org.springframework.social.lastfm.api.impl.LastFmErrorHandler.java Source code

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Here is the source code for org.springframework.social.lastfm.api.impl.LastFmErrorHandler.java

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/*
 * 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.lastfm.api.impl;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.HashMap;
import java.util.Map;

import org.springframework.http.HttpStatus;
import org.springframework.http.client.ClientHttpResponse;
import org.springframework.social.InternalServerErrorException;
import org.springframework.social.NotAuthorizedException;
import org.springframework.social.OperationNotPermittedException;
import org.springframework.social.ResourceNotFoundException;
import org.springframework.social.ServerDownException;
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
 * LastFm's API, interpreting them into appropriate exceptions.
 * 
 * @author Michael Lavelle
 */
class LastFmErrorHandler extends DefaultResponseErrorHandler {

    private void handleUncategorizedError(ClientHttpResponse response, Map<Integer, String> errorDetails) {
        try {
            super.handleError(response);
        } catch (Exception e) {
            if (errorDetails != null && errorDetails.size() > 0) {
                String m = errorDetails.get(errorDetails.values().iterator().next());
                throw new UncategorizedApiException("lastfm", m, e);
            } else {
                throw new UncategorizedApiException("lastfm", "No error details from LastFm", e);
            }
        }
    }

    void handleLastFmError(HttpStatus statusCode, Map<Integer, String> errorDetails) {

        String message = errorDetails.values().iterator().next();
        if (statusCode == HttpStatus.OK) {
            // TODO I've just put a single error code in here for now - need to
            // complete with other error codes
            if (errorDetails.containsKey(3)) {
                throw new ResourceNotFoundException("lastfm", message);
            }
            if (errorDetails.containsKey(6)) {
                throw new ResourceNotFoundException("lastfm", message);
            }
            if (errorDetails.containsKey(10)) {
                throw new NotAuthorizedException("lastfm", message);
            }
            if (errorDetails.containsKey(8)) {
                throw new ResourceNotFoundException("lastfm", message);
            }
            if (errorDetails.containsKey(13)) {
                throw new NotAuthorizedException("lastfm", message);
            }

        } else if (statusCode == HttpStatus.BAD_REQUEST) {
            throw new ResourceNotFoundException("lastfm", message);

        } else if (statusCode == HttpStatus.UNAUTHORIZED) {

            throw new NotAuthorizedException("lastfm", message);
        } else if (statusCode == HttpStatus.FORBIDDEN) {

            throw new OperationNotPermittedException("lastfm", message);
        } else if (statusCode == HttpStatus.INTERNAL_SERVER_ERROR) {
            throw new InternalServerErrorException("lastfm", message);
        } else if (statusCode == HttpStatus.SERVICE_UNAVAILABLE) {
            throw new ServerDownException("lastfm", message);
        }
    }

    @Override
    public void handleError(ClientHttpResponse response) throws IOException {
        Map<Integer, String> errorDetails = extractErrorDetailsFromResponse(response);

        if (errorDetails == null || errorDetails.size() == 0) {
            handleUncategorizedError(response, errorDetails);
        }

        handleLastFmError(response.getStatusCode(), errorDetails);

        // if not otherwise handled, do default handling and wrap with
        // UncategorizedApiException
        handleUncategorizedError(response, errorDetails);
    }

    @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\":");

    }

    /*
     * Attempts to extract SoundCloud error details from the response. Returns
     * null if the response doesn't match the expected JSON error response.
     */
    private Map<Integer, String> extractErrorDetailsFromResponse(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, String>>() {
                    });
            if (responseMap.containsKey("error")) {
                Map<Integer, String> errorMap = new HashMap<Integer, String>();
                errorMap.put(new Integer(responseMap.get("error")), responseMap.get("message"));
                return errorMap;
            } 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();
    }

}