解组XML以构造并转换为切片

Question

I have a simple project in Golang which I use to learn this language. Main purpose of the "service" which I'm developing is to run a daemon to save URLs which are exposed as XML. This way I can "produce" my own read-later service. So far so good :). You can find the project here: https://github.com/rogierlommers/readinglist-golang

I'm using Gin-Gonic as the framework for serving html. I've already managed to read an xml file, unmarshal it but now I want to add some new data into this "thing". In other words: I think I need to convert it into a slice, but I don't know how to manage this.

F.e. the endpoint r.GET("/add/:url") should use the function util.AddRecord to insert the new url into the slice. But how?

[edit] Basically my problem can be viewed in this go playground: http://play.golang.org/p/Vx0s02E12R

Answer 1

In a comment on your question you asked:

I first need to create a slice, right?

The answer is yes, but you already have a slice in your ReadingListRecords struct:

type ReadingListRecords struct {
    XMLName xml.Name `xml:"records"`
    Records []Record `xml:"record"`
}

So, you can simply call append on that slice and pass in a new record struct:

records.Records = append(record.Records, Record{xml.Name{"", "record"}, 4, "url", "2015-03-09 00:00:00"})

You could also expand the API for your ReadingListRecords structure to include a handy Append function:

type RecordSet interface {
    Append(record Record) error
}

func (records *ReadingListRecords) Append(record Record) error {
    newRecords := append(records.Records, record)

    if newRecords == nil {
        return errors.New("Could not append record")
    } else {
        records.Records = newRecords
        return nil
    }
}

Adding an interface seems like a good idea since you would like to use this as a service in multiple applications.

See my fork of your playground here.