I'm new in Next.js and I'm wondering how to redirect from start page ( / ) to /hello-nextjs for example. Once user loads a page and after that determine if path === / redirect to /hello-nextjs
In react-router we do something like:
<Switch>
<Route path="/hello-nextjs" exact component={HelloNextjs} />
<Redirect to="/hello-nextjs" /> // or <Route path="/" exact render={() => <Redirect to="/hello-nextjs" />} />
</Switch>
Update: Next.js >= 13 with AppDir enabled
You can use next/navigation to redirect both in client components and server components.
Ex. in pages :
import { redirect } from 'next/navigation';
export default async function Home({ params }) {
redirect('/hello-nextjs');
// ...
}
Ex. In client components:
'use client';
import { useEffect } from 'react';
import { redirect } from 'next/navigation';
export const Home= () => {
useEffect(() => {
redirect('/hello-nextjs');
}, []);
return <p></p>;
};
Update: Next.js >= 12.1
As #warfield pointed out in his answer from next.js >= 12.1 relative URLs are no longer allowed in redirects and using them will throw an error. I'm reposting here his answer for more visibility :
To redirect using middleware with Next.js >= 12.1:
Create a middleware.ts (or .js) file at the same level as your pages directory
Export a middleware function
Create an absolute URL and pass it to redirect
TypeScript example middleware.ts:
import { NextResponse } from 'next/server'
import type { NextRequest } from 'next/server'
export function middleware(request: NextRequest) {
const url = request.nextUrl.clone()
if (url.pathname === '/') {
url.pathname = '/hello-nextjs'
return NextResponse.redirect(url)
}
}
Update: Next.js >= 12
Now you can do redirects using middleware, create a _middleware.js file inside the pages folder (or any sub folder inside pages)
import { NextResponse, NextRequest } from 'next/server'
export async function middleware(req, ev) {
const { pathname } = req.nextUrl
if (pathname == '/') {
return NextResponse.redirect('/hello-nextjs')
}
return NextResponse.next()
}
Update: Next.js >= 10
From Next.js 10 you can do server side redirects (see below for client side redirects) with a redirect key inside getServerSideProps or getStaticProps :
export async function getServerSideProps(context) {
const res = await fetch(`https://.../data`)
const data = await res.json()
// or use context.resolvedUrl for conditional redirect
// if(context.resolvedUrl == "/")
if (!data) {
return {
redirect: {
destination: '/hello-nextjs',
permanent: false,
},
}
}
return {
props: {}, // will be passed to the page component as props
}
}
Note : Using getServerSideProps will force the app to SSR,also redirecting at build-time is not supported , If the redirects are known at build-time you can add those inside next.config.js
In next.js you can redirect after the page is loaded using Router ex :
import Router from 'next/router'
componentDidMount(){
const {pathname} = Router
if(pathname == '/' ){
Router.push('/hello-nextjs')
}
}
Or with Hooks :
import React, { useEffect } from "react";
import Router from 'next/router'
...
useEffect(() => {
const {pathname} = Router
if(pathname == '/' ){
Router.push('/hello-nextjs')
}
});
If you want to prevent the flashing before the redirect you can use a simple trick :
import React, { useEffect,useState } from "react";
import Router from 'next/router'
const myPage = ()=>{
const [loaded,setLoaded] = useState(false)
useEffect(() => {
const {pathname} = Router
// conditional redirect
if(pathname == '/' ){
// with router.push the page may be added to history
// the browser on history back will go back to this page and then forward again to the redirected page
// you can prevent this behaviour using location.replace
Router.push('/hello-nextjs')
//location.replace("/hello-nextjs")
}else{
setLoaded(true)
}
},[]);
if(!loaded){
return <div></div> //show nothing or a loader
}
return (
<p>
You will see this page only if pathname !== "/" , <br/>
</p>
)
}
export default myPage
I would say that in general is not a good/elegant approach to do client redirects when you can use next.config.js redirects or even better use conditional render of components.
