flask_rdf 0.2.1

Flask decorator to output RDF using content negotiation

A Flask or Bottle or WSGI decorator to output RDF using content negotiation.

Apply the @flask_rdf or @bottle_rdf or @wsgi_rdf decorator to a view function and return an rdflib Graph object. Flask_rdf will automatically format it into an RDF output format, depending on what the request’s Accept header says. If the view function returns something besides an rdflib graph, it will be passed through without modification.

Custom formats can be registered easily. After registering the new serializer with rdflib’s plugin support, use the add_format method to register a new mimetype request to use the new formatter.

The functionality of this module can still help other web frameworks, even if there isn’t a specific decorator yet. The format.decide function will return information about with Content-Type header to send and what serialization format to use with rdflib. The format.wants_rdf function can be used at a high level to determine whether the client even wants RDF.

API

• add_format(mimetype, serialize_format), format.add_format(mimetype, serialize_format)

  Registers a new format to be recognized for content negotiation. It accepts arguments mimetype, serialize_format, and is used to add any custom rdflib serializer plugins to be used for the content negotiation. A third argument, requires_context, will restrict this serializer to only be used by graphs that are context_aware.

• format.decide(accept, context_aware=False)

  Given an Accept header, return a (mimetype, format) tuple that would best satisfy the client’s request. If the Accept header is blank, default to RDF+XML If the Accept header can’t be satisfied, returns (None, None) A second argument, context_aware, may be used to allow formats that require a context_aware graph.

• FormatSelector(), format.FormatSelector()

  Class to decide serialization formats. It supports using the module-level formats added with format.add_format, but it has its own list of formats added with FormatSelector().add_format.

• wants_rdf(accept), format.wants_rdf(accept), FormatSelector.wants_rdf(accept)

  Returns whether the client’s Accept header indicates that the client is prepared to receive RDF data. This can be used in the view to return a pretty HTML page for browsers, for example.

• @flask_rdf, @flask.returns_rdf

  Decorator for a Flask view function to use the Flask request’s Accept header. It handles converting an rdflib Graph object to the proper Flask response, depending on the content negotiation. Other content is returned without modification.

• flask.Decorator

  Class to act as the decorator, in case some behavior needs to be overridden. The constructor accepts a FormatSelector object to do custom negotiation. The Decorator object itself can be used as the decorator, and it also supports the methods .output and .decorate.

• @bottle_rdf, @bottle.returns_rdf

  Decorator for a Bottle view function to use the Bottle request’s Accept header. It handles converting an rdflib Graph object to the proper Bottle response, depending on the content negotiation. Other content is returned without modification.

• bottle.Decorator

  Class to act as the decorator, in case some behavior needs to be overridden. The constructor accepts a FormatSelector object to do custom negotiation. The Decorator object itself can be used as the decorator, and it also supports the methods .output and .decorate.

• @wsgi_rdf, @wsgi.returns_rdf

  Decorator for a WSGI app function to use the WSGI request’s Accept header. It handles converting an rdflib Graph object to the proper Bottle response, depending on the content negotiation. Other content is returned without modification. Calls to WSGI’s start_response will pass data through unchanged. Doing both a start_response and returning an RDF object will result in both outputs being returned, so don’t do that.

• wsgi.Decorator

  Class to act as the decorator, in case some behavior needs to be overridden. The constructor accepts a FormatSelector object to do custom negotiation. The Decorator object itself can be used as the decorator, and it also supports the methods .output and .decorate.

Example

#!/usr/bin/env python
from rdflib import Graph, BNode, Literal, URIRef
from rdflib.namespace import FOAF
from flask import Flask
from flask_rdf.flask import returns_rdf
import random

app = Flask(__name__)

@app.route('/')
@app.route('/<path:path>')
@returns_rdf
def random_age(path=''):
    graph = Graph('IOMemory', BNode())
    graph.add((URIRef(path), FOAF.age, Literal(random.randint(20, 50))))
    return graph

if __name__ == '__main__':
    app.run(host='0.0.0.0', debug=True)