// CgiFrame.java
// $Id: CgiFrame.java,v 1.3 1998/03/30 07:46:59 bmahe Exp $
// (c) COPYRIGHT MIT and INRIA, 1996.
// Please first read the full copyright statement in file COPYRIGHT.html

package org.w3c.jigsaw.frames ;

import java.io.* ;
import java.util.*;
import java.net.*;

import org.w3c.tools.resources.*;
import org.w3c.tools.resources.ProtocolException;
import org.w3c.www.mime.* ;
import org.w3c.jigsaw.http.* ;
import org.w3c.www.http.*;
import org.w3c.jigsaw.auth.AuthFilter;

/**
 * Parsing the CGI output - The CGIHeaderHolder, to hold CGI headers.
 */
class CGIHeaderHolder implements MimeHeaderHolder {
    // Status and Location deserve special treatments:
    String status   = null;
    String location = null;
    // Anyway, he is going to pay for using CGI
    Hashtable headers = null;
    // The MIME parse we are attached to:
    MimeParser parser = null;

    /**
     * The parsing is now about to start, take any appropriate action.
     * This hook can return a <strong>true</strong> boolean value to enforce
     * the MIME parser into transparent mode (eg the parser will <em>not</em>
     * try to parse any headers.
     * <p>This hack is primarily defined for HTTP/0.9 support, it might
     * also be usefull for other hacks.
     * @param parser The Mime parser.
     * @return A boolean <strong>true</strong> if the MimeParser shouldn't
     * continue the parsing, <strong>false</strong> otherwise.
     */

    public boolean notifyBeginParsing(MimeParser parser)
	throws IOException
    {
	return false;
    }

    /**
     * All the headers have been parsed, take any appropriate actions.
     * @param parser The Mime parser.
     */

    public void notifyEndParsing(MimeParser parser)
	throws IOException
    {
	return ;
    }

    /**
     * A new header has been emited by the script.
     * If the script is not an NPH, then it <strong>must</strong> at least
     * emit one header, so we are safe here, although people may not be safe 
     * against the spec.
     * @param name The header name.
     * @param buf The header bytes.
     * @param off The begining of the value bytes  in above buffer.
     * @param len The length of the value bytes  in above buffer.
     */

    public void notifyHeader(String name, byte buf[], int off, int len)
	throws MimeParserException
    {
	if ( name.equalsIgnoreCase("status") ) {
	    status = new String(buf, 0, off, len);
	} else if ( name.equalsIgnoreCase("location") ) {
	    location = new String(buf, 0, off, len);
	} else {
	    String extraval =  new String(buf, 0, off, len);
	    if ( headers == null ) {
		headers = new Hashtable(11);
	    } else {
		String val = (String) headers.get(name.toLowerCase());
		if ( val != null )
		    extraval = val + "," + extraval;
	    }
	    headers.put(name.toLowerCase(), extraval);
	}
    }

    /**
     * Get the status emited by the script.
     */
    
    public String getStatus() {
	return status;
    }

    /**
     * Get the location header value emited by the script.
     */

    public String getLocation() {
	return location;
    }

    /**
     * Get any header value (except status and location).
     * @param name The name of the header to fetch.
     * @return The string value of requested header, or <strong>null</strong>
     * if header was not defined.
     */

    public String getValue(String name) {
	return (headers == null) ? null : (String) headers.get(name);
    }

    /**
     * Enumerate the headers defined by the holder.
     * @return A enumeration of header names, or <strong>null</strong> if no
     * header is defined.
     */
    
    public Enumeration enumerateHeaders() {
	if ( headers == null )
	    return null;
	return headers.keys();
    }

    /**
     * Get the remaining output of the stream.
     * This should be called only once header parsing is done.
     */

    public InputStream getInputStream() {
	return parser.getInputStream();
    }

    CGIHeaderHolder(MimeParser parser) {
	this.parser = parser;
    }

}

/**
 * Parsing the CGI output - Always create a CGIHeaderHolder.
 */

class CGIHeaderHolderFactory implements MimeParserFactory {
    
    /**
     * Create a new header holder to hold the parser's result.
     * @param parser The parser that has something to parse.
     * @return A MimeParserHandler compliant object.
     */

    public MimeHeaderHolder createHeaderHolder(MimeParser parser) {
	return new CGIHeaderHolder(parser);
    }

    CGIHeaderHolderFactory() {
    }

}

/**
 * A simple process feeder class.
 */

class ProcessFeeder extends Thread {
    Process      proc    = null ;
    OutputStream out     = null ;
    InputStream  in      = null ;
    int          count = -1 ;

    public void run () {
	try {
	    byte buffer[] = new byte[4096] ;
	    int  got      = -1 ;
	    
