// $Id: HTTPFrame.java,v 1.115 2007/03/10 12:35:21 ylafon Exp $

// (c) COPYRIGHT MIT and INRIA, 1997.

// Please first read the full copyright statement in file COPYRIGHT.html

* Default class to handle the HTTP protocol, manage FileResource and

* DirectoryResource.

*/

    public static final

    String STATE_CONTENT_LOCATION = "org.w3c.jigsaw.frames.HTTPFrame.cl";

    private static final boolean debug = false;

    /**

     * Condition check return code - Condition existed but failed.

     */

    public static final int COND_FAILED = 1;

    /**

     * Condition check return code - Condition existed and succeeded.

     */

    public static final int COND_OK = 2;

    /**

     * Condition check return code - Condition existed and succeeded

     *                               but is a weak validation.

     */

    public static final int COND_WEAK = 3;   

    private   static HttpTokenList _accept_ranges  = null;

    static {

  String accept_ranges[] = { "bytes" };

  _accept_ranges = HttpFactory.makeStringList(accept_ranges);

    }

    /**

     * Methods allowed by instances of that class in particular:

     */

    protected        HttpTokenList  allowed = null;

    /**

     * Attributes index - The index for the quality attribute.

     */

    protected static int ATTR_QUALITY = -1 ;

    /**

     * Attribute index - The index for the title attribute.

     */

    protected static int ATTR_TITLE = -1 ;

    /**

     * Attribute index - The index for the content languages attribute.

     */

    protected static int ATTR_CONTENT_LANGUAGE = -1 ;

    /**

     * Attribute index - The index for the content encodings attribute.

     */

    protected static int ATTR_CONTENT_ENCODING = -1 ;

    /**

     * Attribute index - The index for the content type attribute.

     */

    protected static int ATTR_CONTENT_TYPE = -1 ;

    /**

     * Attribute index - The index for the charset attribute.

     */

    protected static int ATTR_CHARSET = -1 ;

    /**

     * Attribute index - The index for the content length attribute.

     */

    protected static int ATTR_CONTENT_LENGTH = -1 ;

    /**

     * Attribute index - The icon (if any) associated to the resource.

     */

    protected static int ATTR_ICON = -1 ;

    /**

     * Attribute index - Max age: the maximum drift allowed from reality.

     */

    protected static int ATTR_MAXAGE = -1 ;

    /**

     * Attribute index - Send MD5 Digest: the md5 digest of the resource sent

     */

    protected static int ATTR_MD5 = -1;

    /**

     * Attribute index - delete allowed for the associated resource ?

     */

    protected static int ATTR_ALLOW_DEL = -1;

    //

    // Attribute relative to FileResource

    //

    /**

     * Attribute index - Do we allow PUT method on this file.

     */

    protected static int ATTR_PUTABLE = -1 ;

    //

    // Attribute relative to DirectoryResource

    //

    /**

     * Attribute index - The index for our relocate attribute.

     */

    protected static int ATTR_RELOCATE = -1 ;

    /**

     * Attribute index - our index resource name.

     */

    protected static int ATTR_INDEX = -1 ;

    /**

     * Attribute index - our indexes resource name.

     */

    protected static int ATTR_INDEXES = -1 ;

    /**

     * Attribute index - The icon directory to use in dir listing.

     */

    protected static int ATTR_ICONDIR = -1 ;

    /**

     * Attribute index - Allow the GNN browse method.

     */

    protected static int ATTR_BROWSABLE = -1 ;

    /**

     * Attribute index - Style sheet for directory listing

     */

    protected static int ATTR_STYLE_LINK = -1 ;

    static {

  Attribute a   = null ;

  Class     cls = null ;

  // Get a pointer to our class:

  try {

      cls = Class.forName("org.w3c.jigsaw.frames.HTTPFrame") ;

  } catch (Exception ex) {

      ex.printStackTrace() ;

      System.exit(1) ;

  }

  // The quality attribute:

  a = new DoubleAttribute("quality"

        , new Double(1.0)

        , Attribute.EDITABLE);

  ATTR_QUALITY = AttributeRegistry.registerAttribute(cls, a) ;

  // The title attribute:

  a = new StringAttribute("title"

        , null

        , Attribute.EDITABLE) ;

  ATTR_TITLE = AttributeRegistry.registerAttribute(cls, a) ;

  // The content language attribute:

  a = new LanguageAttribute("content-language"

          , null

          , Attribute.EDITABLE) ;

  ATTR_CONTENT_LANGUAGE = AttributeRegistry.registerAttribute(cls,a);

  // The content encoding attribute:

  a = new EncodingAttribute("content-encoding"

          , null

          , Attribute.EDITABLE) ;

  ATTR_CONTENT_ENCODING = AttributeRegistry.registerAttribute(cls,a);

  // The content type attribute:

  a = new MimeTypeAttribute("content-type"

          , null

          , Attribute.EDITABLE) ;

  ATTR_CONTENT_TYPE = AttributeRegistry.registerAttribute(cls,a);

  // The Charset attribute:

  a = new StringAttribute("charset"

