nativescript authenticating at backend web api - asp.net

Question

I am new to mobile development. My project is build using asp.net. For authentication I am using build it UserManager & User.Identity.
I have bunch of existing web apis and I wish to use them from mobile app.
I know , I could pass a secret hash to web api after authenticating, but that would involve a huge code refactoring.
I been wondering if there other ways to handle authentication & authorization with nativescript & asp.net .
Do you know any useful resources for this topic?
Many thanks for your help!

Answer 1

It depends quite heavily on your API structure, but I would recommend somethign like this:
Firstly you would need to use the Nativescript Http module. An implementation to get a an HTTP GET calls returned header might look like this:
http.request({ url: "https://httpbin.org/get", method: "GET" }).then(function (response) {
//// Argument (response) is HttpResponse!
//for (var header in response.headers) {
// console.log(header + ":" + response.headers[header]);
//}
}, function (e) {
//// Argument (e) is Error!
});
So your backend might return a JSON Web Token as a header. In which case on the success callback you would probably want to store your token in the applications persistent memory. I would use the Application Settings module, which would look something like:
var appSettings = require("application-settings");
appSettings.setString("storedToken", tokenValue);
Then before you make an API call for a new token you can check if there is a stored value:
var tokenValue = appSettings.getString("storedToken");
if (tokenValue === undefined {
//do API call
}
Then with your token, you would want to make an API call, e.g. this POST and add the token as a header:
http.request({
url: "https://httpbin.org/post",
method: "POST",
headers: { "Content-Type": "application/json", "Auth": tokenValue },
content: JSON.stringify({ MyVariableOne: "ValueOne", MyVariableTwo: "ValueTwo" })
}).then(function (response) {
// result = response.content.toJSON();
// console.log(result);
}, function (e) {
// console.log("Error occurred " + e);
});
Your backend would need to check the Auth header and validate the JWT to decide whether to accept or reject the call.
Alternatively, there some nice plugins for various Backends-as-a-Service, e.g. Azure and Firebase