How to set mandatory route parameters - angular-ui-router

Question

I want to make a route with has a mandatory parameter. If not, it should fall into
$urlRouterProvider.otherwise("/home");
Current route:
function router($stateProvider) {
$stateProvider.state("settings", {
url: "^/settings/{id:int}",
views: {
main: {
controller: "SettingsController",
templateUrl: "settings.html"
}
}
});
}
Currently both the routes below are valid:
http://myapp/settings //Should be invalid route
http://myapp/settings/123
Any ideas?

Answer 1

Use a state change start listener to check if params were passed:
$rootScope.$on('$stateChangeStart',
function (event, toState, toParams, fromState, fromParams) {
if(toState.name==="settings")
{
event.preventDefault(); //stop state change
if (toParams.id===undefined)
$state.go("home");
else
$state.go(toState, toParams);
}
});

Answer 2

The following solution is valid for ui-router 1.0.0:
.config(($stateProvider, $transitionsProvider) => {
//Define state
$stateProvider.state('verifyEmail', {
parent: 'portal',
url: '/email/verify/:token/:optional',
component: 'verifyEmail',
params: {
token: {
type: 'string',
},
optional: {
value: null,
squash: true,
},
},
});
//Transition hooks
$transitionsProvider.onBefore({
to: 'verifyEmail',
}, transition => {
//Get params
const params = transition.params();
//Must have token param
if (!params.token) {
return transition.router.stateService.target('error', {
type: 'page-not-found',
});
}
});
})
The above will make the :token parameter mandatory and the :optional parameter optional. If you try to browse to the page without the token parameter it will fail the transition and redirect to your error page. If you omit the :optional parameter however, it will use the default value (null).
Remember to use squash: true on the trailing optional parameters, because otherwise you'll also get a 404 if you omit the trailing / in the URL.
Note: the hook is required, because if you browse to email/verify/ with a trailing slash, ui-router will think the token parameter is an empty string. So you need the additional handling in the transition hook to capture those cases.

Answer 3

In my app I had to make required parameters for a lot of routes. So I needed a reusable and DRY way to do it.
I define a constants area in my app to access global code. I use for other things as well.
I run this notFoundHandler at app config time. This is setting up a router state for handling errors. It is setting the otherwise route to this error route. You could define a different route for when a required parameter is missing, but for us this was defined as being the same as a 404 experience.
Now at app run time I also define a stateChangeErrorHandler which will look for a rejected route resolve with the 'required-param' string.
angular.module('app')
.constant('constants', constants)
.config(notFoundHandler)
.run(stateChangeErrorHandler);
// use for a route resolve when a param is required
function requiredParam(paramName) {
return ['$stateParams', '$q', function($stateParams, $q) {
// note this is just a truthy check. if you have a required param that could be 0 or false then additional logic would be necessary here
if (!$stateParams[paramName]) {
// $q.reject will trigger the $stateChangeError
return $q.reject('required-param');
}
}];
}
var constants = {
requiredParam: requiredParam,
// define other constants or globals here that are used by your app
};
// define an error state, and redirect to it if no other route matches
notFoundHandler.$inject = ['$stateProvider', '$urlRouterProvider'];
function notFoundHandler($stateProvider, $urlRouterProvider) {
$stateProvider
//abstract state so that we can hold all our ingredient stuff here
.state('404', {
url: '/page-not-found',
views: {
'': {
templateUrl: "/app/error/error.tpl.html",
}
},
resolve: {
$title: function () { return 'Page Not Found'; }
}
});
// redirect to 404 if no route found
$urlRouterProvider.otherwise('/page-not-found');
}
// if an error happens in changing state go to the 404 page
stateChangeErrorHandler.$inject = ['$rootScope', '$state'];
function stateChangeErrorHandler($rootScope, $state) {
$rootScope.$on('$stateChangeError', function(evt, toState, toParams, fromState, fromParams, error) {
if (error && error === 'required-param') {
// need location: 'replace' here or back button won't work on error page
$state.go('404', null, {
location: 'replace'
});
}
});
}
Now, elsewhere in the app, when I have a route defined, I can make it have a required parameter with this route resolve:
angular.module('app')
.config(routeConfig);
routeConfig.$inject = ['$stateProvider', 'constants'];
function routeConfig($stateProvider, constants) {
$stateProvider.state('app.myobject.edit', {
url: "/:id/edit",
views: {
'': {
template: 'sometemplate.html',
controller: 'SomeController',
controllerAs: 'vm',
}
},
resolve: {
$title: function() { return 'Edit MyObject'; },
// this makes the id param required
requiredParam: constants.requiredParam('id')
}
});
}

Answer 4

I'd like to point out that there shouldn't be any problem with accessing the /settings path, since it doesn't correspond to any state, unless you've used inherited states (see below).
The actual issue should happen when accessing the /settings/ path, because it will assign the empty string ("") to the id parameter.
If you didn't use inherited states
Here's a solution in plunker for the following problem:
accessing the /state_name/ path, when there's a state with url /state_name/:id
Solution explanation
It works through the onBefore hook (UI router 1.x or above) of the Transition service, which prevents transitioning to states with missing required parameters.
In order to declare which parameters are required for a state, I use the data hash like this:
.state('settings', {
url: '/settings/:id',
data: {
requiredParams: ['id']
}
});
Then in app.run I add the onBefore hook:
transitionService.onBefore({}, function(transition) {
var toState = transition.to();
var params = transition.params();
var requiredParams = (toState.data||{}).requiredParams || [];
var $state = transition.router.stateService;
var missingParams = requiredParams.filter(function(paramName) {
return !params[paramName];
});
if (missingParams.length) {
/* returning a target state from a hook
issues a transition redirect to that state */
return $state.target("home", {alert: "Missing params: " + missingParams});
}
});
If you used inherited states
You could implement the same logic via inherited states:
function router($stateProvider) {
$stateProvider
.state('settings', {
url: '/settings'
})
.state('settings.show", {
url: '/:id'
});
}
then you'd need to add the abstract property to the parent declaration, in order to make /settings path inaccessible.
Solution explanation
Here's what the documentation says about the abstract states:
An abstract state can never be directly activated. Use an abstract state to provide inherited properties (url, resolve, data, etc) to children states.
The solution:
function router($stateProvider) {
$stateProvider
.state('settings', {
url: '/settings',
abstract: true
})
.state('settings.show", {
url: '/:id'
});
}
Note: that this only solves the issue with /settings path and you still need to use the onBefore hook solution in order to also limit the access to /settings/.

Answer 5

it is not very well documented, but you can have required and optional parameters, and also parameters with default values.
Here is how you can set required params:
function router($stateProvider) {
$stateProvider.state("settings", {
url: "^/settings/{id:int}",
params: {
id: {}
},
views: {
main: {
controller: "SettingsController",
templateUrl: "settings.html"
}
}
});
}
I never used params with curly brackets, just with the semicolon, like this url: "^/settings/:id", but from what I read, those are equivalent.
For other types of parameters, please see the other half of my answer here: AngularJS UI Router - change url without reloading state
Please note that when I added that answer, I had to build ui-router from source, but I read that functionality has been added to the official release by now.