFormat: The default return format. It is used in case the same class instance is reused for subsequent queries. :vartype _defaultReturnFormat: string

Variables

• prefix_pattern (re.RegexObject, a compiled regular expression. See the re module of Python) – regular expression used to remove base/prefixes in the process of determining the query type.

• pattern – regular expression used to determine whether a query (without base/prefixes) is of type

CONSTRUCT, SELECT, ASK, DESCRIBE, INSERT, DELETE, CREATE, CLEAR, DROP, LOAD, COPY, MOVE or ADD. :vartype pattern: re.RegexObject, a compiled regular expression. See the re module of Python :cvar comments_pattern: regular expression used to remove comments from a query. :vartype comments_pattern: re.RegexObject, a compiled regular expression. See the re module of Python

__init__(endpoint: str, updateEndpoint: Optional[str] = None, returnFormat: str = 'xml', defaultGraph: Optional[str] = None, agent: str = 'sparqlwrapper 2.0.1a0 (rdflib.github.io/sparqlwrapper)') → None

Class encapsulating a full SPARQL call.

Parameters

• endpoint (string) – SPARQL endpoint’s URI.

• updateEndpoint – SPARQL endpoint’s URI for update operations (if it’s a different one). The default

value is None. :type updateEndpoint: string :param returnFormat: The return format. No local check is done, so the parameter is simply sent to the endpoint. Eg, if the value is set to JSON and a construct query is issued, it is up to the endpoint to react or not, this wrapper does not check. The possible values are JSON, XML, TURTLE, N3, RDF, RDFXML, CSV, TSV, JSONLD (constants in this module). The default value is XML. :param defaultGraph: URI for the default graph. The value can be set either via an explicit call addParameter("default-graph-uri", uri) or as part of the query string. The default value is None. :type defaultGraph: string :param agent: The User-Agent for the HTTP request header. The default value is an autogenerated string using the SPARQLWrapper version number. :type agent: string

resetQuery() → None

Reset the query, ie, return format, method, query, default or named graph settings, etc, are reset to their default values. This includes the default values for parameters, method, timeout or requestMethod.

setReturnFormat(format: str) → None

Set the return format. If the one set is not an allowed value, the setting is ignored.

Parameters

format – Possible values are JSON, XML, TURTLE, N3, RDF,

RDFXML, CSV, TSV, JSONLD (constants in this module). All other cases are ignored. :type format: string :raises ValueError: If JSONLD is tried to set and the current instance does not support JSON-LD.

supportsReturnFormat(format: str) → bool

Check if a return format is supported.

Parameters

format – Possible values are JSON, XML, TURTLE, N3, RDF,

RDFXML, CSV, TSV, JSONLD (constants in this module). All other cases are ignored. :type format: string :return: Returns True if the return format is supported, otherwise False. :rtype: bool

setTimeout(timeout: int) → None

Set the timeout (in seconds) to use for querying the endpoint.

Parameters

timeout (int) – Timeout in seconds.

setOnlyConneg(onlyConneg: bool) → None

Set this option for allowing (or not) only HTTP Content Negotiation (so dismiss the use of HTTP parameters).

New in version 1.8.1.

Parameters

onlyConneg – True if only HTTP Content Negotiation is allowed; False if HTTP parameters

are used. :type onlyConneg: bool

setRequestMethod(method: str) → None

Set the internal method to use to perform the request for query or update operations, either URL-encoded (URLENCODED) or POST directly (POSTDIRECTLY). Further details at query operation in SPARQL and update operation in SPARQL Update.

Parameters

method – Possible values are URLENCODED (URL-encoded) or POSTDIRECTLY (POST directly).

All other cases are ignored. :type method: string

addDefaultGraph(uri: str) → None

Add a default graph URI.

Deprecated since version 1.6.0: Use addParameter("default-graph-uri", uri) instead of this

method.

Parameters

uri (string) – URI of the default graph.

addNamedGraph(uri: str) → None

Add a named graph URI.

Deprecated since version 1.6.0: Use addParameter("named-graph-uri", uri) instead of this

method.

Parameters

uri (string) – URI of the named graph.

addExtraURITag(key: str, value: str) → None

Some SPARQL endpoints require extra key value pairs. E.g., in virtuoso, one would add should-sponge=soft to the query forcing virtuoso to retrieve graphs that are not stored in its local database. Alias of addParameter() method.

