Deep linking single page application with dotNet core - asp.net-core

I am using a dotNet core project to host an Angular2 application. I am having problems with the deep linking URLs.
For example, when I initially browse to http://localhost:54675/app/dashboard I get a 404 error because there is nothing to serve at app/dashboard. I want to actually load index.html (the angular app) and then have routing take me to app/dashboard.
I use the code below to redirect to index.html if I get a 404 and the URL has no extension.
app.Use(async (context, next) =>
{
await next();
if (context.Response.StatusCode == 404 && !Path.HasExtension(context.Request.Path.Value))
{
context.Request.Path = "/index.html";
await next();
}
});
This will not work when I have a routing with parameters that include JSON such as:
http://localhost:54675/app/repairReturnListing;filter=%7B%22Status%22:[%22AWP%22]%7D
My if statement ignores requests with an extension and Path.HasExtension throws and ArgumentException on this path. The path resolves to this on the server side:
"/app/repairReturnListing;filter={\"Status\":[\"AWP\"]}"
I removed the 'HasExtension' condition and then I get a lot of console errors looking for map files that I don't host. Like this:
Failed to parse SourceMap:
http://localhost:54675/lib/js/rxjs/operator/timeout.js.map
I don't get these errors in the network tab. I think this is something used for debugging.
My angular2 app uses HTML5 routing. I use static files to serve the angular2 application. I have one webApi controller that returns some configuration data (the rest of the data is returned by another webApi project).
Waiting on a 404 and redirecting seems like a work-around and it's not even working.
Any suggestions on the best way to do this?

Check out ng2-kestrel-appserver http://tattoocoder.com/kestrel-as-a-static-server-for-angular/
Does exactly what you're looking for. It was created for RC2 but should work for the current release with few or no changes.

Related

Only Map existing Blazor Pages(Razor Components) in the pipeline?

The usual pattern for Blazor (server) apps, is that at the end pf program.cs there is app.MapFallbackToPage("/_Host");
That will result in ALL request paths, that match no earlier endpoint, executing the Blazor App. Sure the Blazor App has a <NotFound> Renderfragment, but that will still result in establishing the SignalR and so on. What if I want to display a static file (.html) from wwwroot or a specfic RAZOR PAGE (.cshtml), which doesnt establlish a websocket for all those cases where the route does NOT EXIST IN ANY BLAZOR PAGE ???
NavigationManager.NavigateTo cannot be used directly inside the BuildRenderTree markup of the <NotFound> ... I could maybe put a component inside there that redirects OnInitialized ... but that would still first require the SignalR.
How can I completely avoid Blazor/SignalR for URLs that don't exist in the Blazor App ?
Idea: I could try to add ALL POSSIBLE Blazor-routes as fallbacks and the most general fallback to some static file or Razor Page... but that seems LIKE A LOT OF DOUBLE WORK and very error prone... is there no way?
app.MapFallbackToPage("~/Admin/{*clientroutes:nonfile}", "/_Host");
app.MapFallbackToPage("~/SomeRoute/More/{*clientroutes:nonfile}", "/_Host");
app.MapFallbackToPage("~/SomePage/{*clientroutes:nonfile}", "/_Host");
app.MapFallbackToPage("/NotValidRoute");
Edit:
#Reason:
I wanted to have a single fallback page (razor page or static) for all routes/urls that don't match any target in the app. But sadly as it seems, that conflicts with blazor'S client side routing. since the server-side routing does not know, which routes should be handled by blazor, it also cannot know, which routes would not map to anything (razor pages and blazor combined). Other please correct me here.
There's server-side routing and client-side routing. On the server side, the middleware pipeline runs first, handling static files and server defined routes, including the fallback route. Fallback routes are routes that don't match static file requests and have the lowest priority, so they are not preferred over other matching routes.
Server-side routing has no idea what routes are going to match on the client-side. That data model is separate. What's happening is, when no server route matches, the host page is rendered, which bootstraps the client. Now you've transitioned to client-side routing and cannot re-enter (without a change to refresh the browser)
What if I want to display a static file (.html) from wwwroot or a specfic RAZOR PAGE (.cshtml), which doesnt establlish a websocket for all those cases where the route does NOT EXIST IN ANY BLAZOR PAGE ???
That requires knowing what routes exists on the client.
Idea: I could try to add ALL POSSIBLE Blazor-routes as fallbacks and the most general fallback to some static file or Razor Page... but that seems LIKE A LOT OF DOUBLE WORK and very error prone... is there no way?
Possible using the <NotFound> component to run some JavaScript and redirect the browser to a fixed route on the server.
Edit:
Another would be to build that found all routable razor components and map them all as fallback routes to "_Host".
Something like this (untested):
// This should match wherever components are declared.
var types = typeof(Program).Assembly.GetTypes();
foreach (var type in types)
{
if (typeof(ComponentBase).IsAssignableFrom(type) && type.GetCustomAttribute<RouteAttribute>() is { } routeAttribute)
{
var route = routeAttribute.Template;
endpointRouteBuilder.MapFallbackToPage(route, "/_Host");
}
}
It partly depends on how your app is hosted. In IIS, you can add applications to any website, which are basically websites of any type you want with a "/path" added.
Currently, my company's main app is "ABCsite.com," and my Blazor app is "ABCsite.com/Blazor"