I have create a simple repo with all the examples above here.
Caveat
First, you should asses whether you need client-side redirection (within React), server-side redirection (301 HTTP response) or server-side redirection + authentication (301 HTTP response but also having some logic to check authentication).
This is the most complete answer I could write. But, in most scenarios, you do not need any of this. Just redirect as you would do in any React app. Prefer client-side redirections first. Just using useEffect + router.push, and that's it.
Server-side redirection are tempting, in particular when you want to "secure" private pages, but you should assess whether you really need them. Usually, you don't. They induce unexpected complexity, like managing auth token and refresh token. Instead, you may want to add a gateway server, a reverse proxy or whatever upfront server to your architecture for instance to handle those kind of checks.
Keep in mind that Next.js are just React app, and using Next.js advanced features like SSR comes at a cost that should be justified in your context.
Next 9.5 update
As stated by #Arthur in the comments, 9.5 also include the possibilities to setup redirects in next.config.js.
The limitations of this feature are not yet clear to me, but they seem to be global redirections, e.g. when you need to move a page or to allow access only during a limited period.
So they are not meant to handle authentication for instance, because they don't seem to have access to the request context. Again, to be confirmed.
Next 10 new doc update
This solution is specific to redirection depending on authentication.
Authentication patterns are now documented
I am not fond of authenticated from getServerSideProps, because it's in my opinion quite too late and can be difficult to set up with advanced patterns such as handling refresh token. But that's the official solution.
You may also want to check the approach documented in this ticket based on how Vercel's dashboard works (at the time of writing), that prevents flash of unauthenticated content
Next 10.2 header and cookies based rewrites update
Next 10.2 introduces Rewrites based on headers and cookies.
That's a great way to redirect server-side, based on the presence of an authentication cookie or header.
However, keep in mind that this is not a secure redirection. User can alter their request headers with a false token. You still need a gateway, a reverse proxy or an upfront server to actually check token validity and correctly set the headers.
Edit: note that the URL won't change. A rewrite points an URL to an existing page of your application, without changing the URL => it allows you to have "virtual" URLs.
Example use case: imagine you have a page src/contact.tsx, that is translated, and i18n redirection setup. You can translate the page name itself ("contact") by rewriting /de/kontact to /de/contact.
Next 12 update
Now middlewares gives you full-control on server-side redirects.
However, keep in mind again, that most of the time a client-side redirect and check is just enough.
Outdated Next 9.4 answer (links are dead sorry)
Hi, here is an example component working in all scenarios:
Vulcan next starter withPrivate access
Example usage here
The answer is massive, so sorry if I somehow break SO rules, but I don't want to paste a 180 lines piece of code. There is no easy pattern to handle redirection in Next, if you want to both support SSR and static export.
The following scenarios each need a specific pattern:
server side rendering: we render the page if allowed, HTTP redirect if not
static rendering (server-side): we render nothing, but we still include the page into the build
client side rendering, after a static export: we check client side if the user is auth, and redirect or not. We display nothing (or a loader) during this check or if we are redirecting.
client side rendering after a client redirect using next/router: same behaviour.
client side rendering after SSR: we use props passed by getInitialProps to tell if the user is allowed, directly at first render. It's just a bit faster, you avoid a blank flash.
At the time of writing (Next 9.4), you have to use getInitialProps, not getServerSideProps, otherwise you lose the ability to do next export.
Even more outdated old answer (works, but will have a messy static render)
Semi-official example
The with-cookie-auth examples redirect in getInitialProps. I am not sure whether it's a valid pattern or not yet, but here's the code:
Profile.getInitialProps = async ctx => {
const { token } = nextCookie(ctx)
const apiUrl = getHost(ctx.req) + '/api/profile'
const redirectOnError = () =>
typeof window !== 'undefined'
? Router.push('/login')
: ctx.res.writeHead(302, { Location: '/login' }).end()
try {
const response = await fetch(apiUrl, {
credentials: 'include',
headers: {
Authorization: JSON.stringify({ token }),
},
})
if (response.ok) {
const js = await response.json()
console.log('js', js)
return js
} else {
// https://github.com/developit/unfetch#caveats
return await redirectOnError()
}
} catch (error) {
// Implementation or Network error
return redirectOnError()
}
}
It handles both server side and client side. The fetch call is the one that actually get the auth token, you might want to encapsulate this into a separate function.
