I've got a Socket coming back with this JSON from a camera
var string:String = socket.readUTFBytes(socket.bytesAvailable);
string = '{"rval":0,"msg_id":514}{ "msg_id": 7, "type": "video_record_complete" ,"param":"/tmp/fuse_d/DCIM/100MEDIA/YDXJ0149.mp4"}';
i.e. 2 JSON objects in the socket.
Is there any way to split them before decoding?
This is the JSON decode error I get when I try and decode them
JSONParseError: Unexpected characters left in input stream
Is there any way to split them before decoding?
Sure, just use split():
var strings:Array = string.split("}{");
However, you can probably just extract each JSON message one at a time using readtUTF() instead of readtUTFBytes() with all bytesAvailable:
while (socket.bytesAvailable) {
var json:String = socket.readUTF();
}
Related
I have a streaming source that produces many JSON objects without separators (or only whitespace in between). If I pass that to json4s parse function, it only produces AST for the first object.
As a workaround, I could parse it manually and either turn it into a JSON array by adding brackets and commas as appropriate or chunk it and call parse on each chunk.
However, this is a rather common format, so I'm sure the problem is already solved. I just cannot find the API for it in json4s documentation.
If you reading it from an InputStream, then use BufferedInputStream wrapper with mark(), read() and reset() calls to skip whitespace(s) between parse() call:
val in = new BufferedInputStream(new FileInputStream("/tmp/your.json"))
try {
var continue = true
in.mark(1)
do {
in.reset()
// <-- here should be call for parse
// skip white spaces or exit if EOF found
var b = 0
do {
in.mark(1)
b = in.read()
if (b < 0) continue = false
} while (Character.isWhitespace(b))
} while (continue)
} finally in.close()
EDIT: Today I have released 0.11.0 version of jsoniter-scala with new ability to parse streaming JSON values or JSON arrays w/o need to hold all values in memory.
so i have this data which is outputted from stringify(doc)
{
"id": "8467fdae-c38c-4b6e-9492-807d7c9eb97e",
"message": "send to nodejs"
}
but im not sure how can i go ahead in getting a single value from it, e.g message. Any help would be appreciated as ive tried different methods and they seem to not be working
After you use stringify method the value you have is string.
So You can not get single property from it, except you convert it become object again and get property it. Like this:
object = {
"id": "8467fdae-c38c-4b6e-9492-807d7c9eb97e",
"message": "send to nodejs"
};
// JSON string is value which you get after use Stringify method
jsonString = JSON.stringify(object);
// Convert jsonString to object again and get message property
message = JSON.parse(jsonString).message
stringify() will convert json to string.
Before running stringify(), doc is already json and you can get message by doc.message.
after running stringify(), the result will be string, if you want to get json back, you can use JSON.parse()
I have a JSON file that contains what I believe to be a correct JSON string:
{"title": "exampleTitle", "tipTitle": "exampleTipTitle", "tip": "exampleTip"}
I'm trying to parse said file and take out the 3 values then store them in variables, however currently, it parses each individual character as a separate object, therefore:
JSONobj[1] = "
and so on. Assuming that currentLocation = the directory location of the json file.
Code
var jsonLocation = currentLocation + "json.txt";
var request = new XMLHttpRequest();
request.open("GET", jsonLocation, false);
request.send(null);
var returnValue = request.responseText;
var JSONobj = JSON.parse(JSON.stringify(returnValue));
var headerTitle = JSONobj[0];
A few clarifications, the stringify is in because it was throwing an unexpected token error. I've tried changing the file tile to .json instead but that also makes no difference. "It also gives off a XMLHttpRequest on the main thread is deprecated" but I'm not particularly sure how to solve that issue. Any help would be appreciated.
var returnValue = request.responseText;
Here returnValue is a string of JSON.
"{\"title\": \"exampleTitle\", \"tipTitle\": \"exampleTipTitle\", \"tip\": \"exampleTip\"}
var JSONobj = JSON.parse(JSON.stringify(returnValue));
Here you convert the string of JSON to JSON. So you have a JSON string representing a string, and that string is a representation of a data structure in JSON.
