CensusAccessObject.java

/*
   Copyright (C) 2005-2012, by the President and Fellows of Harvard College.

   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.

   Dataverse Network - A web application to share, preserve and analyze research data.
   Developed at the Institute for Quantitative Social Science, Harvard University.
   Version 3.0.
*/
package edu.harvard.iq.dvn.core.web.dataaccess;

// java core imports:
import java.io.IOException;
import java.io.InputStream;
import java.io.BufferedReader;
import java.io.InputStreamReader;

import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.zip.ZipInputStream;

import javax.ejb.EJB;


// Apache toolkit imports:
import org.apache.commons.httpclient.methods.GetMethod;
import org.apache.commons.httpclient.methods.PostMethod;
import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.methods.multipart.MultipartRequestEntity;
import org.apache.commons.httpclient.methods.multipart.Part;
import org.apache.commons.httpclient.methods.multipart.StringPart;



// DVN App imports:
import edu.harvard.iq.dvn.core.study.StudyFile;
import edu.harvard.iq.dvn.core.study.StudyServiceLocal;
import edu.harvard.iq.dvn.core.study.RemoteAccessAuth;
import edu.harvard.iq.dvn.core.web.dvnremote.DvnTermsOfUseAccess;
import edu.harvard.iq.dvn.core.web.dvnremote.ICPSRauth;


public class CensusAccessObject extends DataAccessObject {

    public CensusAccessObject () throws IOException {
        this(null);
    }

    public CensusAccessObject(StudyFile file) throws IOException {
        this (file, null);
    }

    public CensusAccessObject(StudyFile file, DataAccessRequest req) throws IOException {

        super(file, req);

        if (!file.isRemote()) {
            throw new IOException ("Not a remote file!");
        }

        // Should also check if the file is from census.gov

        this.setIsRemoteAccess(true);
        this.setIsHttpAccess(true);
        this.setIsSubsetSupported(true);
    }

    @EJB StudyServiceLocal studyService;


    public boolean canAccess (String location) throws IOException{
        return true;
    }

    //public void open (String location) throws IOException{

    //}

    //private void open (StudyFile file, Object req) throws IOException {
    public void open () throws IOException {

        StudyFile file = this.getFile();
        DataAccessRequest req = this.getRequest(); 

        if (req.getParameter("noVarHeader") != null) {
            this.setNoVarHeader(true);
        }

        if (req.getParameter("vars") == null || req.getParameter("vars").equals("")) {
            throw new IOException ("CensusAccess open called without the vars parameter. "+
                    "Only subsetting calls are supported.");
        }


        String remoteFileUrl = file.getFileSystemLocation();
        remoteFileUrl = remoteFileUrl+"?vars="+req.getParameter("vars");

        if (remoteFileUrl != null) {
            remoteFileUrl = remoteFileUrl.replaceAll(" ", "+");
            this.setRemoteUrl(remoteFileUrl);
        }


        Boolean zippedStream = false;


        GetMethod method = null;
        int status = 200;

        try {
            // No authentication is required for census.gov access
            method = new GetMethod(remoteFileUrl);

            // normally, the HTTP client follows redirects
            // automatically, so we need to explicitely tell it
            // not to:

            // method.setFollowRedirects(false); -- not necessary for census

            status = (new HttpClient()).executeMethod(method);

        } catch (IOException ex) {
            //if (method != null) {
            //    method.releaseConnection();
            //}
            status = 404;
        }

        this.setStatus(status);

        if (status != 200) {
            if (method != null) {
                method.releaseConnection();
            }

            throw new IOException ("CensusAccess: HTTP access failed; status: "+status);
        }

        InputStream in = null;
        String[] valueTokens;

        try {
            in = method.getResponseBodyAsStream();
            CensusInputStream cin = new CensusInputStream(in);
            String[] requestedVariables = req.getParameter("vars").split(",", -2);
            cin.setRequestedVariables(requestedVariables);

            this.setInputStream(cin);

        } catch (IOException ex) {
            this.setStatus(404);
            String errorMessage = "I/O error has occured while attempting to retreive a Census data file: "+ex.getMessage()+". Please try again later and if the problem persists, report it to your DVN technical support contact.";
            this.setErrorMessage(errorMessage);

            throw new IOException ("I/O error has occured while attempting to retreive a Census data file: "+ex.getMessage());
        }

        this.setResponseHeaders(method.getResponseHeaders());
        this.setHTTPMethod(method);

    } // End of open;



}