/**********************************************************************************
*
* Copyright (c) 2003, 2004, 2007, 2008 The Sakai Foundation
*
* Licensed under the Educational Community 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.opensource.org/licenses/ECL-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 edu.indiana.lib.twinpeaks.search;
import edu.indiana.lib.twinpeaks.net.*;
import edu.indiana.lib.twinpeaks.util.*;
import java.io.*;
import java.net.*;
import java.util.*;
import javax.servlet.*;
import javax.servlet.http.*;
import javax.xml.parsers.*;
import org.w3c.dom.*;
import org.xml.sax.*;
/**
* Base class for HTTP search activities
*/
public abstract class HttpTransactionQueryBase
extends QueryBase
implements HttpTransactionQueryInterface {
private static org.apache.commons.logging.Log _log = LogUtils.getLog(HttpTransactionQueryBase.class);
/**
* Name of the cookie List (stored with session context)
*/
private static final String COOKIELIST = "CookieList";
/**
* The stored query URL (stored with session context)
*/
private static final String QUERYURL = "QueryUrl";
/**
* Stored query form (stored with session context)
*/
private static final String QUERYFORM = "QueryForm";
/**
* General purpose parameter name prefix
*/
private static final String GP_PREFIX = "GP_";
private HttpTransaction _transaction;
private boolean _followRedirects;
private int _redirectBehavior;
private String _method;
private String _searchString;
private String _url;
private String _searchResult;
private SessionContext _session;
/**
* Constructor
*/
public HttpTransactionQueryBase() {
_transaction = null;
_session = null;
_method = "POST";
_followRedirects = false;
_searchString = null;
_url = null;
_searchResult = null;
}
/**
* One time initialization
* @param session SessionContext object
*/
public void initialize(SessionContext session) {
_session = session;
if ((_session.get(COOKIELIST)) == null) {
_session.put(COOKIELIST, CookieUtils.newCookieList());
}
_transaction = new HttpTransaction();
_transaction.initialize((List) _session.get(COOKIELIST));
}
/**
* Set search URL
* @param url URL string
*/
public void setUrl(String url) {
_url = url;
}
/**
* Set search URL
* @param url URL object
*/
public void setUrl(URL url) {
_url = url.toString();
}
/**
* Fetch the current search URL
* @return The URL (as a String)
*/
public String getUrl() {
return _url;
}
/**
* Specify the search text
* @param searchString Text to look for
*/
public void setSearchString(String searchString) {
_searchString = searchString;
}
/**
* Fetch the current search text
* @return The search string
*/
public String getSearchString() {
return _searchString;
}
/**
* Set the HTTP query method (post or get)
* @param method <code>METHOD_POST</code> or <code>METHOD_GET</code>
*/
public void setQueryMethod(String method) {
_method = method;
}
/**
* Fetch the current HTTP query method
* @return The method (as text)
*/
public String getQueryMethod() {
return _method;
}
/**
* Fetch a named HTTP response parameter
* @param name Parameter name
* @return Parameter value
*/
public String getResponseHeader(String name) {
return _transaction.getResponseHeader(name);
}
/**
* Set the default character set for this transaction
* @param cs Character set (UTF-8, ISO-8859-1, etc)
*/
public void setDefaultCharacterSet(String cs) {
_transaction.setDefaultCharacterSet(cs);
}
/**
* Fetch the response character set
* @return Character set designation (as a String)
*/
public String getResponseCharacterSet() {
return _transaction.getResponseCharacterSet();
}
/*
* The following "query" methods are used only for EBSCO - should
* they be moved to EbscoQueryBase?
