how to filx Unexpected character (at char 1) in flutter - json

Question

hy we have a radio server with the followoing json file
{
"icestats":{
"admin":"icemaster#localhost",
"host":"online.localhost.be",
"location":"Earth",
"server_id":"Icecast 2.4.4",
"server_start":"Sun, 30 Aug 2020 10:50:52 +0200",
"server_start_iso8601":"2020-08-30T10:50:52+0200",
"source":[
{
"audio_info":"ice-samplerate=44100;ice-bitrate=320;ice-channels=2",
"bitrate":320,
"genre":"oldies",
"ice-bitrate":320,
"ice-channels":2,
"ice-samplerate":44100,
"listener_peak":0,
"listeners":0,
"listenurl":"http://127.0.0.1:8000/mp3_320",
"server_description":"Very Oldies!",
"server_name":"loclahost",
"server_type":"audio/mpeg",
"server_url":"https://127.0.0.1:8000",
"stream_start":"Sun, 30 Aug 2020 13:45:16 +0200",
"stream_start_iso8601":"2020-08-30T13:45:16+0200",
"title":"1951: Four Knights - I Love The Sunshine Of Your Smile",
"dummy":null
},
{
"audio_bitrate":320000,
"audio_channels":2,
"audio_info":"ice-samplerate=44100;ice-bitrate=320;ice-channels=2",
"audio_samplerate":44100,
"bitrate":320,
"genre":"oldies",
"ice-bitrate":320,
"ice-channels":2,
"ice-samplerate":44100,
"listener_peak":0,
"listeners":0,
"listenurl":"http://127.0.0.1:8000/ogg_320",
"server_description":"Very Oldies!",
"server_name":"localhost",
"server_type":"application/ogg",
"server_url":"https://127.0.0.1:8000",
"stream_start":"Sun, 30 Aug 2020 13:45:16 +0200",
"stream_start_iso8601":"2020-08-30T13:45:16+0200",
"subtype":"Vorbis",
"dummy":null
}
]
}
}
if io parse this with this model i get the error 'unexpected charcater at 1'
class Autogenerated {
Icestats icestats;
Autogenerated({this.icestats});
Autogenerated.fromJson(Map<String, dynamic> json) {
icestats = json['icestats'] != null
? new Icestats.fromJson(json['icestats'])
: null;
}
Map<String, dynamic> toJson() {
final Map<String, dynamic> data = new Map<String, dynamic>();
if (this.icestats != null) {
data['icestats'] = this.icestats.toJson();
}
return data;
}
}
class Icestats {
String admin;
String host;
String location;
String serverId;
String serverStart;
String serverStartIso8601;
List<Source> source;
Icestats(
{this.admin,
this.host,
this.location,
this.serverId,
this.serverStart,
this.serverStartIso8601,
this.source});
Icestats.fromJson(Map<String, dynamic> json) {
admin = json['admin'];
host = json['host'];
location = json['location'];
serverId = json['server_id'];
serverStart = json['server_start'];
serverStartIso8601 = json['server_start_iso8601'];
if (json['source'] != null) {
source = new List<Source>();
json['source'].forEach((v) {
source.add(new Source.fromJson(v));
});
}
}
Map<String, dynamic> toJson() {
final Map<String, dynamic> data = new Map<String, dynamic>();
data['admin'] = this.admin;
data['host'] = this.host;
data['location'] = this.location;
data['server_id'] = this.serverId;
data['server_start'] = this.serverStart;
data['server_start_iso8601'] = this.serverStartIso8601;
if (this.source != null) {
data['source'] = this.source.map((v) => v.toJson()).toList();
}
return data;
}
}
class Source {
String audioInfo;
int bitrate;
String genre;
int iceBitrate;
int iceChannels;
int iceSamplerate;
int listenerPeak;
int listeners;
String listenurl;
String serverDescription;
String serverName;
String serverType;
String serverUrl;
String streamStart;
String streamStartIso8601;
String title;
Null dummy;
int audioBitrate;
int audioChannels;
int audioSamplerate;
String subtype;
Source(
{this.audioInfo,
this.bitrate,
this.genre,
this.iceBitrate,
