/*
* Copyright 2014 Google Inc. All rights reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.google.iosched.input.fetcher;
import com.google.gson.JsonArray;
import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import com.google.gson.JsonParser;
import com.google.gson.stream.JsonReader;
import com.google.iosched.Config;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.nio.charset.Charset;
import java.util.Map.Entry;
/**
*/
public class RemoteJsonHelper {
public static JsonObject mergeJsonFiles(JsonObject target, String... filenames) throws IOException {
if (target == null) {
target = new JsonObject();
}
for (String filename: filenames) {
String url = Config.CLOUD_STORAGE_BASE_URL+filename;
JsonObject obj = fetchJsonFromPublicURL(url);
if (obj == null) {
throw new FileNotFoundException(url);
} else {
for (Entry<String, JsonElement> entry: obj.entrySet()) {
if (entry.getValue().isJsonArray()) {
// tries to merge an array with the existing one, if it's the case:
JsonArray existing = target.getAsJsonArray(entry.getKey());
if (existing == null) {
existing = new JsonArray();
target.add(entry.getKey(), existing);
}
existing.addAll(entry.getValue().getAsJsonArray());
} else {
target.add(entry.getKey(), entry.getValue());
}
}
}
}
return target;
}
public static JsonObject fetchJsonFromPublicURL(String urlStr) throws IOException {
URL url = new URL(urlStr);
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.setReadTimeout(1000 * 30); // 30 seconds
int response = connection.getResponseCode();
if (response < 200 || response >= 300) {
throw new IllegalArgumentException("Unexpected HTTP response ["+response+"] at URL: "+urlStr);
}
InputStream stream = connection.getInputStream();
JsonReader reader = new JsonReader(new InputStreamReader(stream, Charset.forName("UTF-8")));
return (JsonObject) new JsonParser().parse(reader);
}
}