Weekly Tech Report 2015-11-09

• Weekly Tech Report 2016-01-04
  • Learning
  • Article
  • Blog
  • Open Source
  • Problems

Weekly Tech Report 2016-01-04

Learning

• MQTT Essentials

  The HiveMQ blog posts the blog series of MQTT Essentials, it’s a good summary to MQTT protocol.

  1. Introducing MQTT
  2. Publish / Subscribe
  3. Client, Broker and Connection Establishment
  4. MQTT Publish, Subscribe and Unsubscribe
  5. MQTT Topics & Best Practices
  6. MQTT Quality of Service Levels
  7. Persistent Session and Queuing Messages
  8. Retained Messages
  9. Last Will and Testament
  10. Keep Alive and Client Take-Over
  Special: MQTT over Websockets

• MQTT Community Wiki

  The goal is to collect useful content to help users and developers navigate around the MQTT community and understand how best to make use of the technology.

• MQTT Protocol Specification

  MQTT is a Client/Server publish/subscribe messaging transport protocol, it’s ligth weight, open, simple, and designed so as to be easy to implement.

  OASIS Standard Specification
  IBM/Eurotech Specification
  MQTT Man Page
  Involve Android Phone to IoT via WebSphere MQTT

• IoT Standards

  The IoT Working Group provides open source implementations for IoT protocols such as CoAP, ETSI SmartM2M, MQTT or LwM2M.

Article

• Reading Notes of “TCP/IP Illustrated”

  A reading notes in chinese for the classic book “TCP/IP Illustrated”.

• Deep Experiment on Android Permissions

  Android Permissions has different levels: normal, dangerous, signature, signature or system. To perform your permission, you must declare tags on AndroidManifest.xml.

• Complete Android Permissions

  Developer must declare the permissions they needed on AndroidManifest.xml, for the sake of security. It lists all permissions in Chinese.

• Mosquitto and Broker

  Mosquitto is a messaging broker implementation under BSD license. This article presents a demonstrated practise of Mosquitto on Windows Cygwin.

• Practical MQTT with Paho

  A practical piece presents how to write a MQTT demo with Paho.

• An Exmaple of Using TLS with Paho Embedded C++ Client

  It shows how to work with TLS by using CyaSSL TLS library on mbed platform.

• How to make MQTT connection work over SSL

  It shows how to make the Paho Java client and the ActiveMQ broker talk over SSL, both parties have to be supplied with neccessary digital cerificaties.

• How to Use BKS in HTTPS

  You can use keytool to create bks-format keystore file, and use it in HTTPS.

• MQTT and CoAP, IoT Protocols

  The two protocols used in IoT, also two of the most promising for small devices are MQTT and CoAP, MQTT gives flexibility for binary data, and CoAP is designed for interoperability with the web.

• The Seven Best MQTT Client Tools

  Give a brief overview of the best MQTT client tools for different platforms and highlight special features.

  MQTT Client mqtt.io

Blog

• Learning Eclipse Paho: MQTT Implementation

  A summary of learning Eclipse Paho project, including an overview of MQTT, MQTT packet description, and source analysis of CommsSender/CommsReceiver.

  1. Paho: MQTT Implementation
  2. Socket Internal Paho
  3. Investigate Android Push

• 5 Reasons to Replace PowerPoint with Google Slides

  Why makes the switch for PowerPoint to Google Slides:

  • Built For Collaboration
  • Simple UI Encourage Simpler Presentation
  • Offline Access for Editing and Presenting
  • Access Presentation from Any Device
  • Easy Web Publishing and Sharing

Open Source

• Paho MQTT/C

  A MQTT publish/subscribe client implementations in C language for use on embedded platform

• PickMeUp

  A sample ride sharing application that accompanies IBM Redbooks “Building Realtime Mobile Solutions with MQTT and IBM Message Sight”

• MQTT.js

  A client library for the MQTT protocal, written in JavaScript for node.js and the browser, it’s under MIT license

• RSMB

  While there are few available MQTT brokers, it seems there is only one MQTT-SN broker called Really Small Message Broker, or RSMB.

• Mosquitto

  The Mosquitto project provides an open-source implementation of a MQTT broker and also a MQTT client library.

  Mosquitto Official Site

• CloudMQTT Website

  CloudMQTT is a product to use mosquitto to form cloud message solution, and it is not open source. Here is the link of its website, which is open source, also called Flat UI

Problems

• checkSelfPermission always returns PERMISSION_GRANTED

  For Android verision < Android M (6.0), everything will be ok. For Android M, if targetSdkVersion >= VERSOIN_CODES.M (23), Context#checkSelfPermission is ok, else use PermissionChecker#checkSelfPermission instead.

• java.lang.SecurityException: Requires READ_PHONE_STATE

  Append permission declaration on AndroidManifest.xml, see here:

  <uses-permission android:name="android.permission.READ_PHONE_STATE" />
  

• SSL23_GET_CLIENT_HELLO:unknown protocol

  Correct protocol in server URI to “ssl://” and add sslopts.enableServerAuth = 0

• How to Display Hidden Characters in vim?

  Use the commands, see Make Vim show ALL white spaces:

  :set listchars=eol:$,tab:>-,trail:~,extends:>,precedes:<
  :set list
  

• What happens if I define a 0-size array in C/C++?

  Zero-size array is not allowed in standard C/C++, however it’s been current use in C to indicate a variable length structure. See GCC Doc and zero length arrays vs. pointers.

This work is licensed under a CC BY-NC 4.0 License.