I'm developing a Svelte frontend app which communicates with rails API server.
I like the rails way of abstraction (esp. with simple_form gem) and I'd like to bring some ideas to Svelte. The particular problem I met is how to associate errors from the rails server with inputs on the svelte side
First, I tuned up error responses from the server; in general, they look like this:
{ errors:
{ generic: [<messages without association with particular field>],
email: ["Already taken", <msg_2>, ...],
password: ["Too short", ...],
field_N: [...]
}
}
generic errors can be "Invalid Login Credentials", "Your account is locked", "Internal Server Error", etc.
Other errors must be related to the form fields and must be displayed next to them.
Here is my current approach signup.svelte:
<script>
let email;
let password;
function registerRequest() {
let regURL = baseURL+'/api/users/';
let data = {"user": {"email": email, "password": password}};
fetch(regURL, {
method: 'POST',
body: JSON.stringify(data),
headers: {
'Content-Type': 'application/json'
}
})
.then(function(response) {
if (!response.ok) {
return response.json()
}
})
// if errors present then iterate through errors object
.then(function(error) {
// find id of the message field and insert actual messages
for (let [key, value] of Object.entries(error.errors)) {
document.getElementById(key).insertAdjacentHTML('beforeend',value);
}
});
}
</script>
<style> .errormessage { color: red; } </style>
<form class="col-sm-12 col-lg-6" on:submit|preventDefault={registerRequest}>
<!-- here I need to create errormessage container for each field. -->
<!-- first one is generic to display generic errors -->
<div class="errormessage" id="generic"></div>
<label for="UserEmail">Email address</label>
<input type="email" class="form-control" id="UserEmail" aria-describedby="emailHelp" placeholder="Enter your email here..." bind:value={email}>
<div class="errormessage" id="email"></div>
<label for="UserPassword">Password</label>
<input type="password" class="form-control" id="UserPassword" placeholder="...and your password here" bind:value={password}>
<div class="errormessage" id="password"></div>
<button type="submit" class="btn btn-primary">Register</button>
</form>
I want to unify the code above with frontend validation. If the errors object is presented - show messages next to the fields with errors. It seems to me that using getElementById is overkill. Why should I use it if my DOM never reloading? Every time on input it will search for ids. Maybe it should be listener that listens changes of the errors object? I tried to bind the custom event with Svelte
import { createEventDispatcher } from 'svelte';, but with no luck.
Please help and share your thoughts.
Your intuition is right that using getElementById in a Svelte component feels off - generally Svelte wants you to make you code declarative, where the DOM is a function of the state, rather than imperative where you're manually changing the DOM.
For the error messages, I'd suggest having an errors variable in your component. When server errors come back, you can assign them to errors, which will cause a reactive update and re-render the component. Then the markup can know to render errors when they exist, without you having to explicitly change the DOM. Something like this:
<script>
let email;
let password;
// New `errors` variable.
let errors = {};
function registerRequest() {
// Reset the errors when the user submits a new request.
errors = {};
let regURL = baseURL+'/api/users/';
let data = {"user": {"email": email, "password": password}};
fetch(regURL, {
method: 'POST',
body: JSON.stringify(data),
headers: {
'Content-Type': 'application/json'
}
})
.then(function(response) {
if (!response.ok) {
return response.json()
}
})
.then(function(error) {
// Just save the errors
errors = e.errors;
});
}
</script>
<style> .errormessage { color: red; } </style>
<form class="col-sm-12 col-lg-6" on:submit|preventDefault={registerRequest}>
<!-- first one is generic to display generic errors -->
<!-- note the `|| []` part, which makes sure that
`#each` won't throw an error when `errors.generic` doesn't exist -->
{#each (errors.generic || []) as error}
<div class="errormessage" id="generic">{error}</div>
{/each}
<label for="UserEmail">Email address</label>
<input type="email" class="form-control" id="UserEmail" aria-describedby="emailHelp" placeholder="Enter your email here..." bind:value={email}>
<!-- email errors -->
{#each (errors.email || []) as error}
<div class="errormessage" id="email">{error}</div>
{/each}
<label for="UserPassword">Password</label>
<input type="password" class="form-control" id="UserPassword" placeholder="...and your password here" bind:value={password}>
<!-- password errors -->
{#each (errors.password || []) as error}
<div class="errormessage" id="password">{error}</div>
{/each}
<button type="submit" class="btn btn-primary">Register</button>
</form>
Here's a Svelte REPL with that code working. Hope that helps!