What I would advise instead
1. Redirect on server-side render (avoid flash during SSR)
This is the most common case. You want to redirect at this point to avoid the initial page flashing on first load.
MyApp.getInitialProps = async appContext => {
const currentUser = await getCurrentUser(); // define this beforehand
const appProps = await App.getInitialProps(appContext);
// check that we are in SSR mode (NOT static and NOT client-side)
if (typeof window === "undefined" && appContext.ctx.res.writeHead) {
if (!currentUser && !isPublicRoute(appContext.router.pathname)) {
appContext.ctx.res.writeHead(302, { Location: "/account/login" });
appContext.ctx.res.end();
}
}
return { ...appProps, currentUser };
};
2. Redirect in componentDidMount (useful when SSR is disabled, eg in static mode)
This is a fallback for client side rendering.
componentDidMount() {
const { currentUser, router } = this.props;
if (!currentUser && !isPublicRoute(router.pathname)) {
Router.push("/account/login");
}
}
I could not avoid flashing the initial page in static mode add this point, because you can't redirect during the static build, but it seems better than the usual approaches. I'll try to edit as I make progress.
Full example is here
Relevant issue, which sadly ends up with a client only answer
New issue I've opened regarding redirecton
There are three approaches.
1.Redirect on events or functions:
import Router from 'next/router';
<button type="button" onClick={() => Router.push('/myroute')} />
2.Redirect with hooks:
import Router , {useRouter} from 'next/router';
const router = useRouter()
<button type="button" onClick={() => router.push('/myroute')} />
3.Redirect with Link:
based on Nextjs docs the <a> tag is neccessary inside the link for things like open in a new tab!
import Link from 'next/link';
<Link href="/myroute">
<a>myroute</a>
</Link>
There are some other options for serverside routing which is asPath. in all described approaches you can add asPath to redirect both client and server side.
Edit 13.12.2022
1.Redirect with Link doesn't require anchor tag anymore!
import Link from 'next/link';
<Link href="/myroute">
my route
</Link>
2.Use Nextj.js Redirects
in next.config.js
module.exports = {
async redirects() {
return [
{
source: '/someroute',
destination: '/myroute',
permanent: true,
},
]
},
}
Next.js 10+ is offering us some extra and elegant solution to make a redirection.
SERVER-SIDE - you should use getServerSideProps
The example below assume that we have some extra session to check (but can be
anything that you want). If the session is empty and we are on the server-side
(context.res), that's mean that the user is not logged in and we should
redirect to the login page (/login).. In another way we can pass session
to props and redirect to the /dashboard:
import { getSession } from 'next-auth/client';
export const getServerSideProps = async (context) => {
const session = await getSession(context);
if(context.res && !session) {
return {
redirect: {
permanent: false,
destination: '/login'
}
}
}
return {
props: { session },
redirect: {
permanent: false,
destination: '/dashboard'
}
}
}
CLIENT-SIDE - you can use for example useRouter hook:
import { useRouter } from 'next/router';
import { useSession } from 'next-auth/client';
const router = useRouter();
const [ session, loading ] = useSession();
if (typeof window !== 'undefined' && loading) return null;
if (typeof window !== 'undefined' && !session) {
router.push('/login');
}
router.push('/dashboard');
More info here: https://github.com/vercel/next.js/discussions/14890
Valid for NextJS 9.5.0+
Create next.config.js file
add source and destination url (you can set to permanent redirect if external domain)
module.exports = {
async redirects() {
return [
{
source: '/team',
destination: '/about',
permanent: false,
},
{
source: "/blog",
destination:
"https://blog.dundermifflin.com",
permanent: true,
},
];
},
};
https://github.com/vercel/next.js/tree/canary/examples/redirects
Here are 2 copy-paste-level examples: one for the Browser and one for the Server.
