go-jnode

go-jnode is a Go module that makes using generic JSON structures easy. Its API is modeled on Java's jackson tree model.

Go's builtin generic JSON object uses map[string]interface{} for objects, []interface{} for arrays, and string, bool, float64 for everything else. However, using these generic interfaces safely is awkward and verbose.

go-jnode makes things a little easier:

• Create a *jnode.Node with any of the factory methods e.g. jnode.NewObjectNode() or jnode.FromJSON()
• Use chained n.Path(field) or n.Get(index) calls to navigate an object.
• Use n.Entries() to iterate over maps, and n.Elements() to iterate over arrays.
• Use n.AsText() to get a text value. (Or n.AsBool(), n.AsInt() etc)
• Navigation is safe - if the object doesn't have a field or an array doesn't have an index a single MissingNode is returned, for which n.IsMissing() returns true. (The text value of a missing node is empty.)

To install:

go get github.com/soluble-ai/go-jnode

Short example:

import "github.com/soluble-ai/go-jnode"

func example() {
  n := jnode.NewObjectNode().Put("greeting", "hello").Put("subject", "world")

  fmt.Printf("%v\n", n)                     // {"greeting":"hello","subject":"world"}
  fmt.Println(n.Path("greeting").AsText())  // greeting
  fmt.Println(n.Path("not-there").AsText()) // <empty-string>

  n.PutArray("list").Append(1).Append(2)    // adds an Array
  fmt.Println(n.Path("list").Get(1))        // 2

  // can also add slices, which get flattened
  n.Path("list").Append([]string{ "hello", "world" })

  // iteration: use Elements() for arrays, Entries() for maps
  for _, e := range n.Path("list").Elements() {
    fmt.Println(e.AsText());    // "hello" followed by "world"
  }

  // construct from a string
  m, _ := jnode.FromJSON(`{"code":200,"message":"howdy"})`)
  fmt.Println(m.Path("code").AsInt())       // 200
}