List all Unavailable layers in QGIS (3.x) project with PyQGIS

Hunting Down Missing Layers in Your QGIS Projects with PyQGIS

Ever opened a QGIS project only to be greeted by those frustrating “layer missing” icons? We’ve all been there. It’s a common headache, especially when you’re juggling projects across different computers or digging into older files. These unavailable layers pop up when QGIS can’t find the data it expects – maybe a file got moved, a database connection went sour, or a network drive is playing hide-and-seek.

But don’t despair! PyQGIS, the Python powerhouse behind QGIS, comes to the rescue. It gives you the tools to sniff out these missing layers programmatically. Think of it as your own personal layer detective! This is super handy for automating project check-ups, generating reports, or even building custom tools to keep your data sources in line.

Unmasking Unavailable Layers with PyQGIS

The secret weapon in our arsenal is the isValid() method, part of the QgsMapLayer class. This little guy simply tells you if a layer’s data source is reachable and the layer is, well, valid. True means all good; False means Houston, we have a problem.

Here’s a bit of Python magic to list those pesky unavailable layers in your QGIS project:

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