org.phaidra.apihooks.APIRESTHooksImpl.java Source code

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Here is the source code for org.phaidra.apihooks.APIRESTHooksImpl.java

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/* The contents of this file are subject to the same license and copyright terms
 * as Fedora Commons (http://fedora-commons.org/).
 */
package org.phaidra.apihooks;

import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.net.URL;
import java.net.URLConnection;
import java.net.URLEncoder;
import java.util.Iterator;
import java.util.Map;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.fcrepo.common.Constants;
import org.fcrepo.server.Context;
import org.fcrepo.server.Server;
import org.fcrepo.server.errors.ModuleInitializationException;
import org.fcrepo.server.storage.DOWriter;

/**
 * REST-Capable API hook class.
 * @author Thomas Wana <thomas.wana@univie.ac.at>
 *
 */
public class APIRESTHooksImpl extends APIHooksImpl implements APIHooks {
    protected static Log log = LogFactory.getLog(APIRESTHooksImpl.class);

    public APIRESTHooksImpl(Map moduleParameters, Server server, String role) throws ModuleInitializationException {
        super(moduleParameters, server, role);
    }

    /**
     * Initializes the Module based on configuration parameters.
     * 
     * @throws ModuleInitializationException
     *             If initialization values are invalid or initialization fails
     *             for some other reason.
     */
    public void initModule() throws ModuleInitializationException {
        super.initModule();

        // check if all required parameters are available
        if (getParameter("restmethod") == null) {
            throw new ModuleInitializationException("APIRESTHooksImpl: missing required parameters",
                    this.getRole());
        }

        log.debug("initialized");
    }

    /**
     * Runs the hook if enabled in fedora.fcfg.
     *
     * @param method The name of the method that calls the hook
     * @param pid The PID that is being accessed
     * @param params Method parameters, depend on the method called
     * @return String Hook verdict. Begins with "OK" if it's ok to proceed.
     * @throws APIHooksException If the remote call went wrong
     */
    public String runHook(String method, DOWriter w, Context context, String pid, Object[] params)
            throws APIHooksException {
        String rval = null;

        // Only do this if the method is enabled in fedora.fcfg
        if (getParameter(method) == null) {
            log.debug("runHook: method |" + method + "| not configured, not calling webservice");
            return "OK";
        }

        Iterator i = context.subjectAttributes();
        String attrs = "";
        while (i.hasNext()) {
            String name = "";
            try {
                name = (String) i.next();
                String[] value = context.getSubjectValues(name);
                for (int j = 0; j < value.length; j++) {
                    attrs += "&attr=" + URLEncoder.encode(name + "=" + value[j], "UTF-8");
                    log.debug("runHook: will send |" + name + "=" + value[j] + "| as subject attribute");
                }
            } catch (NullPointerException ex) {
                log.debug(
                        "runHook: caught NullPointerException while trying to retrieve subject attribute " + name);
            } catch (UnsupportedEncodingException ex) {
                log.debug("runHook: caught UnsupportedEncodingException while trying to encode subject attribute "
                        + name);
            }
        }
        String paramstr = "";
        try {
            for (int j = 0; j < params.length; j++) {
                paramstr += "&param" + Integer.toString(j) + "=";
                if (params[j] != null) {
                    String p = params[j].toString();
                    paramstr += URLEncoder.encode(p, "UTF-8");
                }
            }
        } catch (UnsupportedEncodingException ex) {
            log.debug("runHook: caught UnsupportedEncodingException while trying to encode a parameter");
        }

        String loginId = context.getSubjectValue(Constants.SUBJECT.LOGIN_ID.uri);

        log.debug("runHook: called for method=|" + method + "|, pid=|" + pid + "|");
        try {
            // TODO: timeout? retries?
            URL url;
            URLConnection urlConn;
            DataOutputStream printout;
            BufferedReader input;

            url = new URL(getParameter("restmethod"));
            urlConn = url.openConnection();
            urlConn.setDoInput(true);
            urlConn.setDoOutput(true);
            urlConn.setUseCaches(false);
            urlConn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
            printout = new DataOutputStream(urlConn.getOutputStream());
            String content = "method=" + URLEncoder.encode(method, "UTF-8") + "&username="
                    + URLEncoder.encode(loginId, "UTF-8") + "&pid=" + URLEncoder.encode(pid, "UTF-8") + paramstr
                    + attrs;
            printout.writeBytes(content);
            printout.flush();
            printout.close();

            // Get response data.
            input = new BufferedReader(new InputStreamReader(urlConn.getInputStream(), "UTF-8"));
            String str;
            rval = "";
            while (null != ((str = input.readLine()))) {
                rval += str + "\n";
            }
            input.close();

            String ct = urlConn.getContentType();
            if (ct.startsWith("text/xml")) {
                log.debug("runHook: successful REST invocation for method |" + method + "|, returning: " + rval);
            } else if (ct.startsWith("text/plain")) {
                log.debug("runHook: successful REST invocation for method |" + method
                        + "|, but hook returned an error: " + rval);
                throw new Exception(rval);
            } else {
                throw new Exception("Invalid content type " + ct);
            }
        } catch (Exception ex) {
            log.error("runHook: error calling REST hook: " + ex.toString());
            throw new APIHooksException("Error calling REST hook: " + ex.toString(), ex);
        }

        return processResults(rval, w, context);
    }

}