etesync-android/app/src/main/java/at/bitfire/davdroid/journalmanager/BaseManager.java

package at.bitfire.davdroid.journalmanager;

import org.apache.commons.codec.Charsets;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.logging.Level;

import at.bitfire.davdroid.App;
import at.bitfire.davdroid.GsonHelper;
import lombok.AccessLevel;
import lombok.Getter;
import lombok.Setter;
import okhttp3.HttpUrl;
import okhttp3.MediaType;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.Response;

import static at.bitfire.davdroid.journalmanager.Helpers.hmac;

abstract class BaseManager {
    final static protected MediaType JSON = MediaType.parse("application/json; charset=utf-8");

    protected HttpUrl remote;
    protected OkHttpClient client;

    Response newCall(Request request) throws Exceptions.HttpException {
        Response response;
        try {
            response = client.newCall(request).execute();
        } catch (IOException e) {
            App.log.log(Level.SEVERE, "Couldn't download external resource", e);
            throw new Exceptions.ServiceUnavailableException("Failed downloading");
        }

        if (!response.isSuccessful()) {
            switch (response.code()) {
                case 401:
                    throw new Exceptions.UnauthorizedException("Failed to connect");
                default:
                    throw new Exceptions.HttpException("Error getting");
            }
        }

        return response;
    }

    static class Base {
        @Setter(AccessLevel.PACKAGE)
        @Getter(AccessLevel.PACKAGE)
        private byte[] content;
        @Setter(AccessLevel.PACKAGE)
        private String uid;

        public String getUuid() {
            return uid;
        }

        public String getContent(String keyBase64) {
            // FIXME: probably cache encryption object
            return new String(new Helpers.Cipher().decrypt(keyBase64, content), Charsets.UTF_8);
        }

        void setContent(String keyBase64, String content) {
            // FIXME: probably cache encryption object
            this.content = new Helpers.Cipher().encrypt(keyBase64, content.getBytes(Charsets.UTF_8));
        }

        byte[] calculateHmac(String keyBase64, String uuid) {
            ByteArrayOutputStream hashContent = new ByteArrayOutputStream();

            try {
                if (uuid != null) {
                    hashContent.write(uuid.getBytes(Charsets.UTF_8));
                }

                hashContent.write(content);
            } catch (IOException e) {
                // FIXME: Do something
                e.printStackTrace();
            }

            return hmac(keyBase64, hashContent.toByteArray());
        }

        protected Base() {
        }

        Base(String keyBase64, String content, String uid) {
            setContent(keyBase64, content);
            setUid(uid);
        }

        @Override
        public String toString() {
            return getClass().getSimpleName() + "<" + uid + ">";
        }

        String toJson() {
            return GsonHelper.gson.toJson(this, getClass());
        }
    }
}