Cache donation campaign responses

mastodon/src/main/java/org/joinmastodon/android/api/MastodonAPIController.java

@@ -12,10 +12,12 @@ import com.google.gson.JsonParser;
 import com.google.gson.JsonSyntaxException;
 
 import org.joinmastodon.android.BuildConfig;
+import org.joinmastodon.android.MastodonApp;
 import org.joinmastodon.android.api.gson.IsoInstantTypeAdapter;
 import org.joinmastodon.android.api.gson.IsoLocalDateTypeAdapter;
 import org.joinmastodon.android.api.session.AccountSession;
 
+import java.io.File;
 import java.io.IOException;
 import java.io.Reader;
 import java.time.Instant;
@@ -29,6 +31,8 @@ import java.util.concurrent.TimeUnit;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import me.grishka.appkit.utils.WorkerThread;
+import okhttp3.Cache;
+import okhttp3.CacheControl;
 import okhttp3.Call;
 import okhttp3.Callback;
 import okhttp3.OkHttpClient;
@@ -49,8 +53,11 @@ public class MastodonAPIController{
 			.connectTimeout(60, TimeUnit.SECONDS)
 			.writeTimeout(60, TimeUnit.SECONDS)
 			.readTimeout(60, TimeUnit.SECONDS)
+			.cache(new Cache(new File(MastodonApp.context.getCacheDir(), "http"), 10*1024*1024))
 			.build();
 
+	private static final CacheControl NO_CACHE_WHATSOEVER=new CacheControl.Builder().noCache().noStore().build();
+
 	private AccountSession session;
 
 	static{
@@ -80,6 +87,9 @@ public class MastodonAPIController{
 				if(token!=null)
 					builder.header("Authorization", "Bearer "+token);
 
+				if(!req.cacheable)
+					builder.cacheControl(NO_CACHE_WHATSOEVER);
+
 				if(req.headers!=null){
 					for(Map.Entry<String, String> header:req.headers.entrySet()){
 						builder.header(header.getKey(), header.getValue());

mastodon/src/main/java/org/joinmastodon/android/api/MastodonAPIRequest.java

@@ -46,6 +46,7 @@ public abstract class MastodonAPIRequest<T> extends APIRequest<T>{
 	boolean canceled;
 	Map<String, String> headers;
 	long timeout;
+	boolean cacheable;
 	private ProgressDialog progressDialog;
 	protected boolean removeUnsupportedItems;
 
@@ -132,6 +133,10 @@ public abstract class MastodonAPIRequest<T> extends APIRequest<T>{
 		this.timeout=timeout;
 	}
 
+	protected void setCacheable(){
+		cacheable=true;
+	}
+
 	protected String getPathPrefix(){
 		return "/api/v1";
 	}

mastodon/src/main/java/org/joinmastodon/android/api/requests/catalog/GetDonationCampaigns.java

@@ -12,6 +12,7 @@ public class GetDonationCampaigns extends MastodonAPIRequest<DonationCampaign>{
 		super(HttpMethod.GET, null, DonationCampaign.class);
 		this.locale=locale;
 		this.seed=seed;
+		setCacheable();
 	}
 
 	@Override