Explore topic-wise InterviewSolutions in .

The correct choice is (d) 2 arguments

To elaborate: This METHOD accepts two positional arguments: the topic to publish to, and the BODY of the message.

The correct choice is (B) DEMO Keyset

To explain: Click on Demo keyset pane and PubNub will display public, subscribe, and secret keys. We MUST copy and PASTE each of these keys to use them in our CODE that will publish messages and subscribe to them.

The correct OPTION is (b) UNICODE

Easy explanation: In python 2 the text STRING is called as str, and in python 2 it is called as unicode.

Right CHOICE is (d) ROSTOPIC find

For explanation: Rostopic find, FINDS topics by type. Rostopic is implemented in python. ROSTOPIC uses YAML_syntax at the COMMAND line

Right option is (c) PUBLISHING DATA

Explanation: dweet.io is used to publish the data retrieved from the SENSORS and make it AVAILABLE to DIFFERENT computers and devices all over the world.

Right answer is (a) public_key and subscribe_key

Best explanation: Then, the constructor declares two LOCAL variables: public_key and subscribe_key. These local variables SAVE the public and subscribe keys that we had generated with the PUBNUB Admin PORTAL.

Correct option is (a) YAML_syntax

For EXPLANATION: ROSTOPIC uses YAML_syntax at the command line for representing the content of the MESSAGE. For information on how to USE this YAML SYNTAX for commands LIKE rostopic pub.

The CORRECT answer is (a) True

The best I can explain: PUBLISH() method also ACCEPTS arbitrary KEYWORD arguments, which are passed along as attributes of the message.

Right choice is (B) False

To EXPLAIN: If the USER has no authority on topic a warning RESPONSE will come which INDICATES which are not published, if not those topics are published.

The correct CHOICE is (a) Topics which has header

To explain I would say: Rostopic DELAY DISPLAY the delay for topic which has header. Rostopic is IMPLEMENTED in python.

Right answer is (a) True

Easy EXPLANATION: We want to send and receive DATA in real time through INTERNET and RESTFUL API is not the most appropriate option to do this. Instead, we will work on MQTT which is LIGHTER than HTTP.

The correct option is (B) Dashboard

The explanation is: Freeboard.io ALLOWS US to build a dashboard by selecting DATA source and dragging and dropping customizable WIDGETS.

The CORRECT option is (d) KEYS

To EXPLAIN I would say: It is necessary to generate our PubNub publishes and subscribes keys in ORDER to send and receive messages in the NETWORK.

Right answer is (C) Methods

Easy explanation: client() class provides the method to CREATE TOPICS. publish() method publishes messages to pub/sub. PUBLISHING message is handled through the client class.

Right option is (c) LINE graph

The explanation: The visual VIEW DISPLAYS line graph of whatever we want the information that is getting from the SENSORS. Examples are temperature and humidity VALUES.

Right OPTION is (a) command_key

Explanation: The messageChannel CLASS declares the command_key class ATTRIBUTE that defines the KEY string that defines what the code will understand as the command.

Right choice is (a) MQTT

The best explanation: MQTT is a lightweight PROTOCOL that RUNS on top of the TCP/IP protocol and WORKS with publish subscribe mechanism.

The CORRECT option is (d) Dash

For explanation: Dash uses a CLEAN interface to provide DATA from VARIOUS SOCIAL and new sites, as well as websites monitoring tools and fitness tracking sites.

The correct CHOICE is (c) Connect

To explain I would say: The call to this message specifies many methods DECLARED in the MessageChannel class

Connect: specifies the function that will be called when a SUCCESSFUL connection with the PUBNUB cloud.

Correct answer is (d) Callback

Easy explanation: The call to this MESSAGE SPECIFIES MANY methods declared in the MessageChannel class

Callback: specifies the FUNCTION that will be CALLED when there is a new message received from the channel.

Correct CHOICE is (C) __Init__

Explanation: __Init__ method saves the received arguments in three ATTRIBUTES with the same NAMES.