Deprecated since version 1.6.0: Use addParameter(key, value) instead of this method

Parameters

• key (string) – key of the query part.

• value (string) – value of the query part.

addCustomParameter(name: str, value: str) → bool

Method is kept for backwards compatibility. Historically, it “replaces” parameters instead of adding.

Deprecated since version 1.6.0: Use addParameter(key, value) instead of this method

Parameters

• name (string) – name.

• value (string) – value.

Returns

Returns True if the adding has been accomplished, otherwise False.

Return type

bool

addParameter(name: str, value: str) → bool

Some SPARQL endpoints allow extra key value pairs. E.g., in virtuoso, one would add should-sponge=soft to the query forcing virtuoso to retrieve graphs that are not stored in its local database. If the parameter query is tried to be set, this intent is dismissed. Returns a boolean indicating if the set has been accomplished.

Parameters

• name (string) – name.

• value (string) – value.

Returns

Returns True if the adding has been accomplished, otherwise False.

Return type

bool

addCustomHttpHeader(httpHeaderName: str, httpHeaderValue: str) → None

Add a custom HTTP header (this method can override all HTTP headers).

Important: Take into account that each previous value for the header field names Content-Type, User-Agent, Accept and Authorization would be overriden if the header field name is present as value of the parameter httpHeaderName.

New in version 1.8.2.

Parameters

• httpHeaderName (string) – The header field name.

• httpHeaderValue (string) – The header field value.

clearCustomHttpHeader(httpHeaderName: str) → bool

Clear the values of a custom HTTP Header previously set. Returns a boolean indicating if the clearing has been accomplished.

New in version 1.8.2.

Parameters

httpHeaderName (string) – HTTP header name.

Returns

Returns True if the clearing has been accomplished, otherwise False.

Return type

bool

clearParameter(name: str) → bool

Clear the values of a concrete parameter. Returns a boolean indicating if the clearing has been accomplished.

Parameters

name (string) – name

Returns

Returns True if the clearing has been accomplished, otherwise False.

Return type

bool

setCredentials(user: Optional[str], passwd: Optional[str], realm: str = 'SPARQL') → None

Set the credentials for querying the current endpoint.

Parameters

• user (string) – username.

• passwd (string) – password.

• realm (string) – realm. Only used for DIGEST authentication. The default value is SPARQL

Changed in version 1.8.3: Added realm parameter.

setHTTPAuth(auth: str) → None

Set the HTTP Authentication type. Possible values are BASIC or DIGEST.

Parameters

auth (string) – auth type.

Raises

• TypeError – If the auth parameter is not an string.

• ValueError – If the auth parameter has not one of the valid values: BASIC or

DIGEST.

setQuery(query: Union[str, bytes]) → None

Set the SPARQL query text.

Note

No check is done on the validity of the query (syntax or otherwise) by this module, except for testing the query type (SELECT, ASK, etc). Syntax and validity checking is done by the SPARQL service itself.

Parameters

query (string) – query text.

Raises

TypeError – If the query parameter is not an unicode-string or utf-8 encoded byte-string.

_parseQueryType(query: str) → Optional[str]

Internal method for parsing the SPARQL query and return its type (ie, SELECT, ASK, etc).

Note

The method returns SELECT if nothing is specified. This is just to get all other methods running; in fact, this means that the query is erroneous, because the query must be, according to the SPARQL specification. The SPARQL endpoint should raise an exception (via urllib) for such syntax error.

Parameters

query (string) – query text.

Returns

the type of SPARQL query (aka SPARQL query form).

Return type

string

setMethod(method: str) → None

Set the invocation method. By default, this is GET, but can be set to POST.

Parameters

method (string) – should be either GET or POST. Other cases are ignored.

setUseKeepAlive() → None

Make urllib2 use keep-alive.

Raises

ImportError – when could not be imported keepalive.HTTPHandler.

isSparqlUpdateRequest() → bool

Returns True if SPARQLWrapper is configured for executing SPARQL Update request.

Returns

Returns True if SPARQLWrapper is configured for executing SPARQL Update request.

