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ASP.NET Core 2.1 get current web hostname and port in Startup.cs

I want to register my WebAPI to Consul service discovery and for that I should provide URL of my WebAPI (for example: http://service1.com) and health check endpoint (http://service1.com/health/check). How can I get that URL?
I found this piece of code:
var features = app.Properties["server.Features"] as FeatureCollection;
var addresses = features.Get<IServerAddressesFeature>();
var address = addresses.Addresses.First();
var uri = new Uri(address);
It returns 127.0.0.1:16478 instead of localhost:5600. I think first one used by dotnet.exe and second one is IIS which forwards 5600 to 16478. How can I get localhost:5600 in Startup.cs?

Well, there are multiple solutions for this problem. Your address is this:
string myurl = $"{this.Request.Scheme}://{this.Request.Host}{this.Request.PathBase}";
It returns 127.0.0.1:16478 instead of localhost:5600
You got this right yes. One is from IIS and one from dotnet. So, you have a problem of trying to get correct url. Ok, so what happens if you service is behind reverse proxy? https://en.wikipedia.org/wiki/Reverse_proxy
Then your service will not be exposed directly to internet, but requests made to specific url will be passed from reverse proxy to your service. Also, you can configure reverse proxy to forward additional headers that are specifying where the original request came from. I think that most reverse proxies are using X-Forwarded-For (Some of them are using X-Original-Host etc).
So if you have proper header set on RP, then you can get url like this:
url = url.RequestContext.HttpContext.Request.Headers["X-Forwarded-For"]
Url is of type UrlHelper. To simplify this method, you can create extension method (GetHostname(this UrlHelper url)) and then us it in your controller or wherever you want. Hope it helps

I don't think it is possible since there is usually a reverse proxy in production that handles public address and the application itself should not be exposed to public and, therefore, be aware of public address. But there can be some workarounds:
Place URL is some kind of config file that can be updated during deploy steps to have the correct URL.
Application can get full URL of the request like this, so after first actual request to the application we can get hostname.

EDIT: I reread your question. You wanted to know how to do this in Startup.cs. You can, but with fewer fallbacks. Your only choices are configuration or raw DNS.GetHostName(), which are less than ideal. Instead, upon any request to your service, lazily register your API. This is when you have context. Prior to that, your service knows nothing Jon Snow. The first request to your API is likely going to be health-checks, so that will kick off your registration with consul.
A solution I've used is a combination of configuration and headers in a fallback scenario.
Rely first on the X-Forwarded-For header. If there are cases where that doesn't apply or you have a need to... you can fallback to configuration.
This works for your use case, discovery. That said, it also works when you want to generate links for any reason, (e.g. for hypermedia for JSON API or your own REST implementation).
The fallback can be useful when there are reconfigurations occuring, and you have a dynamic configuration source that doesn't require a redeployment.
In the ASP.NET Core world, you can create a class and inject it into your controllers and services. This class would have a method that knows to try config first (to see if overriding is needed) and then the X-Forwarded-For header, and if neither is appropriate, fallback further to HttpContext.Request to get relevant URI parts.
What you're doing is enabling your API to be contextless and resiliency (to change) by giving it some contextual awareness of where "it lives".

This happens when you try to get current URL in Startup.cs. I've faced this issue before. What i did as Solution for my problem is. I Just declared Custom Setting in AppSettings in web.config(For Local) file and web.release.config(For Live)
like following
in web.config
<appSettings>
<add key="MyHost" value="http://localhost:5600" />
</appSettings>
in web.release.config
<appSettings>
<add key="MyHost" value="http://myLiveURL.com" />
</appSettings>
in startup.cs
string hostSetting = ConfigurationSettings.AppSettings["MyHost"];
And different host in release file. so what it helped is i can get Localhost URL in local website from web.config and Live URL from web.release.config.
if you are using Azure for live. it will be more easier for live(you would not need to add setting web.release.config file). add app setting in your website application setting https://learn.microsoft.com/en-us/azure/app-service/configure-common
In Case of ASP.NET Core you can use appsettings.json instead of web.config

