Extension Email Verification

Email — Verification

Email verification extension for Caffeine AI.

Overview

This skill adds email address verification via a click-to-verify link. The MixinEmailVerification handles the verification callback; verifiedEmails tracks verified addresses.

Backend

This component is for sending an email to users with a verification link which the user can click to prove they own the email address.

To check if an email address has been verified

Use the prefabricated module mo:caffeineai-email-verification/verifiedEmails.mo which cannot be modified.

```mo:caffeineai-email-verification/verifiedEmails.mo module { public type State = { var verifiedEmails : Set.Set<Text>; };

public func new() : State { { var verifiedEmails = Set.empty<Text>(); }; };

public func contains(state : State, email : Text) : Bool;

public func iter(state : State) : Iter.Iter<Text>;

public func size(state : State) : Nat; };

To check whether an email is verified use the `contains` function. Do NOT try to track the email verification status independently by storing it against the user profile.

### To handle the verification link

Use the prefabricated module `mo:caffeineai-email-verification/verificationMixin.mo` which cannot be modified.

The MixinEmailVerification handles calls to the verification link to verify an email address.

import MixinEmailVerification "mo:caffeineai-email-verification/verificationMixin";

### For sending users a verification email

- This extension depends on the [extension-email](../extension-email/SKILL.md) for sending emails.
- Use the sendVerificationEmail function. 
- It returns a SendResult which is #ok if the email is sent successfully otherwise #err(error) with the error text. 
- Each recipient receives an individual email with a specific verification link for them
- The htmlBody MUST contain the placeholder text {{VERIFICATION_URL}}

module { public type SendResult = { #ok; #err : Text; };

public func sendVerificationEmail( fromUsername : Text, recipients : [Text], subject : Text, htmlBody : Text, ) : async SendResult; };

### Example usage with endpoints for registering a user and for checking whether a user is verified.

import Map "mo:core/Map"; import Runtime "mo:core/Runtime"; import Principal "mo:core/Principal"; import Text "mo:core/Text"; import EmailClient "mo:caffeineai-email/emailClient"; import MixinEmailVerification "mo:caffeineai-email-verification/verificationMixin"; import VerifiedEmails "mo:caffeineai-email-verification/verifiedEmails";

actor { // Stores which emails are verified let verifiedEmails = VerifiedEmails.new();

// User profiles storage let users = Map.empty<Principal, User>();

// Email to principal mapping for uniqueness check let emailToPrincipal = Map.empty<Text, Principal>();

// Handles the verification link and updates the verifiedEmails store include MixinEmailVerification(verifiedEmails);

type User = { name : Text; email : Text; };

public shared ({ caller }) func registerUser(email : Text, name : Text) : async () { if (users.containsKey(caller)) { Runtime.trap("User already registered"); }; if (emailToPrincipal.containsKey(email)) { Runtime.trap("Email already registered"); };

let user : User = { name; email; }; users.add(caller, user); emailToPrincipal.add(email, caller); let result = await EmailClient.sendVerificationEmail( "no-reply", [email], "Welcome to Our Service", "Hello " # name # ",<br><br>Thank you for registering with our service. Please <a href=\"{{VERIFICATION_URL}}\">click here</a> to verify your email address<br><br>Best regards,<br>The Team", );

switch (result) { case (#ok) {}; case (#err(error)) { Runtime.trap("Couldn't send verification email: " # error); }; }; };

public shared ({ caller }) func isEmailVerified() : async Bool { switch (users.get(caller)) { case (null) { Runtime.trap("User not registered"); }; case (?user) { VerifiedEmails.contains(verifiedEmails, user.email); }; }; }; };

# Frontend

If there is a UI for the admin to enter the content of a verification email then indicate that the placeholder text {{VERIFICATION_URL}} must be present in the email body.