After reading a JSON result from a web service response:
val jsonResult: JsValue = Json.parse(response.body)
Containing content something like:
{
result: [
["Name 1", "Row1 Val1", "Row1 Val2"],
["Name 2", "Row2 Val1", "Row2 Val2"]
]
}
How can I efficiently map the contents of the result array in the JSON with a list (or something similar) like:
val keys = List("Name", "Val1", "Val2")
To get an array of hashmaps?
Something like this ?
This solution is functional and handles None/Failure cases "properly" (by returning a None)
val j = JSON.parseFull( json ).asInstanceOf[ Option[ Map[ String, List[ List[ String ] ] ] ] ]
val res = j.map { m ⇒
val r = m get "result"
r.map { ll ⇒
ll.foldRight( List(): List[ Map[ String, String ] ] ) { ( l, acc ) ⇒
Map( ( "Name" -> l( 0 ) ), ( "Val1" -> l( 1 ) ), ( "Val2" -> l( 2 ) ) ) :: acc
}
}.getOrElse(None)
}.getOrElse(None)
Note 1: I had to put double quotes around result in the JSON String to get the JSON parser to work
Note 2: the code could look nicer using more "monadic" sugar such as for comprehensions or using applicative functors
Related
I am trying to generate auto json paths from given json structure but stuck in the programatic part. Can someone please help out with the idea to take it further?
Below is the code so far i have achieved.
def iterate_dict(dict_data, key, tmp_key):
for k, v in dict_data.items():
key = key + tmp_key + '.' + k
key = key.replace('$$', '$')
if type(v) is dict:
tmp_key = key
key = '$'
iterate_dict(v, key, tmp_key)
elif type(v) is list:
str_encountered = False
for i in v:
if type(i) is str:
str_encountered = True
tmp_key = key
break
tmp_key = key
key = '$'
iterate_dict(i, key, tmp_key)
if str_encountered:
print(key, v)
if tmp_key is not None:
tmp_key = str(tmp_key)[:-str(k).__len__() - 1]
key = '$'
else:
print(key, v)
key = '$'
import json
iterate_dict_new(dict(json.loads(d_data)), '$', '')
consider the below json structure
{
"id": "1",
"categories": [
{
"name": "author",
"book": "fiction",
"leaders": [
{
"ref": ["wiki", "google"],
"athlete": {
"$ref": "some data"
},
"data": {
"$data": "some other data"
}
}
]
},
{
"name": "dummy name"
}
]
}
Expected output out of python script:
$id = 1
$categories[0].name = author
$categories[0].book = fiction
$categories[0].leaders[0].ref[0] = wiki
$categories[0].leaders[0].ref[1] = google
$categories[0].leaders[0].athlete.$ref = some data
$categories[0].leaders[0].data.$data = some other data
$categories[1].name = dummy name
Current output with above python script:
$.id 1
$$.categories.name author
$$.categories.book fiction
$$$.categories.leaders.ref ["wiki", "google"]
$$$$$.categories.leaders.athlete.$ref some data
$$$$$$.categories.leaders.athlete.data.$data some other data
$$.name dummy name
The following recursive function is similar to yours, but instead of just displaying a dictionary, it can also take a list. This means that if you passed in a dictionary where one of the values was a nested list, then the output would still be correct (printing things like dict.key[3][4] = element).
def disp_paths(it, p='$'):
for k, v in (it.items() if type(it) is dict else enumerate(it)):
if type(v) is dict:
disp_paths(v, '{}.{}'.format(p, k))
elif type(v) is list:
for i, e in enumerate(v):
if type(e) is dict or type(e) is list:
disp_paths(e, '{}.{}[{}]'.format(p, k, i))
else:
print('{}.{}[{}] = {}'.format(p, k, i, e))
else:
f = '{}.{} = {}' if type(it) is dict else '{}[{}] = {}'
print(f.format(p, k, v))
which, when ran with your dictionary (disp_paths(d)), gives the expected output of:
$.categories[0].leaders[0].athlete.$ref = some data
$.categories[0].leaders[0].data.$data = some other data
$.categories[0].leaders[0].ref[0] = wiki
$.categories[0].leaders[0].ref[1] = google
$.categories[0].book = fiction
$.categories[0].name = author
$.categories[1].name = dummy name
$.id = 1
Note that this is unfortunately not ordered, but that is unavoidable as dictionaries have no inherent order (they are just sets of key:value pairs)
If you need help understanding my modifications, just drop a comment!
