Java tutorial
/* * Copyright (c) 2016 s1mpl3x <jan[at]over9000.eu> * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in all * copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE * SOFTWARE. */ package eu.over9000.cathode; import com.google.gson.FieldNamingPolicy; import com.google.gson.Gson; import com.google.gson.GsonBuilder; import com.google.gson.reflect.TypeToken; import eu.over9000.cathode.data.Panel; import eu.over9000.cathode.data.PanelList; import eu.over9000.cathode.data.deserializers.ThumbnailListDeserializer; import eu.over9000.cathode.data.parameters.Parameter; import org.apache.http.*; import org.apache.http.client.HttpClient; import org.apache.http.client.methods.*; import org.apache.http.impl.client.BasicResponseHandler; import org.apache.http.impl.client.HttpClients; import org.apache.http.impl.conn.PoolingHttpClientConnectionManager; import org.apache.http.message.BasicHeader; import java.io.IOException; import java.io.InputStream; import java.lang.reflect.Type; import java.util.ArrayList; import java.util.List; import java.util.function.Function; public class Dispatcher { private static final int CONNECTION_COUNT = 100; private final Gson GSON = new GsonBuilder().setFieldNamingPolicy(FieldNamingPolicy.LOWER_CASE_WITH_UNDERSCORES) .registerTypeAdapter(ThumbnailListDeserializer.THUMBNAIL_LIST_TYPE, new ThumbnailListDeserializer()) .create(); private final HttpClient HTTP_CLIENT; private final BasicResponseHandler RESPONSE_HANDLER = new BasicResponseHandler(); public UndocumentedDispatcher undocumented; Dispatcher(final String clientID, final String authToken) { undocumented = new UndocumentedDispatcher(); final PoolingHttpClientConnectionManager connectionManager = new PoolingHttpClientConnectionManager(); connectionManager.setMaxTotal(CONNECTION_COUNT); connectionManager.setDefaultMaxPerRoute(CONNECTION_COUNT); final List<Header> headers = new ArrayList<>(); headers.add(new BasicHeader(HttpHeaders.ACCEPT, "application/vnd.twitchtv.v3+json")); headers.add(new BasicHeader("Client-ID", clientID)); if (authToken != null) { headers.add(new BasicHeader("Authorization", "OAuth " + authToken)); } HTTP_CLIENT = HttpClients.custom().setDefaultHeaders(headers).setConnectionManager(connectionManager) .build(); } public <ResponseType> Result<ResponseType> performGet(final Class<ResponseType> resultClass, final String path, final Parameter... parameters) { return performInternal(HttpGet.METHOD_NAME, resultClass, path, null, parameters); } public <ResponseType> Result<ResponseType> performDelete(final Class<ResponseType> resultClass, final String path, final Parameter... parameters) { return performInternal(HttpDelete.METHOD_NAME, resultClass, path, null, parameters); } public <ResponseType> Result<ResponseType> performPut(final Class<ResponseType> resultClass, final String path, final HttpEntity payload, final Parameter... parameters) { return performInternal(HttpPut.METHOD_NAME, resultClass, path, payload, parameters); } public <ResponseType> Result<ResponseType> performPost(final Class<ResponseType> resultClass, final String path, final HttpEntity payload, final Parameter... parameters) { return performInternal(HttpPost.METHOD_NAME, resultClass, path, payload, parameters); } private <ResponseType> Result<ResponseType> performInternal(final String method, final Class<ResponseType> resultClass, final String path, final HttpEntity payload, final Parameter... parameters) { try { final String baseUrl = String.join("/", Twitch.API_BASE_URL, path); final String strResponse = getResponseString(method, baseUrl, payload, parameters); final ResponseType objResponse = GSON.fromJson(strResponse, resultClass); return new Result<>(objResponse); } catch (final Exception e) { return new Result<>(e); } } private String getResponseString(final String method, final String baseUrl, final HttpEntity payload, final Parameter... parameters) throws IOException { final RequestBuilder requestBuilder = RequestBuilder.create(method).setUri(baseUrl); handleParameters(requestBuilder, parameters); if (payload != null) { requestBuilder.setEntity(payload); } final HttpUriRequest request = requestBuilder.build(); final HttpResponse httpResponse = HTTP_CLIENT.execute(request); return RESPONSE_HANDLER.handleResponse(httpResponse); } public Result<String> getResponseRaw(final String url) { try { return new Result<>(getResponseString(HttpGet.METHOD_NAME, url, null)); } catch (final Exception e) { return new Result<>(e); } } private void handleParameters(final RequestBuilder requestBuilder, final Parameter[] parameters) { for (final Parameter parameter : parameters) { if (parameter != null) { final List<NameValuePair> nameValuePairs = parameter.buildParamPairs(); nameValuePairs.forEach(requestBuilder::addParameter); } } } public <ImageFormat> Result<ImageFormat> retrieveImage(final String url, final Function<InputStream, ImageFormat> converter) { try { final RequestBuilder requestBuilder = RequestBuilder.get(url); final HttpUriRequest request = requestBuilder.build(); final HttpResponse httpResponse = HTTP_CLIENT.execute(request); final InputStream inputStream = httpResponse.getEntity().getContent(); final ImageFormat image = converter.apply(inputStream); inputStream.close(); return new Result<>(image); } catch (final Exception e) { return new Result<>(e); } } public class UndocumentedDispatcher { public Result<PanelList> getPanels(final String channelName) { final String url = "https://api.twitch.tv/api/channels/" + channelName + "/panels"; final Result<String> result = getResponseRaw(url); if (result.isOk()) { final Type panelsListType = new TypeToken<List<Panel>>() { }.getType(); final List<Panel> panels = GSON.fromJson(result.getResultRaw(), panelsListType); return new Result<>(new PanelList(panels)); } return new Result<>(result.getErrorRaw()); } } }