URI in DELETE request's URI with MVC 5

We have a version control service which should be accessible through our REST API. One of those operations allows to delete a directory in SVN. Ideally, I'd like to send a DELETE request with the URI of the target to delete, something like this: http://service:4711/directory/http%3A%2F%2Fsome%2Fdirectory
What happens isn't new and there are plenty of answers out there. Unfortunately, they do not work for me. Depending on what I try, I get a 404 or a 403 (due to the malicious colon).
Let me show you some code and what I've tried without success so far:
// The action in my controller
[HttpDelete]
[Route("directory/{uri}/")]
public void DeleteDirectory(string uri)
{
var x = HttpUtility.UrlDecode(uri);
}
I am using MVC version 5.2.3.0.
I've tried:
[System.Web.Mvc.ValidateInput(false)] on the action and/or the class.
Setting runAllManagedModulesForAllRequests="true" in the web.config.
Setting requestPathInvalidCharacters="" in the web.config.
Setting requestValidationMode="true" in the web.config.
Right now, I see four possible solutions:
I've done something wrong with the previous approaches.
I have to create a custom RequestValidator.
I have to double encode the URI in the request.
Send a POST request instead of DELETE.
One may say, put it in the body of the DELETE request. But this option is highly controversial, so I'd like to ignore this one from the very beginning.
So what have I done wrong and what do you suggest to do?
Best regards,
Carsten

Colons in URI's in MVC are not allowed to be used until after the querystring '?' character in an URL, even when it is encoded as %3A.
Therefore, unless the SVN is http/s independent you could drop the initial http: from the parameter passed in an append it in the code.

Why does DotNetNuke log me out on post ajax requests?

Previously, when I tried to do an ajax call to an ashx as a non-superuser account (i.e. as portal specific user) my web server would return cookies to clear my authorization. I posted a question about this and it seemed the answer was to make sure that the portalid=xx was specified in my GET parameters.
However, I have just found out that if I add portalid=xx in a POST request, DotNetNuke seems to ignore and and log out any non-superuser account.
How can I keep authorization during DNN POST ajax requests?

I think I have a good handle on the whole situation, and unfortunately it appears that the only true solution is to make sure each child portal has its own subdomain rather than a sub-url (e.g. portal.domain.com rather than domain.com/portal).
The problem is that when your portal 0 is domain.com but portal 1 is domain.com/portal everything works correctly until you need to access an .ashx file via ajax. What happens then is the URL that's requested is instead domain.com/DesktopModules/MyModule/Handler.ashx, which does not contain the /portal/ in it, thus causing DNN to think you are doing a request on portal 0 and logging you out.
While GET requests can overcome this with a portal=1 parameter, this does not seem to work for POST requests.
Therefore, the best solution it seems is to have your portal on a distinct subdomain (portal.domain.com), and then you don't risk missing something like this.

I've found a few things for you to check out and see if any of them solve your problem.
Make sure you are using a ScriptManagerProxy. This allows ascx pages to use AJAX while the parent page is also using AJAX.
There have been many reports of people not being able to run AJAX with DNN if Page State Persistence is set to "Memory". Those who experience this have been able to fix it by switching Page State Persistence to "Page". The easiest way to do this is to run this query:
update HostSettings
set SettingValue='P'
where SettingName='PageStatePersister'
After you run that, you'll need to recycle the application. If you don't have access to the server, just add a space or carriage return to your web.config file (that will force the app to recycle).
Lastly, you might see if you have this line in your web.config. Sometimes removing it will help:
<system.web>
<xhtmlConformance mode="Legacy" />
</system.web>

Receiving a 500 internal server error when I have a '%' symbol in the query string

