The reason of usage axios-mock-adapter - reactjs

I'm a beginner to test axios calls and started using axios-mock-adapter but I don't get why we use axios-mock-adapter.
mock.onPost('/api').reply(200, userData, headers);
In this code snippet, does the request really go to the server or is this just a simulation?
Because if I give wrong credentials, it responses with 200 status as I identify it on 'reply' to return 200.
So if I identify the response status, what is the reason to use it?
If it doesn't really go to server, it seems like this is useless.
Maybe I miss something I don't know because I'm new but someone should put the light on this issue on my mind.

Answers to your questions
In this code snippet, does the request really go to the server or is this just a simulation?
It is just a simulation. No request is made, just the "reply" is returned. This is called mocking and is hugely popular and useful for writing tests.
If you are new to different kinds of testing in general, this answer is well worth reading.
If it doesn't really go to server, it seems like this is useless.
If you want to test the system as a whole: i.e. your website + backend logic (like auth, data retrieval etc.) then yes, this is useless. But you would not use a mock for that.
Integration tests typically are executed against a running system, they are valuable, but very hard to maintain and are generally slower to execute. You have to take care of not just your tests, but even the data.
When would you use a mock
Mocks are essential for unit testing your code. Mocks help isolate your front end code logic from the dynamic behavior. This makes it easier for you to simulate many scenarios without the overhead of maintaining data.
Example Scenario
Use Case
In your application, you have to authenticate a user against a REST end point. It is expected that:
When user is logged in successfully, Logout button is shown in the header.
When users password has expired, a "change your password" screen is shown.
When user has entered wrong credentials, a warning is shown
When backend is not responding user is shown a screen to try again later
Without mocks, you need to ensure that you have the exact data configured in your authentication system. From experience I can tell you it is hard, especially #2 & #4.
But with mocks, you can just configure the mock to return the response you expect for each scenarios, in/before each it() block.
This is also easier to maintain as expectation (assert/expect statements) is set near the test data (mock.reply()).

Related

What's the best way to prevent React app being scraped?

I'm still very new to React so forgive me if the question is too naive. To my understand, React usually requires an API to do XHR requests. So someone with very basic tech background can easily figure out what the api looks like by looking at the network tab in web browser's debug console.
For example, people might find a page that calls to api https://www.example.com/product/1, then they can just do brute force scraping on product id 1 - 10000 to get data for all products.
https://www.example.com/api/v1/product/1
https://www.example.com/api/v1/product/2
https://www.example.com/api/v1/product/3
https://www.example.com/api/v1/product/4
https://www.example.com/api/v1/product/5
https://www.example.com/api/v1/product/6
...
Even with user auth, one can just use same cookie or token when they login to make the call and get the data.
So what is the best way to prevent scraping on React app? or maybe the api shouldn't be designed as such, hence I'm just asking the wrong question?
Here are some suggestions to address the issue you're facing:
This is a common problem. You need to solve it by using id's that are GUID's and not sequentially generated integers.
Restricting to the same-origin won't work because someone can make a request through Postman or Insomnia or Curl.
You can also introduce rate-limiting
In addition, you can invalidate your token after a certain number of requests or require it to be renewed after every 10 requests
I think no matter what you do to the JavaScript code, reading your API endpoint is the easiest thing in the world(Wireshark is an easy, bad example), once it is called upon from the browser. Expect it to be public, with that said, protecting it it is easier than you might anticipate.
Access-Control-Allow-Origin is your friend
Only allow requests to come from given urls. This may or may not allow GET requests but it will always allow direct access on GET routes. Keep that in mind.
PHP Example
$origin = $_SERVER['HTTP_ORIGIN'];
$allowed_domains = [
'http://mysite1.com',
'https://www.mysite2.com',
'http://www.mysite2.com',
];
if (in_array($origin, $allowed_domains)) {
header('Access-Control-Allow-Origin: ' . $origin);
}
Use some form of token that can be validated
This is another conventional approach, and you can find more about this here: https://www.owasp.org/index.php/REST_Security_Cheat_Sheet
Cheers!

