+package de.juplo.facebook.errors;
+
+
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.charset.Charset;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.client.ClientHttpResponse;
+import org.springframework.util.FileCopyUtils;
+import org.springframework.web.client.DefaultResponseErrorHandler;
+import org.springframework.web.client.ResponseErrorHandler;
+
+
+
+/**
+ * Error-Handler for error-messages from the Facebook Graph-API.
+ * <p>
+ * This error-handler handels responses withe the HTTP-status code
+ * {@code 400 BAD REQUEST}. It tries to extract and parse the error-message
+ * from the HTTP-body. Successfully extracted and parsed messages are mapped
+ * to a hierarchy of exceptions, that reflects the hierarchy of the error-
+ * codes and -types.
+ * <p>
+ * If the HTTP-status-code of the response is not {@code 400 BAD REQUEST} or
+ * the HTTP-body could not be extracted or parsed, this error-handler
+ * delegates the handling to its parent.
+ *
+ * @see <a href="https://developers.facebook.com/docs/graph-api/using-graph-api/v2.5#errors">Graph-API Documentation</a>
+ * @see <a href="http://fbdevwiki.com/wiki/Error_codes">Inofficial Wiki For Facebook-Developers</a>
+ * @author Kai Moritz
+ */
+public class GraphApiErrorResponseErrorHandler implements ResponseErrorHandler
+{
+ private final static Logger LOG =
+ LoggerFactory.getLogger(GraphApiErrorResponseErrorHandler.class);
+
+ private final ResponseErrorHandler parent;
+
+
+ public GraphApiErrorResponseErrorHandler()
+ {
+ this(null);
+ }
+
+ public GraphApiErrorResponseErrorHandler(ResponseErrorHandler errorHandler)
+ {
+ this.parent =
+ errorHandler == null
+ ? new DefaultResponseErrorHandler()
+ : errorHandler;
+ }
+
+
+ @Override
+ public boolean hasError(ClientHttpResponse response) throws IOException
+ {
+ return
+ HttpStatus.Series.CLIENT_ERROR.equals(response.getStatusCode().series())
+ || this.parent.hasError(response);
+ }
+
+ @Override
+ public void handleError(final ClientHttpResponse response) throws IOException
+ {
+ GraphApiErrorResponseErrorHandler.handleError(parent, response);
+ }
+
+ public static void handleError(
+ final ResponseErrorHandler parent,
+ final ClientHttpResponse response
+ )
+ throws
+ IOException
+ {
+ if (response.getBody() == null)
+ {
+ // There is no body to interpret in the HTTP-message
+ LOG.warn("Could not convert the response into an exception, because there is no message-body.");
+ parent.handleError(response);
+ return;
+ }
+
+ final byte[] body = FileCopyUtils.copyToByteArray(response.getBody());
+ GraphApiException error;
+
+ try
+ {
+ error = GraphApiException.create(response.getStatusCode(), response.getHeaders(), body);
+ if (LOG.isInfoEnabled())
+ LOG.info("error-response: {}", new String(body, Charset.forName("UTF-8")));
+ }
+ catch (Exception e)
+ {
+ // The body of the HTTP-message could not be parsed.
+ // Let the parent error-handler try to handle the response.
+
+ LOG.warn(
+ "Could not convert the response into an exception, " +
+ "because the body is unparsable: error={}, body={}",
+ e.toString(),
+ new String(body, Charset.forName("UTF-8"))
+ );
+
+ // To do so, we have to wrap the original response to fill in
+ // the buffered body, if needed
+ ClientHttpResponse buffered = new ClientHttpResponse()
+ {
+ @Override
+ public HttpStatus getStatusCode() throws IOException
+ {
+ return response.getStatusCode();
+ }
+
+ @Override
+ public synchronized InputStream getBody() throws IOException
+ {
+ return new ByteArrayInputStream(body);
+ }
+
+ @Override
+ public HttpHeaders getHeaders()
+ {
+ return response.getHeaders();
+ }
+
+ @Override
+ public String getStatusText() throws IOException
+ {
+ return response.getStatusText();
+ }
+
+ @Override
+ public void close()
+ {
+ response.close();
+ }
+
+ @Override
+ public int getRawStatusCode() throws IOException
+ {
+ return response.getRawStatusCode();
+ }
+ };
+
+ parent.handleError(buffered);
+ return;
+ }
+
+ throw error;
+ }
+}
projects / facebook-errors / commitdiff