I'm trying to find URLs in a nested JSON response and map them. My function so far looks like this:
def list(env, id) do
Service.get_document(env, id)
|> Poison.decode!
|> Enum.find(fn {_key, val} -> String.starts_with?(val, 'https') end)
end
The JSON looks roughly like this:
"stacks": [
{
"boxes": [
{
"content": "https://ddd.cloudfront.net/photos/uploaded_images/000/001/610/original/1449447147677.jpg?1505956120",
"box": "photo"
}
]
}
],
"logo": "https://ddd.cloudfront.net/users/cmyk_banners/000/000/002/original/banner_CMYK.jpg?1397201875"
So URLs can have any key, and be at any level.
With that code I get this error:
no function clause matching in String.starts_with?/2
Anyone got a better way to find in JSON responses?
You'll have to use recursive function for this, which handles three types of data:
For map, it recurses over all its values.
For list, it recurses over all its elements.
For string, it selects strings that start with "https"
Here's a simple implementation which accepts a term and a string to check with starts_with?:
defmodule A do
def recursive_starts_with(thing, start, acc \\ [])
def recursive_starts_with(binary, start, acc) when is_binary(binary) do
if String.starts_with?(binary, start) do
[binary | acc]
else
acc
end
end
def recursive_starts_with(map, start, acc) when is_map(map) do
Enum.reduce(map, acc, fn {_, v}, acc -> A.recursive_starts_with(v, start, acc) end)
end
def recursive_starts_with(list, start, acc) when is_list(list) do
Enum.reduce(list, acc, fn v, acc -> A.recursive_starts_with(v, start, acc) end)
end
end
data = %{
"stacks" => [
%{
"boxes" => [
%{
"content" => "https://ddd.cloudfront.net/photos/uploaded_images/000/001/610/original/1449447147677.jpg?1505956120",
"box" => "photo"
}
]
}
],
"logo" => "https://ddd.cloudfront.net/users/cmyk_banners/000/000/002/original/banner_CMYK.jpg?1397201875"
}
data |> A.recursive_starts_with("https") |> IO.inspect
Output:
["https://ddd.cloudfront.net/photos/uploaded_images/000/001/610/original/1449447147677.jpg?1505956120",
"https://ddd.cloudfront.net/users/cmyk_banners/000/000/002/original/banner_CMYK.jpg?1397201875"]
I need to create a Json with 2 elements. The First element is a List and the second element is simple key-value pair.
My output looks as follows:
"{
"tables":[
{"table": "sn: 2134"},
{"table": "sn: 5676"},
{"table": "sn: 4564"},
],
"paid": 219
}"
In the example , the first element is tables which is List of table. The second element is paid.
I tried it using play.api.libs.json lib , but stuck while adding second element.
My code looks as follows:
case class Input(table:String){
override def toString = s""""table" : "sn: $table""""
}
implicit val userFormat = Json.format[Input]
val inputsSeq = Seq(Input(table1),Input(table2),Input(table3))
val users = Json.obj("tables" -> inputsSeq)
println(users)
This code print Json as :
"{
"tables":[
{"table": "sn: 2134"},
{"table": "sn: 5676"},
{"table": "sn: 4564"},
]
}
I am not sure, how to add the second element in this json. any suggestion how to
resolve this.
Json.obj accepts multiple pairs of (String, JsValueWrapper) as its arguments:
object Json {
...
def obj(fields: (String, JsValueWrapper)*): JsObject = JsObject(fields.map(f => (f._1, f._2.asInstanceOf[JsValueWrapperImpl].field)))
...