https://dev.to/justincy/client-side-and-server-side-redirection-in-next-js-3ile
Let's say you want to redirect from your root (/) to a page called home: (/home)
In your main index file, paste this:
Client Side
import { useRouter } from 'next/router'
function RedirectPage() {
const router = useRouter()
// Make sure we're in the browser
if (typeof window !== 'undefined') {
router.push('/home')
}
}
export default RedirectPage
Server Side
import { useRouter } from 'next/router'
function RedirectPage({ ctx }) {
const router = useRouter()
// Make sure we're in the browser
if (typeof window !== 'undefined') {
router.push('/home');
return;
}
}
RedirectPage.getInitialProps = ctx => {
// We check for ctx.res to make sure we're on the server.
if (ctx.res) {
ctx.res.writeHead(302, { Location: '/home' });
ctx.res.end();
}
return { };
}
export default RedirectPage
#Nico's answer solves the issue when you are using classes.
If you are using function you cannot use componentDidMount. Instead you can use React Hooks useEffect .
import React, {useEffect} from 'react';
export default function App() {
const classes = useStyles();
useEffect(() => {
const {pathname} = Router
if(pathname == '/' ){
Router.push('/templates/mainpage1')
}
}
, []);
return (
null
)
}
In 2019 React introduced hooks. which are much faster and efficient than classes.
In NextJs v9.5 and above you can configure redirects and rewrites in the next.config.js file.
But if you are using trailingSlash: true ensure that the source path ends with a slash for proper matching.
module.exports = {
trailingSlash: true,
async redirects() {
return [
{
source: '/old/:slug/', // Notice the slash at the end
destination: '/new/:slug',
permanent: false,
},
]
},
}
You also need to account for other plugins and configurations that may affect routing, for example next-images.
Documentation: https://nextjs.org/docs/api-reference/next.config.js/redirects
redirect-to.ts
import Router from "next/router";
export default function redirectTo(
destination: any,
{ res, status }: any = {}
): void {
if (res) {
res.writeHead(status || 302, { Location: destination });
res.end();
} else if (destination[0] === "/" && destination[1] !== "/") {
Router.push(destination);
} else {
window.location = destination;
}
}
_app.tsx
import App, {AppContext} from 'next/app'
import Router from "next/router"
import React from 'react'
import redirectTo from "../utils/redirect-to"
export default class MyApp extends App {
public static async getInitialProps({Component, ctx}: AppContext): Promise<{pageProps: {}}> {
let pageProps = {};
if (Component.getInitialProps) {
pageProps = await Component.getInitialProps(ctx);
}
if (ctx.pathname === "" || ctx.pathname === "/_error") {
redirectTo("/hello-next-js", { res: ctx.res, status: 301 }); <== Redirect-To
return {pageProps};
}
return {pageProps};
}
render() {
const {Component, pageProps} = this.props;
return <Component {...pageProps}/>
}
}
I have implemented this functionality in my Next.JS app by defining a root page this does the redirect server side and client side. Here is the code for the root page:
import { useEffect } from "react";
import Router from "next/router";
const redirectTo = "/hello-nextjs";
const RootPage = () => {
useEffect(() => Router.push(redirectTo));
return null;
};
RootPage.getInitialProps = (ctx) => {
if (ctx.req) {
ctx.res.writeHead(302, { Location: redirectTo });
ctx.res.end();
}
};
export default RootPage;
Next.js >= 12.1
Relative URLs are no longer allowed in redirects and will throw:
Error: URLs is malformed. Please use only absolute URLs.
