Cordova插件可检测互联网连接

Question

my cordova app requires internet connection for some actions. i am using https://github.com/apache/cordova-plugin-network-information to get an event whenever the app goes online or offline. It works well with Mobile Data, but for Wifi, it acts a bit strange. Whether my wifi is connected to the internet or not, it reports that i am online in both cases.

The behavior that i am expecting is to say i am online only when the wifi is connected to the internet. i am running ionic framework, angularjs, cordova 3.5.1, and using an Android, Galaxy S3 for testing.

Answer 1

The plugin does not detect if the user has access to the Internet, but only if the user is on a network. Since your phone is on a WiFi network even though the WiFi network doesn't have access to the Internet, the plugin is performing as designed.

In order to test connectivity, you must always attempt the request -- this is the only way to truly know if the device has Internet access. So if you're trying to reach www.google.com , you have to attempt the request and handle any errors that result. The only benefit to having the network plugin in place is that you have a little more information about whether or not it is even worth attempting the request in the first place -- if the device is not connected to any network, you know there is little benefit in trying the request.

If there is no route, your request should fail nearly immediately. If there is some other issue, your request may time out instead. Be sure to indicate some progress to the user in the case of a long request, since time outs can take several seconds (or minutes) to occur.

If your app needs to target specific hosts, those would be the same hosts you'd use to verify connectivity. If your app targets generic hosts (or user-entered hosts), test with the specific host to test connectivity.

• Don't assume that because a device can reach one host that it means it can reach another, either -- some networks may block certain hosts while allowing access to others.
• Don't test with a host that isn't part of the actual request, especially if it is one you don't control. That is, if you want to test if the user can reach www.example.com , don't ping www.google.com . Your attempt might be taken as a malicious attack, especially if your app became popular.

One other tip:

DO check the network type to see if you need to limit data (in the case of cellular networks) but DON'T assume the network type can be used to indicate data transfer speeds -- just because you're on a 4G network does not mean that you will be guaranteed fast data transfer. Of course, the same applies to WiFi.