Sending a model to glu in java

GluProxy.java

package com.outbrain.glu;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.util.Arrays;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.HttpException;
import org.apache.commons.httpclient.URI;
import org.apache.commons.httpclient.UsernamePasswordCredentials;
import org.apache.commons.httpclient.auth.AuthScope;
import org.apache.commons.httpclient.methods.InputStreamRequestEntity;
import org.apache.commons.httpclient.methods.PostMethod;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.util.Assert;

/**
 * Talks to Glu and asks it to do things for it.
 *
 * @author Ran Tavory
 *
 */
public class GluProxy {

  private static final Logger log = LoggerFactory.getLogger(GluProxy.class);

  private final String GLU_API_BASE = "rest/v1/";
  private final String SYSTEM_MODEL = "/system/model";
  private final Pattern ID_PATTERN = Pattern.compile("id=(.*)");

  private final String gluUrl;
  private final String fabric;
  private final HttpClient client;
  private final PostMethod post;

  public GluProxy(String gluUrl, String fabricName, HttpClient client, PostMethod postMethod,
      String username, String password) {
    Assert.notNull(gluUrl, "gluUrl is null");
    Assert.notNull(fabricName, "fabric is null");
    Assert.notNull(client, "http client is null");
    Assert.notNull(postMethod, "http method is null");
    this.gluUrl = gluUrl;
    this.fabric = fabricName;
    this.client = client;
    this.post = postMethod;
    setupAuthentication(username, password);
  }

  private void setupAuthentication(String username, String password) {
    client.getState().setCredentials(AuthScope.ANY,
        new UsernamePasswordCredentials(username, password));
    client.getParams().setAuthenticationPreemptive(true);
    post.setDoAuthentication(true);
  }

  public String getUrl() {
    return gluUrl;
  }

  /**
   * Loads the jsonModel string into glu.
   * <p>
   * To post an update to glu we issue a POST request to
   * http://glu.outbrain.com/console/rest/v1/outbrain/system/model The body of the request should
   * contain the json model. See https://github.com/linkedin/glu/wiki/Console
   *
   * @param jsonModel
   * @throws IOException
   * @throws HttpException
   * @return planId the ID of the execution plan created by this update. null if the model was
   *         already up to date (so there's no plan ID)
   */
  public String loadModel(String jsonModel) throws HttpException, IOException {
    post.setURI(new URI(getPostModelUrl(), true));
    post.addRequestHeader("Content-Type", "text/json");
    post.setRequestEntity(new InputStreamRequestEntity(new ByteArrayInputStream(
        jsonModel.getBytes()), jsonModel.length()));
    log.info("Sending a request to glu to update model: {}", jsonModel);
    int status = client.executeMethod(post);
    log.debug("Request returned with status {}", status);
    String responseText = post.getResponseBodyAsString();
    if (status < 200 || status >= 300) {
      String message = "Glu returned an error for the request containing " + jsonModel + "\n"
          + "Status code: " + status + "\n" + "Response headers: "
          + Arrays.toString(post.getResponseHeaders()) + "\n" + "Response text: " + responseText;
      log.error(message);
      throw new HttpException(message);
    }
    String planId = extractPlanId(responseText);
    log.info("Model loaded successfuly to glu. The new plan ID is {}", planId);
    return planId;
  }

  private String extractPlanId(String responseText) {
    if (responseText == null) {
      return null;
    }
    Matcher m = ID_PATTERN.matcher(responseText);
    if (m.find()) {
      return m.group(1);
    }
    return null;
  }

  private String getPostModelUrl() {
    return gluUrl + GLU_API_BASE + fabric + SYSTEM_MODEL;
  }
}