Next.js serving static files that are not included in the build or source code

I have files that are not stored in a CDN and would like to serve them with Next.js. These files are not intended to be integrated into Next.js and should not be placed in the public folder. More files will be added and I want to avoid using a custom Next.js server to do simple file serving for images that are not available during building. Additionally, this application will only be deployed locally and using a CDN is overkill for this situation.
Currently, I use Express.js and a Next.js custom server to use express.static to serve files, but this ends up slowing down Next.js and adds lots of unnecessary complexity to my stack. I'd rather just use the Next.js CLI to run my app instead of reinventing the wheel.
Is there a simple way I can serve static files within Next.js and outside the public directory?
I posted this question and my own answer here on StackOverflow because I was unable to find a good tutorial on how to do this. Nearly every google search says to use a custom server or to just put your files in the public folder, which is not what I was looking for. Hopefully, others who are looking for the same thing may find it here.
Disclaimer: I do not use Vercel to publish my applications, and I do not know if this answer will be applicable to Next.js on Vercel.
Next.js allows API routes to be customized to support Node.js HTTP handlers, which means express can also be used within Next.js API routes.
Here is some code to utilize express.static on a Next.js API route.
// pages/api/images/[name].js
// Tell Next.js to pass in Node.js HTTP
export const config = {
api: { externalResolver: true }
}
import express from 'express';
const handler = express();
const serveFiles = express.static('./path/to/files');
handler.use(['/api/images', '/images'], serveFiles);
// ^ ^
// Multiple endpoints are passed. The first one is used when visiting /api/images.
// The second one is used when visiting /images using the middleware rewrite I mention below.
// express is just a function that takes (http.IncomingMessage, http.ServerResponse),
// which Next.js supports when externalResolver is enabled.
export default handler;
However to get around visiting this endpoint via /api/images/filename, you can use Next.js's new middleware to rewrite the request!
// pages/images/_middleware.js
import { NextResponse } from 'next/server';
export function middleware(req) {
// Rewrite /images/... to /api/images/...
return NextResponse.rewrite('/api' + req.nextUrl.pathname);
}
With both these in use, visiting /images/photo.png will internally rewrite to /api/images/photo.png and in turn be handled by express.static, allowing you to serve files outside an API route and without using a custom server!
This code can surely be simplified and get rid of the need of initializing a express.js app just to handle a request, but its incredibly simple to integrate express.js into next.js without using a custom server!
I posted this question and my own answer here on StackOverflow because I was unable to find a good tutorial on how to do this. Nearly every google search says to use a custom server or to just put your files in the public folder, which is not what I was looking for. Hopefully, others who are looking for the same thing may find it here.
The public folder can only serve those files that were included at build time.
But we can do some workaround that can serve files that were not included at build time.
Solution starts here
We can create an api endpoint. For example /api/images-endpoint/[...slug].js
import fs from "fs";
import path from "path";
export default function handler(req, res) {
const imagePath = req.query.slug.join("/");
const filePath = path.resolve(".", `images-directory/${imagePath}`);
const imageBuffer = fs.readFileSync(filePath);
res.setHeader("Content-Type", "image/jpg");
return res.send(imageBuffer);
}
By this, our endpoint will read the image from the image directory and send it as a response.
Benifit/Note: This solution works for images that were added after Next project is build i-e npm run build or next build
Drawback: Using this, We can not build optimized images in Next JS Image component i-e next/image

NextJS API route conflict

I have been transitioning to NextJS from CRA. I'm re-implementing authentication using SSR, and I would like to use NextJS built-in API routes to set HTTPOnly cookies.
There is a weird problem where my backend base URL is https://somesite.com/api and my frontend's - https://somesite.com/. This means that NextJS built-in API routes will be in conflict with my own backend.
I have been researching online and couldn't find any way on changing routing in NextJS, and I don't want to change base URL of my backend, since there are other services depending on it.
Has anyone had the same issue? How can I resolve this issue?
Try next.js rewrite
Rewrites allow you to map an incoming request path to a different destination path. Docs
Check Live Example here: https://stackblitz.com/edit/nextjs-rewrite
If Path is /api it'll point to JSON placeholder APIs.(ex. /api/todos)
module.exports = {
async rewrites() {
return [
{
source: '/api/:slug*',
destination: 'https://jsonplaceholder.typicode.com/:slug*'
}
];
}
};

Asp Core UsePathBase : how to deal with AJAX calls?

