Dealing with NIL in JSON::Any in Crystal Lang

One of the challenges when developing with Crystal is that it is not as forgiving about data types as, say, Python or Ruby. nil will keep you occupied. The following error message: cast from Nil to String failed, at /usr/share/crystal/src/json/any.cr:220:5:220 can be solved by: # cast to string, THEN check if it is nil if…

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Chromium exit code -5

While running Chromium with chromium-browser –display=:0 https://www.picockpit.com will allow you to start Chromium from an SSH connection (and it will output to the main display in the X Server), this will fail when you try to run it with subprocess.Popen in Python: „command“: [„chromium-browser“, „–display=:0“, “https://picockpit.com”] (this is part of the JSON format I have…

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secure command execution with Python: subprocess.Popen

Security is important for me while developing the picockpit-client. The following applies to Linux systems (but probably is applicable to all Unix like systems, including macOS) Python allows to run external commands using the subprocess module. import subprocess In the upcoming version of PiCockpit, users will be able to create their own buttons (simply editing…

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TermiShell: a web-based shell for the Raspberry Pi (development notes)

Introduction In the course of development of PiCockpit, I am going to add a web-based Terminal called TermiShell. TermiShell icon, by: Stephanie Harvey via unsplash.com TermiShell is going to allow you to log into your Raspberry Pi using PiCockpit.com (and the picockpit-client) – no additional application required on either side. This should be very comfortable,…

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