	    // Send the data to the target process:
	    if ( count >= 0 ) {
		while ( (count > 0) && ((got = in.read(buffer)) > 0) ) {
		    out.write (buffer, 0, got) ;
		    count -= got ;
		}
	    } else {
		while ( (got = in.read(buffer)) > 0 ) {
		    out.write (buffer, 0, got) ;
		}
	    }
	} catch (Exception e) {
	    System.out.println ("ProcessFeeder: caught exception !") ;
	    e.printStackTrace() ;
	} finally {
	    // Clean up the process:
	    try { out.flush() ; } catch (IOException ex) {}
	    try { out.close() ; } catch (IOException ex) {}
	    try { proc.waitFor() ; } catch (Exception ex) {}
	}
    }
	
    ProcessFeeder (Process proc, InputStream in) {
	this (proc, in, -1) ;
    }
	
    ProcessFeeder (Process proc, InputStream in, int count) {
	this.proc   = proc ;
	this.out    = proc.getOutputStream() ;
	this.in     = in ;
	this.count  = count ;
    }
}

/**
 * Handle CGI scripts.
 */
public class CgiFrame extends HTTPFrame {

    private final static 
	String STATE_EXTRA_PATH = "org.w3c.jigsaw.frames.CgiFrame.extraPath";

    /**
     * Attribute index - The interpreter to use, if any.
     */
    protected static int ATTR_INTERPRETER = -1;
    /**
     * Attribute index - The array of string that makes the command to run.
     */
    protected static int ATTR_COMMAND = -1 ;
    /**
     * Attribute index - Does the script takes care of its headers ?
     */
    protected static int ATTR_NOHEADER = -1 ;
    /**
     * Attribute index - Does the script generates the form on GET ?
     */
    protected static int ATTR_GENERATES_FORM = -1 ;
    /**
     * Attribute index - Do DNS, to fill in REMOTE_HOST env var.
     */
    protected static int ATTR_REMOTE_HOST = -1;
    /**
     * Attribute index - Turn the script in debug mode.
     */
    protected static int ATTR_CGI_DEBUG = -1;

    static {
	Attribute a   = null ;
	Class     cls = null ;
	try {
	    cls = Class.forName("org.w3c.jigsaw.frames.CgiFrame") ;
	} catch (Exception ex) {
	    ex.printStackTrace() ;
	    System.exit(1) ;
	}
	// The interpreter attribute:
	a = new StringAttribute("interpreter"
				, null
				, Attribute.EDITABLE);
	ATTR_INTERPRETER = AttributeRegistry.registerAttribute(cls, a);
	// The command attribute:
	a = new StringArrayAttribute("command"
				     , null
				     , Attribute.MANDATORY|Attribute.EDITABLE);
	ATTR_COMMAND = AttributeRegistry.registerAttribute(cls, a) ;
	// The noheader attribute:
	a = new BooleanAttribute("noheader"
				 , Boolean.FALSE
				 , Attribute.EDITABLE) ;
	ATTR_NOHEADER = AttributeRegistry.registerAttribute(cls, a) ;
	// The generates form attribute
	a = new BooleanAttribute("generates-form"
				 , Boolean.TRUE
				 , Attribute.EDITABLE) ;
	ATTR_GENERATES_FORM = AttributeRegistry.registerAttribute(cls, a);
	// Registerr the DODNS attribute.
	a = new BooleanAttribute("remote-host"
				 , null
				 , Attribute.EDITABLE);
	ATTR_REMOTE_HOST = AttributeRegistry.registerAttribute(cls, a);
	// Register the debug mode flag:
	a = new BooleanAttribute("cgi-debug"
				 , Boolean.FALSE
				 , Attribute.EDITABLE);
	ATTR_CGI_DEBUG = AttributeRegistry.registerAttribute(cls, a);
    }

    /**
     * Get the interpreter to use to execute the script.
     * This is most usefull for operating systems that don't have a
     * <code>!#</code> convention ala UNIX.
     * @return The interpreter to run the script.
     */

    public String getInterpreter() {
	return getString(ATTR_INTERPRETER, null);
    }

    /**
     * Get the command string array.
     */

    public String[] getCommand() {
	return (String[]) getValue(ATTR_COMMAND, null) ;
    }

    /**
     * Get the noheader flag.
     * @return The boolean value of the noheader flag.
     */

    public boolean checkNoheaderFlag() {
	return getBoolean(ATTR_NOHEADER, false) ;
    }