*/
/**
* Create the session context name for a specified consumer
* @param base The base name for session context object
* @param consumer A unique name for the "user"
* @return Full session context name
*/
private String scn(String base, String consumer) {
StringBuilder name = new StringBuilder(base);
if (!StringUtils.isNull(consumer))
{
name.append('.');
name.append(consumer);
}
return name.toString();
}
/**
* Create the session context name for a specified consumer/parameter pair
* @param base The base name for session context object
* @param consumer A unique name for the "user"
* @return Full session context name
*/
private String gp_scn(String base, String consumer) {
StringBuilder name = new StringBuilder(GP_PREFIX);
name.append(scn(base, consumer));
return name.toString();
}
/**
* Save the URL for the query page
* @param consumer A unique name for the "user" of this object
* @param queryUrl Address of the final query page
*/
public void setQueryUrl(String consumer, String queryUrl) {
_session.put(scn(QUERYURL, consumer), queryUrl);
}
/**
* Fetch the URL for the query
* @param consumer A unique name for the "user" of this object
* @return Address of the final query page
*/
public String getQueryUrl(String consumer) {
return (String) _session.get(scn(QUERYURL, consumer));
}
/**
* Delete a stored query URL
* @param consumer A unique name for the "user" of this object
*/
public void removeQueryUrl(String consumer) {
_session.remove(scn(QUERYURL, consumer));
}
/**
* Save the final query form as a DOM document
* @param consumer A unique name for the "user" of this object
* @param queryForm Query page as a DOM document
*/
public void setQueryDocument(String consumer, Document queryForm) {
_session.put(scn(QUERYFORM, consumer), queryForm);
}
/**
* Fetch the final query form as a DOM document
* @param consumer A unique name for the "user" of this object
* @return Query form (as a DOM document)
*/
public Document getQueryDocument(String consumer) {
return (Document) _session.get(scn(QUERYFORM, consumer));
}
/**
* Save a general purpose parameter
* @param consumer A unique name for the "user" of this object
* @param name Parameter name
* @param value Parameter value
*/
public void setSessionParameter(String consumer, String name, String value) {
_session.put(gp_scn(name, consumer), value);
}
/**
* Fetch the requested general purpose parameter
* @param consumer A unique name for the "user" of this object
* @param name Parameter name
* @return Parameter value (null if none)
*/
public String getSessionParameter(String consumer, String name) {
return (String) _session.get(gp_scn(name, consumer));
}
/**
* Save a general purpose parameter
* @param consumer A unique name for the "user" of this object
* @param name Parameter name
* @param value Parameter value
*/
public void setSessionValue(String consumer, String name, Object value) {
_session.put(gp_scn(name, consumer), value);
}
/**
* Delete the requested general purpose parameter
* @param consumer A unique name for the "user" of this object
* @param name Parameter name
*/
public void removeSessionParameter(String consumer, String name) {
_session.remove(gp_scn(name, consumer));
}
/**
* Fetch the requested general purpose parameter
* @param consumer A unique name for the "user" of this object
* @param name Parameter name
* @return Parameter value (null if none)
*/
public Object getSessionValue(String consumer, String name) {
return _session.get(gp_scn(name, consumer));
}
/**
* Get the SessionContext object for this user
* @return The current SessionContext
*/
public SessionContext getSessionContext() {
return _session;
}
/**
* Establish a mechanism for handling redirects
* @param behavior Specifies the desired behavior. Use one of:
*<ul>
*<li> REDIRECT_AUTOMATIC - <code>URLConnection</code> handles
all redirects
*<li> REDIRECT_MANAGED - The <code>submit()</code> code
* handles any redirects
*<li> REDIRECT_MANAGED_SINGLESTEP - The caller will handle each redirect
*</ul>
*/
public void setRedirectBehavior(int behavior) throws SearchException {
switch (behavior) {
case REDIRECT_AUTOMATIC:
_followRedirects = true;
break;
case REDIRECT_MANAGED:
case REDIRECT_MANAGED_SINGLESTEP:
_followRedirects = false;
break;
default:
throw new SearchException("Invalid redirect behavior: " + behavior);
}
_redirectBehavior = behavior;
}
/**
* Set the "file preservation state" for getBaseUrlSpecification()
* @param state true to preserve URL file portion
*/
public void setPreserveBaseUrlFile(boolean state) {
_transaction.setPreserveBaseUrlFile(state);
}
/**
* Should URLConnection follow redirects?
