spaceapi-server/spaceapi_server/server/__init__.py

import os
import sys
import json
import signal
import importlib

import bottle

from spaceapi_server import template, config


# The SpaceAPI response template instance
__TEMPLATE = None


def render_traverse(obj):
    """
    Walk through a complex, JSON-serializable data structure, and pass
    string objects through the Jinja2 templating engine.
    :param obj: The object to traverse.
    """
    if isinstance(obj, list):
        # list -> recurse into each item
        for i in range(len(obj)):
            obj[i] = render_traverse(obj[i])
        return obj
    elif isinstance(obj, dict):
        # dict -> recurse into the value of each (key, value)
        for k, v in obj.items():
            obj[k] = render_traverse(obj[k])
        return obj
    elif isinstance(obj, str):
        # str -> template
        return template.render(obj)
    else:
        # anything else -> return as-is
        return obj


@bottle.route('/')
def serve():
    global __TEMPLATE
    # Render the response template
    rendered = render_traverse(__TEMPLATE)
    # Set the response Content-Type
    bottle.response.content_type = 'application/json; charset=utf-8'
    # CORS "whitelist"
    # https://spaceapi.io/getting-started/#common-issues
    bottle.response.headers['Access-Control-Allow-Origin'] = '*'
    # Return the JSON-serialized rendered data as response body,
    # indented with two spaces
    return json.dumps(rendered, indent=2)


def load(*args, **kwargs):
    global __TEMPLATE

    # If a config file path was passed, load it
    if len(sys.argv) > 1:
        config.load(sys.argv[1])
    # Get the current config
    conf = config.get()

    # Get the absoulute plugins dir path
    plugin_dir = os.path.abspath(conf.get('plugins_dir', 'plugins'))
    # Iterate the plugins dir and take all python files
    for f in os.listdir(plugin_dir):
        if f.endswith('.py'):
            # Get the full name to the plugin file
            plugin_fname = os.path.join(plugin_dir, f)
            # Load the file as module and import it
            # https://stackoverflow.com/a/67692
            m_spec = importlib.util.spec_from_file_location(f[:-3], plugin_fname)
            module = importlib.util.module_from_spec(m_spec)
            m_spec.loader.exec_module(module)

    # Get the template path
    template_path = conf.get('template', 'template.json')
    # Load and parse the JSON template
    with open(template_path, 'r') as f:
        __TEMPLATE = json.load(f)


def init():
    # Register SIGHUP config reload handler
    signal.signal(signal.SIGHUP, load)
    # Prepare everything
    load()


def start():
    init()
    # Start the HTTP server
    conf = config.get()
    bottle.run(
        server=conf.get('server', 'wsgiref'),
        host=conf.get('address', '::'),
        port=int(conf.get('port', 8080))
    )