In django view I want to be able to serialize whole context, that is usually used to send to template (typically by calling render and passing locals).
I want to experiment with SPA+API and possibilities to go forward with and I'd like to create function, that would serialize locals to json and return it as json response.
Now problem is, that locals is typically mix of lists, dists and querysets of models.
I can serialize models using django.core.serializers or using django-rest-framework. I can serialize dict with primitive types using json library, but I don't know any simple way how to do mix of those.
Ideal would be way to go through locals dictionary and replace all found models with their serialized representations and then put it all together, maybe even specify before what serializer (in sense of drf) to use for which model. But I really don't want to reinvent wheel in case it already exists.
Anoher question is - is this even a good idea to try to do this? Return json context as alternative to server side rendering? I am in prototyping stage so I am still thinking of how to move forward and any input in the area is appreciated.
I would recommand to go with DRF
ModelSerializer will return a Json encoded array of model
Serializer with DictField will return a Json encoded dict
Serializer with ListField will return a Json encoded list
You can create Serializer with field is another Serializer for nesting purpose.
https://www.django-rest-framework.org/api-guide/fields/#composite-fields
https://www.django-rest-framework.org/api-guide/serializers/#dealing-with-nested-objects
For your' question is this a good idea, i would said :
If you push data to an external source (not django) it's fine
If you push data to django template it's a bad idea, you loose a lot of django power :(
Related
To keep this simple:
I have classes defined in typescript which have methods and properties (with lots of getter/setter logic). I then retrieve json data matching such classes. I need to be able to project these json objects into my "smart" classes. I know about class transformer but I wonder if this is really go-to approach to do this kind of stuff. Furthermore, I'm planning on using ngrx, so this whole class-transformation just looks wrong (server to json, json to state, state to class? and viceversa? I just dont see a clear pattern.
Any clarity is appreciated. Thanks!
I'm doing almost exactly what you describe in a fairly large app.
I'm using class-transformer to transform the JSON from http calls to instances of the appropriate objects, and then using the resulting objects as state in a store (except that I'm using Redux instead of ngrx).
I find that it works very well.
I'm not sure exactly what you mean by "server to json, json to state, state to class? and viceversa?".
For me (using your terminology), it's server to json, json to class, class to state
(but state is just a collection of objects, i.e. class instances. I.E. state is objects).
If I need to send state back to the server, then yes, I typically pull the appropriate objects from the store, serialize them to JSON, and send them to the server. But...the Angular HttpClient does the serialization for you, so you don't typically have to write that part, unless you need some custom serialization.
I want to parse JSON data from a RESTful service.
Unlike a SOAP-based service, where a service consumer can create stubs and skeleton from WSDL, in the case of the RESTful service, the service consumer gets a raw JSON string.
Since the service consumer does not have a Java object matching the JSON structure, we are not able to use the JSON to Java Mappers like GSON, Jackson etc.
One another way is to use parsers like JsonPath, minimal-json, etc which help traversing the JSON structure and read the data.
Is there any better way of reading JSON data?
The official docs for Jackson mention 3 different ways to parse a JSON doc from Java. The first 2 do not require "Java object matching the JSON structure". In Summary :
Streaming API (aka "Incremental parsing/generation") reads and writes JSON content as discrete events.
Tree Model provides a mutable in-memory tree representation of a JSON document. ObjectMapper can build trees that consist of JsonNode nodes.
Data Binding converts JSON to and from POJOs based either on property accessor conventions or annotations.
With simple data binding you convert to and from Java Maps, Lists, Strings, Numbers, Booleans and nulls
With full data binding you convert to and from any Java bean type (as well as "simple" types mentioned above)
Another option is to generate Java Beans from JSON documents. You mileage may vary and you may/probably will have to modify the generated files. There are at least 5 online tools for that purpose that you can try:
http://www.jsonschema2pojo.org/
http://pojo.sodhanalibrary.com/
https://timboudreau.com/blog/json/read
http://jsongen.byingtondesign.com/
http://json2java.azurewebsites.net/
There are also IDE plugins that you can use. For instance this one for Intellij https://plugins.jetbrains.com/idea/plugin/7678-jackson-generator-plugin
The GSON supports work without objects, too. Something as this:
JsonObject propertiesWrapper = new JsonParser().parse(responseContent).getAsJsonObject();
assertNotNull(propertiesWrapper);
propertiesWrapper = propertiesWrapper.getAsJsonObject("properties");
assertNotNull(propertiesWrapper);
JsonArray propertiesArray = propertiesWrapper.getAsJsonArray("property");
assertNotNull(propertiesArray);
assertTrue(propertiesArray.size()>0, "The list of properties should not be empty. ");
The problem is that the work this way is so inconvenient that it is really better to create objects instead.
Jackson has absolutely the same problems, and to greater extent - extremal inconvenient for direct json reading/creation. All its tutorials advice to use POJOs instead, too.
The only really convenient way is use Groovy. Groovy works as an envelope on Java, you can simply write Java code and use Groovy operators at need. And in JSON or XML reading and creation Groovy is incomparably more powerful that Java with all its libraries multiplied on each other! It is even much more convenient than already prepared by somebody else tree structure of ready POJOs.
I am looking for either guidance or a good example where I can map data coming from rest services to JSON "type" object which can then be used in a number of different react components.
The JSON Object will be used to map data from a few different rest services, which essentially hold very similar data which makes it better to use one object and then to bind the data to the respective React Components.
I am fairly new to React.JS and I have googled around to find a data mapper to JSON from Rest Service example.
Can anyone help?
You typically don't have to do too much, at least on the front end side. As long as the REST endpoint can return JSON responses you'll be fine. Just make sure you set the appropriate Content-Type headers in the request. Note that setting the header doesn't guarantee a JSON response, the server has to be able to send it in that format.
If you're creating the REST service yourself, you have many options. If you're using node, you can simply return a javascript object. If you're using some other language like Java, C#, etc., they come with libraries that can serialize objects into JSON for you. I use JSON.net when working with C#. In these cases, because the data will be returned as a string, you'll just need to JSON.parse() it upon receiving it and then set it to the appropriate React component's state.
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
In my GWT project I need to process json data retrieved from a database via PHP. I have seen the Google examples using JavaScriptObject overlay classes. What I don't understand is why this seems to be the prefered method of processing the json data. Why shouldn't I use all native Java code to pull in the data?
Think about it the other way around: what does it mean to use POJOs? (or native Java classes as you name them)
You have to:
parse the JSON into some Java-accessible structure (e.g. com.google.gwt.json.client.JSONObject, or elemental.json.JsonObject)
create POJOs
fill the POJOs with the data from the parsed JSON structure
now you can forget the parsed JSON structure from step 1
On the other hand, with JavaScriptObject, you use JsonUtil.safeEval and TA-DA! you get your JSON parsed right into a typed Java object!
Now, to deal with JSON, there's also AutoBeans.
Choose your poison.