Documenting fields in Django Rest Framework - django-rest-framework

We're providing a public API that we use internally but also provide to our SaaS users as a feature. I have a Model, a ModelSerializer and a ModelViewSet. Everything is functional but it's blurting out the Model help_text for the description in the API documentation.
While this works for some fields, we would like to be a lot more explicit for API users, providing examples, not just explanations of guidance.
I realise I can redefine each field in a Serializer (with the same name, then just add a new help_text argument, but this is pretty boring work.
Can I provide (eg) a dictionary of field names and their text?
If not, how can I intercede in the documentation process to make something like that work?
Also, related, is there a way to provide a full example for each Viewset endpoint? Eg showing what is submitted and returned, like a lot of popular APIs do (Stripe as an example). Or am I asking too much from DRF's documentation generation? Should I handle this all externally?

To override help_text values coming from the models, you'll need to use your own schema generator subclass and override get_path_fields. There you'd be able to prioritize a mapping on the viewset (as you envision) over the model fields help_text values.
On adjusting the example generation - you could define a JSON language which just deals with raw JSON and illustrate the request side of things pretty easily, however, illustrating responses is difficult without really getting deep into the plumbing, as the default schema generated does not contain response structure data.

Related

Protocol buffers: read only fields?

Is it possible to mark fields as read only in a .proto file such that when the code is generated, these fields do not have setters?
Ultimately, I think the answer here will be "no". There's a good basic guidance rule that applies to DTOs:
DTOs should generally be as simple as possible to convey the data for serialization in a manner well-suited to the specific serializer.
if that basic model is sufficient for you to work with above that layer, then fine
but if not: do not fight the serializer; instead, create a separate domain model above the DTO layer, and simply map between the two models before serialization or after deserialization
Or put another way: the fact that the generator doesn't want to expose read-only members is irrelevant, because if you need something exotic, you shouldn't be using the generated type outside of the code that directly touches serialization. So: in your domain type that mirrors the DTO: make it read-only there.
As for why read-only fields aren't usually a thing in serialization tools: you presumably want to be able to give it a value. Serialization tools usually want to be able to write everything they can read, and read everything they can write.
Minor note for completeness since you mention C#: if you are using a code-first approach with protobuf-net, it'll work fine with {get;}-only auto-props, and with {get;}-only manual props if all public members trivially map to an obvious constructor.

With the Simple API in Stanford CoreNLP, is there a way to get multi-token entity mentions?

This question is very similar to my question, however due to the way SO works, I think it is better to ask a new question rather than just continue a thread.
CoreNLP has the Simple API which allows for quicker access to various components of the NLP pipeline. The way to get named entities appears to be:
Form a document annotation from the text
Get the sentences from the document object
Use nerTags() from the sentences object to get the token-by-token ner labeling.
Via other mechanisms, as talked about in the question link above, one can retrieve full multi-token entity mentions such as George Washington, which is an entity mention composed of 2 tokens. Is there a way using the simple api to get these multi-token entity mentions?
Yes, though it gives you less information than the full API, returning only the String spans of the mention. See Sentence#mentions(String) and Sentence#mentions().
If you want to get more information about a mention, you'll have to either use the regular API, or re-implement the logic in these functions. You can also try mucking around in the raw Proto, which will certainly have all the information you could possibly want, but in a less-than-pleasant proto interface. The proto definition is here.

Generating Navigation for different user types, MVC, PHP

I have this idea of generating an array of user-links that will depend on user-roles.
The user can be a student or an admin.
What I have in mind is use a foreach loop to generate a list of links that is only available for certain users.
My problem is, I created a helper class called Navigation, but I am so certain that I MUST NOT hard-code the links in there, instead I want that helper class to just read an object sent from somewhere, and then will return the desired navigation array to a page.
Follow up questions, where do you think should i keep the links that will only be available for students, for admins. Should i just keep them in a text-file?
or if it is possible to create a controller that passes an array of links, for example
a method in nav_controller class -> studentLinks(){} that will send an array of links to the helper class, the the helper class will then send it to the view..
Sorry if I'm quite crazy at explaining. Do you have any related resources?
From your description it seems that you are building some education-related system. It would make sense to create implementation in such way, that you can later expand the project. Seems reasonable to expect addition of "lectors" as a role later.
Then again .. I am not sure how extensive your knowledge about MVC design pattern is.
That said, in this situation I would consider two ways to solve this:
View requests current user's status from model layer and, based on the response, requests additional data. Then view uses either admin or user templates and creates the response.
You can either hardcode the specific navigation items in the templates, from which you build the response, or the lit of available navigation items can be a part of the additional information that you requested from model layer.
The downside for this method is, that every time you need, when you need to add another group, you will have to rewrite some (if not all) view classes.
Wrap the structures from model layer in a containment object (the basis of implementation available in this post), which would let you restrict, what data is returned.
When using this approach, the views aways request all the available information from model layer, but some of it will return null, in which case the template would not be applied. To implement this, the list of available navigation items would have to be provided by model layer.
P.S. As you might have noticed from this description, view is not a template and model is not a class.
It really depends on what you're already using and the scale of your project. If you're using a db - stick it there. If you're using xml/json/yaml/whatever - store it in a file with corresponding format. If you have neither - hardcode it. What I mean - avoid using multiple technologies to store data. Also, if the links won't be updated frequently and the users won't be able to customize them I'd hardcode them. There's no point in creating something very complex for the sake of dynamics if the app will be mostly static.
Note that this question doesn't quite fit in stackoverflow. programmers.stackexchange.com would probably be a better fit

Can Content Negotiation Be Used to Control Return Types in the ASP.NET WebApi?