To redirect using middleware with Next.js >= 12.1:
Create a middleware.ts (or .js) file at the same level as your pages directory
Export a middleware function
Create an absolute URL and pass it to redirect
TypeScript example middleware.ts:
import { NextResponse } from 'next/server'
import type { NextRequest } from 'next/server'
export function middleware(request: NextRequest) {
const url = request.nextUrl.clone()
if (url.pathname === '/') {
url.pathname = '/hello-nextjs'
return NextResponse.redirect(url)
}
}
🤷♂️ useEffect will redirect but jump immediately back to current page
✅ useLayoutEffect works like a charm:
const router = useRouter();
useLayoutEffect(() => {
router.isFallback && router.replace("/course");
}, [router]);
ℹ️ I've used the same code above for useEffect.
If your intention is to ensure your app is running like a SPA and wanting to intercept an incoming invalid (or valid) pathname, which the user pasted into the address bar, then here's a fast/hacky way to do that.
Assume your paths are,
enum ERoutes {
HOME = '/',
ABOUT = '/about',
CONTACT = '/contact'
}
Add a custom _error page if you don't have one already, and add this to it:
import React from 'react';
import { NextPage } from 'next';
import { useDispatch } from 'react-redux';
import { useRouter } from 'next/router';
const Error: NextPage = () => {
const { asPath, push } = useRouter();
const dispatch = useDispatch();
React.useEffect(() => {
const routeValid = Object.values(ERoutes).includes(asPath);
if (routeValid) {
// do some stuff, such as assigning redux state to then render SPA content in your index page
} else {
// you can either continue to render this _error component, or redirect to your index page,
// where you may have your own error component that is displayed based on your app state.
// In my case, I always redirect to '/' (as you can see below, where I push('/'), but before doing so,
// I dispatch relevant redux actions based on the situation
}
// I redirect to root always, but you can redirect only if routeValid === true
push('/');
}, []);
return (
<div>Error because '{asPath}' does not exist</div>
);
};
export default Error;
Redirects
Starting from Next.js 9.5 you are now able to create a list of redirects in next.config.js under the redirects key:
// next.config.js
module.exports = {
async redirects() {
return [
{
source: '/about',
destination: '/',
permanent: true,
},
];
},
};
Ofiicial Docs
Here's the middleware solution to avoid URLs is malformed. Please use only absolute URLs error.
Also, using paths object may be the cleaner way to handle redirection.
// pages/_middleware.ts
import { NextRequest, NextResponse } from 'next/server';
export async function middleware(req: NextRequest) {
const { pathname, origin } = req.nextUrl;
const paths: { [key: string]: string } = {
'/admin/appearance': `${origin}/admin/appearance/theme`,
};
const rePath = paths[pathname];
if (rePath) return NextResponse.redirect(rePath);
else return NextResponse.next();
}
You can set a base path. Next Js allows you to do this. For example, to use /login instead of / (the default), open next.config.js and add the basePath config:
const nextConfig = {
basePath: "/login",
};
module.exports = nextConfig;
You can also check out their docs here https://nextjs.org/docs/api-reference/next.config.js/basepath
I spent the day setting up ssl on my local machine. I am running a wamp stack to build an api locally for testing. This endpoint is set up for ssl now and works perfect. I have a simple route setup that returns a json response.
https://localhost/api/test
It works via firefox by visiting that address.
Now, I am running a react app on
localhost:3000
The problem I am having is that I am trying out the fetch() api and using an example found on the react site (https://reactjs.org/docs/faq-ajax.html). Here is the code but it's extremely simple.
import React, { Component } from "react";
class Api extends Component {
constructor(props) {
super(props);
this.state = {
error: null,
isLoaded: false,
items: []
};
}
componentDidMount() {
fetch("https://localhost/api/test")
.then(res => res.json())
.then(
result => {
this.setState({
isLoaded: true,
items: result.items
});
},
// Note: it's important to handle errors here
// instead of a catch() block so that we don't swallow
// exceptions from actual bugs in components.
error => {
this.setState({
isLoaded: true,
error
});
}
);
}
render() {
const { error, isLoaded, items } = this.state;
if (error) {
return <div>Error: {error.message}</div>;
} else if (!isLoaded) {
return <div>Loading...</div>;
} else {
return (
<ul>
{items.map(item => (
<li key={item.name}>
{item.name} {item.price}
</li>
))}
</ul>
);
}
}
}
export default Api;
The kicker is, if I look at the console, I am getting a 200 response code from the request and also the actual JSON response with the proper data....yet for some reason in the app it is printing NetworkError when attempting to fetch resource.
