Integrating Gravatar and Anonymizing Email Address in Feedback Section

SUSI skills are having a very nice feedback system that allows the user to rate skills from 1-star to 5-star and showing ratings in skills screens. SUSI also allow the user to post feedback about skills and display them. You can check out how posting feedback implemented here and how displaying feedback feature implemented here. To enhance the user experience, we are adding user gravatar in the feedback section and to respect user privacy, we are anonymizing the user email displayed in the feedback section. In this post, we will see how these features implemented in SUSI iOS.

Integrating Gravatar –

We are showing gravatar of the user before feedback. Gravatar is a service for providing globally-unique avatars. We are using user email address to get the gravatar. The most basic gravatar image request URL looks like this:

where HASH is replaced with the calculated hash for the specific email address we are requesting. We are using the MD5 hash function to hash the user’s email address.

The MD5 hashing algorithm is a one-way cryptographic function that accepts a message of any length as input and returns as output a fixed-length digest value to be used for authenticating the original message.

In SUSI iOS, we have MD5Digest.swift file that gives the hash value of email string. We are using the following method to set gravatar:

if let userEmail = feedback?.email {
setGravatar(from: userEmail)
func setGravatar(from emailString: String) {
let baseGravatarURL = ""
let emailMD5 = emailString.utf8.md5.rawValue
let imageString = baseGravatarURL + emailMD5 + ".jpg"
let imageURL = URL(string: imageString)
gravatarImageView.kf.setImage(with: imageURL)

Anonymizing User’s Email Address –

Before the implementation of this feature, the user’s full email address was displayed in the feedback section and see all review screen. To respect the privacy of the user, we are now only showing user email until the `@` sign.

In Feedback object, we have the email address string that we modify to show until `@` sign by following way:

if let userEmail = feedback?.email, let emailIndex = userEmail.range(of: "@")?.upperBound {
userEmailLabel.text = String(userEmail.prefix(upTo: emailIndex)) + "..."


Final Output –

Resources –

  1. Post feedback for SUSI Skills in SUSI iOS
  2. Displaying Skills Feedback on SUSI iOS
  3. What is MD5?
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How Anonymous Mode is Implemented in SUSI Android

Login and signup are an important feature for some android apps like chat app because user wants to save messages and secure messages from others. In SUSI Android we save messages for logged in user on the server corresponding to their account. But  users can also  use the app without logging in. In this blog, I will show you how the anonymous mode is implemented in SUSI Android .

When the user logs in using the username and password we provide a token to user for a limited amount of time, but in case of anonymous mode we never provide a token to the user and also we set ANONYMOUS_LOGGED_IN flag true which shows that the user is using the app anonymously.


PrefManager.putBoolean(Constant.ANONYMOUS_LOGGED_IN, true)

We use ANONYMOUS_LOGGED_IN flag to check user is using the app anonymously or not. When a user opens the app we first check user is already logged in or not. If the user is not logged in then we check ANONYMOUS_LOGGED_IN flag is true or false. The true means user is using the app in anonymous mode.

if(PrefManager.getBoolean(Constant.ANONYMOUS_LOGGED_IN, false)) {

 intent = new Intent(LoginActivity.this, MainActivity.class);



Else we show login page to the user. The user can use app either by login using username and password or anonymously by clicking skip button. On clicking skip button ANONYMOUS_LOGGED_IN flag set to true.

public void skip() {

Intent intent = new Intent(LoginActivity.this,MainActivity.class);


PrefManager.putBoolean(Constant.ANONYMOUS_LOGGED_IN, true);



If the user is using the app in anonymous mode but he/she want to login then he/she can login. There is an option for login in menu.

When the user selects login option from the menu, then it redirects the user to the login screen and ANONYMOUS_LOGGED_IN flag is set to false. ANONYMOUS_LOGGED_IN flag is set to false to ensure that instead of login if the user closes the app and again open it, then he/she can’t use the app until logged in or click skip button.


PrefManager.putBoolean(Constant.ANONYMOUS_LOGGED_IN, false);


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