NePA TesT: Community Network Emulator

import json

import sys

import networkx as nx

def load_json(json_file):

    """ import a json file in NetJSON format, convert to Graph class

    Parameters

    ----------

    json_file : string with file path

    """

    try:

        file_p = open(json_file, "r")

    except IOError:

        raise

    try:

        netjson_net = json.load(file_p)

    except ValueError as err:

        print "Could not decode file", err

    # TODO add a schema to validate the subset of features we are

    # able to consider

    G = nx.Graph()

    cost_label = ""

    if "metric" in netjson_net and netjson_net["metric"] == "ETX":

        cost_label = "cost"

    for node in netjson_net["nodes"]:

        G.add_node(node["id"])

    for link in netjson_net["links"]:

        if cost_label:

            cost = float(link["cost"])

        else:

            cost = 1.0

        G.add_edge(link["source"], link["target"],

                   {"weight": cost})

    return G

def loadGraph(fname, remap=False, connected=True, silent=False):

    """ Parameters

    --------------

    fname : string

        filname to open

    remap : bool

        remap the labels to a sequence of integers

    connected : bool

        return only the larges component subgraph

    """

    G = nx.Graph()

    if not silent:

        print "Loading/Generating Graph"

    # load a file using networkX adjacency matrix structure

    if fname.lower().endswith(".adj"):

        try:

            G = nx.read_adjlist(fname, nodetype=int)

        except IOError as err:

            print

            print err

            sys.exit(1)

    # load a file using networkX .edges structure

    elif fname.lower().endswith(".edges"):

        try:

            G = nx.read_weighted_edgelist(fname, nodetype=int)

        except IOError as err:

            print

            print err

            sys.exit(1)

    # load a a network in NetJSON format

    elif fname.lower().endswith(".json"):

        try:

            G = load_json(fname)

        except IOError as err:

            print

            print err

            sys.exit(1)

    else:

        print >> sys.stderr, "Error: Allowed file extensions are .adj for",\

            "adjacency matrix, .json for netjson and .edges for edge-list"

        sys.exit(1)

    if connected:

        C = sorted(list(nx.connected_component_subgraphs(G)),

                   key=len, reverse=True)[0]

        G = C

    if not silent:

        print >> sys.stderr, "Graph", fname, "loaded",

    # remap node labels so we don't have "holes" in the numbering

    if remap:

        mapping = dict(zip(G.nodes(), range(G.order())))

        H = nx.relabel_nodes(G, mapping)

        return H

    return G