Return type

bool

isSparqlQueryRequest() → bool

Returns True if SPARQLWrapper is configured for executing SPARQL Query request.

Returns

Returns True if SPARQLWrapper is configured for executing SPARQL Query request.

Return type

bool

_cleanComments(query: str) → str

Internal method for returning the query after all occurrence of singleline comments are removed (issues #32 and #77).

Parameters

query (string) – The query.

Returns

the query after all occurrence of singleline comments are removed.

Return type

string

_getRequestEncodedParameters(query: Optional[Tuple[str, str]] = None) → str

Internal method for getting the request encoded parameters.

Parameters

query – a tuple of two items. The first item can be the string query (for SELECT, DESCRIBE, ASK, CONSTRUCT query) or the string

update (for SPARQL Update queries, like DELETE or INSERT). The second item of the tuple is the query string itself. :type query: tuple :return: the request encoded parameters. :rtype: string

_getAcceptHeader() → str

Internal method for getting the HTTP Accept Header.

See also

`Hypertext Transfer Protocol – HTTP/1.1 - Header Field Definitions

<https://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.1>`_

_createRequest() → urllib.request.Request

Internal method to create request according a HTTP method. Returns a urllib2.Request object of the urllib2 Python library

Raises

NotImplementedError – If the HTTP authentification method is not one of the valid values: BASIC

or DIGEST. :return: request a urllib2.Request object of the urllib2 Python library

_query() → Tuple[http.client.HTTPResponse, str]

Internal method to execute the query. Returns the output of the urllib2.urlopen() method of the urllib2 Python library

Returns

tuples with the raw request plus the expected format.

Raises

• QueryBadFormed – If the HTTP return code is 400.

• Unauthorized – If the HTTP return code is 401.

• EndPointNotFound – If the HTTP return code is 404.

• URITooLong – If the HTTP return code is 414.

• EndPointInternalError – If the HTTP return code is 500.

• urllib2.HTTPError – If the HTTP return code is different to 400, 401, 404, 414, 500.

query() → SPARQLWrapper.Wrapper.QueryResult

Execute the query. Exceptions can be raised if either the URI is wrong or the HTTP sends back an error (this is also the case when the query is syntactically incorrect, leading to an HTTP error sent back by the SPARQL endpoint). The usual urllib2 exceptions are raised, which therefore cover possible SPARQL errors, too.

Note that some combinations of return formats and query types may not make sense. For example, a SELECT query with Turtle response is meaningless (the output of a SELECT is not a Graph), or a CONSTRUCT query with JSON output may be a problem because, at the moment, there is no accepted JSON serialization of RDF (let alone one implemented by SPARQL endpoints). In such cases the returned media type of the result is unpredictable and may differ from one SPARQL endpoint implementation to the other. (Endpoints usually fall back to one of the “meaningful” formats, but it is up to the specific implementation to choose which one that is.)

Returns

query result

Return type

QueryResult instance

queryAndConvert() → Optional[Union[bytes, str, Dict[Any, Any], Graph, xml.dom.minidom.Document]]

Macro like method: issue a query and return the converted results.

Returns

the converted query result. See the conversion methods for more details.

class SPARQLWrapper.Wrapper.QueryResult(result: Union[http.client.HTTPResponse, Tuple[http.client.HTTPResponse, str]])

Wrapper around an a query result. Users should not create instances of this class, it is generated by a SPARQLWrapper.query() call. The results can be converted to various formats, or used directly.

If used directly: the class gives access to the direct HTTP request results response obtained from the call to urllib.urlopen(). It is a file-like object with two additional methods:

• geturl() to return the URL of the resource retrieved

• info() that returns the meta-information of the HTTP result as a dictionary-like object.

For convenience, these methods are also available on the QueryResult instance.

The __iter__() and next() methods are also implemented (by mapping them to response). This means that the common idiom for l in obj : do_something_with_line(l) would work, too.

Variables

• response – the direct HTTP response; a file-like object, as return by the urllib2.urlopen() library call.

• requestedFormat – The requested format. The possible values are: JSON, XML, RDFXML,

TURTLE, N3, RDF, CSV, TSV, JSONLD. :type requestedFormat: string

__init__(result: Union[http.client.HTTPResponse, Tuple[http.client.HTTPResponse, str]]) → None

Parameters

result – HTTP response stemming from a SPARQLWrapper.query() call, or a tuple with the expected

format: (response, format).

geturl() → str

Return the URL of the original call.

