Is anyone knows how Flutter URI encoding/decoding works? - flutter

Question

Is anyone knows how Flutter URI encoding/decoding works?
I have one issue. Let me give you some background on the issue. We have one deep link which will give us the email and access token code to reset the password. We will validate the token on the front end and then allow users to do a reset.
Here is the sample URL from Firebase dynamic link
https://example.com/auth/resetPassword/?access_token=abcd&email=test+abc#xyz.com
Firebase dynamic link will give us this URL in the URI object. The issue is when I try to fetch the query params from this URI object, it removes plus sign from an email and replaces it with the space character instead. E-mail should same as displayed in the above link. This is the email received when I fetch query params: test abc#xyz.com
I have created two dart pads to figure out the issue. Here is the 1st sample where I am parsing (since firebase dynamic link is doing the same) the URL into the URI object and tried printing the output. As expected it removes the plus sign.
Code:
main() {
var httpsUri = Uri.parse("https://example.com/auth/resetPassword/?access_token=abcd&email=test+abc#xyz.com");
print(httpsUri.queryParameters);
}
Output:
{access_token: abcd, email: test abc#xyz.com}
In another sample, I tried creating the URI object from the same parameters and link but manually. Here is the code
Code:
main() {
var httpsUri = Uri(
scheme: 'https',
host: 'example.com',
path: '/auth/resetPassword/',
queryParameters: {
'access_token': 'abcd',
'email': 'test+abc#xyz.com'
});
print(httpsUri.queryParameters);
}
Output:
{access_token: abcd, email: test+abc#xyz.com}
If you see here, the email is correctly displayed.
My exact scenario is matching with the first sample code. Based on my findings it removes the plus sign due to encoding and decoding of the URL as a plus sign has a special meaning in the URL. But on the other hand why it is not happening in 2nd example?
Any help would be appreciated!

Answer 1

+ is a reserved character for URIs and therefore should be encoded to %2B if you want a literal + character.
But on the other hand why it is not happening in 2nd example?
Your second example works because it constructs a Uri object directly, and if you were to convert it to a String, it would perform necessary encodings for you. That is, print(httpsUri) would output:
https://example.com/auth/resetPassword/?access_token=abcd&email=test%2Babc%40xyz.com
rather than original (malformed) URL:
https://example.com/auth/resetPassword/?access_token=abcd&email=test+abc#xyz.com