I am completely new to this community but would really appreciate if someone can help me with this problem I am facing. I am currently following the basic tutorial of the simple Hello World app but how can we update the code to say something else and that to be updated in our output on the browser in real time?
package main
import (
"log"
"github.com/gofiber/fiber/v2"
)
func main() {
// Fiber instance
app := fiber.New()
// Routes
app.Get("/", hello)
// Start server
log.Fatal(app.Listen(":3000"))
}
// Handler
func hello(c *fiber.Ctx) error {
return c.SendString("Hello, World 👋!")
}
You're talking about hot-reloading (live-reloading). Go itself do not have it implemented by default to achieve that, but you can do it with the package called air https://github.com/cosmtrek/air. Here is a great tutorial how to use it with Fiber: https://dev.to/komfysach/go-live-reload-using-air-40ll
Related
I'm trying to find a way to make my Stimulus controller more robust and maintainable by checking that all the required targets are present. If something is missing, I would like it to fail fast and loud.
Below is what I'm using so far:
export default class extends Controller {
static targets = ['name'];
connect() {
if (!that.hasNameTarget) {
throw new Error('expected to find name target');
}
}
}
Perhaps someone knows of a more idiomatic/clean solution?
Option 1 - use the Stimulus debugger tooling
Stimulus has a debug mode that logs out info/warnings etc for Stimulus controllers. You can enable this by stimulus.debug = true;
You can call this in your own controllers via this.application.logDebugActivity() - see https://github.com/hotwired/stimulus/blob/main/src/core/application.ts#L95
export default class extends Controller {
static targets = ['name'];
connect() {
if (!that.hasNameTarget) {
this.logDebugActivity(this.identifier, 'error', { message: 'target missing'});
throw new Error('expected to find name target');
}
}
}
Option 2 - Use the window.onerror callback
If you keep your current code where an error is thrown, Stimulus will not 'break' anything where possible as all calls within Stimulus use try/catch.
However, you can ensure that your error does something 'loud' by creating a onerror function.
See docs - https://stimulus.hotwired.dev/handbook/installing#error-handling
See an example where this can be used for something like Sentry https://blog.sentry.io/2016/01/04/client-javascript-reporting-window-onerror
You could also just be really loud and block the UI with something similar to this.
window.onerror = (message, url, lineNo, columnNo, error) => {
document.body.style.backgroundColor = 'red';
window.alert(message);
}
Reminders
Remember to only enable these debugging features in local development, you can do this with something like Webpack environment variables but this will be different depending on your tooling.
In production though you may want to push your onerror calls to whatever logging infrastructure you have.
stimulus.debug mode is quite 'noisy' and may be too much information, depending on your set up.
I am very new to both java and vaadin. Hope to be able to get some good tips on how I can improve my code.
I would like to rewrite the code below to use Vaadin´s -> LoginOverlay instead of the code below.
As I said, I'm trying to learn so I have used the code for this example: https://www.youtube.com/watch?v=oMKks5AjaSQ&t=1158s
However, LoginOverlay seems to be a better way to display its login part through. As in this example: https://www.youtube.com/watch?v=pteip-kZm4M
So my question is how can you write the code below as a LoginOverlay.
public class LoginView extends Div {
public LoginView(AuthService authService) {
setId("login-view");
var username = new TextField("Username");
var password = new PasswordField("Password");
add(
new H1("Welcome"),
username,
password,
new Button("Login", event -> {
try {
authService.authenticate(username.getValue(), password.getValue());
UI.getCurrent().navigate("home");
} catch (AuthService.AuthException e) {
Notification.show("Wrong credentials.");
}
}),
new RouterLink("Register", RegisterView.class)
);
}
}
I have only come this far to convert the code.
A clarification of the new part of the code. The code does not work. The part with loginOverlay.addLoginListener (event -> probably needs to be written in a different way.
I'm using IntelliJ 2020.3.4 if that is of any help.
public class LoginView2 extends Composite<LoginOverlay> {
public LoginView2(AuthService authService) {
setId("login-view");
LoginOverlay loginOverlay = getContent();
loginOverlay.setTitle("Welcom");
loginOverlay.setDescription("Manage your business tasks");
loginOverlay.setOpened(true);
loginOverlay.addLoginListener(event -> {try {
if(authService.authenticate(username.getValue(), password.getValue());
UI.getCurrent().navigate("home");
} catch (AuthService.AuthException e) {
Notification.show("Wrong credentials.");
}
}),
new RouterLink("Register", RegisterView.class);
}
}
}
}
Super grateful for all the help you can give.
Many thanks to everyone who makes stackoverflow so amazing.
Copy-pasting code snippets with little idea about what the code does is a recipe for disaster, especially when it comes to security.
You have all kinds of errors in your code: misplaced braces, using variables that do not exist, and a RouterLink far from where it belongs.
I understand you've got to start somewhere. I would recommend starting from code that actually compiles, and then gradually adding things, testing what you have so far at every step.
Here are some tips for your LoginView2:
Remove the whole loginOverlay.addLoginListener(...) code, including the authService.authenticate call and the RouterLink. Make sure that you can run the application at this point, and that you can see the login overlay.
Add back the login listener, but for now just show a notification in it. Test that you can run the application, and that if you click Login, your notification is displayed.
loginOverlay.addLoginListener(event -> {
Notification.show("This is working");
});
Implement the authentication. You have a call to authService.authenticate(...) inside an if-statement, but the method does not return anything. Instead, it throws an exception if the authentication fails, hence the try-catch. This means that inside the try { ... } block, any code you put after the authService.authenticate(...) call is only executed if it did not throw an exception, i.e. if the authentication was successful.
