After some trail and error I'd like to share the issue I am dealing with.
I'm populating an struct and convert it to an XML ( xml.Marshal ) As you can see below the Foo example works as expected. The Bar example however creates an empty group1.
So my question is : "How do I prevent Group1 to be generated if there are no children set."
package main
import (
"fmt"
"encoding/xml"
)
type Example1 struct{
XMLName xml.Name `xml:"Example1"`
Element1 string `xml:"Group1>Element1,omitempty"`
Element2 string `xml:"Group1>Element2,omitempty"`
Element3 string `xml:"Group2>Example3,omitempty"`
}
func main() {
foo := &Example1{}
foo.Element1 = "Value1"
foo.Element2 = "Value2"
foo.Element3 = "Value3"
fooOut, _ := xml.Marshal(foo)
fmt.Println( string(fooOut) )
bar := &Example1{}
bar.Element3 = "Value3"
barOut, _ := xml.Marshal(bar)
fmt.Println( string(barOut) )
}
Foo Output :
<Example1>
<Group1>
<Element1>Value1</Element1>
<Element2>Value2</Element2>
</Group1>
<Group2>
<Example3>Value3</Example3>
</Group2>
</Example1>
Bar Output :
<Example1>
<Group1></Group1> <------ How to remove the empty parent value ?
<Group2>
<Example3>Value3</Example3>
</Group2>
</Example1>
Addition
Additionally i have tried doing the following, but still generates an empty "Group1":
type Example2 struct{
XMLName xml.Name `xml:"Example2"`
Group1 struct{
XMLName xml.Name `xml:"Group1,omitempty"`
Element1 string `xml:"Element1,omitempty"`
Element2 string `xml:"Element2,omitempty"`
}
Element3 string `xml:"Group2>Example3,omitempty"`
}
The full code can be found here : http://play.golang.org/p/SHIcBHoLCG . example to
EDIT : Changed the golang example to use MarshalIndent for readability
Edit 2 The example from Ainar-G Works good for hiding the empty parent, but Populating it makes it a lot harder. "panic: runtime error: invalid memory address or nil pointer dereference
"
Example1
doesn't work because apparently the ,omitempty
tag only works on the element itself and not the a>b>c
enclosing elements.
Example2
doesn't work because ,omitempty
doesn't recognise empty structs as empty. From the doc:
The empty values are false, 0, any nil pointer or interface value, and any array, slice, map, or string of length zero.
No mention of structs. You can make the baz
example work by changing Group1
to a pointer to a struct:
type Example2 struct {
XMLName xml.Name `xml:"Example1"`
Group1 *Group1
Element3 string `xml:"Group2>Example3,omitempty"`
}
type Group1 struct {
XMLName xml.Name `xml:"Group1,omitempty"`
Element1 string `xml:"Element1,omitempty"`
Element2 string `xml:"Element2,omitempty"`
}
Then, if you want to fill Group1
, you'll need to allocate it separately:
foo.Group1 = &Group1{
Element1: "Value1",
}
Example: http://play.golang.org/p/mgpI4OsHf7
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With