    /**
     * Get the generates form flag.
     * @return The boolean value of the generates form flag.
     */

    public boolean checkGeneratesFormFlag() {
	return getBoolean(ATTR_GENERATES_FORM, true) ;
    }

    /**
     * Get the remote host attribute value.
     * If turned on, this flag will enable the REMOTE_HOST env var computation.
     * @return A boolean.
     */

    public boolean checkRemoteHost() {
	return getBoolean(ATTR_REMOTE_HOST, false);
    }

    /**
     * Get the CGI debug flag.
     * @return The boolean value of the CGI debug flag.
     */

    public boolean checkCgiDebug() {
	return getBoolean(ATTR_CGI_DEBUG, false);
    }

    /**
     * Turn the given header name into it's env var canonical name.
     * This guy is crazy enough to run CGI scripts, he can pay for that 
     * overhead.
     * @param name The header name.
     * @return A String giving the official env variable name for that header.
     */

    public String getEnvName(String name) {
	int          sl = name.length();
	StringBuffer sb = new StringBuffer(5+sl);
	sb.append("HTTP_");
	for (int i = 0 ; i < sl ; i++) {
	    char ch = name.charAt(i);
	    sb.append((ch == '-') ? '_' : Character.toUpperCase(ch));
	}
	return sb.toString();
    }

    /**
     * Handle the CGI script output.
     * This methods handles the CGI script output. Depending on the
     * value of the <strong>noheader</strong> attribute it either:
     * <ul>
     * <li>Sends back the script output directly,</li>
     * <li>Parses the script output, looking for a status header or a 
     * location header, or a content-length header, or any combination
     * of those three.
     * </ul>
     * @param process The underlying CGI process.
     * @param request The processed request.
     * @exception ProtocolException If an HTTP error should be sent back 
     * to the client.
     */

    protected Reply handleCGIOutput (Process process, Request request) 
	throws ProtocolException
    {
	// No header script don't deserve attention:
	if ( checkNoheaderFlag() ) {
	    Reply reply = request.makeReply(HTTP.NOHEADER) ;
	    reply.setStream (process.getInputStream()) ;
	    return reply ;
	}
	// Check for debugging mode:
	if ( checkCgiDebug() ) {
	    Reply reply = request.makeReply(HTTP.OK);
	    reply.setContentType(MimeType.TEXT_PLAIN);
	    reply.setStream(process.getInputStream());
	    return reply;
	}
	// We MUST parse at least one header:
	MimeParser p = new MimeParser(process.getInputStream(),
				      new CGIHeaderHolderFactory());
	Reply           reply  = null ;
	try {
	    CGIHeaderHolder h = (CGIHeaderHolder) p.parse();
	    // Check for a status code:
	    String svalue   = h.getStatus();
	    String location = h.getLocation();
	    if ( svalue != null ) {
		int status = -1;
		try {
		    status = Integer.parseInt(svalue);
		} catch (Exception ex) {
		    // This script has emited an invalid status line:
		    String msg = ("Emited an invalid status line ["+
				  svalue + "].");
		    getServer().errlog(this, msg);
		    // Throw an HTTPException:
		    reply = request.makeReply(HTTP.INTERNAL_SERVER_ERROR);
		    reply.setContent("CGI script emited invalid status.");
		    throw new HTTPException(reply);
		}
		reply = request.makeReply(status);
	    } else {
		// No status code available, any location header ?
		reply = request.makeReply((location == null)
					  ? HTTP.OK
					  : HTTP.MOVED_TEMPORARILY);
	    }
	    // Set up the location header if needed:
	    if ( location != null ) {
		try {
		    reply.setLocation(new URL(getURL(request), location));
		} catch (MalformedURLException ex) {
		    // This should really not happen:
		    getServer().errlog(this, "unable to create location url "+
				       location+
				       " in base "+getURL(request));
		}
	    }
	    // And then, the remaining headers:
	    Enumeration e = h.enumerateHeaders();
	    if ( e != null ) {
		while ( e.hasMoreElements() ) {
		    String hname = (String) e.nextElement();
		    reply.setValue(hname, (String) h.getValue(hname));
		}
	    }
	    reply.setStream(p.getInputStream()) ;
	} catch (IOException ex) {
	    ex.printStackTrace();
	} catch (MimeParserException ex) {
	    // This script has generated invalid output:
	    String msg = (getURL(request)
			  +": emited invalid output ["+
			  ex.getMessage() +"]");
	    getServer().errlog(this, msg);
	    // Throw an HTTPException:
	    Reply error = request.makeReply(HTTP.INTERNAL_SERVER_ERROR) ;
	    error.setContent("CGI error: unable to parse script headers.") ;
	    throw new HTTPException (error) ;
	}
	return reply ;
    }

