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1 | /*
* Copyright 2014 Telefonica Investigación y Desarrollo, S.A.U
*
* This file is part of iotagent-lwm2m-lib
*
* iotagent-lwm2m-lib is free software: you can redistribute it and/or
* modify it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 3 of the License,
* or (at your option) any later version.
*
* iotagent-lwm2m-lib is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
* See the GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public
* License along with iotagent-lwm2m-lib.
* If not, seehttp://www.gnu.org/licenses/.
*
* For those usages not covered by the GNU Affero General Public License
* please contact with::[contacto@tid.es]
*/
'use strict';
var async = require('async'),
apply = async.apply,
objectRegistry = require('./objectRegistry'),
errors = require('../../errors'),
logger = require('logops'),
_ = require('underscore'),
observers = {};
/**
* Extract Object type and id from the request URI, returning it using the callback.
*
* @param {Object} req Arriving COAP Request to be handled.
* @param {Object} res Outgoing COAP Response.
*/
function extractUriInfo(req, res, callback) {
if (req.urlObj.pathname.match(/\/\d+\/\d+\/\d+/)) {
var resourceIndex = req.urlObj.pathname.lastIndexOf('/'),
resourceId = req.urlObj.pathname.substring(resourceIndex + 1),
objectUri = req.urlObj.pathname.substring(0, resourceIndex);
callback(null, objectUri, resourceId);
} else Eif (req.urlObj.pathname.match(/\/\d+(\/\d+)?/)) {
callback(null, req.urlObj.pathname, null);
} else {
callback(new errors.WrongObjectUri(req.urlObj.pathname));
}
}
/**
* Invoke the user handler for this operation, with all the information from the query parameters as its arguments.
* This method handling gives the client an opportunity to change or overwrite the values before returning them to
* the client. The handler must call the callback with the overwritten value it wants to return. If the callback is
* called without parameters, the original value is returned instead.
*
* @param {Object} queryParams Object containing all the query parameters.
* @param {Function} handler User handler to be invoked.
*/
function applyHandler(resourceId, handler, storedObject, callback) {
if (storedObject.attributes[resourceId]) {
handler(
storedObject.objectType,
storedObject.objectId,
resourceId,
storedObject.attributes[resourceId],
function handleReadOverwrite(error, result) {
Eif (result) {
callback(error, result);
} else {
callback(error, storedObject.attributes[resourceId]);
}
});
} else {
callback(new errors.ResourceNotFound(storedObject.objectType, storedObject.objectId, resourceId));
}
}
/**
* Generates the end of request handler that will generate the final response to the COAP Client.
*
* @param {Object} req Arriving COAP Request to be handled.
* @param {Object} res Outgoing COAP Response.
* @returns {Function} Request handler, receiving an optional error and the read operation result.
*/
function endRead(req, res) {
return function (error, result) {
var body;
if (error) {
res.code = error.code;
body = '';
} else {
res.code = '2.05';
body = result.toString();
}
if (_.some(req.options, _.matches({name: 'Observe'}))) {
res.setOption('Observe', 1);
res.write(body);
} else {
res.end(body);
}
};
}
/**
* Constructs the resource observer. The observer listens in the object registry bus for attribute modifications,
* sending a new information update to the server each time the selected attribute changes its value.
*
* @param {Object} stream Stream where the new data will be written to the server.
* @param {Number} resourceId Resource to read from.
* @param {Object} storedObject Object instance to observe.
* @returns {{uri: (object.objectUri|*|string), stream: *, observation: number}}
* @constructor
*/
function ResourceObserver(stream, resourceId, storedObject) {
var data = {
id: storedObject.objectUri + '/' + resourceId,
uri: storedObject.objectUri,
stream: stream,
observation: 1,
listener: function newModification(method, id, value) {
if (method === 'setResource' && resourceId === id.toString()) {
stream.setOption('Observe', data.observation);
stream.write(value.toString());
data.observation++;
data.lastObservation = Date.now();
}
}
};
function getLastMeasure() {
objectRegistry.get(storedObject.objectUri, function (error, obj) {
if (error) {
logger.error('Error retrieving the last resource value');
} else {
data.listener('setResource', resourceId, obj.attributes[resourceId]);
}
});
}
objectRegistry.getAttributes(storedObject.objectUri + '/' + resourceId, function(error, attributes) {
Iif (error) {
logger.error('Couldn\'t find attributes for the [%s] resource URI. Falling back to value changed');
}
if (attributes) {
Eif (attributes.pmax) {
data.scheduler = setInterval(function handleMaxPeriod() {
getLastMeasure(storedObject.objectUri, resourceId);
}, attributes.pmax);
}
} else {
objectRegistry.bus.on(storedObject.objectUri, data.listener);
}
});
return data;
}
/**
* If the Read request comes with the observation option, apart from resolving the information request, a subscription
* has to be created, so every time the selected resource changes in value (or in a timely basis, depending on the
* configuration), the server is updated on the new value.
