I have a json file that I'm getting from the web that starts with the characters )]}',. Example:
)]}',
{<DATA START HERE>}
I want to read this data with Response response = await dio.get(url);, but the first line of that json file is causing errors. How can I tell dio to skip the first line?
That's rather strange. I wonder if it's some special guard characters generated by the server. Ask them why they add it.
That said, as long as it's the same pattern each time, it looks like the garbage is on a different line from the json. So, just split the string and pick up the second line.
Here's an example using http. Adapt it for dio if you prefer that.
main() async {
http.Response response = await http.get(
'https://25live.collegenet.com/25live/data/umd/run/availability/availabilitydata.json?etc');
String val = response.body;
String validJson = val.split('\n')[1];
Map<String, dynamic> decodedJson = json.decode(validJson);
print(decodedJson);
}
Related
I got my data from the server. I need to JSON decode them, before I use it. The problem is, the response data contains some extra text data too. So, when I use
String/ Iterable decodedData = json.decode(responseData)/ jsonDecode(responseData);
It gives me an error:
SyntaxError: Unexpected token < in JSON at position 0
My response from the server:
Message has been sent{"unique_id":"2021080504511401","role_id":3,"category_id":"1","first_name":"Nasir","phone":"23423423430","nid":"234234234","f_name":"sadfasdf","blood_group":"AB+","profession":"Farmer","gender":"female","address":"asdfasdfasdf","image":null,"district_id":null,"upazilla_id":"1","union_id":null,"email":"alskdsfjserdf#gmail.com","updated_at":"2021-08-05T10:51:14.000000Z","created_at":"2021-08-05T10:51:14.000000Z","id":60}
I need to get the object only. I can remove the non-used string data by accessing the index. But what if the text before the object is dynamic? I need a stable solution now.
I prepared an example for you, I hope it solves your problem.
final response = '''
Message has been sent{"unique_id":"2021080504511401","role_id":3,"category_id":"1","first_name":"Nasir","phone":"23423423430","nid":"234234234","f_name":"sadfasdf","blood_group":"AB+","profession":"Farmer","gender":"female","address":"asdfasdfasdf","image":null,"district_id":null,"upazilla_id":"1","union_id":null,"email":"alskdsfjserdf#gmail.com","updated_at":"2021-08-05T10:51:14.000000Z","created_at":"2021-08-05T10:51:14.000000Z","id":60}
''';
final objectStartIndex = response.indexOf('{');
final objectData = response.substring(objectStartIndex);
final decodedData = jsonDecode(objectData);
print('Result: $decodedData');
I am making a curl call to rest api visa curl in groovy. Response is coming fine but the response is very large, it is a 17MB of data, following is my script :
def converter = "curl.......'"
def initialSize = 4096
def out = new ByteArrayOutputStream(initialSize)
def err = new ByteArrayOutputStream(initialSize)
def process = [ 'bash', '-c', converter].execute()
process.consumeProcessOutput(out, err)
process.waitFor()
Curl response is coming fine, when I print response on console ,store in variable out, it gives response data where it is not neat json as I see some "/n" characters. When I write this to file then I dont see any new line and neat json, all I see data in one line in key value format.
{"key1":"value1","key2":"value2",} in one huge line only
This is when i view in sublime. Now I want to convert this to pretty json and write neatly into file.I tried following to approaches but both prints empty ({ }) in console and in file.
def json = JsonOutput.toJson(out)
println new JsonBuilder(out).toPrettyString()
What did I miss?
I am trying to use groovy libraries only.
UPDATE:
As i try to debug, i found that it may be because all JSON parsers expect string but my output is ByteArrayOutputStream. But now how can I convert the out to string ? I tried out.toString and out.text, it does not work.
Use StringWriter instead of ByteArrayOutputStream
Then JsonOutput.prettyPrint( stringWriter.toString() )
I have installed TileServer.php. When I navigate to it, I can see my tiles (so it's working).
My issue is when I query for the getCapabilities file the resulting json file is malformed.
The json is prefixed with part of the query string at the start of the json response.
Here is the full query string:
http://<=my ip=>/tileserver/index.html?service=wmts&request=getcapabilities&version=1.0.0
Actual Json Response I Receive
(Notice wmts&request is prefixed to the otherwise valid json)
====JSON===============================
wmts&request([{"name":"190322","type":"overlay","description":"190322","version":"1.1","format":"png","bounds":[174.92249449474565,-36.991878207885335,174.93635413927785,-36.98244705946717],"maxzoom":22,"minzoom":14,"basename":"1313_190322","profile":"mercator","scale":1,"tiles": ...
==================================================
I have tried removing part of the query string to test for the results, oddly enough it grabs the part of the query string again.