I want to host two version of my ASP Core website on the same VPS, one for each supplied environement (Staging and Test). I would like both web sites to be accessible from a subfolder of the same URL:
http://www.mywebsite/Staging
http://www.mywebsite/Test
After reading a lot I found the following Github issue: https://github.com/aspnet/Hosting/issues/815
This tip works but for AJAX calls it crashes: Indeed, the JavaScript calls are not aware of this new path (BUG?). All requests are sent to the root base path (ignoring /Staging or /Test).
I partially solved it usig a middleware that redirects my AJAX calls to the correct path. It works for GET requests but it obviously fails for POST request that have a body.
Note that if we don't redirect, and just change the original PathBase request in the middleware, if the API call needs any authentication schema, it will throws a 401 error: The original PathBase is the root / where the response has a different path base, i.e. /Staging, then the cookie in the header prevents from this cross path base request/response.
Could someone tell me what is the recomanded practice to achieve my needs?
Startup.cs
public void Configure(IApplicationBuilder app, IHostingEnvironment env
{
app.UsePathBase($"/{env.EnvironmentName}");
...
}
My Middleware :
public async Task Invoke(HttpContext context)
{
if (context.Request.Headers[RequestedWithHeader] == XmlHttpRequest)
{
if (string.IsNullOrEmpty(context.Request.PathBase))
{
if (context.Request.Method == HttpMethod.Post.Method)
{
// Do what ?
}
else
{
//Get request : set environement name + original path + original query string
context.Response.Redirect(context.Request.Path.ToString().Insert(0, "/" + _env.EnvironmentName) + context.Request.QueryString);
return;
}
}
}
}
Of course, your client-side code will not be able to automatically change its code based on the path base that is active for the current request. JavaScript code is (usually) static content, so unless you actually rewrite the code dynamically, it cannot update URLs that are embedded inside.
You could determine the base path from the current request’s URL but that is a rather fragile solution since you need to find a logic that will work regardless of where in the application you are. So doing so is not recommended.
The overall problem is that on the client-side, there is no concept of a path base (or even an environment). So you will have to transfer that knowledge from the server to the client. And just like the path base is set for the server-side code using the path base middleware, you will need some server-side code that will pass the path base to the client-side code.
What I personally do is just configure the root path to the API in the application layout. So my _Layout.cshtml contains the following line:
<body data-api="#Url.Content("~/api/")">
That way, I can then retrieve the root path to the API using document.body.dataset.api in JavaScript. My AJAX calls are then all made so they respect that value. That way, I can host the site at any path, and the AJAX calls will use the proper path too.
You could also just use "~" as the content path to just refer to the root of your application. And you could also expose this value in a JavaScript variable inside a <script> block instead, if you prefer that.

How to do routing/navigation in Elm without the # (hash) in the URL?

Using the UrlParser.parseHash function i was able to successfully parse the following url:
http://localhost:8000/MyRepl.elm/#home/something-else
The behavior is as expected, when i copy paste this in the browser and hit enter - the app loads with the appropriate view.
But now i want to remove the # and for this i used UrlParser.parsePath function. I kept the rest of the code exactly as before - but for some reason this doesn't work.
When i copy paste this and hit enter:
http://localhost:8000/MyRepl.elm/home/something-else - notice no #.
The browser creates a direct request to the elm -reactor localhost server.
There is no routing happening. The elm reactor server returns a 404 - as if there is no file named /MyRepl.elm/home/something-else
But routing without # should be possible because the http://package.elm-lang.org/packages - Docs site is written in elm and there is no # in the url as you can see.
Questions:
Anyone has experienced the same problem? Any ideas how to fix this?
Or can you point me to a repo where navigation without # works as expected?
You need a backend that servers your index page for every request. After serving the index page the routing will happen as usual in Elm.
For example in express it would look something like:
router.get('/', function(req, res) {
res.sendFile(path.join(__dirname, 'public/index.html'));
});
router.get('/*', function(req, res) {
res.sendFile(path.join(__dirname, 'public/index.html'));
});
Elm reactor doesn't support this.
If you are using webpack you can do the same with the historyApiFallback attribute How to tell webpack dev server to serve index.html for any route