The argument type 'String' can't be assigned to the parameter type 'Uri'

Question

Asked by Adventune on March 04, 2021 (source).

I am trying to make an HTTP POST request with the flutter plugin HTTP but I am getting an error of the title. Does anyone know the cause of this since in my other applications this works just perfectly fine?

await http.post(Uri.encodeFull("https://api.instagram.com/oauth/access_token"), body: {
      "client_id": clientID,
      "redirect_uri": redirectUri,
      "client_secret": appSecret,
      "code": authorizationCode,
      "grant_type": "authorization_code"
    });

Answer

Question answered by jamesdlin (source).

To improve compile-time type safety, package:http 0.13.0 introduced breaking changes that made all functions that previously accepted Uris or Strings now accept only Uris instead. You will need to explicitly use Uri.parse to create Uris from Strings. (package:http formerly called that internally for you.)

Old Code Replace With
http.get(someString) http.get(Uri.parse(someString))
http.post(someString) http.post(Uri.parse(someString))

(and so on.)

In your specific example, you will need to use:

await http.post(
  Uri.parse("https://api.instagram.com/oauth/access_token"),
  body: {
    "client_id": clientID,
    "redirect_uri": redirectUri,
    "client_secret": appSecret,
    "code": authorizationCode,
    "grant_type": "authorization_code",
  });
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