    /**
     * Add an enviornment binding to the given vector.
     * @param name The name of the enviornment variable.
     * @param val Its value.
     * @param into The vector to which accumulate bindings.
     */

    private void addEnv (String name, String val, Vector into) {
	into.addElement (name+"="+val) ;
    }
    
    /**
     * Prepare the command to run for this CGI script, and run it.
     * @param request The request to handle.
     * @return The running CGI process object.
     * @exception HTTPException If we weren't able to build the command or
     *    the environment.
     */

    protected Process makeCgiCommand (Request request) 
	throws ProtocolException, IOException 
    {
	// Check the command attribute first:
	String      query     = null;
	String      command[] = getCommand() ;
	if ( command == null ) {
	    Reply error = request.makeReply(HTTP.INTERNAL_SERVER_ERROR) ;
	    error.setContent("CgiResource mis-configured: it doesn't have a "
			     + " command attribute");
	    throw new HTTPException(error);
	}
	// Ok:
	Vector      env       = new Vector(32) ;
	httpd       server    = request.getClient().getServer() ;
	InetAddress sadr      = server.getInetAddress() ;
	// Specified environment variables:
	// We do not handle the following variables:
	// - PATH_TRANSLATED: I don't understand it
	// - REMOTE_IDENT: would require usage of IDENT protocol.
	// Authentification type, if any:
	String svalue = (String) request.getState(AuthFilter.STATE_AUTHTYPE);
	if ( svalue != null )
	    addEnv("AUTH_TYPE", svalue, env);
	// Content length, if available:
	svalue = request.getValue("content-length");
	if ( svalue != null )
	    addEnv("CONTENT_LENGTH", svalue, env);
	// Content type, if available:
	svalue = request.getValue("content-type");
	if ( svalue != null )
	    addEnv("CONTENT_TYPE", svalue, env);
	// The gateway interface, hopefully 1.1 !
	addEnv ("GATEWAY_INTERFACE", "CGI/1.1", env) ;
	// The PATH_INFO, which I am afraid I still don't understand:
	svalue = (String) request.getState(STATE_EXTRA_PATH);
	if ( svalue == null )
	    addEnv ("PATH_INFO", "/", env) ; 
	else
	    addEnv ("PATH_INFO", svalue, env) ; 
	// The query string:
	query = request.getQueryString();
	if ( query != null ) 
	    addEnv("QUERY_STRING", query, env) ;
	// The remote client IP address:
	svalue = request.getClient().getInetAddress().toString();
	addEnv ("REMOTE_ADDR", svalue, env);
	// Authentified user:
	svalue = (String) request.getState(AuthFilter.STATE_AUTHUSER);
	if ( svalue != null )
	    addEnv("REMOTE_USER", svalue, env);
	// Remote host name, if allowed:
	if ( checkRemoteHost() ) {
	    String host = request.getClient().getInetAddress().getHostName();
	    addEnv("REMOTE_HOST", host, env);
	}
	// The request method:
	addEnv ("REQUEST_METHOD", request.getMethod(), env) ;
	// The script name :
	addEnv("SCRIPT_NAME", getURLPath(), env);
	// Server name:
	addEnv ("SERVER_NAME", getServer().getHost(), env) ;
	// Server port:
	svalue = Integer.toString(getServer().getLocalPort());
	addEnv ("SERVER_PORT", svalue, env);
	// Server protocol:
	addEnv ("SERVER_PROTOCOL", request.getVersion(), env) ;
	// Server software:
	addEnv ("SERVER_SOFTWARE", server.getSoftware(), env) ;
	// All other request fields, yeah, let's lose even more time:
	Enumeration e = request.enumerateHeaderDescriptions(false);
	while ( e.hasMoreElements() ) {
	    HeaderDescription d = (HeaderDescription) e.nextElement();
	    addEnv(getEnvName(d.getName())
		   , request.getHeaderValue(d).toString()
		   , env);
	}
	// Command line:
	if ( query != null ) {
	    String querycmd[] = new String[command.length+1] ;
	    System.arraycopy(command, 0, querycmd, 0, command.length) ;
	    querycmd[command.length] = query ;
	    command = querycmd ;
	}
	String aenv[] = new String[env.size()] ;
	env.copyInto (aenv) ;
	// Run the process:
	if ( getInterpreter() != null ) {
	    String run[] = new String[command.length+1];
	    run[0] = getInterpreter();
	    System.arraycopy(command, 0, run, 1, command.length);
	    return Runtime.getRuntime().exec (run, aenv) ;
	} else {
	    return Runtime.getRuntime().exec (command, aenv) ;
	}
    }

