Adding Attribute to XML

[rseeton]

Hello all,

I'm attempting to use Dasel to modify an existing XML file.

Adding or Updating elements works fine.
Updating an existing attribute works fine.

However, I'm stuck with the creation of new attribute:

Sample File: dasel_test.xml

<greddle>
  <bar>
    <baz/>
    <fizz id=""/>
  </bar>
</greddle>

I can update the greddle.bar.fizz element with:

~/bin/dasel_linux_386 put -f dasel_test.xml -r xml --pretty=true -v 'test_ood' 'greddle.bar.fizz.-id'

However, attempts to add the attribute 'id' to the baz element fails:

 ~/bin/dasel_linux_386 put -f dasel_test.xml -r xml --pretty=true -v 'test_ood' 'greddle.bar.baz.-id'
Error: cannot use property selector on non map/struct types: string: property not found: -id

~/bin/dasel_linux_386 put -f dasel_test.xml -r xml --pretty=true -v 'test_ood' 'greddle.bar.baz.-id.append()'
Error: cannot use property selector on non map/struct types: string: property not found: -id

~/bin/dasel_linux_386 put -f dasel_test.xml -r xml --pretty=true -v 'test_ood' 'greddle.bar.baz.-id.[]'
Error: cannot use property selector on non map/struct types: string: property not found: -id

Is this possible within Dasel - if so, can someone point me to what I'm missing?

[agammann]

An empty XML element is read as a string, so assigning an attribute underneath it fails because there isn't a map to put -id into.

With v3.11.2, you can replace that empty element's value with a map containing the attribute:

dasel -i xml -o xml --root \
  'greddle.bar.baz = {"-id": "test_ood"}' \
  < dasel_test.xml > dasel_test.updated.xml

I tested this against your sample. It produced:

<greddle>
  <bar>
    <baz id="test_ood"></baz>
    <fizz id=""></fizz>
  </bar>
</greddle>

--root outputs the complete modified document after the assignment. This example uses the v3 query syntax and requires upgrading from v2. Replacing the whole value is appropriate here because <baz/> has no existing text, children or attributes to preserve.

See the v3 modification examples.