"\"{\\"title\\": \\"exampleTitle\\", \\"tipTitle\\": \\"exampleTipTitle\\", \\"tip\\": \\"exampleTip\\"}"
Then you parse it and convert it back to the original string of JSON.
"{\"title\": \"exampleTitle\", \"tipTitle\": \"exampleTipTitle\", \"tip\": \"exampleTip\"}
So you end up back where you start.
Just don't use JSON.stringify here, and you'll convert your JSON to a JavaScript object:
var javascript_object = JSON.parse(returnValue);
Then you have an object, but it doesn't have a 0 property so it doesn't make sense to access it with javascript_object[0]. The properties have names, such as javascript_object.title.
Your JSON doesn't describe an array, so indexing into it with an index like 0 doesn't make sense. Your JSON describes an object, which will have properties with the names title, tipTitle, and tip.
Additionally, you're overdoing your parsing: You just want to parse, not stringify (which is the opposite of parsing):
var JSONobj = JSON.parse(returnValue);
So:
var JSONobj = JSON.parse(returnValue);
var headerTitle = JSONobj.title;
console.log(headerTitle); // "exampleTitle"
Side note: By the time you've assigned it to the variable you've called JSONobj, it isn't JSON anymore, it's just a normal JavaScript object, so that name is a bit misleading. If you're writing source code, and you're not dealing with a string, you're not dealing with JSON anymore. :-)
I want to store the result from a call to a Domino Access Service (DAS) in a localStorage however when I try to convert the result object to a JSON string I get an error.
With DAS you get the result as an Array e.g.:
[
{
"#entryid":"1-CD90722966A36D758025725800726168",
"#noteid":"16B46",
Does anyone know how I get rid of the square brackets or convert the Array quickly to a JSON object?
Here is a snippet of my code:
var REST = "./myREST.xsp/notesView";
$.getJSON(REST,function(data){
if(localStorage){
localStorage.setItem('myCatalog',JSON.stringify(data));
}
});
Brackets are part of the JSON syntax. They indicate that this is an array of objects. And as you point to a view it is very likely that you would get more than one object back (one for each entry in the view).
So if you are only interested in the first element you could do this:
var REST = "./myREST.xsp/notesView";
$.getJSON(REST,function(data){
if(localStorage){
var firstRecord = data[0] || {};
localStorage.setItem('myCatalog',JSON.stringify(firstRecord));
}
});
Otherwise, you would need to define a loop to handle each of the objects :-)
/John
I'm trying to deserialize some JSON coming back from couchbase into a dynamic type.
The document is something like this so creating a POCO for this would be overkill:
{
UsersOnline: 1
}
I figured that something like this would do the trick, but it seems to deserialize into a dynamic object with the value just being the original JSON
var jsonObj = _client.GetJson<dynamic>(storageKey);
results in:
jsonObj { "online": 0 }
Is there anyway I can get the couchbase deserializer to generate the dynamic type for me?
Cheers
The default deserializer for the client uses .NET's binary serializer, so when you save or read a JSON string, it's just a string. GetJson will always just return a string. However, there are a couple of options:
You could convert JSON records to Dictionary instances:
var appJson = "{ \"UsersOnline\" : 1, \"NewestMember\" : \"zblock\" }";
var result = client.ExecuteStore(StoreMode.Set, "userCount", appJson);
var item = client.GetJson<Dictionary<string, object>>("userCount");
Console.WriteLine("There are {0} users online. The newest member is {1}.",
item["UsersOnline"], item["NewestMember"]);
Or you could use a dynamic ExpandoObject instance:
var appJson = "{ \"UsersOnline\" : 1, \"NewestMember\" : \"zblock\" }";
var result = client.ExecuteStore(StoreMode.Set, "userCount", appJson);
dynamic item = client.GetJson<ExpandoObject>("userCount");
Console.WriteLine("There are {0} users online. The newest member is {1}.",
item.UsersOnline, item.NewestMember);
In either case you're losing static type checking, which seems like it's OK for your purposes. In both cases you get access to the JSON properties without having to parse the JSON into a POCO though...
Edit: I wrote a couple of extension methods that may be useful and blogged about them at http://blog.couchbase.com/moving-no-schema-stack-c-and-dynamic-types