Is it possible to access the current request information (HttpRequestMessage) outside of the context of a controller?
I would like to setup a tenant strategy (ITenantIdentificationStrategy) that involves the incoming request headers. In self hosted mode HttpContext.Current is not an option and I haven't found any other solutions.
It sounds like a HttpMessageHandler is what you are looking for. MessageHandlers allow you to perform some kind of processing on every request and provides full access to the request and response message.
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I am learning Django Rest Framework and one of the things I have noticed is that Viewsets provide actions such as .list, .post instead of method handlers such as .get, .post which in turn are provided by Views. The documentation says that actions are more flexible than method handlers but I can't seem to find any reason for this. Could you please share some information on why does Viewsets use actions and not the method handlers?
request handlers like .get() and .post() are based on http request methods, while actions like .create() or .list() are from a functionality point of view. Suppose you have a view class that can return a single user's info by user id or return all users in sorted order. These two requests are all GET requests from the client side, but with different parameters and purposes. If you just want to use .get() handler in this case you will need to define two view functions and register the two urls in url config. Or you can use ViewSet class or generic view with mixins that has action functions .list() and .retrieve() to handle these requests, then using router class to set the url configs that follows the REST url standards.
GET and POST are the only HTTP methods to use when dealing with forms.
Django’s login form is returned using the POST method, in which the browser bundles up the form data, encodes it for transmission, sends it to the server, and then receives back its response.
GET, by contrast, bundles the submitted data into a string, and uses this to compose a URL. The URL contains the address where the data must be sent, as well as the data keys and values. You can see this in action if you do a search in the Django documentation, which will produce a URL of the form https://docs.djangoproject.com/search/?q=forms&release=1.
GET and POST are typically used for different purposes.
Any request that could be used to change the state of the system - for example, a request that makes changes in the database - should use POST. GET should be used only for requests that do not affect the state of the system.
GET would also be unsuitable for a password form, because the password would appear in the URL, and thus, also in browser history and server logs, all in plain text. Neither would it be suitable for large quantities of data, or for binary data, such as an image. A Web application that uses GET requests for admin forms is a security risk: it can be easy for an attacker to mimic a form’s request to gain access to sensitive parts of the system. POST, coupled with other protections like Django’s CSRF protection offers more control over access.
On the other hand, GET is suitable for things like a web search form, because the URLs that represent a GET request can easily be bookmarked, shared, or resubmitted.
I have a general REST API (developed using Spring MVC) that takes a list of API requests as its request body.
Each API request in the list has its own URL and request body.
In the implementation of this general REST API, I need to call the corresponding Spring controller method (in the same app) for each of these individual API requests (with their appropriate URL and request body).
(I will then merge all those individual API responses and return it in one big response from the general REST API).
I've been searching around, but I'm unclear how to programmatically call Spring to execute each individual API request. I would ideally like to get back the ResponseEntity from each call instead of the actual JSON response.
(More information:
On the same app server as the general API, I need to translate the URL and JSON request body for each individual API into the arguments to the controller method. I also need to take the URL and have Spring determine which controller method to invoke itself.)
Any help would be greatly appreciated.
Thanks,
Matt
Answer depend on whether the individual URLs that you are planning to invoke is with in the same server (Accessible without using network call) or not
If it is with in the same app server, spawn multiple threads and invoke the individual methods and join the response together and send it back
If it is not within the same app server, there are many Async Restclients are there besides spring's own webclient/restTemplate etc
Please let me help to understand when to use session instead of RequestDispatcher.
So far I have seen I can pass data from servlet to servlet and jsp forwarding the request and It can pretty much distinguish two different request. So when and why should I use Session? Please help me to understand that.
HTTP is stateless protocol following request/response pattern. It means that you get request from client and send back response. There is no conversational state between client and server.
So if you need to keep conversational state (example : shopping card, wizard, etc.) - you need to recognize your client (understand which request comes from which client). This is what is session used for.
I was trying to pass data around between controllers all day long, but now I'm at the point where I think I haven't quite understood the basics.
Throughout the documentation of ASP .NET core, they use the word "request". I was under the assumption that this is the HttpRequest that is made by the client of the WebServer.
There are also different things that are supposed to be bound to the lifetime of a request:
The HttpContext and its HttpContext.Items dictionary.
Services added with AddScoped via dependency injection.
The TempData dictionary? (not so sure about that)
But when trying to pass data around, I made the observation that when I do return RedirectToAction(...); the HttpContext changes (HttpContext.GetHashCode() has a different value), TempData changes and services added via AddScoped are also new objects.
That would suggest that on RedirectToAction a new request is made, going through all the steps of the request pipeline again. My expectation though was that a RedirectToAction only continues the current request pipeline with a different controller action.
I also thought that the browser or whatever client only made one request and got one response during that entire process.
So what is actually happening when calling RedirectToAction in a controller action and returning the result?
UPDATE:
Using TempData works, but a TempDataProvider has to be configured first. For example add services.AddSingleton<ITempDataProvider,SessionStateTempDataProvider>(); to Startup.cs. Thanks #RonC.
As mentioned, RedirecToAction will cause the browser to make a new request, and when that new request comes in, it will create a totally new HttpContext. As mentioned, To pass data between the two requests, you can use the query string, session or cookies. But there is another option to consider.
TempData
Data can be passed from one request to another via the TempData collection which is accessible in the controller action method. The TempData collection was specifically designed for passing data from one request to another. The beauty of TempData is that the lifetime of an object placed in TempData is exactly one additional request. So anything placed in TempData in request 1 will be there for request 2 but then be automatically removed from TempData at the conclusion of request 2. This makes TempData perfect for passing data from one request to another without having to disclose that information in a query string or possibly forgetting it in session and bloating the session object.
It's impossible to save state of current request, because... HTTP is stateless. Every RedirectToAction really tells browser to make another HTTP request. As documentation says.
Returns an HTTP 302 response to the browser, which causes the browser to make a GET request to the specified action.
If you would like to pass some data between HTTP requests, you have to use cookies or session mechanism.
i have the following problem:
i need to send some custom info with every request made by a WebBrowser control. For example one of the infos is the used app version.
Now i have already read here that it is impossible to set custom headers for a WebBrowser control.
I have already tried to intercept all requests and perform them on my own with a WebClient (or HttpWebRequest). It partially works but is very buggy and often throws errors.
Any other ideas how to send the custom infos with every request that is made by the WebBrowser control?
Is the web server you are interacting with your own? Could you just add a query string parameter for all the data you want? Something like
http://yourwebsite/YourPage.aspx?version=2
Then you'd be able to process it on the server, either during that request in the aspx page, or via the logfiles for the web server.
I suspect that as you can't modify the content that gets sent directly from the WebBrowser and that intercepting every call and acting as a proxy for every request, while still maintaining all browser functionality may be too cumbersome.
Instead I'd suggest sending an additional request with just the additional information you want to record every time you make a request.
That could lead to a lot of overhead so it might be easier to send this once and then pass a hash of it, or some other identifying key to the webpage (as a querystring parameter) on the first request so it can reconcile the 2 pieces of information. Assuming that you are in control of the web server you could then have the web server set that hash/key as a cookie so it would be passed again with subsequent request from the control.