Paho failure to subscribe

By Maximilian Batz | 2019-08-08

Problem AMQJS0005E Internal error. Error Message: Cannot read property ‘show’ of undefined This error is shown sporadically, especially when you Shift-Reload the whole page. Solution I have a Vue.js Plugin to show “toast” messages (Vue.toasted). I currently use it for debugging purposes. Everything worked fine initially, as my code was executed after Vue was initialized…

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Shopify & Langify modify checkout link

By Maximilian Batz | 2019-07-21

Shopify checkout is multilingual The shopify checkout is multilingual: The trick is to have a &locale=en or &locale=en at the end of the link: You can therefore create buttons, etc. which take your user to the checkout, under the links of https://buyzero.de/checkout?locale=de https://buyzero.de/checkout?locale=en which will set the locale to the appropriate language. (replace buyzero.de by…

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Changing the mountpoint on auth_on_register webhook for VerneMQ

By Maximilian Batz | 2019-06-09

It is possible to pass modifiers along with the “result”: “ok” return value of your webhook for VerneMQ. The official documentation of VerneMQ gives some examples for the syntax. changing the mountpoint It is also possible to change the mountpoint, however the client_id apparently has to be passed in as well! I have raised an…

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Debugging VerneMQ connection / authentication problems for dual authentication with webhooks and vmq_diversity

By Maximilian Batz | 2019-06-04

TL;DR https://github.com/vernemq/vernemq/blob/master/apps/vmq_diversity/src/vmq_diversity_plugin.erl includes a statement which will block authentication / authorization through any other channels if your Lua script returns “false”: will lead to: instead of trying other plugins, as you might have assumed! In order to avoid this problem, simply do not return anything from your Lua script, if you do not want to…

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MQTT Topic Tree Design best practices, tips & examples

By Maximilian Batz | 2019-05-29

Generic MQTT Background With MQTT the sender and receiver are not aware of each other – the broker handles the messaging. This allows the messages to be separated in space, time, and intensity. The sender can send at the speed it wants, and the time it wants. The receiver can pick up the messages at…

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VerneMQ: econnrefused & Webhook example

By Maximilian Batz | 2019-05-20

Webhooks activate webhooks like this in your vernemq.conf.local (.local when running on docker, so that settings at bottom of the file will persist): plugins.vmq_webhooks = on vmq_webhooks.js_auth_on_register.hook = auth_on_register vmq_webhooks.js_auth_on_register.endpoint = http://container_picockpit:1200/example/path Note that if your webhook is not accessible (econnrefused), the db based authentication will also fail … ! If you get errors like…

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