    /**
     * Lookup sub-resources.
     * Accumulate the remaning path in some special state of the request.
     * <p>This allows us to implement the <code>PATH_INFO</code> 
     * CGI variable properly.
     * @param ls Current lookup state.
     * @param lr Lookup result under construction.
     * @return A boolean <strong>true</strong> if lookup should continue,
     * <strong>false</strong> otherwise.
     */

    public boolean lookup(LookupState ls, LookupResult lr) 
	throws ProtocolException 
    {
	// Get the extra path information:
	String extraPath = ls.getRemainingPath(true);
	if ((extraPath == null) || extraPath.equals(""))
	    extraPath = "/";
	// Keep this path info into the request, if possible:
	Request request = (Request) ls.getRequest();
	if ( request != null )
	    request.setState(STATE_EXTRA_PATH, extraPath);
	lr.setTarget(getResource().getResourceReference());
	return super.lookup(ls, lr);
    }
  
    /** 
     * GET method implementation.
     * this method is splitted into two cases:
     * <p>If the resource is able to generates its form, than run the script
     * to emit the form. Otherwsie, use our super class (FileResource) ability
     * to send the file that contains the form.
     * <p>Note that there is no need to feed the underlying process with
     * data in the GET case.
     * @param request The request to handle.
     * @exception ProtocolException If processing the request failed.
     */
    public Reply get(Request request)
	throws ProtocolException, NotAProtocolException
   {
       if ( ! checkGeneratesFormFlag() )
	   return super.get (request) ;
       Process       process = null ;
       try {
	   process = makeCgiCommand (request) ;
       } catch (IOException e) {
	   Reply error = request.makeReply(HTTP.NOT_FOUND) ;
	   error.setContent("The resource's script wasn't found.") ;
	   throw new HTTPException (error) ;
       }
       return handleCGIOutput (process, request) ;
   }


    /**
     * Handle the POST method according to CGI/1.1 specification.
     * The request body is sent back to the launched CGI script, as is, and
     * the script output is handled by the handleCGIOutput method.
     * @param request The request to process.
     * @exception ProtocolException If the processing failed.
     */
    public Reply post(Request request)
	throws ProtocolException, NotAProtocolException
    {
	Process       process = null ;
	// Launch the CGI process:
	try {
	    process = makeCgiCommand(request) ;
	} catch (IOException ex) {
	    // The process wasn't executable, emit a errlog message:
	    String msg = ("The process "+
			  getCommand()[0] +" couldn't be executed ["+
			  ex.getMessage() + "]");
	    getServer().errlog(this, msg);
	    // Throw an internal server error:
	    Reply error = request.makeReply(HTTP.INTERNAL_SERVER_ERROR) ;
	    error.setContent("CGI script is misconfigured.");
	    throw new HTTPException (error) ;
	}
	// Now feed the process:
	try {
	    // Send the 100 status code:
	    Client client = request.getClient();
	    if ( client != null ) 
		client.sendContinue();
	    InputStream in = request.getInputStream();
	    if ( in == null ) {
		// There was no input to that CCI, close process stream
		process.getOutputStream().close();
	    } else {
		// Some input to feed the process with:
		(new ProcessFeeder(process, in)).start();
	    }
	} catch (IOException ex) {
	    // This is most probably a bad request:
	    Reply error = request.makeReply(HTTP.BAD_REQUEST);
	    error.setContent("The request didn't have a valid input.");
	    throw new HTTPException(error);
	}
	return handleCGIOutput(process, request);
    }
    
    /**
     * At register time, if no command, use a suitable default.
     * THis method will set the command to the identifier, if it is not
     * provided.
     * @param values Default attribute values.
     */
    
    public void registerResource(FramedResource resource) {
	super.registerResource(resource);
	//if no command is specified look for a file resource attached
	//and get its File absolute path if available.
	if (getCommand() == null) {
	    if (getFileResource() != null) {
		if (getFileResource().getFile() != null) {
		    String cmd[] = new String[1];
		    cmd[0] = getFileResource().getFile().getAbsolutePath();
		    setValue(ATTR_COMMAND, cmd);
		}
	    }
	}
    }
}