Related
I'm using backend functions on my website to gather data from a separate website.
I can access the data easily with something like...
fetch( DataURL, {"method": "get"} )
.then( httpResponse => httpResponse.json() )
.then( json => { console.log(json); } )
However, there is additional data fields in the json data that aren't visible unless you are logged in.
I'm trying to use a POST fetch to complete the login form, and then send the GET to retrieve the API data afterwards. Have been unsuccessful so far.
fetch( LoginURL, {
"method": "post",
"body": "Username=myusername&Password=mypassword",
"headers": {"Content-Type": "application/x-www-form-urlencoded"}
})
.then( fetch( DataURL, {"method": "get"} )
.then( httpResponse => httpResponse.json() )
.then( json => { console.log(json); })
})
I'm basing the body data on what I see in the form in their source code. Not completely sure if I'm doing that right.
This is a phpBB style website that needs to be logged into.
<form action="./ucp.php?mode=login" method="post" id="navloginform" name="loginform">
<div class="form-group">
<input type="text" placeholder="Username" name="username" size="10" class="form-control" title="Username"/>
</div>
<div class="form-group">
<input type="password" placeholder="Password" name="password" size="10" class="form-control" title="Password"/>
</div>
<div class="form-group">
<div class="checkbox">
<label for="autologin-navbar"><input type="checkbox" name="autologin" id="autologin-navbar" tabindex="4" /> Remember me</label>
</div>
</div>
<input type="hidden" name="redirect" value="./ucp.php?mode=login" />
<button type="submit" name="login" class="btn btn-primary btn-block"><i class="fa fa-sign-in fa-fw" aria-hidden="true"></i> Login</button>
</form>
I'm very clearly doing something wrong.
I think my main issues I'm struggling with are:
Is my guess at how to use their form data correct?
How do I verify the login even worked to begin with?
Do I need to do something special to maintain the login before sending a second fetch?
Just going to share how I got mine working, though may be different for other cases.
--
Go to the website you're trying to login to, and open up your browser development tools.
Select the 'Network' tab, and login.
Find the network entry from your login, and go to the 'Headers' tab. Near the bottom of the entry will show which headers were used. Not all of these are critical. Something like below:
When using your fetch call, create the same headers as needed in the body.
const LoginURL = 'www.ExampleWebpageLogin.com./ucp.php?mode=login';
let form = new FormData();
form.append('username', 'MyUsername');
form.append('password', 'MyPassword');
form.append('login', 'Login');
var headers = { 'method': 'post',
'body': form,
'credentials': 'include'}
await fetch( LoginURL, headers)
.then( loginResponse => {
console.log(loginResponse);
})
In my case, the loginResponse included 2 critical cookies.
user_id - This cookie value remained =1 when not logged in, and was set to my user id once successful.
sid - Most likely session ID, which they use to preserve login session.
For both the login post and future GET requests, 'credentials' are required.
I have a registration form in one of my reactJs files, which takes all values of input fields (works as I expect).
SignUp.js
import React, { Component } from 'react';
import { Link } from 'react-router-dom';
class SignUpForm extends Component {
constructor() {
super();
this.state = {
email: '',
password: '',
username: '',
hasAgreed: false,
formErrors: {email: '', password: ''},
emailValid: false,
passwordValid: false,
formValid: false
};
this.handleChange = this.handleChange.bind(this);
this.handleSubmit = this.handleSubmit.bind(this);
}
handleChange(e) {
let target = e.target;
let value = target.type === 'checkbox' ? target.checked : target.value;
let name = target.name;
this.setState({[name]: value});
}
handleSubmit(e) {
e.preventDefault();
console.log('The form was submitted with the following data:');
console.log([this.state.email, cryptr.encrypt(this.state.password), this.state.username, this.state.hasAgreed]);
//I want to send my above data to node server
}
render() {
return (
<div className="FormCenter">
<form onSubmit={this.handleSubmit} className="FormFields" method="POST" action="/register">
<div className="FormField">
<label htmlFor="name">Username</label>
<input type="text" id="name" placeholder="Enter your username" name="username" value={this.state.username} onChange={this.handleChange} />
</div>
<div className="FormField">
<label htmlFor="password">Password</label>
<input type="password" id="password" placeholder="Enter your password" name="password" value={this.state.password} onChange={this.handleChange} />
<div className="FormField">
<label htmlFor="email">E-Mail Address</label>
<input type="email" id="email" placeholder="Enter your email" name="email" value={this.state.email} onChange={this.handleChange} />
</div>
</div>
<div className="FormField">
<label>
<input type="checkbox" name="hasAgreed" value={this.state.hasAgreed} onChange={this.handleChange} /> I agree all statements in terms of service
</label>
</div>
</form>
</div>
);
}
}
export default SignUpForm;
Now I want to send the mentioned data to the created node server.