I would understand the error if it wasn't getting the proper response or code but this just doesn't make sense.
Any advice would be helpful and appreciated!
Well, it looks like it was a CORS issue...which I didn't think would be a problem since everything is local. I had to add the following to my Flight Api backend.
Flight::before('json', function () {
header('Access-Control-Allow-Origin: *');
header('Access-Control-Allow-Methods: GET,PUT,POST,DELETE');
header('Access-Control-Allow-Headers: Content-Type');
});
You have to make sure that CORS is enabled in your HTTP headers which you can do from server side and for client side you have to just write mode:'cors' in your fetch api call, because the server would throw an error and your browser would not be able to load the content served for the requested client.
I am attempting to load some local json data with redux and display in react app. But i'm getting the pageId is undefined in the reducer.
Not sure what I am doing wrong here, I think it might be something wrong with how I'm passing the data but im very new to redux so i'm not sure.
Data
const page = [
{"title":"Mollis Condimentum Sem Ridiculus"},
{"title":"Pharetra Tellus Amet Commodo"}
]
export default page;
Action
const getPage = (pageId) => {
const page = { pageId: pageId }
return {
type: 'GET_PAGE_SUCCESS',
payload: page
}
}
export default getPage
Reducer
import getPage from '../actions/actionCreators'
import pageData from './../data/pageData';
const defaultState = pageData
const pageReducer = (state = defaultState, action) => {
if (action.type = 'GET_PAGE_SUCCESS') {
state.page[action.payload.pageId].title = action.payload
}
return state
}
export default PageReducer
Component
import React, { Component, PropTypes } from 'react'
import { connect } from 'react-redux'
import getpage from '../../actions/actionCreators'
const mapStateToProps = (state, props) => {
const page = state.page[props.pageId]
return { page }
}
class Page extends Component {
componentDidMount () {
this.props.getpage(this.props.pageId)
}
render() {
return (<div><PageContainer pageId={0} /></div>)
}
}
const PageContainer = connect(mapStateToProps, { getpage })(page)
export default Page
I've modified your code into a working JSFiddle for reference: https://jsfiddle.net/qodof048/11/
I tried to keep it as close to your example, but let me explain the changes I made to get it working (also note that JSFiddle does not use the ES6 import syntax).
1) Your PageContainer was not constructed correctly. The last parameter should have been a reference to the Page component (not 'page').
const PageContainer = connect(mapStateToProps, { getPageSimple, getPageAsync })(PageComponent)
2) You used PageContainer in the Page component, but PageContainer is the 'wrapper' around Page. You use PageContainer instead of Page in your render method, so it loads the data (maps state and actions).
ReactDOM.render(
<Provider store={store}>
<div>
<PageContainer pageId="0" async={false} />
<PageContainer pageId="1" async={true} />
</div>
</Provider>,
document.getElementById('root')
);
3) The store was mixed up a bit. If I understood your example correctly you want to load a page into the local store from the pageData array, which simulates a server call maybe. In that case you intialState can't be pageData, but rather is an empty object. Think of it like a local database you're going to fill. The call to your action getPage then gets the page (here from your array) and dispatches it into the store, which will save it there.
const getPageSimple = (pageId) => {
const page = pageDatabase[pageId]; // this call would be to the server
// then you dispatch the page you got into state
return {
type: 'GET_PAGE_SUCCESS',
payload: {
id: pageId,
page: page
}
}
}
4) I've added an async example to the JSFiddle to explain how you would actually fetch the page from the server (since the simple example would not be sufficient). This needs the thunk middleware for redux to work (since you need access to the dispatch method in order to async call it). The setTimeout simulates a long running call.