Right option is (B) Ducksboard

To explain: Ducksboard can TAP MANY sites APIs to display DATA, but it also offers its own API, which lets you send your own data into your dashboard. Ducksboard supports Google spreadsheets as a data source.

Correct ANSWER is (d) Dweeting

Explanation: Once we have chosen a UNIQUE for ONE THING, we can start publishing data, a process known as Dweeting.

The correct ANSWER is (C) Publisher to broker and broker to publisher

Best explanation: The PUBLIC COMMAND message is sent from a publisher to a broker or from a broker to a subscriber, to publish information on a specified topic or topics.

Right answer is (a) TYPEERROR

Best explanation: If we send a TEXT STRING the method will RAISE TypeError. TypeError will show if we try to send text string instead of bytes.

Right ANSWER is (B) BYTES

Best explanation: The message in pub/sub is an opaque blob of bytes, and as such, you must SEND a bytes object in python 3.

The correct option is (d) MQ TELEMETRY TRANSPORT

For EXPLANATION: MQTT was KNOWN as MQ Telemetry Transport protocol. MQTT is a LIGHTWEIGHT protocol that runs on top of the TCP/IP protocol.

Right ANSWER is (d) rostopic bw

Explanation: Rostopic bw displays the bandwidth. The bandwidth reported is the RECEIVED bandwidth. If there are NETWORK CONNECTIVITY ISSUES or rostopic cannot keep up with the publisher.

The correct choice is (B) Ducksboard

Best explanation: Ducksboard offers a number of UNIQUE background images INCLUDING the default, which LOOKS like wood flooring.

Correct ANSWER is (C) Batch

To explain I would say: Whenever we publish a MESSAGE, a batch is automatically created. This way, if you publish a large volume of MESSAGES, it reduces the number of requests made to the SERVER.

Right option is (a) .jar

For EXPLANATION I WOULD say: JAVA IDE to run the example in any computer or build .jar file with all the dependencies included and launch it any computer or devices that you want to use as the MQTT client with a command similar to the following line.

Right option is (a) RETful API

For explanation I WOULD say: RETful API that allows US to control electronic COMPONENTS CONNECTED to our INTEL Galileo Gen 2 board through HTTP requests.

Correct answer is (c) Cloud based SERVICE

For EXPLANATION I would say: Freeboard.io defines itself as a cloud based service that allows US to VISUALIZE the internet of things.

Right answer is (a) DATA sharing

Easiest EXPLANATION: The dweet.io data sharing UTILITY allows us to easily publish data or messages and alerts from IoT DEVICES and then use other devices to subscribe to this data.

The CORRECT CHOICE is (d) Disconnect

To explain I would SAY: The call to this message SPECIFIES many methods declared in the MessageChannel class

Disconnect: specifies the function that will be called when the client disconnects from the PubNub cloud.

The correct answer is (a) Key-value PAIRS

To ELABORATE: The DICTIONARY defines the key value pairs that we want to send as JASON DATA to dweet.io for our thing. The keys may be the values what we want to KNOW like, temperature, humidity etc.

The correct option is (d) DASHZEN

Easy EXPLANATION: Dashzen contains many GADGETS. One unique feature of Dashzen is that WORLD of Warcraft GADGET.

Right CHOICE is (a) Client()

For explanation I WOULD say: Publishing message is HANDLED through the client CLASS(aliased as google-cloud-pubsub-publisherclient).

The correct ANSWER is (d) TWITTER

Explanation: dweet.io DATA SHARING UTILITY defines itself as something similar to twitter for social machines.

The CORRECT answer is (b) Canonical form

For explanation I WOULD SAY: The topic is passed ALONG as a string; all topics have the canonical form of projects/{project_name}/topic/{topic_name}.

The correct CHOICE is (d) Client

To explain I would say: Message is sent to the input queue of a message flow that contains a PUBLISHING node. AUTHORITY to put a message into the queue and to PUBLISH on the specified TOPIC.