Is implementing client-side validation through an API realistic when it comes to performance?

So in an ideal world both client side validation and server side validation can be defined in one place, so the validation only has to be written once and can be reused where ever.
The idea i have to solve this is to do all the validation through an API using ASP.NET Core. When the form data on the client changes it will send an AJAX request with the updated data model, which the API validates and in turn returns any possible errors. The client then shows these errors to the user directly.
This way it still looks like the good old client-side validation, but it actually all happens on the server.
I can already imagine the server load is going to be increased since a lot more API calls will be send, however the question is:
will this server load be manageable in for example a big enterprise application with huge forms and complex validation?
And are there any other big drawbacks of this solution which i have to watch out for?
You are talking about an API not any other type of application with a back-end.
In this world, yes the validation of the payloads is important and needs to happen on the API side. In a way, the validation is the easiest part and less resource consuming since this is the first thing you check and if it doesn't pass then the API returns a 400 BadRequest HTTP code and nothing else happens.
There are systems where the validation, especially business rules validation does not happen on the API side. You could have for example a financial platform and the API is simply the gateway inside that world. In this case, the API acts as a pass-through and doesn't do much itself.
This being said, everything is susceptible to too much traffic, but you should be able to either throw enough resources at it, or have it deployed in the cloud and let it scale based on demand. You can load test APIs as well, to see how well they do under pressure, you must have an idea of how many calls you can expect in a certain period of time.
I wouldn't worry too much about it, I'd say validate what you can client side, so you don't even hit the API if there is no need for it and leave the rest to the API

Securing a single page application built on react/react-router

I've been putting together a single-page application using React and React-Router and I can't seem to understand how these applications can be secured.
I found a nice clear blog post which shows one approach, but it doesn't look very secure to me. Basically, the approach presented in that post is to restrict rendering of components which the user is not authorized to access. The author wrote a couple more posts which are variations on the idea, extending it to React-Router routes and other components, but at their hearts all these approaches seem to rely on the same flawed idea: the client-side code decides what to do based on data in the store at the time the components are composed. And that seems like a problem to me - what's to stop an enterprising hacker from messing around with the code to get access to stuff?
I've thought of three different approaches, none of which I'm very happy with:
I could certainly write my authorization code in such a way that the client-side code is constantly checking with the server for authorization, but that seems wasteful.
I could set the application up so that modules are pushed to the client from the server only after the server has verified that the client has authority to access that code. But that seems to involve breaking my code up into a million little modules instead of a nice, monolithic bundle (I'm using browserify).
Some system of server-side rendering might work, which would ensure that the user could only see pages for which the server has decided they have authority to see. But that seems complicated and also seems like a step backward (I could just write a traditional web app if I wanted the server to do everything).
So, what is the best approach? How have other people solved this problem?
If you’re trying to protect the code itself, it seems that any approach that either sends that code to the client, or sends the code able to load that code, would be a problem. Therefore even traditional simple approaches with code splitting might be problematic here, as they reveal the filename for the bundle. You could protect it by requiring a cookie on the server, but this seems like a lot of fuss.
If hiding the internal code from unauthorized users is a requirement for your application, I would recommend splitting it into two separate apps with separate bundles. Going from one to another would require a separate request but this seems to be consistent with what you want to accomplish.
Great question. I'm not aware of any absolute best practices floating around out there that seem to outstrip others, so I'll just provide a few tips/thoughts here:
a remote API should handle the actual auth, of course.
sessions need to be shared, so a store like redis is usually a good idea, esp. for fast reads.
if you're doing server-side rendering that involves hydration, you'll need a way to share the session state between server and client. See the link below for one way to do universal react
on the client, you could send down a session cookie or JWT token, read it into memory (maybe using redux and keep it in your state tree?) and maybe use middleware (a la redux?) to set it as a header on requests.
on the client, you could also rely on localStorage to save the cookie/JWT
maybe split the code into two bundles, one for auth, one for the actual app logic?
See also:
https://github.com/erikras/react-redux-universal-hot-example for hydration example
https://github.com/erikras/react-redux-universal-hot-example/issues/608
As long as the store does not contain data that the user is not authorized to have, there shouldn't be too much of a problem even if a hacker checks the source and sees modules/links that he shouldn't have access to.
The state inside the store as well as critical logic would come from services and those need to be secured, whether it's an SPA or not; but especially on an SPA.
Also: server-side rendering with Redux isn't too complex. You can read about it here:
http://redux.js.org/docs/recipes/ServerRendering.html
It's basically only used to serve a root html with a predefined state. This further increases security and loading speeds but does not defy the idea behind SPAs.