Returns

URL of the original call.

Return type

string

info() → SPARQLWrapper.KeyCaseInsensitiveDict.KeyCaseInsensitiveDict[str]

Return the meta-information of the HTTP result.

Returns

meta-information of the HTTP result.

Return type

dict

_convertJSON() → Dict[Any, Any]

Convert a JSON result into a Python dict. This method can be overwritten in a subclass for a different conversion method.

Returns

converted result.

Return type

dict

_convertXML() → xml.dom.minidom.Document

Convert an XML result into a Python dom tree. This method can be overwritten in a subclass for a different conversion method.

Returns

converted result.

Return type

xml.dom.minidom.Document

_convertRDF() → Graph

Convert a RDF/XML result into an RDFLib Graph. This method can be overwritten in a subclass for a different conversion method.

Returns

converted result.

Return type

rdflib.graph.Graph

_convertN3() → bytes

Convert a RDF Turtle/N3 result into a string. This method can be overwritten in a subclass for a different conversion method.

Returns

converted result.

Return type

string

_convertCSV() → bytes

Convert a CSV result into a string. This method can be overwritten in a subclass for a different conversion method.

Returns

converted result.

Return type

string

_convertTSV() → bytes

Convert a TSV result into a string. This method can be overwritten in a subclass for a different conversion method.

Returns

converted result.

Return type

string

_convertJSONLD() → Graph

Convert a RDF JSON-LD result into an RDFLib Graph. This method can be overwritten in a subclass for a different conversion method.

Returns

converted result

Return type

rdflib.graph.Graph

convert() → Optional[Union[bytes, str, Dict[Any, Any], Graph, xml.dom.minidom.Document]]

Encode the return value depending on the return format:

• in the case of XML, a DOM top element is returned

• in the case of JSON, a json conversion will return a dictionary

• in the case of RDF/XML, the value is converted via RDFLib into a RDFLib Graph instance

• in the case of JSON-LD, the value is converted via RDFLib into a RDFLib Graph instance

• in the case of RDF Turtle/N3, a string is returned

• in the case of CSV/TSV, a string is returned

• In all other cases the input simply returned.

Returns

the converted query result. See the conversion methods for more details.

_get_responseFormat() → Optional[str]

Get the response (return) format. The possible values are: JSON, XML, RDFXML, TURTLE, N3, CSV, TSV, JSONLD. In case there is no Content-Type, None is return. In all other cases, the raw Content-Type is return.

New in version 1.8.3.

Returns

the response format. The possible values are: JSON, XML, RDFXML,

TURTLE, N3, CSV, TSV, JSONLD. :rtype: string

print_results(minWidth: Optional[int] = None) → None

This method prints a representation of a QueryResult object that MUST has as response format JSON.

Parameters

minWidth (int) – The minimum width, counting as characters. The default value is None.

SPARQLWrapper.SmartWrapper module

class SPARQLWrapper.SmartWrapper.Bindings(retval: SPARQLWrapper.Wrapper.QueryResult)

Bases: object

Class encapsulating one query result, based on the JSON return format. It decodes the return values to make it a bit more usable for a standard usage. The class consumes the return value and instantiates a number of attributes that can be consulted directly. See the list of variables.

The Serializing SPARQL Query Results in JSON explains the details of the JSON return structures. Very succinctly: the return data has “bindings”, which means a list of dictionaries. Each dictionary is a possible binding of the SELECT variables to Value instances. This structure is made a bit more usable by this class.

Variables

• fullResult (dict) – The original dictionary of the results, stored for an easier reference.

• head (dict) – Header part of the return, see the JSON return format document for details.

• variables (list) – List of unbounds (variables) of the original query. It is a list of strings. None in the case of an ASK query.

• bindings (list) – The final bindings: list of dictionaries, mapping variables to Value instances. If unbound, then no value is set in the dictionary; that can be easily checked with var in res.bindings[..], for example.

• askResult (bool) – by default, set to False; in case of an ASK query, the result of the query.

