server/protocols/jmap-draft/src/main/java/org/apache/james/jmap/http/AccessTokenAuthenticationStrategy.java

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package org.apache.james.jmap.http;

import jakarta.inject.Inject;

import org.apache.james.jmap.api.access.AccessToken;
import org.apache.james.jmap.api.access.exceptions.InvalidAccessToken;
import org.apache.james.jmap.api.access.exceptions.NotAnAccessTokenException;
import org.apache.james.jmap.draft.api.AccessTokenManager;
import org.apache.james.jmap.exceptions.UnauthorizedException;
import org.apache.james.mailbox.MailboxManager;
import org.apache.james.mailbox.MailboxSession;

import com.github.fge.lambdas.Throwing;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.collect.ImmutableMap;

import reactor.core.publisher.Mono;
import reactor.netty.http.server.HttpServerRequest;

public class AccessTokenAuthenticationStrategy implements AuthenticationStrategy {
    private final AccessTokenManager accessTokenManager;
    private final MailboxManager mailboxManager;

    @Inject
    @VisibleForTesting
    AccessTokenAuthenticationStrategy(AccessTokenManager accessTokenManager, MailboxManager mailboxManager) {
        this.accessTokenManager = accessTokenManager;
        this.mailboxManager = mailboxManager;
    }

    @Override
    public Mono<MailboxSession> createMailboxSession(HttpServerRequest httpRequest) {
        return Mono.fromCallable(() -> authHeaders(httpRequest))
            .filter(tokenString -> !tokenString.startsWith("Bearer"))
            .map(AccessToken::fromString)
            .flatMap(item -> Mono.from(accessTokenManager.getUsernameFromToken(item)))
            .map(Throwing.function(user -> mailboxManager.authenticate(user).withoutDelegation()))
            .onErrorResume(InvalidAccessToken.class, error -> Mono.error(new UnauthorizedException("Invalid access token", error)))
            .onErrorResume(NotAnAccessTokenException.class, error -> Mono.error(new UnauthorizedException("Not an access token", error)));
    }

    @Override
    public AuthenticationChallenge correspondingChallenge() {
        return AuthenticationChallenge.of(
            AuthenticationScheme.of("Bearer"),
            ImmutableMap.of("realm", "JMAP Draft access token"));
    }
}