Java tutorial
/* * Copyright 2011 the original author or authors. * * 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 org.springframework.social.mixcloud.api.impl; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.util.Arrays; import java.util.List; import java.util.Map; import org.springframework.http.HttpStatus; import org.springframework.http.client.ClientHttpResponse; import org.springframework.social.InternalServerErrorException; import org.springframework.social.InvalidAuthorizationException; import org.springframework.social.NotAuthorizedException; import org.springframework.social.OperationNotPermittedException; import org.springframework.social.ResourceNotFoundException; import org.springframework.social.ServerDownException; import org.springframework.social.SocialException; import org.springframework.social.UncategorizedApiException; import org.springframework.web.client.DefaultResponseErrorHandler; import com.fasterxml.jackson.core.JsonFactory; import com.fasterxml.jackson.core.JsonParseException; import com.fasterxml.jackson.core.type.TypeReference; import com.fasterxml.jackson.databind.ObjectMapper; /** * Subclass of {@link DefaultResponseErrorHandler} that handles errors from * Mixcloud's API, interpreting them into appropriate exceptions. * * @author Michael Lavelle */ public class MixcloudErrorHandler extends DefaultResponseErrorHandler { private final static String INCORRECT_CLIENT_CREDENTIALS = "incorrect_client_credentials"; private final static String BAD_VERIFICATION_CODE = "bad_verification_code"; private final static String REDIRECT_URI_MISMATCH = "redirect_uri_mismatch"; private final static List<String> AUTHORIZATION_FAILURE_MESSAGES = Arrays.asList(INCORRECT_CLIENT_CREDENTIALS, BAD_VERIFICATION_CODE, REDIRECT_URI_MISMATCH); @Override public void handleError(ClientHttpResponse response) throws IOException { SocialException exception = extractExceptionFromResponse(response); if (exception == null) { handleUncategorizedError(response, exception); } handleMixcloudError(response.getStatusCode(), exception); // if not otherwise handled, do default handling and wrap with // UncategorizedApiException handleUncategorizedError(response, exception); } @Override public boolean hasError(ClientHttpResponse response) throws IOException { if (super.hasError(response)) { return true; } // only bother checking the body for errors if we get past the default // error check String content = readFully(response.getBody()); return content.startsWith("{\"error\":"); } /** * Examines the error data returned from Mixcloud and throws the most * applicable exception. * * @param errorDetails * a Map containing an "error" */ void handleMixcloudError(HttpStatus statusCode, SocialException errorDetails) { if (statusCode == HttpStatus.OK) { } else if (statusCode == HttpStatus.BAD_REQUEST) { if (errorDetails instanceof UncategorizedApiException) { String message = errorDetails.getMessage(); if (AUTHORIZATION_FAILURE_MESSAGES.contains(message)) { throw new NotAuthorizedException("mixcloud", message); } else { throw errorDetails; } } else { throw errorDetails; } } else if (statusCode == HttpStatus.UNAUTHORIZED) { throw new NotAuthorizedException("mixcloud", errorDetails.getMessage()); } else if (statusCode == HttpStatus.FORBIDDEN) { throw new OperationNotPermittedException("mixcloud", errorDetails.getMessage()); } else if (statusCode == HttpStatus.INTERNAL_SERVER_ERROR) { throw new InternalServerErrorException("mixcloud", errorDetails.getMessage()); } else if (statusCode == HttpStatus.SERVICE_UNAVAILABLE) { throw new ServerDownException("mixcloud", errorDetails.getMessage()); } } private void handleUncategorizedError(ClientHttpResponse response, SocialException errorDetails) { try { super.handleError(response); } catch (Exception e) { if (errorDetails != null) { throw errorDetails; } else { throw new UncategorizedApiException("mixcloud", "No error details from Mixcloud", e); } } } /* * Attempts to extract Mixcloud error details from the response. Returns * null if the response doesn't match the expected JSON error response. */ @SuppressWarnings("rawtypes") private SocialException extractExceptionFromResponse(ClientHttpResponse response) throws IOException { ObjectMapper mapper = new ObjectMapper(new JsonFactory()); try { String json = readFully(response.getBody()); Map<String, String> responseMap = mapper.<Map<String, String>>readValue(json, new TypeReference<Map<String, Object>>() { }); if (responseMap.containsKey("error")) { Object error = responseMap.get("error"); if (error instanceof String) { return new UncategorizedApiException("mixcloud", responseMap.get("error"), new RuntimeException(responseMap.get("error"))); } else if (error instanceof Map) { Map errorMap = (Map) error; String type = (String) ((Map) error).get("type"); if ("OAuthException".equals(type)) { return new InvalidAuthorizationException("mixcloud", (String) errorMap.get("message")); } if ("ResourceNotFoundException".equals(type)) { return new ResourceNotFoundException("mixcloud", (String) errorMap.get("message")); } return new UncategorizedApiException("mixcloud", responseMap.get("error"), new RuntimeException(responseMap.get("error"))); } else { return null; } } else { return null; } } catch (JsonParseException e) { return null; } } private String readFully(InputStream in) throws IOException { BufferedReader reader = new BufferedReader(new InputStreamReader(in)); StringBuilder sb = new StringBuilder(); while (reader.ready()) { sb.append(reader.readLine()); } return sb.toString(); } }