* @return true if URLConnection should handle redirects
*/
public boolean getFollowRedirects() {
return _followRedirects;
}
/**
* Set up a name=value pair
* @param name Parameter name
* @param value Parameter value
*/
public void setParameter(String name, String value) {
_transaction.setParameter(name, value);
}
/**
* Get a named parameter
* @param name Parameter name
* @return Parameter value
*/
public String getParameter(String name) {
return _transaction.getParameter(name);
}
/**
* Get the parameter name associated with the 1st occurance of this value
* @param value Parameter value
* @return Parameter name
*/
public String getParameterName(String value) {
return _transaction.getParameterName(value);
}
/**
* Clear the parameter list
*/
public void clearParameters() {
_transaction.clearParameters();
}
/**
* Submit a request (POST or GET) and read the response. Various aspects
* of the response can be inspected using the "getXXX()" methods.
* @return Submission status code (200 = success)
*/
public int submit() throws SearchException {
int status;
/*
* Send the request
*/
try {
_transaction.setFollowRedirects(_followRedirects);
_transaction.setTransactionType(_method);
status = _transaction.doTransaction(_url);
switch (_redirectBehavior) {
case REDIRECT_AUTOMATIC:
case REDIRECT_MANAGED_SINGLESTEP:
return status;
default:
break;
}
/*
* Were we redirected to another page? If so, try to fetch
*/
while (HttpTransactionUtils.isHttpRedirect(status)) {
String location = _transaction.getResponseHeader("Location");
String baseUrl = _transaction.getBaseUrlSpecification();
URL fullUrl = newFullUrl(baseUrl, location);
setUrl(fullUrl);
_transaction.setTransactionType("GET");
status = _transaction.doTransaction(fullUrl);
}
/*
* Done, return final status
*/
return status;
} catch (Exception exception) {
_log.error("Exception seen, the current URL is \"" + getUrl() + "\"");
exception.printStackTrace(System.out);
throw new SearchException(exception.toString());
}
}
/**
* Get the server response text
* @return The response (as a String)
*/
public String getResponseString() {
return _transaction.getResponseString();
}
/**
* Get the server response text
* @return The response (as a byte array)
*/
public byte[] getResponseBytes() {
return _transaction.getResponseBytes();
}
/**
* Parse the server response (override as required)
* @return Response Document
*/
public Document getResponseDocument() throws SearchException {
try {
return DomUtils.parseHtmlBytes(getResponseBytes());
} catch (Exception exception) {
throw new SearchException(exception.toString());
}
}
/*
* Helpers
*/
/**
* Locate the HTML BODY element in the page document
* @param pageDocument An HTML page (as a DOM)
* @return The body Element
*/
public Element getBody(Document pageDocument) {
Element root = pageDocument.getDocumentElement();
return DomUtils.getElement(root, "BODY");
}
/**
* Construct a new URL from base and relative components
* @param baseComponent Base URL - the relative URL is added to this
* @param relativeComponent A partial (or full) URL that represents our target
* @return A full URL composed of the relative URL combined with "missing"
* portions taken from the base
*/
public URL newFullUrl(String baseComponent, String relativeComponent) {
try {
URL baseUrl = new URL(baseComponent);
return new URL(baseUrl, relativeComponent);
} catch (MalformedURLException exception) {
throw new SearchException(exception.toString());
}
}
/**
* Set query parameters based on page-wide INPUTs
* @param pageDocument The search engine query page (as a DOM Document)
* @param nameList A list of the parameters we're looking for
* @deprecated Replaced by {@link #setParametersFromInputNames()}
*/
public void setParametersFromInputs(Document pageDocument, List nameList) {
setParametersFromInputNames(pageDocument, nameList);
}
/**
* Set query parameters based on page-wide INPUTs
* @param pageDocument The search engine query page (as a DOM Document)
* @param nameList A list of the parameters we're looking for
*/
public void setParametersFromInputNames(Document pageDocument, List nameList) {
setParametersFromNameList(DomUtils.getElementList(getBody(pageDocument), "INPUT"),
nameList);
}
/**
* Set query parameters based on page-wide INPUTs
* @param pageDocument The search engine query page (as a DOM Document)
* @param nameList A list of the parameters we're looking for
*/
