jsongraph3.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-

"""JSON Graph Python Library

Parameters
----------
None

Returns
-------
None

Long Description
"""

import io
import json
import os.path
import ssl
import sys
import urllib.error
import urllib.parse
import urllib.request

from jsonschema import Draft4Validator
from objects.edge import Edge
from objects.graph import Graph
from objects.multigraph import Multigraph
from objects.node import Node  # TODO add in original

ssl._create_default_https_context = ssl._create_unverified_context


def load_json_string(jsonstring):
    """Check if string is JSON and if so return python dictionary"""

    try:
        json_object = json.loads(jsonstring)
    except ValueError as e:
        return False
    return json_object


def get_github_masterschema():
    """Read JSON Graph Schema file from Github Master branch"""
    link = "https://raw.githubusercontent.com/jsongraph/json-graph-specification/master/json-graph-schema_v2.json"
    f = urllib.request.urlopen(link)
    js = json.load(f)
    f.close

    return js


def get_json(jsongraph):
    """Check if parameter is a file object, filepath or JSON string

        Return:  dictionary object OR False for failure
    """
    if type(jsongraph) is dict:
        return jsongraph
    elif isinstance(jsongraph, io.IOBase):
        return json.load(jsongraph)
    elif os.path.isfile(jsongraph):
        with open(jsongraph, "rb") as f:
            return json.load(f)

    jg = load_json_string(jsongraph)
    if jg:
        return jg
    else:
        return False


def validate_schema(schema="", verbose=False):
    """Validate schema file"""

    if not schema:
        schema = get_github_masterschema()
    else:
        schema = get_json(schema)

    results = Draft4Validator.check_schema(schema)

    if verbose and results:
        print("    Schema doesn't validate!")
        print(results)
    elif verbose:
        print("    Schema Validates!")

    if results:
        return (False, results)

    return (True, "")


def validate_jsongraph(jsongraph, schema="", verbose=False):
    """Validate JSON Graph against given jsongraph object and schema object"""

    jg = get_json(jsongraph)

    if not schema:
        schema = get_github_masterschema()
    else:
        schema = get_json(schema)

    if not jg:
        sys.exit(
            "JSON Graph parameter does not appear to be a file object, filepath or JSON string."
        )
    if not schema:
        sys.exit(
            "JSON Graph Schema parameter does not appear to be a file object, filepath or JSON string."
        )

    schema = Draft4Validator(schema)  # transform schema in a Schema validation object

    errors = [error for error in schema.iter_errors(jg)]
    if verbose and errors:
        print("Problem with JSON Graph")
        for error in errors:
            print(error)

        quit()

    elif verbose:
        print("    Validated!")

    if errors:
        return errors

    return (True, "")


def load_graphs(jsongraphs, validate=False, schema="", verbose=False):
    """Loads one or more graphs from jsongraphs JSON as a generator"""

    jgs = get_json(jsongraphs)

    if validate:
        (status, results) = validate_jsongraph(jsongraphs, schema, verbose)
        sys.exit("JSON Graph does not validate")

    if "graph" in jgs:
        yield jgs["graph"]

    if "graphs" in jgs:
        for graph in jgs["graphs"]:
            yield graph


def test_example_graphs():
    """Test and usage example"""
    single_graph_link = "https://raw.githubusercontent.com/jsongraph/json-graph-specification/master/examples/usual_suspects.json"
    multiple_graph_link = "https://raw.githubusercontent.com/jsongraph/json-graph-specification/master/examples/car_graphs.json"

    f = urllib.request.urlopen(single_graph_link)
    sg = json.load(f)
    f.close

    f = urllib.request.urlopen(multiple_graph_link)
    mg = json.load(f)
    f.close

    print("Does JSON Graph Schema validate?")
    validate_schema(schema="", verbose=True)

    print("\nDoes Single Graph example validate?")
    validate_jsongraph(sg, schema="", verbose=True)

    print("\nShow Label of Single Graph")
    graphs = load_graphs(sg, validate=False, schema="", verbose=False)
    print("    Label: ", next(graphs)["label"])

    print("\nShow Label's of Multiple Graphs")
    graphs = load_graphs(mg, validate=False, schema="", verbose=False)
    for graph in graphs:
        print("    Label: ", graph["label"])


def main():
    test_example_graphs()


if __name__ == "__main__":
    main()