server.js
const express = require("express");
const bodyParser = require("body-parser");
const path = require("path");
const app = express();
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: false }));
app.use(express.static(path.join(__dirname, "src/containers/user")));
//the request in which I expect input data
app.post('/register', (req, res) => {
if (!req.body) return res.sendStatus(400);
console.log(req.body, "body");
res.send('welcome, ' + req.body.username)
});
app.listen(5000, () => {
console.log("is listening on port 5000");
});
As I expect, in form tag writing method="POST" action="/register"would do it's job, but even the console.log from /register request is not responding.
Note: The next thing I should implement is to write all the data in txt file. So fetching the data in back end is a must.
What you need to do is pass the data as an object to axios like so, which you indicated you have installed in your project.
const formData = {
email: this.state.email,
password: cryptr.encrypt(this.state.password)
username: this.state.username,
hasAgreed: this.state.hasAgreed
}
axios({
method: 'post',
url: '/register',
data: formData,
config: { headers: {'Content-Type': 'multipart/form-data' }}
})
.then(function (response) {
//handle success
})
.catch(function (response) {
//handle error
});
The default behavior of a form is to submit when a submit button is clicked, or if a user hits enter. In your case however, you have a submit handler like so;
handleSubmit(e) {
e.preventDefault();
console.log('The form was submitted with the following data:');
console.log([this.state.email, cryptr.encrypt(this.state.password), this.state.username, this.state.hasAgreed]);
//I want to send my above data to node server
}
In this handler your are writing e.preventDefault(); which as the name implies, prevents the form's default behavior from happening. As a result no request is actually being made to the server.
Now the surest way I know to make this work, would be to use some kind of ajax library. You can use fetch, or something like axios.
The other way which MAY work is to remove the e.preventDefault();. Now this way is a bit more tricky. Usually react apps are not served from the same server as the api, in which case your request's url would need to look something more like this.
http://localhost:5000/register. Alternatively, you can tell webpack dev server to proxy your requests. Even then I personally am not sure this would work simply because I have never tried it.
Its important to note, either approach you choose will require the full url in the request if the react app is not served from the same place as the api, or if there is no proxying done by wepback. In other words, you may very well need http://localhost:5000/register.
My suggestion would be to use an ajax library like I mentioned.
Hope this helps.
as the title says, I want to submit a form and update the values from the form (Mysql result) without refreshing the whole page.
See Image 1, I want if I press the blue button that the values updated.
Can someone help me?
Thanks.
If you are willing to use newer apis like Promise and fetch, it's super easy and neat.
foo.submit.addEventListener("click", (e) => {
e.preventDefault();
fetch("YOUR_URL", {
method: 'POST',
body: new URLSearchParams({
name: foo.user_name_value,
email: foo.user_mail.value
})
}).then(response => {
return response.json() // assume returning data is in json format, otherwise .text() could be used
}).then(data => {
// deal with return data
}).catch(err => {
// deals with errors
})
})
<form name="foo">
<div>
<label for="name">Name:</label>
<input type="text" id="name" name="user_name">
</div>
<div>
<label for="mail">E-mail:</label>
<input type="email" id="mail" name="user_mail">
</div>
<div>
<button name="submit" type="submit">Send your message</button>
</div>
</form>
Older method XHR shares same idea, but requires a bit more code. You may use axios or so to simplify the process.