public void setParametersFromInputValues(Document pageDocument, List nameList) {
setParametersFromValueList(DomUtils.getElementList(getBody(pageDocument), "INPUT"),
nameList);
}
/**
* Produce a target URL for this query by combining the form "action" value
* with the base URL of the query page
* @param pageDocument The search engine query page (as a DOM Document)
* @param formName The name of the FORM to lookup
* (eg <code>FORM name="formName"</code>)
* @param nameList A list of the parameters we're looking for
*/
public void setParametersFromFormInputs(Document pageDocument,
String formName,
List nameList)
throws SearchException {
Element formElement;
if ((formElement = getFormElement(pageDocument, formName)) == null) {
throw new SearchException("No such form: " + formName);
}
setParametersFromElementInputs(formElement, nameList);
}
/**
* Set query parameters based on INPUTs within an Element
* @param element The base element (often a FORM)
* @param nameList A list of the parameters we're looking for
*/
private void setParametersFromElementInputs(Element element, List nameList) {
setParametersFromNameList(DomUtils.getElementList(element, "INPUT"), nameList);
}
/**
* Set query parameters based on element names (save name=value pairs)
* @param nodeList List of Elements to evaluate
* @param nameList A list of the parameters we're looking for
*/
public void setParametersFromNameList(NodeList nodeList, List nameList) {
setParametersFromList(nodeList, KEY, "name", "value", nameList);
}
/**
* Set query parameters based on element values (save name=value pairs)
* @param nodeList List of Elements to evaluate
* @param nameList A list of the parameters we're looking for
*/
public void setParametersFromValueList(NodeList nodeList, List nameList) {
setParametersFromList(nodeList, VALUE, "value", "name", nameList);
}
/**
* {@link #setParametersFromInputNames()}: Use one of KEY or VALUE as the saved parameter name
*/
private static final int KEY = 0;
private static final int VALUE = 1;
/**
* Set query parameters based on element attributes
* @param nodeList List of Elements to evaluate
* @param useAsParameterName Use one of KEY or VALUE as the saved parameter name
* @param key Parameter "name"
* @param value Parameter "value"
* @param nameList A list of the parameters we're looking for
*/
private void setParametersFromList(NodeList nodeList, int useAsParameterName,
String key, String value, List nameList) {
int nodeSize = nodeList.getLength();
for (int i = 0; i < nodeSize; i++) {
Element element = (Element) nodeList.item(i);
String fetchedValue = element.getAttribute(key);
if (nameList.contains(fetchedValue)) {
switch (useAsParameterName) {
case KEY:
setParameter(fetchedValue, element.getAttribute(value));
break;
case VALUE:
setParameter(element.getAttribute(value), fetchedValue);
break;
default:
throw new IllegalArgumentException("Unknown name selection: "
+ useAsParameterName);
}
}
}
}
/**
* Produce a target URL for this query by combining an anchor "href" value
* with the base URL of the query page
* @param anchor Anchor element
*/
public void setUrlFromAnchor(Element anchor) throws SearchException {
String href = anchor.getAttribute("href");
try {
setUrl(newFullUrl(_transaction.getBaseUrlSpecification(), href));
} catch (MalformedURLException exception) {
throw new SearchException(exception.toString());
}
}
/**
* Produce a target URL for this query by combining the form "action" value
* with the base URL of the query page
* @param pageDocument The search engine query page (as a DOM Document)
* @param formName The name of the FORM to lookup
* (eg <code>FORM name="formName"</code>)
*/
public void setUrlFromForm(Document pageDocument, String formName) throws SearchException {
Element form;
if ((form = getFormElement(pageDocument, formName)) == null) {
throw new SearchException("No such form: " + formName);
}
try {
setUrl(newFullUrl(_transaction.getBaseUrlSpecification(),
form.getAttribute("action")));
} catch (MalformedURLException exception) {
throw new SearchException(exception.toString());
}
}
/**
* Find a named FORM element
* @param pageDocument The search engine query page (as a DOM Document)
* @param formName The name of the FORM to lookup
* (eg <code>FORM name="formName"</code>)
*/
public Element getFormElement(Document pageDocument, String formName) {
return DomUtils.selectFirstElementByAttributeValue(getBody(pageDocument),
"FORM",
"name", formName);
}
}