const getPageAsync = (pageId)=>{
return (dispatch, getState) => {
setTimeout(()=>{
const page = pageDatabase[pageId]; // this call would be to the server, simulating with a setTimeout
console.log("dispatching");
// then you dispatch the page you got into state
dispatch({
type: 'GET_PAGE_SUCCESS',
payload: {
id: pageId,
page: page
}
});
}, 2000);
}
}
The JSFiddle loads 2 containers, one with your simple getPage and one with the async version, which loads the title after 2 seconds.
Hope that helps you along on your react/redux journey.
Hey I see a small mistake in you component, I think. You are doing this.props.pageId, when you are setting page and not pageId on the component's props. So shouldn't it be this.props.getPage(this.props.page.pageId) instead? Could that be it?
Also a small side note, an important tip for using redux is to not mutate state. In you reducer where you are doing state.page[action.payload.pageId].title = action.payload you should probably not set state like that, but instead return a new object called newState which is identical to state, but with the title updated. It is important to treat objects as immutable in Redux. Cheers
I am trying to use Ionic2 and I made a service to fetch a local stored Json.
import {Injectable} from 'angular2/core';
import {Http, Response} from 'angular2/http';
import {Observable} from 'rxjs/Rx';
import 'rxjs/add/operator/map';
#Injectable()
export class Page1Service {
public constructor(private _http: Http) {}
public GetItems() {
return this._http.get('/app/Ressources/Items.json').map((response: Response) => response.json().data);
}
public PrintJson():boolean {
var myresult;
this.GetItems().subscribe((result) => {
myresult = result;
console.log(result);
});
}
I also a made PrintJson() method that just print the json for test purpose.I got the error:
GET http://localhost:8100/app/Ressources/slides.json 404 (Not Found)
I don't get why. And I can't find an easy and uptodate tutorial. Or should I use fetch()?
First copy your json to the following dir(you can create the folder "data"):
[appname]/www/data/data.json
Type in the following command in your console:
ionic g provider JsonData
It should create a provider for you.Go to that page and enter the following in load() function:
load() {
if (this.data) {
// already loaded data
return Promise.resolve(this.data);
}
// don't have the data yet
return new Promise(resolve => {
// We're using Angular Http provider to request the data,
// then on the response it'll map the JSON data to a parsed JS object.
// Next we process the data and resolve the promise with the new data.
this.http.get('data/data.json').subscribe(res => {
// we've got back the raw data, now generate the core schedule data
// and save the data for later reference
this.data = res.json();
resolve(this.data);
console.log(this.data);
});
});
}
I usually create an Observable wrapped around the api-call like this:
public GetItems() {
return Observable.create(observer => {
this._http.get('/app/Ressources/Items.json').map(res =>res.json()).subscribe(data=>{
observer.next(data)
observer.complete();
});
});
}
Then I have to subscribe on that method in order to get the results and do something with it. (You could be to delegate the result to a list in the GUI)
GetItems().subscribe(data=>{
myResult = data;
});
EDIT: It might help to put this in the class as well
export class MyClass{
static get parameters(){
return [[Http]];
}
}
Just try to get the response.json() rather than response.json().data in GetItems() method
The issue is because of different paths of json files in local browser(computer) and device (android). Create data folder inside the src\assets folder. Move your json file into that.
When we run ionic serve, it will move that folder (with file) into www\assets folder. Then do following things:
Import Platform service of ionic2
import { Platform } from 'ionic-angular';
Inject Platform Service.
constructor(private http: Http, private platform: Platform ) { }
Use Platform Service.
public getItems() {
var url = 'assets/data/Items.json';
if (this.platform.is('cordova') && this.platform.is('android')) {
url = "/android_asset/www/" + url;
}
return this.http.get(url)
.map((res) => {
return res.json()
});
}