}
So you can add both elements like this:
val users = Json.obj("tables" -> inputsSeq, "paid" -> 219)
I have a JSON structure that contains an array of events. The array is "polymorphic" in the sense that there are three possible event types A, B and C:
{
...
"events": [
{ "eventType": "A", ...},
{ "eventType": "B", ...},
{ "eventType": "C", ...},
...
]
}
The three event types don't have the same object structure, so I need different Reads for them. And apart from that, the target case class of the whole JSON document distinguishes between the events:
case class Doc(
...,
aEvents: Seq[EventA],
bEvents: Seq[EventB],
cEvents: Seq[EventC],
...
)
How can I define the internals of Reads[Doc] so that the json array events is split into three subsets which are mapped to aEvents, bEvents and cEvents?
What I tried so far (without being succesful):
First, I defined a Reads[JsArray] to transform the original JsArray to another JsArray that only contains events of a particular type:
def eventReads(eventTypeName: String) = new Reads[JsArray] {
override def reads(json: JsValue): JsResult[JsArray] = json match {
case JsArray(seq) =>
val filtered = seq.filter { jsVal =>
(jsVal \ "eventType").asOpt[String].contains(eventTypeName)
}
JsSuccess(JsArray(filtered))
case _ => JsError("Must be an array")
}
}
Then the idea is to use it like this within Reads[Doc]:
implicit val docReads: Reads[Doc] = (
...
(__ \ "events").read[JsArray](eventReads("A")).andThen... and
(__ \ "events").read[JsArray](eventReads("B")).andThen... and
(__ \ "events").read[JsArray](eventReads("C")).andThen... and
...
)(Doc.apply _)
However, I don't know how to go on from here. I assume the andThen part should look something like this (in case of event a):
.andThen[Seq[EventA]](EventA.reads)
But that doesn't work since I expect the API to create a Seq[EventA] by explicitly passing a Reads[EventA] instead of Reads[Seq[EventA]]. And apart from that, since I've never got it running, I'm not sure if this whole approach is reasonable in the first place.
edit: in case the original JsArray contains unknown event types (e.g. D and E), these types should be ignored and left out from the final result (instead of making the whole Reads fail).
put implicit read for every Event type like
def eventRead[A](et: String, er: Reads[A]) = (__ \ "eventType").read[String].filter(_ == et).andKeep(er)
implicit val eventARead = eventRead("A", Json.reads[EventA])
implicit val eventBRead = eventRead("B", Json.reads[EventB])
implicit val eventCRead = eventRead("C", Json.reads[EventC])
and use Reads[Doc] (folding event list to separate sequences by types and apply result to Doc):
Reads[Doc] = (__ \ "events").read[List[JsValue]].map(
_.foldLeft[JsResult[ (Seq[EventA], Seq[EventB], Seq[EventC]) ]]( JsSuccess( (Seq.empty[EventA], Seq.empty[EventB], Seq.empty[EventC]) ) ){
case (JsSuccess(a, _), v) =>
(v.validate[EventA].map(e => a.copy(_1 = e +: a._1)) or v.validate[EventB].map(e => a.copy(_2 = e +: a._2)) or v.validate[EventC].map(e => a.copy(_3 = e +: a._3)))
case (e, _) => e
}
).flatMap(p => Reads[Doc]{js => p.map(Doc.tupled)})
it will create Doc in one pass through events list
JsSuccess(Doc(List(EventA(a)),List(EventB(b2), EventB(b1)),List(EventC(c))),)
the source data
val json = Json.parse("""{"events": [
| { "eventType": "A", "e": "a"},
| { "eventType": "B", "ev": "b1"},
| { "eventType": "C", "event": "c"},
| { "eventType": "B", "ev": "b2"}
| ]
|}
|""")
case class EventA(e: String)
case class EventB(ev: String)
case class EventC(event: String)
I would model the fact that you store different event types in your JS array as a class hierarchy to keep it type safe.