I am trying to diagnose a problem that a client site has come across. Basically when you do an address search on their website you can specify a % symbol for wildcard searches. For example you can search for Be% to return Belfast etc.
This queries the database and then redirects you to the results page, passing the search criteria in the querystring for example results.aspx?criteria=Search%20criteria%20is%20Be%
This caused problems if you searched for something like %Belf as %Be is a reserved character in URL encoding. I therefore coded it to replace % with %25 (URL encoding representation of % symbol). This works fine on my test machine, where the URL is now results.aspx?criteria=Search%20Criteria%20is%20%25Be .
This however doesn't work on our clients website for some reason and I can't work out why. The page keeps error-ing with:
Error Code: 500 Internal Server Error. The request was rejected by the
HTTP filter. Contact the server administrator. (12217)
any time you search for something like %Be %Fa %Fe etc etc
Does anyone know if there is an IIS setting for this or something similar?

You might have URLScan installed on your server. URLScan intercepts requests and reject them if it detects invalid characters. It is meant to protect your website from malicious attacks and SQL injection. If you don't configure it correctly then it will reject perfectly reasonable requests. Take a look at the ISAPI filters on your website and see if URLScan is there.

Could this solve your problems? It is written by Zubair Alexander at http://blog.techgalaxy.net/archives/2521

Rewriting URLs in ASP.NET?

I am using ASP.NET C#.
How do I implement URL re-writing procedure that is similar to StackOverflow.com?
http://stackoverflow.com/questions/358630/how-to-search-date-in-sql
Also, what is the meaning of values such as "358630" in the URL? Is this the question ID (the basis for which they use to fetch the data from the table)? Whatever it is, in my application I am identifying records using an "ID" field. This field is an identity column in an SQL table. Right now, my URLs are like the following:
http://myweb.com/showdetails.aspx?id=9872
But I'd like them to appear like:
http://myweb.com/showdetails/9872/my_question_title
Or:
http://myweb.com/9872/my_question_title
Or whatever the best way, which will taste good to search bots.
My application is hosted on Go Daddy's shared hosting service, and I feel that no customized ASP.NET "HTTP module" or no customized DLL for URL re-writing is working on their server. I tried many samples but no luck yet!
I found that Stack Overflow is hosted on Go Daddy (shared hosting?). Maybe Stack Overflow's method will work for me.

SO is using ASP.NET MVC. You really need to read in details how MVC URL rewriting works, but the gist of it is that the 'questions' part in the URL is the name of the Controller class (which roughly corresponds to the 'showdetails' in your URL) and the number is a ID parameter for the default action on that Controller (same as the parameter 'id' in your URL).

Since MVC isn't an option you can try redirecting the 404s. This will work in ASP.NET 1.1 and above: Redirect 404s and 405s to your own handler using either IIS config or web.config, parse out the request in the handler and redirect to the appropriate resource.
<configuration>
<system.web>
<customErrors mode="On" defaultRedirect="error.html">
<error statusCode="404" redirect="newHandler.aspx"/>
</customErrors>
</system.web>
</configuration>

Before the advent of System.Web.Routing, the common practice was to use UrlRewriter.NET. Worked well enough, but could bite you when configuring IIS. I'm not sure if there are any simple ways of using the new Routing classes in ASP.NET (i.e., drop it in and go vs. refactoring code).

please explain the meaning of values
such as "358630" in the URL
That is (presumably) the ID for the question in the database. In the MVC model
myurl.com/questions/358630
is analogous to
myurl.com/questions.aspx?id=358630
The question title on the end of the URL is actually being ignored by the app. It's generally "tacked on" for search engine optimization and human readability purposes. In fact, you can change the title of this question in the URL and notice the page still loads just fine.

The new System.Web.Routing dll is part of ASP.NET 3.5 SP1, and is bin deployable on ASP.NET 3.5, so you could use the features of that on a classic ASP.NET WebForms site.
You'll probably want to take note of Phil Haack's comments in his post on using MVC on IIS 6 as you'll probably need to include the .aspx extension in your routed urls
http://www.mysite.com/controler.aspx/action/id
You might also want to check out Questions Tagged SEO.
The ignored question name at the end of the url is often called a "Slug", and is used for SEO purposes to include the page title in the url.