Flutter - Making a web request

Question

I would like to know if there is a way to format special characters when parsing JSON requests from Flutter. I have tested a http request as such:

void curlRequest() async
  {
    String urlRequest = "http://my.web.url/webservice/rest/server.php?wstoken=my_token&moodlewsrestformat=json&wsfunction=core_user_create_users&users[0][username]=test_user_4&users[0][firstname]=John&users[0][lastname]=Doe&users[0][email][email protected]&users[0][password]=Johns_Password";

    http.post(urlRequest, headers: {'Content-type': 'application/json; charset=utf-8'}).then((response){
        print("Response status: ${response.statusCode}");
        print("Response body: ${response.body}");
    });
  }

I get the following response:

http://my.web.url/webservice/rest/server.php?wstoken=my_token&moodlewsrestformat=json&wsfunction=core_user_create_users&users%5B0%5D%5Busername%5D=test_user_4&users%5B0%5D%5Bfirstname%5D=John&users%5B0%5D%5Blastname%5D=Doe&users%5B0%5D%5Bemail%[email protected]&users%5B0%5D%5Bpassword%5D=Johns_Password&i=1

The request was invalid due to special characters being used. How do I make a request so that the special characters are also handled properly?

Answer 1

In a http restful request, the http GET request must be url encoded, which means that most special characters must be encoded in a way understandable by a webserver.

As such, characters such as the plus sign (+) or the question mark (?) must be replaced by their URL encoded equivalents (%2b for the plus sign and %3F for a question mark for instance) and vice versa for decoding.

Several URL encoders can be found online such as http://www.url-encode-decode.com/

In Dart you can use Uri.encodeFull() to encode string and Uri.encodeComponent() to encode a string component

Similarly to decode you can use Uri.decodeFull() and others

read more about this here Uri class

Answer 2

Switching to a better web hosting service resolved my issue. I was using AeonFree, which was a free web hosting service and had limited access for obvious reasons.

I also switched from the http package to using the dio package.