__init__(retval: SPARQLWrapper.Wrapper.QueryResult)

Parameters

retval (QueryResult) – the query result.

convert() → SPARQLWrapper.SmartWrapper.Bindings

This is just a convenience method, returns self.

Although SPARQLWrapper2.Bindings is not a subclass of SPARQLWrapper.QueryResult, it is returned as a result by SPARQLWrapper2.query(), just like QueryResult is returned by SPARQLWrapper.query(). Consequently, having an empty convert() method to imitate QueryResult's convert() method may avoid unnecessary problems.

getValues(key: str) → Optional[List[SPARQLWrapper.SmartWrapper.Value]]

A shorthand for the retrieval of all bindings for a single key. It is equivalent to [b[key] for b in self[key]]

Parameters

key (string) – possible variable name.

Returns

list of Value instances.

Return type

list

class SPARQLWrapper.SmartWrapper.SPARQLWrapper2(baseURI: str, defaultGraph: Optional[str] = None)

Bases: SPARQLWrapper.Wrapper.SPARQLWrapper

Subclass of SPARQLWrapper that works with a JSON SELECT return result only. The query result is automatically set to a Bindings instance. Makes the average query processing a bit simpler…

__init__(baseURI: str, defaultGraph: Optional[str] = None)

Class encapsulating a full SPARQL call. In contrast to the SPARQLWrapper superclass, the return format cannot be set (it is defaulted to JSON).

Parameters

• baseURI (string) – string of the SPARQL endpoint’s URI.

• defaultGraph (string) – URI for the default graph. Default is None, can be set via an explicit call, too.

query() → Union[SPARQLWrapper.SmartWrapper.Bindings, SPARQLWrapper.Wrapper.QueryResult]

Execute the query and do an automatic conversion.

Exceptions can be raised if either the URI is wrong or the HTTP sends back an error. The usual urllib2 exceptions are raised, which cover possible SPARQL errors, too.

If the query type is not SELECT, the method falls back to the corresponding method in the superclass.

Returns

query result

Return type

Bindings instance

queryAndConvert() → Optional[Union[SPARQLWrapper.SmartWrapper.Bindings, SPARQLWrapper.Wrapper.QueryResult, bytes, str, Dict[Any, Any], Graph, xml.dom.minidom.Document]]

This is here to override the inherited method; it is equivalent to query.

If the query type is not SELECT, the method falls back to the corresponding method in the superclass.

Returns

the converted query result.

setReturnFormat(format: Optional[str]) → None

Set the return format (overriding the inherited method).

Warning

This method does nothing; this class instance should work with JSON only. The method is defined just to avoid possible errors by erroneously setting the return format. When using this class, the user can safely ignore this call.

Parameters

format (string) – return format

class SPARQLWrapper.SmartWrapper.Value(variable: str, binding: Dict[str, str])

Bases: object

Class encapsulating a single binding for a variable.

Variables

• variable (string) – The original variable, stored for an easier reference.

• value (string) – Value of the binding.

• type (string) – Type of the binding. One of Value.URI, Value.Literal, Value.TypedLiteral, or Value.BNODE.

• lang (string) – Language tag of the binding, or None if not set.

• datatype (string) – Datatype of the binding, or None if not set. It is an URI.

BNODE = 'bnode'

the string denoting a blank node variable.

Literal = 'literal'

the string denoting a Literal variable.

TypedLiteral = 'typed-literal'

the string denoting a typed literal variable.

URI = 'uri'

the string denoting a URI variable.

__init__(variable: str, binding: Dict[str, str]) → None

Parameters

• variable (string) – the variable for that binding. Stored for an easier reference.

• binding (dict) – the binding dictionary part of the return result for a specific binding.