*
* @param {Object} req Arriving COAP Request to be handled.
* @param {Object} res Outgoing COAP Response.
* @param {Number} resourceId ID of the resource to be observed.
* @param {Object} storedObject Object instance to be read.
*/
function createObservers(req, res, resourceId, storedObject, callback) {
if (_.some(req.options, _.matches({name: 'Observe'}))) {
var observer = new ResourceObserver(res, resourceId, storedObject);
observers[observer.id] = observer;
}
callback(null, storedObject);
}
function addAttribute(previous, value) {
return previous + ';' + value[0] + '=' + value[1];
}
function discoverResourceAttributes(objectUri, resourceId, callback) {
objectRegistry.getAttributes(objectUri + '/' + resourceId, function (error, attributes) {
Iif (error) {
callback(error);
} else {
var payload = '<' + objectUri + '/' + resourceId + '>';
if (attributes) {
payload = _.pairs(attributes).reduce(addAttribute, payload);
}
callback(null, payload);
}
});
}
function discoverObjectResources(objectUri, callback) {
async.series([
apply(objectRegistry.get, objectUri),
apply(objectRegistry.getAttributes, objectUri)
], function handleGetObject(error, results) {
var obj = results[0],
attributes = results[1];
if (error) {
callback(error);
} else {
var payload = '<' + objectUri + '>',
resources = _.keys(obj.attributes);
if (attributes) {
payload += _.pairs(attributes).reduce(addAttribute, '');
}
for (var i = 0; i < resources.length; i++) {
payload += ',<' + objectUri + '/' + resources[i] + '>';
}
callback(null, payload);
}
});
}
function discoverObjectTypeInstances(objectTypeUri, callback) {
async.series([
objectRegistry.list,
apply(objectRegistry.getAttributes, objectTypeUri)
], function handleListResult(error, results) {
var objList = results[0],
attributes = results[1];
Iif (error) {
callback(error);
} else {
var payload = '<' + objectTypeUri + '>',
objectType = objectTypeUri.substring(1);
if (attributes) {
payload += _.pairs(attributes).reduce(addAttribute, '');
}
for (var i = 0; i < objList.length; i++) {
Eif (objList[i].objectType === objectType) {
payload += ',<' + objList[i].objectUri + '>';
}
}
callback(null, payload);
}
});
}
/**
* Handle the read operation.
*
* @param {Object} req Arriving COAP Request to be handled.
* @param {Object} res Outgoing COAP Response.
* @param {Function} handler User handler to be executed if everything goes ok.
*/
function handleRead(req, res, handler) {
extractUriInfo(req, res, function (error, objectUri, resourceId) {
Iif (error) {
endRead(req, res)(error);
} else {
if (_.some(req.options, _.matches({name: 'Accept', value: 'application/link-format'}))) {
if (resourceId) {
discoverResourceAttributes(objectUri, resourceId, endRead(req, res));
} else if (objectUri.match(/\/\d+\/\d+/)) {
discoverObjectResources(objectUri, endRead(req, res));
} else {
discoverObjectTypeInstances(objectUri, endRead(req, res));
}
} else {
async.waterfall([
apply(objectRegistry.get, objectUri),
apply(createObservers, req, res, resourceId),
apply(applyHandler, resourceId, handler)
], endRead(req, res));
}
}
});
}
function cancelObservation(objUri, resourceId, callback) {
Eif (observers[objUri + '/' + resourceId]) {
Eif (observers[objUri + '/' + resourceId].stream) {
observers[objUri + '/' + resourceId].stream.end();
}
Eif (observers[objUri + '/' + resourceId]) {
clearInterval(observers[objUri + '/' + resourceId].scheduler);
}
objectRegistry.bus.removeListener(objUri, observers[objUri + '/' + resourceId].listener);
delete observers[objUri + '/' + resourceId];
} else {
logger.error('Tried to remove an unexistant observation on obj URI [%s] and resourceId [%s]',
objUri, resourceId);
}
callback(null);
}
function listObservers(callback) {
callback(null, _.values(observers));
}
function cancelAllObservers(callback) {
var observers = _.values(observers),
cancellations = [];
for (var i = 0; i < observers.length; i++) {
cancellations.push(apply(cancelObservation, observers[i].objUri, observers[i].resourceId));
}
async.series(cancellations, callback);
}
exports.handle = handleRead;
exports.cancel = cancelObservation;
exports.list = listObservers;
exports.cancelAll = cancelAllObservers; |