        , null

        , Attribute.EDITABLE) ;

  ATTR_CHARSET = AttributeRegistry.registerAttribute(cls,a);

        // The content length attribute:

  a = new IntegerAttribute("content-length"

         , null

         , Attribute.COMPUTED);

  ATTR_CONTENT_LENGTH = AttributeRegistry.registerAttribute(cls,a);

  // The icon attribute:

  a = new StringAttribute("icon"

        , null

        , Attribute.EDITABLE) ;

  ATTR_ICON = AttributeRegistry.registerAttribute(cls, a) ;

  // The max age attribute (in ms)

  a = new LongAttribute("maxage"

            , null

            , Attribute.EDITABLE) ;

  ATTR_MAXAGE = AttributeRegistry.registerAttribute(cls, a) ;

  // Should we send MD5 digest?

  a = new BooleanAttribute("send-md5"

         , Boolean.FALSE

         , Attribute.EDITABLE);

  ATTR_MD5 = AttributeRegistry.registerAttribute(cls, a) ;

  // delete allowed for the associated resource ?

  a = new BooleanAttribute("allow-delete"

         , Boolean.FALSE

         , Attribute.EDITABLE);

  ATTR_ALLOW_DEL = AttributeRegistry.registerAttribute(cls, a) ;

  //

  // Attribute relative to a FileResource

  //

  // The putable flag:

  a = new BooleanAttribute("putable"

         , Boolean.FALSE

         , Attribute.EDITABLE) ;

  ATTR_PUTABLE = AttributeRegistry.registerAttribute(cls, a) ;

  //

  // Attribute relative to a DirectoryResource

  //

  //Should we relocate invalid request to this directory ?

  a = new BooleanAttribute("relocate"

         , Boolean.TRUE

         , Attribute.EDITABLE);

  ATTR_RELOCATE = AttributeRegistry.registerAttribute(cls, a) ;

  // Our index resource name (optional).

  a = new StringAttribute("index"

        , null

        , Attribute.EDITABLE) ;

  ATTR_INDEX = AttributeRegistry.registerAttribute(cls, a) ;

  // Our indexes resource name

  a = new StringArrayAttribute("indexes"

             , null

             , Attribute.EDITABLE) ;

  ATTR_INDEXES = AttributeRegistry.registerAttribute(cls, a) ;

  // Our icon directory.

  a = new StringAttribute("icondir"

        , null

        , Attribute.EDITABLE) ;

  ATTR_ICONDIR = AttributeRegistry.registerAttribute(cls,a);

  // The browsable flag:

  a = new BooleanAttribute("browsable"

         , Boolean.FALSE

         , Attribute.EDITABLE) ;

  ATTR_BROWSABLE = AttributeRegistry.registerAttribute(cls, a) ;

  // The style sheet attribute:

  a = new StringAttribute("style-sheet-link"

        , null

        , Attribute.EDITABLE) ;

  ATTR_STYLE_LINK = AttributeRegistry.registerAttribute(cls, a) ;

    }

    /**

     * The associated DirectoryResource (if any)

     */

    protected DirectoryResource dresource  = null;

    /**

     * The associated FileResource (if any)

     */

    protected FileResource      fresource  = null;

    /**

     * Register this frame to the given resource.

     * @param resource The resource associated with this frame.

     */

    public void registerResource(FramedResource resource) {

  super.registerResource(resource);

  if (resource instanceof FileResource)

      fresource = (FileResource) resource;

  else if (resource instanceof DirectoryResource)

      dresource = (DirectoryResource) resource;

    }

    /**

     * Get the associated FileResource (if any)

     * @return a FileResource instance or <strong>null</strong>

     * if no FileResource is associated with this frame.

     */

    public FileResource getFileResource() {

  return fresource;

    }

    /**

     * Get the associated DirectoryResource (if any)

     * @return a DirectoryResource instance or <strong>null</strong>

     * if no DirectoryResource is associated with this frame.

     */

    public DirectoryResource getDirectoryResource() {

  return dresource;

    }

    /**

     * use this one instead of registerResource if the resource type

     * doesn't matter or if this is not a file or a directory resource.

     * In subclasses you should have to do that:

     * <pre>

     *  public void registerResource(FramedResource resource) {

     *   super.registerOtherResource(resource);

     *  }

     * </pre>

     * @param the resource to register.

     */

    public void registerOtherResource(FramedResource resource) {

  super.registerResource(resource);

  dresource = null;

  fresource = null;

    }

    // The HTTPResource keeps a cache of ready to use Http values. This

    // allows to save converting to/from wire rep these objects. Not

    // much CPU time, but also memory is spared.

    HttpMimeType  contenttype     = null;

    HttpInteger   contentlength   = null;

    HttpDate      lastmodified    = null;

    HttpTokenList contentencoding = null;

    HttpTokenList contentlanguage = null;

    // The Http entity tag for this resource (for FileResource only)

    HttpEntityTag etag   = null;

    // the MD5 digest for this resource (for FileResource only)

    HttpString md5Digest = null;

    /**

     * Get this resource's help url.