There are no username or password variables. The first YouTube video had defined these variables in the form of text fields. With the login overlay, it creates those fields for you, so how do you get the corresponding values from it?
I would appreciated some help please even if this is maybe a trivial question.
I've written a SwiftUI app that reads the media library from the device and plays it depending on user settings. That is all fine.
The problem I have is that if you install the app for the first time, the user needs to grant permission to access the media library. This appears to be a system generated dialog but I cannot see which step in the also triggers it. I tried to have the access request be triggered code generated but that doesn't seem to trigger the pop up but it still only appears at a later stage in the app load process. The code seems to recognise though that the user reacted to the access request pop up and does select the correct switch case.
What it does not seem to do though is that it still can't read the media library. The MPMediaQuery returns nil.
My suspicion is that it somehow connected to the fact that the access request doesn't run on the main thread but I am not experienced enough in Swift programming to know what the problem is. I would be most grateful for some helpful hints.
Here is my code:
import MediaPlayer
import SwiftUI
import Foundation
class Library {
var artists : [Artist] = []
#EnvironmentObject var settings : UserSettings
var counter : Float = 0
init() {
switch MPMediaLibrary.authorizationStatus() {
case .authorized:
print("authorized")
case .denied:
print("denied")
return
case .notDetermined:
print("not determined")
MPMediaLibrary.requestAuthorization() { granted in
if granted != .authorized {
return
}
}
case .restricted:
print("restricted")
#unknown default:
print("default")
}
if MPMediaLibrary.authorizationStatus() == .notDetermined { return }
let filter : Set<MPMediaPropertyPredicate> = [MPMediaPropertyPredicate(value: MPMediaType.music.rawValue, forProperty: MPMediaItemPropertyMediaType)]
let mediaQuery = MPMediaQuery(filterPredicates: filter )
var artistsInCollection : [Artist] = []
guard let _ = mediaQuery.items?.count else { return }
for item in mediaQuery.items! {
//here I do something but that's not relevant to my question
}
self.artists = artistsInCollection
}
}
I am trying to refactor some test code and in two packages I need to do the same thing (connect to a DB). I am getting an import cycle. I get why I can't do it, but am wondering what the best way around it is.
Some specifics, I have three packages: testutils, client, engine.
In engine I define an interface & implementation (both exported).
package engine
type interface QueryEngine {
// ...
}
type struct MagicEngine {
// ...
}
And then in the testutils package I will create a MagicEngine and try and return it.
package testutils
func CreateAndConnect() (*engine.MagicEngine, error) {
// ....
}
Now in the test code (using a TestMain) I need to do something like
package engine
func TestMain(m *testing.M) {
e, err := testutils.CreateAndConnect()
// ....
os.Exit(m.Run())
}
This is of course a cycle. I want to do this so that I can in the client package also use this testutils.CreateAndConnect() method. I don't want to repeat the code in both packages. I don't want it in the main code of the engine package, it is very specific to the tests.
I tried adding it as an exported method on the engine test class (engine/engine_test.go) and using it in the client/client_test.go. No dice. :/
I feel I have done this in other languages, but could be crazy. What is the best way to structure this code for reusability?
You could use black-box style testing because the components of engine are exported. Change your tests to be in package engine_test:
package engine_test
import "engine"
import "testutils"
func TestMain(m *testing.M) {
e, err := testutils.CreateAndConnect()
// ....
os.Exit(m.Run())
}
I'm doing an experiment with wxWebConnect test application, incorporating the xpcom tutorial at "http://nerdlife.net/building-a-c-xpcom-component-in-windows/"
I adapt MyComponent class as necessary to compile together with testapp.exe (not as separate dll), and on MyApp::OnInit I have the following lines:
ns_smartptr<nsIComponentRegistrar> comp_reg;
res = NS_GetComponentRegistrar(&comp_reg.p);
if (NS_FAILED(res))
return false;
ns_smartptr<nsIFactory> prompt_factory;
CreateMyComponentFactory(&prompt_factory.p);
nsCID prompt_cid = MYCOMPONENT_CID;
res = comp_reg->RegisterFactory(prompt_cid,
"MyComponent",
"#mozilla.org/mycomp;1",
prompt_factory);
Those lines are copied from GeckoEngine::Init(), using the same mechanism to register PromptService, etc. The code compiles well and testapp.exe is running as expected.
I put javascript test as below :
try {
netscape.security.PrivilegeManager.enablePrivilege("UniversalXPConnect");
const cid = "#mozilla.org/mycomp;1";
obj = Components.classes[cid].createInstance();
alert(typeof obj);
// bind the instance we just created to our interface
alert(Components.interfaces.nsIMyComponent);
obj = obj.QueryInterface(Components.interfaces.nsIMyComponent);
} catch (err) {
alert(err);
return;
}
and get the following exception:
Could not convert JavaScript argument arg 0 [nsISupport.QueryInterface]
The first alert says "object", so the line
Components.classes[cid].createInstance()
is returning the created instance.
The second alert says "undefined", so the interface nsIMyComponent is not recognized by XULRunner.
How to dynamically registering nsIMyComponent interface in wxWebConnect environment ?
Thx
I'm not sure what is happening here. The first thing I would check is that your component is scriptable (I assume it is, since the demo you copy from is). The next thing I would check is whether you can instantiate other, standard XULRunner components and get their interface (try something like "alert('Components.interfaces.nsIFile');" - at least in my version of wxWebConnect this shows an alert box with string "nsIFile".
Also, I think it would be worth checking the Error Console to make sure there are no errors or warnings reported. A magic string to do that (in Javascript) is:
window.open('chrome://global/content/console.xul', '', 'chrome,dialog=no,toolbar,resizable');