We are trying to decode a large json string (~200MB) from web api, the dart:convert json decode performance are really bad. We have using compute so it wont affect the UI but the long loading time are blocking the users.
Any other better json decode library in dart?
You can check out this article from Andrea : https://codewithandrea.com/articles/parse-large-json-dart-isolates/
By using compute() we can move our parsing code to the worker isolate and get all the performance benefits we want.
Related
I need to deserialize some JSON objects. I tried to use Tiny-json library, but it's too slow. I tried to use Newtonsoft.Json, but it fails in webplayer with this error:
MissingMethodException: Method not found: 'System.Collections.ObjectModel.KeyedCollection.
What JSON parser do you recommend?
You can try one of these open source solutions:
https://github.com/jacobdufault/fullserializer
https://github.com/mtschoen/JSONObject (https://www.assetstore.unity3d.com/en/#!/content/710) I am using this one most of the times, it's versbose but does its job well, not sure about performance however
Or go with paid ones:
https://www.assetstore.unity3d.com/en/#!/content/11347
Unity 5.3 added Native support of Json Serializer. It is faster than others.
JsonUtility.ToJson to convert a class to Json.
JsonUtility.FromJson to convert Json back to class.
For complete example and information regarding json arrays, see
Serialize and Deserialize Json and Json Array in Unity
So there is a nice library for VB6 JSON parsing. HERE
but i actually used one that built on the original and optimized. HERE
Essentially I'm using the parser to deserialize the json i get from a web service. I need to update some values, and resend to the server. Using the Collection/Dictionary objects made it very easy. But now, How do i take those objects and serialize them to a JSON string? is there a library for that?
thanks you for your help.
There are quite a few JSON parser/serializer/DOM classes written in VB6. Perhaps you might want to consider one of those instead. E.g.:
JsonBag, Another JSON Parser/Generator
I am loading data from a mongodb collection to a mysql table through Kettle transformation.
First I extract them using MongodbInput and then I use json input step.
But since json input step has very low performance, I wanted to replace it with a
javacript script.
I am a beginner in Javascript and even though i tried somethings, the kettle javascript script is not recognizing any keywords.
can anyone give me sample code to convert Json data to different columns using javascript?
To solve your problem you need to see three aspects:
Reading from MongoDB
Reading from JSON
Reading from (probably) String
Reading from MongoDB Except if you changed the interface, MongoDB returns not JSON but BSON files (~binary JSON). You need to see the MongoDB documentation about reading and writing BSON: probably something like BSON.to() and BSON.from() but I don't know it by heart.
Reading from JSON Once you have your BSON in JSON format, you can read it using JSON.stringify() which returns a String.
Reading from (probably) String If you want to use the capabilities of JSON (why else would you use JSON?), you also want to use JSON.parse() which returns a JSON object.
My experience is that to send a JSON object from one step to the other, using a String is not a bad idea, i.e. at the end of a JavaScript step, you write your JSON object to a String and at the beginning of the next JavaScript step (can be further down the stream) you parse it back to JSON to work with it.
I hope this answers your question.
PS: writing JavaScript steps requires you to learn JavaScript. You don't have to be a master, but the basics are required. There is no way around it.
you could use the json input step to get the values of this json and put in common rows
I'm want to try changing a SOAP WCF to accept requests and return results in JSON format to make the data traffic less bulky.
I see that JSON requests functions looks like this:
wcfClient.OpenReadAsync(http://yourUrl.com/wcf/service1.svc/GetEmployees)
and do the regular SOAP requests functions instead that looks like :
wcfClient.GetEmployeesAsync();
1) For JSON results, do you need to parse them into an object or is it automatically parsed like SOAP?
2) Is there a way to do this without doing too much work like changing every single WCF calls in the project to looks "JSON-ish"?
To complement Davut's answer - WCF does support building RESTful services, although I agree that the ASP.NET Web API framework in general easier to use than WCF. JSON.NET is a great library, and it has nice deserialization capabilities (e.g., it can easily take the JSON which represent the list of Employee objects and convert them into the actual List<Employee> instance)
But for completeness sake, if you want to use a "normal" WCF client to access WCF-based services which return JSON, you can do it. It's not too straightforward, but you can do that by using a new encoder and behavior which does the conversion. The post at http://blogs.msdn.com/b/carlosfigueira/archive/2010/04/29/consuming-rest-json-services-in-silverlight-4.aspx talks more about it, and has a pointer to a code sample.
In short, it's possible to consume JSON using a WCF client in Silverlight, but due to its complexity it's usually not done, and Davut's option (use a HTTP client such as WebClient to download JSON, then a library such as JSON.NET to parse it into objects) is preferred.
Firstly the idea "make the data traffic less bulky." is good.
Especially for Mobile devices. Beside this don't think that WCF xml causes network issues for PC. XM is the one of most compressible format. By WCF binary it goes as compressed.
For "Is there a way to do this without doing too much work?"
Yes there is a way name on it RESTFul Services(Restless Services). Now Microsoft directly support it by WEBApi.
Also you may use ODATA for filtering,ordering operations
Here are some links,
http://msdn.microsoft.com/en-us/library/system.servicemodel.web.webgetattribute.aspx
http://blogs.msdn.com/b/rjacobs/archive/2010/06/14/how-to-do-api-key-verification-for-rest-services-in-net-4.aspx
ODATA
http://www.odata.org/documentation/uri-conventions#FilterSystemQueryOption
A few practice notes,Some restrictions:
EntityFrameWork entities derived from EntityObject which has IsReferenceType attribute doesn't allow you to JSON serialize. ( I produced POCO objects using an automapper mapped them and serialized json)
WEBAPI support you much think such as WebGet,WebInvoke GetXML Give JSON ,ODATA features(just select and format not allowed.)
Note:In your web request's header you should accept text/json to get really json.
"For JSON results, do you need to parse them into an object or..."
I can say you should try JSON.NET it's portable library works everywhere. When you deserialize with a generic function it returns you the collection you expect.
Hope it helps someone. While discovering these stackoverflow helped me like an assistant.
I'm working on a custom control that will be fed by JSON content and I'm trying to find the best approach to produce and consume it.
Let say the JSON could be from:
Notes View (all documents)
Notes View (subset of documents based on a category or filter)
Notes Document Collection (from database.Search or database.FTSearch)
What I have on my mind is to define some Custom Properties where I can define:
URL that produces the JSON
Object
etc.
So far I'm considering:
REST Service control from ExtLib
XAgent that produces JSON
Domino URL ?ReadViewEntries and OutputFormat=JSON
Does anyone knows if the JSON object loaded in memory has a size limit?
Any suggestion will be appreciated.
Definitely go for the REST Service control from the Extension Library, offers by far the best combination of flexibility vs performance vs development time.
Matt
What about creating the JSON in the view itself and then just read the column values? http://www.eknori.de/2011-07-23/formula-magic/
If you want to parse the json object using ssjs, you can fetch it using an URLConnection and put the resulting object into a repeat control using the eval statement.