SPARQLWrapper.SPARQLExceptions module

SPARQL Wrapper exceptions

exception SPARQLWrapper.SPARQLExceptions.SPARQLWrapperException(response: Optional[bytes] = None)

Bases: Exception

Base class for SPARQL Wrapper exceptions

__init__(response: Optional[bytes] = None)

Parameters

response (string) – The server response

exception SPARQLWrapper.SPARQLExceptions.EndPointInternalError(response: Optional[bytes] = None)

Bases: SPARQLWrapper.SPARQLExceptions.SPARQLWrapperException

Exception type for Internal Server Error responses. Usually HTTP response status code 500.

exception SPARQLWrapper.SPARQLExceptions.QueryBadFormed(response: Optional[bytes] = None)

Bases: SPARQLWrapper.SPARQLExceptions.SPARQLWrapperException

Query Bad Formed exception. Usually HTTP response status code 400.

exception SPARQLWrapper.SPARQLExceptions.EndPointNotFound(response: Optional[bytes] = None)

Bases: SPARQLWrapper.SPARQLExceptions.SPARQLWrapperException

End Point Not Found exception. Usually HTTP response status code 404.

exception SPARQLWrapper.SPARQLExceptions.Unauthorized(response: Optional[bytes] = None)

Bases: SPARQLWrapper.SPARQLExceptions.SPARQLWrapperException

Access is denied due to invalid credentials (unauthorized). Usually HTTP response status code 401.

New in version 1.8.2.

exception SPARQLWrapper.SPARQLExceptions.URITooLong(response: Optional[bytes] = None)

Bases: SPARQLWrapper.SPARQLExceptions.SPARQLWrapperException

The URI requested by the client is longer than the server is willing to interpret. Usually HTTP response status code 414.

New in version 1.8.3.

SPARQLWrapper.KeyCaseInsensitiveDict module

A simple implementation of a key case-insensitive dictionary. ..

Developers involved: * Ivan Herman <http://www.ivan-herman.net> * Sergio Fernández <http://www.wikier.org> * Carlos Tejo Alonso <http://www.dayures.net> * Alexey Zakhlestin <https://indeyets.ru/> Organizations involved: * World Wide Web Consortium * Foundation CTIC :license: W3C® Software notice and license

class SPARQLWrapper.KeyCaseInsensitiveDict.KeyCaseInsensitiveDict(d: Mapping[str, SPARQLWrapper.KeyCaseInsensitiveDict._V] = {})

Bases: Dict[str, SPARQLWrapper.KeyCaseInsensitiveDict._V]

A simple implementation of a key case-insensitive dictionary

__init__(d: Mapping[str, SPARQLWrapper.KeyCaseInsensitiveDict._V] = {}) → None

Parameters

d (dict) – The source dictionary.

SPARQLWrapper’s changelog

YYYY-MM-DD X.Y.Z

• TODO

2022-03-14 2.0.0

• Ported codebase to Python 3. Dropped support for Python 2

• Removed nosetest in favour of unittest

• Added a CLI: rqw

• Updated for RDFLib >= 6.1.1

• Added type hints

Special thanks to @eggplants for making this release happen.

2019-12-22 1.8.5

• Improve/tests for development (#131)

• Changed. Be more strict on Accept Turtle header (#137)

• Migrated documentation from epydoc to sphinx and readthedocs

2019-04-18 1.8.4

• Added example

• hotfix: Added custom_fixers folder in MANIFEST, in order to be used in python3 (#129)

2019-04-17 1.8.3

• Include ChangeLog.txt in the distribution

• Removed import of SPARQLWrapper in setup.py (fixed #113 and closed #115)

• Added support for querying RDF/XML in a CONSTRUCT query type

• Updated the procedure for determining the query type (#120)

• Do not send format parameter for the results ([format, output, results]) when the query is a SPARQL Update query

• Added test for new agrovoc SPARQL endpoint (using Fuseki2)

• Added test for 4store SPARQL endpoint (used by agroportal)

• Added/Updated tests

• Added examples

• Updated doc

• Fixed code generated for python3 using 2to3, adding a custom fixer (#109)

2018-05-26 1.8.2

• Fixed bug (#100)

• Updated doc

• Added Unauthorized exception in SPARQLWrapperExceptions

• Added support for custom HTTP headers (#52)

• Changed timeout setting (#106)

2018-02-25 1.8.1

• Update classifiers (Python 3.6)

• Added some documentation about the parameter to indicate the output format

• Fixed typo in width calculation

• Added support for CSV, TSV (PR #98)

• Added support for Only HTTP Content Negotiation (#82)

2016-12-07 1.8.0

• Updated return formats for not content negotiation situations

• Included license in the MANIFEST (issue #76)

• Added explicit support for RDF/XML as allowed format (issue #75)

• Added proper shebang (issue #78)

• Moved keepalive as optional dependency (issue #79)