We're building a web api whose GET methods return DTOs. We'd like to build it so that, under certain circumstances, these DTOs are stripped of unnecessary properties in an effort to control the volume of data being sent down to the client. For example, when we return one of our email DTOs we sometimes would like the client to specify that it only needs a subject, date and ID and not the body of the email. In other scenarios, of course, the body of the email is needed.
What's the best way in the MVC WebApi to do this? I've looked into MediaTypeFormatters but they seem focused on the format of the data (JSONP, XML) rather than the content.
It sounds to me like you would like to have a custom mediatype.
This could be used in combination with a custom MediaTypeFormatter.
For instance, you could define your own mediatype (this is a bad example of a name):
application/vnd.me-shortform
And then, in your code you can omit filling in the emailbody and let the default formatter format your result.
Or you could write your own MediaTypeFormatter (subclassing an existing one) and register it for your custom mediatype.
Then, in the MediaTypeFormatter you could either through attributes on your DTO or something similar decide that the email body is not necessary and omit having it as part of the result.
Mark Seeman on Vendor Media Types should give you a good starting point.

Where does language translation fit in the MVC pattern?

I'm building a multi-lingual web application using the MVC pattern as the starting position. The application has a number of forms that users will be interacting with and many of these forms will have fields that do a lookup from a database table, 'Province' for example.
If I need the options in these lists to be displayed in the users' language on the screen, I can see a couple of ways to do this:
In the model. When querying the model, I can provide the language that I desire the results to be returned in. This would allow translations to be used everywhere that data from the model is displayed without changes. However, this also means that the Province model in my example (plus all other application models) now need to know how to do language translations.
In the controller. I can query the model in the controller action as usual and then create a 'Translator' object that I can pass the results into before completing the action. This would imply that each controller action would potentially be duplicating the same translation code, violating the DRY principle.
In the view. Since the presentation of the application is generally expected to exist in the views, and the language of the user doesn't impact the business logic of the system, an argument could be made that language translations belong here. Especially considering that a page could also contain static content that will need to be translated. The downside to this is that it would complicate the views somewhat, especially for the front-end designers who will have to work around the new translation code.
Is there an accepted best-practice for where text translations belong in the MCV pattern for web applications? Does this change at all if I were to be loading the select list options via an AJAX call instead of at page load time?
Thanks for the help!
The best place to handle it is in the view. Your question only references dynamic data from the database, but you also have to handle the static information in your views as well. Best to handle both of those in the same place. A common practice in MVC for handling multiple language is resource strings, separate views for each language, or a combination of both. For information from the database resource strings would work well. You would store a token in the database for the options in the list (that token could be the English translation) and the view would get the appropriate translation from a resource for the specified country/locale. There is a good detailed explanation on this approach in this blog post.
If you need to translate part of your UI, then I would create a helper method that would read a resource file and output a translated string for that resources. E.g.
#Translate("NewUserHeading")
So regarding the UI, it makes sense to handle this in the UI.
If the data that you are going to translate at some point might be shown in a Flash client, or a mobile app, then it should be translated by a server and it should have nothing to do with your MVC application.
Honestly, any interaction with a database should be handled in the model, and that's the only thing handled in the model. Interpreting/organizing that data should be handled in the controller. I guess more information would be need as to where this translation is coming from and how that works to really give a solid answer.
The view will just display strings from a resource file. Including the correct resource file for the locale should do it. In Web applications, it's often a single language JS file defining the UI strings per locale, e.g, strings.en-us.js, strings.pt-br.js and so on.
Some strings do come from the server dynamically, the controller doesn't need to know about it, the model should just grab the localized strings and return is as part of the data request.
So it's either in the view (if it's static) or in the model, (if it's dynamic). Controllers should just translate data from the view to the model and from the model to the view
Another very important thing to consider is WHEN to Translate. Using a once-per-each-translation method like #Translate("NewUserHeading") is fine if you only have 100 translations on your page, but what if you have more?
Because think about it, translation is based upon language choice and that only happens once-per-page or even once-per-session. The way that the Kendo UI people do it in their demo is that way, when the User clicks a new language a new set of server files is loaded. That would mean having something like:
/src/html/en-us/
/src/js/en-us/
/src/html/es/
/src/js/es/
etc..
Check it out at https://demos.telerik.com/kendo-ui/grid/localization
It's a trade off of more work for better performance. The ultimate use-case of translation right now is https://www.jw.org/ with over 900 languages!

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