'Dart / Flutter - Validating a string for URL

I'm trying to create a system in which I can validate a string to check if it's a url or not. (https://www.google.com/)

I found the flutter package validator but this isn't dart 2 compatible, so won't be compatible with my code.

Similarly named, I also found the validators package but I can't seem to get it working correctly with my code, as it throws the following error; (hope you like my project name ;) 

Because every version of flutter_test from sdk depends on test 1.3.0 
and every version of validators depends on test ^1.3.3, flutter_test from sdk is incompatible with validators.
So, because gucci depends on both validators ^1.0.0+1 and flutter_test any from sdk, version solving failed.
Unable to reload your application because "flutter packages get" failed to update package dependencies.
Exception: pub get failed (1)

If you could either find a fix for validators so that it doesn't throw this error and thus works correctly with my code, or suggest another method of validating a string to be URL compliant that would be great.

Thanks

Edit - My pubspec.yaml file

name: gucci
description: A new Flutter project.

dependencies:
  flutter:
    sdk: flutter

  cupertino_icons:
  barcode_scan:
  gradient_app_bar:
  url_launcher:
  validate: ^1.7.0

dev_dependencies:
  flutter_test:
    sdk: flutter

  fonts:
    - family: PlayfairDisplay
      fonts:
        - asset: fonts/PlayfairDisplay-BoldItalic.ttf

    - family: Kanit
      fonts:
        - asset: fonts/Kanit-ExtraBoldItalic.ttf

    - family: Poppins
      fonts:
        - asset: fonts/Poppins-BoldItalic.ttf

    - family: PoppinsLightItalic
      fonts:
        - asset: fonts/Poppins-LightItalic.ttf

    - family: PoppinsMediumItalic
      fonts:
        - asset: fonts/Poppins-MediumItalic.ttf
stringdartflutterurl-validation


Solution 1:[1]

For some reason, the validators package is requiring a pretty recent version of flutter's testing library rather than leaving it up to the application. Maybe there's a good reason for that (i.e. they're using a new feature).

The flutter engine internally requires a particular version of the flutter_test library (which is why it's generally a bad idea to specify a version of it). So to fix this you'll have to upgrade your flutter by running flutter upgrade. If you're already at the most recent version of the channel you're in, you may have to run flutter channel dev or flutter channel master to switch to a channel (branch really) that's updated more often.

I run on the dev branch/channel for the most part and while it very occasionally has problems, it doesn't happen a lot. I'd advise against using the master branch if possible though.

Solution 2:[2]

To check Valid URL string you just have to use Uri.parse() like below.

bool _validURL = Uri.parse(_adVertData.webLink).isAbsolute;

Just check value of _validURL

Solution 3:[3]

Uri.tryParse(mystring)?.hasAbsolutePath ?? false;

Some example results:

url result
'https://stackoverflow.com/questions/52975739/dart-flutter-validating-a-string-for-url' true
asd false
asd:asd false
%EMPTY_STRING% false
google.nl false
https: false
https:// false
https://a false
https://a/ true

Solution 4:[4]

var urlPattern = r"(https?|http)://([-A-Z0-9.]+)(/[-A-Z0-9+&@#/%=~_|!:,.;]*)?(\?[A-Z0-9+&@#/%=~_|!:??,.;]*)?";
var match = new RegExp(urlPattern, caseSensitive: false).firstMatch('https://www.google.com');
match = RegExp(urlPattern, caseSensitive: false).firstMatch('http://www.google.com');

You can use RegExp too.

Solution 5:[5]

I used the following method below. Depending on your rec, all valid URLs need to have a host (ex, google.com). If a URL does not have a host it returns an empty string (not undefined or null).

  bool isURLValid = Uri.parse("https://google.com/").host.isNotEmpty;

Using .isAbsolute, as some have already reported, marks URLs such as 'http:' to be valid URLs which not.

Solution 6:[6]

Validation using RegEx

String hasValidUrl(String value) {
   String pattern = r'(http|https)://[\w-]+(\.[\w-]+)+([\w.,@?^=%&:/~+#-]*[\w@?^=%&/~+#-])?';
   RegExp regExp = new RegExp(pattern);
   if (value.length == 0) {
        return 'Please enter url';
   }
   else if (!regExp.hasMatch(value)) {
     return 'Please enter valid url';
   }
   return null;
}

Validation using in-built package

final Uri uri = Uri.tryParse(value);
if (!uri.hasAbsolutePath) {
     return 'Please enter valid url';
}

If you want some special case like you have to validate deepLink then RegEx practice is best.

Solution 7:[7]

For RegExp, if you are going to find URL in a string, you can use this one.

r'^((?:.|\n)*?)((http:\/\/www\.|https:\/\/www\.|http:\/\/|https:\/\/)?[a-z0-9]+([\-\.]{1}[a-z0-9]+)([-A-Z0-9.]+)(/[-A-Z0-9+&@#/%=~_|!:,.;]*)?(\?[A-Z0-9+&@#/%=~_|!:??,.;]*)?)'

It can be used when you are highlighting URL in a string. For example in a chat app, you can highlight URL in a sent chat message. This validates google.com, https://google.com, http://google.com all.

Solution 8:[8]

I'm using this way to validate Urls. In your TextFormField's use this validator. here your url should be start from www.

validator: (website) {
                      String pattern =
                          r'^((?:.|\n)*?)((http:\/\/www\.|https:\/\/www\.|http:\/\/|https:\/\/)?[a-z0-9]+([\-\.]{1}[a-z0-9]+)([-A-Z0-9.]+)(/[-A-Z0-9+&@#/%=~_|!:,.;]*)?(\?[A-Z0-9+&@#/%=~_|!:??,.;]*)?)';
                      RegExp regExp = RegExp(pattern);
                      if (website.isEmpty) {
                        return "Please enter your website";
                      } else if (!(regExp.hasMatch(website))) {
                        return "Website Url must be started from www";
                      } else {
                        return null;
                      }
                    },

Sources

This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.

Source: Stack Overflow

Solution Source
Solution 1 rmtmckenzie
Solution 2 iPatel
Solution 3
Solution 4 John Wang
Solution 5 user7856586
Solution 6 Dharmesh Mansata
Solution 7 Ares
Solution 8 Shailandra Rajput

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