I am attempting to set up user login and role authentication with Vue, without using Vuex, as it's a bit much for the scope of our application. After a failed initial attempt to use jQuery AJAX outside of Vue, I resigned myself to making it work with Vue's data-oriented model, which I've been struggling with (I'm a designer by trade, not really a developer). My backend developer is writing in plain PHP and using mySQL, for reference.
Taking inspiration from this tutorial, I am trying to use v-model to send the form data to the server via axios.
Template:
<form class="login-form" id="loginform" #submit.prevent="login">
<div class="form-group space">
<label class="float-label" for="username">Username</label>
<input v-model="username" type="username" id="username" class="form-control" placeholder="username">
</div>
<div class="form-group">
<label class="float-label" for="username">Password</label>
<input v-model="password" type="password" id="password" class="form-control" placeholder="password">
</div>
<div class="form-group">
<button type="submit" class="btn btn-primary float-right" id="login">Log in</button>
</div>
</form>
Script:
export default {
name: 'Login',
data () {
return {
username: '',
password: ''
}
},
methods: {
login: function () {
const loginInfo = { username, password }
console.log(loginInfo)
new Promise ((resolve, reject) => {
axios({url: 'api.com/index.php', data: loginInfo, method: 'POST' })
.then(resp => {
const token = resp.data.token
localStorage.setItem('user_token', token) // store the token in localstorage
const employeeId = resp.data.employee_id
localStorage.setItem('employee_id', employeeId) // store the id in localstorage
resolve(resp)
console.log(resp);
})
.catch(err => {
localStorage.removeItem('user_token') // if the request fails, remove any possible user token if possible
reject(err)
})
})
// myLoginRoutine(loginInfo).then(() => {
// this.$router.push('/')
// })
}
}
}
The request was going through no problem, but wasn't returning anything! I decided to check and see what I was sending him... and lo and behold, const loginInfo was not the input value, as expected, but {username: input#username.form-control, password: input#password.form-control}
I am, quite frankly, very confused. I've used v-model previously on form inputs with no issues, and have no clue why this is happening or how to fix it. Any thoughts?
For future visitors: The axios data expects an object with those keys for the backend, but you don't fill the object properly.
Change
const loginInfo = { username, password }
to
const loginInfo = { username: this.username, password: this.password }
I've built a login component with the below code for users to log in the backend is flask and is using flask_login.
const LoginScreen = {
template: `
<div>
<h1>Sign In</h1>
<form id="loginform" class="pure-form">
<fieldset>
<input type="text" name="email" placeholder="email" v-model="logindetails.email"/>
<input type="password" name="password" placeholder="password" v-model="logindetails.password"/>
<button class="pure-button pure-button-primary" v-on:click="login">Login</button>
</fieldset>
</form>
</div>
`,
data: function () {
return {
logindetails:{}
}
},
methods: {
login: function(){
axios.post('/login/',
this.logindetails,
{
headers: {
'Content-type': 'application/json',
'Accept': 'application/json',
'X-CSRF-TOKEN': document.querySelector('#csrftoken').getAttribute('content')
}
}
).then(response => { this.logindetails = {};
this.$router.push({path: '/'});
}
)
.catch(function (error) {
console.log(error);
});
}
}
};
It seems to work correctly (though there are times when it asks me to log in again for seemingly no reason), however the component is putting the submitted form details into the querystring of the url ( example ).
Would anyone be able to tell me what I am doing wrong or, if I am doing this totally incorrectly, point me in the direction of a codebase/guide that is doing logins correctly?
Many thanks in advance.
Take a look at Vue v-on event modifiers to modify the default element behavior.
In your case you can do:
<button #click.prevent="login">Login</button>
Or in the form tag (ensure your submit button is type "submit"):
<form #submit.prevent="login">
with regards to the component is putting the submitted form details into the querystring of the url, the reason is that clicking on the button also trigger submit on the form.
HTML form submits form values to the server.
But normally in JS frameworks like Vue or React, form values are submited through ajax, without any page refresh. So using <form> has not much value here.
2 things you could do in this case
Remove <form> element. it should still works corectly
handle the form submit event.
For e.g.
<form #submit="handleSubmit($event)">
methods: {
handleSubmit:(e) =>{
e.preventDefault();
}
}