clbanning/mxj

Locate and modify

Closed this issue · 2 comments

suntong commented

Related to issue #28, what I am looking forward to in mxj, is able to locate some records according to XPath/JPath or something similar, them modify the located record.

Please take a look at this .xml file for example, I need to, expressed in xpath term,

  • locate //Request nodes; and for each node found,
  • change its attribute according to other attributes.

For example, these changes were to change

//Request's ./[ReportingName] use the basename of ./[Url]( and prefix with ../TransactionTimer[Name] as well, but that's a bonus request if it is too difficult at first).

The final result is posted here.

How can I do that? Thx.

clbanning commented

I have posted a new example - https://github.com/clbanning/mxj/blob/master/examples/jpath.go - that demonstrates using this package to perform the JPath use cases in the 2nd reference you provided in issue #28. There are a number of methods that allow changing values in the Map itself:

  • m.NewMap()
  • m.Remove()
  • m.SetValueForPath()
  • m.UpdateValuesForPath()

See some use cases in https://github.com/clbanning/mxj/tree/master/examples - gonuts1a, gonuts10.go, gonuts10seq.go, gonuts11seq.go, and gonuts12seq.go are pertinent. (The last 4 are examples I did based on a gonuts posting you made last year - https://groups.google.com/forum/?fromgroups#!topic/golang-nuts/tf4aDQ1Hn_c. In fact, gonuts11seq.go and gonuts12seq.go are working with XML that is [similar to] that which you reference, above. I think you'll find gonuts12seq.go doing something close to what you describe.)

The mxj package originated to decode XML to map[string]interface{} values as is supported by encoding/json stdlib package for generic data extraction. It is not focussed on directly manipulating XML ... only later was encoding map[string]interface{} values to XML added. The following two libs implement XPath in go.

There is a go JPath implementation here:

  • 👍1
suntong commented

Thanks.

I'll give it a try. I found a more expressive solution, a very elegant one which documented here (78 lines in total, including all the document texts):

the following were to change
//Request's ./[ReportingName] use the basename of ./[Url](and also prefixing it with ../TransactionTimer[Name] as well).

Thanks to your goxpath recommendation.