this.iceChannels,
this.iceSamplerate,
this.listenerPeak,
this.listeners,
this.listenurl,
this.serverDescription,
this.serverName,
this.serverType,
this.serverUrl,
this.streamStart,
this.streamStartIso8601,
this.title,
this.dummy,
this.audioBitrate,
this.audioChannels,
this.audioSamplerate,
this.subtype});
Source.fromJson(Map<String, dynamic> json) {
audioInfo = json['audio_info'];
bitrate = json['bitrate'];
genre = json['genre'];
iceBitrate = json['ice-bitrate'];
iceChannels = json['ice-channels'];
iceSamplerate = json['ice-samplerate'];
listenerPeak = json['listener_peak'];
listeners = json['listeners'];
listenurl = json['listenurl'];
serverDescription = json['server_description'];
serverName = json['server_name'];
serverType = json['server_type'];
serverUrl = json['server_url'];
streamStart = json['stream_start'];
streamStartIso8601 = json['stream_start_iso8601'];
title = json['title'];
dummy = json['dummy'];
audioBitrate = json['audio_bitrate'];
audioChannels = json['audio_channels'];
audioSamplerate = json['audio_samplerate'];
subtype = json['subtype'];
}
Map<String, dynamic> toJson() {
final Map<String, dynamic> data = new Map<String, dynamic>();
data['audio_info'] = this.audioInfo;
data['bitrate'] = this.bitrate;
data['genre'] = this.genre;
data['ice-bitrate'] = this.iceBitrate;
data['ice-channels'] = this.iceChannels;
data['ice-samplerate'] = this.iceSamplerate;
data['listener_peak'] = this.listenerPeak;
data['listeners'] = this.listeners;
data['listenurl'] = this.listenurl;
data['server_description'] = this.serverDescription;
data['server_name'] = this.serverName;
data['server_type'] = this.serverType;
data['server_url'] = this.serverUrl;
data['stream_start'] = this.streamStart;
data['stream_start_iso8601'] = this.streamStartIso8601;
data['title'] = this.title;
data['dummy'] = this.dummy;
data['audio_bitrate'] = this.audioBitrate;
data['audio_channels'] = this.audioChannels;
data['audio_samplerate'] = this.audioSamplerate;
data['subtype'] = this.subtype;
return data;
}
}
the code i have used i pretty simple this is the code i have used.
if i parse the same code with a simple xml structure this works but with the icecast parsing this does not succeed.
please advice me
var JsonData = 'http://127.0.0.1:8000/status-json.xsl';
var parsedJson = json.decode(JsonData);
var title = Source.fromJson(parsedJson);
is the json formatting of the icecast server incorrect ? it starts with a {
update 1
class User {
String title;
User(Map<String, dynamic> data){
title = data['title'];
}
}
Future<Source> fetchData() async{
var jsonData = 'http://online.doobeedoo.be:8000/status-json.xsl';
final response =
await http.get(jsonData); //wacht to de data is ontvangen (200)
if(response.statusCode == 200)
{
var parsedJson = json.decode(response.body); //parsen van response
var user = User(parsedJson);
return('${user.title}'); //error here (A value of type 'String' can't be returned from function 'fetchData' because it has a return type of 'Future<Source>'.)
}
else
{
throw Exception('Failed to load status.json response file');
}
}

Answer 1

Use the http package to make a request to your server and retrieve a response. Then parse the JSON the way your currently have it. You're currently parsing a String URL. Not a JSON.
import 'package:http/http.dart' as http;
var url = 'http://127.0.0.1:8000/status-json.xsl';
var response = await http.get(url);//Actually get the data at the URL
var parsedJson = json.decode(response.body);//Parse the response
var title = Source.fromJson(parsedJson);