Paprika

Paprika is a JSON library for Scala that aims at simplifying JSON operation in Scala in a fashion similar to Javascript.
Paprika provides JSON parsing and composition as well as dynamic data member access.

Usage

Parsing Text

The following are all valid ways of parsing JSON using Paprika:

Json.parse("[ 15, true, null, { \"prop\": \"value\" }]")
Json.parseFile("data.json")
Json.parseUrl("http://example.com/api/data.json")

When invalid JSON is encountered, Paprika tries to let you know where the error occurred:

A JSON parsing error occurred:
char(27): 5e-3, 3.1,? -4.96 ]
                    ^

Creating a Json Object

There are two ways of creating a Json object. The first is to parse JSON from a string or external source using the static parse methods seen above. The second way is to pass any value to the Json constructor, which will attempt to wrap the value in a JSON structure. The following are equivalent:

val parsed  = Json.parse("[1, 2, 3]")
val wrapped = Json(List(1, 2, 3))

Accessing Data Members

Much like JavaScript, Paprika allows dynamic access to JSON data members without knowing if they actually exist or what their type is. Paprika supports both dot and dictionary notation for property access. Array member access uses standard () notation.

Say we have the following JSON schema in a file "data.json":

{
    "title": "Example Schema",
    "type": "object",
    "properties": {
        "firstName": {
            "type": "string"
        },
        "lastName": {
            "type": "string"
        },
        "age": {
            "description": "Age in years",
            "type": "integer",
            "minimum": 0
        }
    },
    "required": ["firstName", "lastName"]
}

Here's how you can use Paprika to parse it and access its data members:

val json = Json.parseFile("data.json")

println(json.title)      // prints out "Example Schema" - dot notation
println(json("title"))   // also prints out "Example Schema" - dictionary notation

println(json.properties.age.minimum)       // prints out "0" - chaining dot notation
println(json.properties("age").minimum)    // also prints out "0" - alternating between dot and dictionary notation

println(json.required(1))      // prints out "lastName" - array member access
println(json("required")(1))   // also prints out "lastName" - combining dictionary notation with array member access

When a data member that does not exist is accessed, the object JsonUndefined is returned.

val json = Json.parse("{ }")

println(json.prop) // prints out "undefined"       

Data Types

By default, all data members returned from a Json object are also Json objects. However, Json provides both implicit and explicit conversions:

val json = Json.parse("{ \"data\": 2.74 }")

val a = json.data                  // default, a is a Json object
val b = json.data.toDouble         // explicit conversion, b is Double(2.74)
val c : Double = json.data         // implicit conversion, c is Double(2.74)

Iterator

If the JSON structure is an array, then calling .iterator() will return an iterator for the array.
This allows Json objects to be used in for loops:

val json = Json.parse("[ 1, 9 ,0 6, 2 ]")
    
for (n <- json) {
  println(n)
}

This holds true for data members as well:

val json = Json.parse("{ \id"\": 12, \"data\": [ 1, 9 ,0 6, 2 ] }")
    
for (n <- json.data) {
  println(n)
}

Composing JSON String

You can compose a JSON string from an existing Json object using the .mkString() method:

val json = new Json(List(1, 2, 3))
println(json.mkString) // prints out: "[1,2,3]" 

You can also use the static method Json.makeJSON() to convert any object to a JSON string:

val nums = List(1,2,3)
val json = new Json(nums)

println(Json.makeJSON(json)) // prints out: "[1,2,3]"
println(Json.makeJSON(nums)) // prints out: "[1,2,3]"

When converting regular objects to JSON strings, Lists are converted to JSON arrays and Maps are converted to JSON objects. All primitive data types are kept the same; when an incompatible object is found, it is stored as a string by calling that object's .toString() method.

All generated JSON strings are minified.