• Fixed hash check on prefixes (issue #77)

• Fixed epydoc warnings (issue #41)

2015-12-18 1.7.6

• Removed wrong response encoding (issue #70)

• Authorization header bug when using Python 3 (issue #71)

2015-11-19 1.7.5

• Removed pip dependency on setup (issue #69)

2015-11-05 1.7.4

• Fixed packaging (issue #66)

2015-11-05 1.7.3

• Finally fixed the keepalive issue in all Pyhon versions (issue #65)

• Removed old JSON layer in favor of the native json module

2015-11-03 1.7.2

• Moved to the new keepalive package (issues #53 and #61)

2015-10-29 1.7.1

• Fixed build in Python 3.x (issue #57)

2015-10-29 1.7.0

• Added support to HTTP Digest Auth Support (issue #45)

• Improved print_results showing language tag (xml:lang) and datatype

• Updated to RDFLib 4.x

2014-08-26 1.6.4

• Fixed unicode problems on setup (issue #42)

2014-08-26 1.6.3

• Fixed unicode problems with urllib in Python 3 (issue #35)

• Restored SPARQLWrapper2 class (issue #36)

• Enhanced warning for missing rdflib-jsonld (issue #38)

• Fixed build system (issue #39)

2014-07-24 1.6.2

• Fixed query type detection with comments (issue #32)

2014-07-21 1.6.1

• Added missing query types (issue #17)

• Added a new method to the API to select the request method to be fully SPARQL 1.1 Protocol compliant (issue #28)

• Improved the test suite coverage, including support to run the tests under Python 3.x (issues #20, #24 and #31)

2014-05-09 1.6.0

• Returning raw response in case of unknown content type returned

• Fixed some issues with the last version of the SPARQL 1.1 Update Protocol

• setQuery() doesn’t imply resetQuery() anymore

• Deprecated addCustomParameter(), addParameter() and clearParameter() come to provide all required functionality

• SPARQLWrapper, QueryResult, Value, Bindings (and classes inherited from them) are new-style classes now

• POST queries are accompanied by full set of parameters now

• Added rudimentary support for JSON-LD

• Added proper unit tests without dependencies of external endpoints

• Fixed Python 3 compatibility issues in SmartWrapper module

2012-08-28 1.5.2

• Implemented update operation according the latest SPARQL 1.1 Protocol drafts (i.e., switching to ‘update’ parameter)

2012-07-10 1.5.1

• Added the possibility to use two different endpoints for reading and writing operations

• New print_results() function for users testing

2012-02-01 1.5.0

• Update handling 500’s coming from SPARQL endpoint (feature request #3198363)

• Added Python 3.x support (feature request 3022722)

• Warning when returned format would be different than the requested one

2011-01-28 1.4.2

• Updated for working with RDFLib3 too (feature request #3117442)

• fixed bug with prefixes’ regex (#2320024)

2010-01-11 1.4.1

• Supporting keep-alive in SPARQLWrapper if urlgrabber is available (ticket #2929881)

• fixed bugs (#2949834)

2009-12-14 1.4.0

• Added some support for SPARUL

• Improved HTTP related code

• Many other minor bugs fixed

2009-09-23 1.3.2

• Remove pyxml dependency. Instead, use xml.dom.minidom

• Updated setup installation (added rdflib dependency)

• Updated example.py (added XML, N3 and RDF examples)

2009-09-11 1.3.1

• Remove simplejson dependency for python => 2.6 version

• Added feature to choose the json module to use

2009-05-06 1.3.0

• Added a new method to add custom parameters (deprecated old way to do it)

2009-04-27 1.2.1

• Updated setup installation

• Patched to work with JSON in Python>=2.6

2008-07-10 1.2.0

• Allowed non-standard extensions (such as SPARUL).

• Exceptions fixed.

• Added another example.

2008-03-24 1.1.0

• Renamed package name to SPARQLWrapper.

• Added a basic catalog of exceptions.

2008-03-07 1.0.1

• Fixed some cosmetic things.

2008-02-14 1.0.0

• First stable release.

• Main functionality stabilized.

• Project moved to SourceForge.

2007-07-06 0.2.0

• First public release of the library.

Indices and tables

• Index

• Module Index

• Search Page