Here is the full query string I tested with:
http://<=my ip=>/tileserver/index.html?request=getcapabilities&version=1.0.0
(Actual Json Response I Receive)
====JSON===============================
getcapabilities&version([{"name":"190322","type":"overlay","description":"190322","version":"1.1","format":"png","bounds":[174.92249449474565,-36.991878207885335,174.93635413927785,-36.98244705946717],"maxzoom":22,"minzoom":14,"basename":"1313_190322","profile":"mercator","scale":1,"tiles": ...
=======================================================
I could parse this out I suppose but I would like to find the cause for this issue.
I am using ASP.Net 5.0.
Here is roughly my code:
private static readonly string _tileserver_ip = "http://<my ip>/tileserver/";
HttpClient client = new HttpClient();
client.DefaultRequestHeaders.Accept.Clear();
client.DefaultRequestHeaders.Accept.Add(
new MediaTypeWithQualityHeaderValue("application/json"));
var query = new Dictionary<string, string>
{
["service"] = "wmts",
["request"] = "getcapabilities",
["version"] = "1.0.0"
};
var response = await client.GetAsync(QueryHelpers.AddQueryString(_tileserver_ip, query));
var capabilitiesString = await response.Content.ReadAsStringAsync();
// the result of the query string => "http://<my ip>/tileserver/?service=wmts&request=getcapabilities&version=1.0.0"
EDIT
Opps! Turns out I was requesting the getCapabilities file from the TileServer in the completely wrong way.
I will leave this here encase it helps someone in the future.
Here is the correct URL: http://<= my url =>/tileserver/1.0.0/WMTSCapabilities.xml/wmts
I found the answer and I will leave this post here encase it helps someone in the future.
In my URL I was using index.html as the index page, however I should have been using index .json instead.
As soon as I switched to .json I received the JSON response as I was expecting.
Full URL with query string:
http://<=my ip=>/tileserver/index.json?service=wmts&request=getcapabilities&version=1.0.0
How are you doing?
I'm trying to get data from a json to show on a screen that should be like the image below. I'm able to get most of the data, except for one field coded as String which consists of the image and a description like this one:
"lessonText": "{\"ops\":[{\"insert\":{\"image\":\"data:image/jpeg;base64,(IMAGE CODE HERE)=\"}},{\"attributes\":{\"color\":\"#444444\"},\"insert\":\"(LESSON TEXT HERE)\"},{\"insert\":\"\\n\"}]}",
How do I extract data from here? I have tried to convert this to a Map but it is not working.
Thanks for the help!
Something in line with this should give you the image
// json string containing the base64 image string
String jsonString = "{\"ops\":[{\"insert\":{\"image\":\"data:image/png;base64,(IMAGE CODE HERE)=\"}},{\"attributes\":{\"color\":\"#444444\"},\"insert\":\"(LESSON TEXT HERE)\"},{\"insert\":\"\\n\"}]}";
// convert the string to a map structure
Map<String, dynamic> json = jsonDecode(jsonString);
// extract the image string
String imageString = json['ops'][0]['insert']['image'];
// extract the base64 string
var prefix = "data:image/png;base64,";
var imageBase64String = imageString.substring(prefix.length);
// decode the base 64 string
var bytes = base64Decode(imageBase64String);
// build the image widget from bytes
var imageWidget = Image.memory(bytes);
As I mentioned in the comments, use a combination of decoding the base64 string to bytes and then loading the image from memory. See the the relevant documentation for base64Decode and Image.memory. If you would like a full code sample just let me know and I would be happy to throw one together.
Note: you should run the base64Decode method asynchronously, as it may take some time to decode an entire image (especially on lower-end hardware).
I am reading a JSON file using fs.readFileSync(fileName, 'utf8'); but the results include newline characters, and the output is getting like:
"{\r\n \"name\":\"Arka\",\r\n \"id\": \"13\"\r\n}"
How do I avoid these characters?
my local file looks like:
{
"name":"Arka",
"id": "13"
}
Its unnecessary to read JSON in using fs.readFileSync(). This requires you to also write a try/catch block around the fs.readFileSync() usage and then use JSON.parse() on the file data. Instead you can require JSON files in Node as if they were packages. They will get parsed as if you read the file in as a string and then used JSON.parse(), this simplifies the reading of JSON to one line.
let data = require(fileName)
console.log(data) // { name: 'Arka', id: '13' }
If you want to serialize the parsed JS object within data to a file without the new line & carriage return characters you can write the JSON string to a file using JSON.stringify() only passing in data.
const {promisify} = require('util')
const writeFile = util.promisify(require('fs').writeFile)
const data = require(fileName)
const serializeJSON = (dest, toJson) => writeFile(dest, JSON.stringify(toJson))
serializeJSON('./stringify-data.json', data)
.then(() => console.log('JSON written Successfully'))
.catch(err => console.log('Could not write JSON', err))
You could read the file and then remove them with a regex:
var rawJson = fs.readFileSync(fileName, 'utf8');
rawJson = rawJson.replace(/\r|\n/g, '');
Keep in mind though that for parsing JSON with JSON.parse, you don't need to do this. The result will be the same with and without the newlines.