sealed abstract class Event
case class EventA() extends Event
case class EventB() extends Event
case class EventC() extends Event
Then you can store all your events in a single collection and use pattern matching later to refine them. For example:
case class Doc(events: Seq[Event]) {
def getEventsA: Seq[EventA] = events.flatMap(_ match {
case e: EventA => Some(e)
case _ => None
})
}
Doc(Seq(EventA(), EventB(), EventC())).getEventsA // res0: Seq[EventA] = List(EventA())
For implementing your Reads, Doc will be naturally mapped to the case class, you only need to provide a mapping for Event. Here is what it could look like:
implicit val eventReads = new Reads[Event] {
override def reads(json: JsValue): JsResult[Event] = json \ "eventType" match {
case JsDefined(JsString("A")) => JsSuccess(EventA())
case JsDefined(JsString("B")) => JsSuccess(EventB())
case JsDefined(JsString("C")) => JsSuccess(EventC())
case _ => JsError("???")
}
}
implicit val docReads = Json.reads[Doc]
You can then use it like this:
val jsValue = Json.parse("""
{
"events": [
{ "eventType": "A"},
{ "eventType": "B"},
{ "eventType": "C"}
]
}
""")
val docJsResults = docReads.reads(jsValue) // docJsResults: play.api.libs.json.JsResult[Doc] = JsSuccess(Doc(List(EventA(), EventB(), EventC())),/events)
docJsResults.get.events.length // res1: Int = 3
docJsResults.get.getEventsA // res2: Seq[EventA] = List(EventA())
Hope this helps.
Given a JSON array like this one:
{
"success": true,
"data": [
{
"id": 600,
"title": "test deal",
"e54cbe3a434d8e6": 54
},
{
"id": 600,
"title": "test deal",
"e54cbe3a434d8e6": 54
},
],
"additional_data": {
"pagination": {
"start": 0,
"limit": 100,
"more_items_in_collection": false
}
}
}
In my Play 2.2.2 application, using the Scala JSON Reads Combinator, everything works going this way:
implicit val entityReader = Json.reads[Entity]
val futureJson: Future[List[Entity]] = futureResponse.map(
response => (response.json \ "data").validate[List[Entity]].get
The problem now is the key named 'e54cbe3a434d8e6' which I would like to name 'value' in my object:
// This doesn't work, as one might expect
case class Entity(id: Long, title: String, e54cbe3a434d8e6: Long)
// I would like to use 'value' instead of 'e54cbe3a434d8e6'
case class Entity(id: Long, title: String, value: Long)
There is vast information about the combinators here and here but I only want to use a fieldname which is different from the key name in the JSON array. Can some one help me to find a simple way?
I suppose it has got something to do with JSON.writes?!
One simple way without trying to apply transformations on json itself is to define a custom Reads in such a way to handle this:
val json = obj(
"data" -> obj(
"id" -> 600,
"title" -> "test deal",
"e54cbe3a434d8e6" -> 54))
case class Data(id: Long, title: String, value: Int)
val reads = (
(__ \ "id").read[Long] ~
(__ \ "title").read[String] ~
(__ \ "e54cbe3a434d8e6").read[Int] // here you get mapping from your json to Scala case class
)(Data)
def index = Action {
val res = (json \ "data").validate(reads)
println(res) // prints "JsSuccess(Data(600,test deal,54),)"
Ok(json)
}
Another way is to use combinators like this:
... the same json and case class
implicit val generatedReads = reads[Data]
def index = Action {
val res = (json \ "data").validate(
// here we pick value at 'e54cbe3a434d8e6' and put into brand new 'value' branch
__.json.update((__ \ "value").json.copyFrom((__ \ "e54cbe3a434d8e6").json.pick)) andThen
// here we remove 'e54cbe3a434d8e6' branch
(__ \ "e54cbe3a434d8e6").json.prune andThen
// here we validate result with generated reads for our case class
generatedReads)
println(res) // prints "JsSuccess(Data(600,test deal,54),/e54cbe3a434d8e6/e54cbe3a434d8e6)"
Ok(prettyPrint(json))
}