Downsides using front-end frameworks for API handling? Performance and security

So, while practising all the new tech. Angular 2, AngularJS, Firebase, Loopback, NodeJS etc .. I'm kind of confused on some topics that people don't really talk about. It might go into too much detail, but I'll try to split it as much as I can.
Part 1 -- Performance
I like the approach of: MyApp (Web, Mobile, ..) --> API <-- Database
Okay, we perform API requests to the same server over HTTP which is slower, but for small projects this should be a non issue right? Or are there any other solutions for this matter?
I know they often just do: MyApp --> Framework <-- Database and add an API interface which calls the correct actions to get the necessary logic/data out to eg. a mobile app
-- End Part 1
Part 2 -- Security
So, assume we have an API up and running either with Lumen, LoopBack or anything else like a realtime Firebase database (not really an API). Then we can connect with it over HTTP requests via Angular, jQuery... If a user inspects our source code, they can easily see how we handle data in the backend. How can this be secured in a way that only the necessary applications have control over the API (OAuth2 ?) and also that we limit the insight of users into our API.
-- End Part 2
Thanks.
Okay, I thought, it's a "too broad" question, but actually, it has a short answer.
Performance
Irrelevant. If you gotta fetch data, you gotta fetch data. Be it API call or some custom action in your laravel code (or something). Same HTTP stuff.
Security
... where a user can check the source code of the API calls.
Security through obscurity doesn't work. Always consider that your client is compromised. Use proper authentication/authorization methods (OAuth and the like). So even if a malicious user knows (which he will) your api endpoint signatures (or whatever you were trying to hide), he can't abuse them.

Validation on route change in Backbone.js

I have the following tiny dilemma: I have a backbone app, which is almost entirely route based, i.e. if I do to nameoftheapp/photos/1/edit I should go to the edit page for a given photo. The problem is, since my view logic happens almost 100% on the client side (I use a thin service-based server for storage and validation) how do I avoid issues of the sort of an unauthorized user reaching that page? Of course, I can make the router do the check if the user is authorized, but this already leads to duplication of efforts in terms of validation. Of course, I cannot leave the server side without validation, because then the API would be exposed to access of any sort.
I don't see any other way for now. Unless someone comes up with a clever idea, I guess I will have to duplicate validation both client and server-side.
The fundamental rule should be "never trust the client". Never deliver to the client what they're not allowed to have.
So, if the user goes to nameoftheapp/photos/1/edit, presumably you try to fetch the image from the server.
The server should respond with a HTTP 401 response (unauthorized).
Your view should have an error handler for this and inform the user they're not authorized for that - in whatever way you're interested in - an error message on the edit view, or a "history.back()" to return to the previous "page".
So, you don't really have to duplicate the validation logic - you simply need your views to be able to respond meaningfully to the validation responses from the server.
You might say, "That isn't efficient - you end up making more API calls", but those unauthorized calls are not going to be a normal occurrence of a user using the app in any regular fashion, they're going to be the result of probing, and I can find out all the API calls anyway by watching the network tab and hit the API directly using whatever tools I want. So, there really will be no more API traffic then if you DID have validation in the client.
I encountered the same issue a while ago, and it seems the best practice is to use server-side validation. My suggestion... Use a templating engine like Underscore, which is a dependency of Backbone, design the templates, and for those routes that only authenticated users or those with rights to do so, can access... you ask the server for the missing data (usually small pieces of json data) based on some CSRF token, or session_id, or both, (or any other server-side validation method you choose), and you render the template... otherwise you render a predefined error with the same template... Logic is simple enough...

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