     * @return An URL, encoded as a String, or <strong>null</strong> if not

     * available.

     */

    public String getHelpURL() {

  httpd server = (httpd) getServer();

  if ( server == null )

      return null;

  String docurl = server.getDocumentationURL();

  if ( docurl == null )

      return null;

  return docurl + "/" + getClass().getName() + ".html";

    }

    /**

     * Get the help URL for that resource's attribute.

     * @param topic The topic (can be an attribute name, or a property, etc).

     * @return A String encoded URL, or <strong>null</strong>.

     */

    public String getHelpURL(String topic) {

  httpd server = (httpd) getServer();

  if ( server == null )

      return null;

  String docurl = server.getDocumentationURL();

  if ( docurl == null )

      return null;

  Class defines = AttributeRegistry.getAttributeClass(getClass(), topic);

  if ( defines != null )

      return docurl + "/" + defines.getName() + ".html";

  return null;

    }

    /**

     * give the md5 digest from cache or calculate it

     * @return the HttpString version of the digest

     */

    private HttpString getMd5Digest() {

  if (md5Digest != null)

      return md5Digest;

  // not found, compute it if necessary!

  Resource r = getResource();

  if (r instanceof FileResource) {

      try {

    Md5 md5 = new Md5 (

        new FileInputStream(((FileResource)r).getFile()));

    String s = null;

    try {

        byte b[] = md5.getDigest();

        Base64Encoder b64;

        ByteArrayOutputStream bos = new ByteArrayOutputStream();

        b64 = new Base64Encoder(new ByteArrayInputStream(b), bos);

        b64.process();

        s = bos.toString();

        md5Digest = HttpFactory.makeString(s);

    } catch (Exception mdex) {

        // error, set it to null

        md5Digest = null;

    }

    return md5Digest;

      } catch (FileNotFoundException ex) {

    // silent fail

    md5Digest = null;

      }

  }

  return null;

    }

    /**

     * Listen its resource.

     */

    public void attributeChanged(AttributeChangedEvent evt) {

  super.attributeChanged(evt);

  String name = evt.getAttribute().getName();

  if (name.equals("file-stamp")) {

      etag = null;

      lastmodified = null;

      md5Digest = null;

  } else if (name.equals("file-length")) {

      setValue(ATTR_CONTENT_LENGTH, evt.getNewValue());

  } else if (name.equals("last-modified")) {

      setValue(ATTR_LAST_MODIFIED, evt.getNewValue());

  } else {

      lastmodified = null;

  }

    }

    /**

     * Catch setValue, to maintain cached header values correctness.

     * @param idx The index of the attribute to be set.

     * @param value The new value for the attribute.

     */

    public synchronized void setValue(int idx, Object value) {

  super.setValue(idx, value);

  if (idx == ATTR_CONTENT_TYPE) {

      contenttype = null;

  } else if (idx == ATTR_CHARSET) {

      contenttype = null;

  } else if (idx == ATTR_CONTENT_LENGTH) {

      contentlength = null;

  } else if ( idx == ATTR_CONTENT_ENCODING ) {

      contentencoding = null;

  } else if ( idx == ATTR_CONTENT_LANGUAGE ) {

      contentlanguage = null;

  } else if ( idx == ATTR_PUTABLE) {

      allowed = null;

  } else if (idx == ATTR_ALLOW_DEL) {

      allowed = null;

  } else if (idx == ATTR_MD5) {

      md5Digest = null; // reset the digest state

  }

  // Any attribute setting modifies the last modified time:

  lastmodified = null;

    }

    /**

     * Get the full URL for that resource.

     * @return An URL instance.

     */

    public URL getURL(Request request) {

  try {

      return new URL(request.getURL(), resource.unsafeGetURLPath());

  } catch (MalformedURLException ex) {

      throw new RuntimeException("unable to build "+

               getURLPath()+

               " full URL, from server "+

               getServer().getURL());

  }

    }

    /**

     * Get this resource quality.

     * @return The resource quality, or some negative value if not defined.

     */

    public double getQuality() {

  return getDouble(ATTR_QUALITY, -1.0) ;

    }

    /**

     * Get this resource quality.

     * @return The resource quality, or some negative value if not defined.

     */

    public double unsafeGetQuality() {

  return unsafeGetDouble(ATTR_QUALITY, -1.0) ;

    }

    /**

     * Get this resource title.

     * @return This resource's title, or <strong>null</strong> if not

     *    defined.

     */

    public String getTitle() {

  return getString(ATTR_TITLE, null) ;

    }

    /**

     * Get this resource content language.

     * Language are stored as a comma separated String of tokens.

     * @return A comma separated string of language tokens, or

     *    <strong>null</strong> if undefined.

     */

    public String getContentLanguage() {

  return (String) getValue(ATTR_CONTENT_LANGUAGE, null) ;

    }

    /**

     * Get this resource content encoding.

     * The content encoding of a resource is stored as a comma separated

     * list of tokens (as decribed in the Content_encoding header of the

     * HTTP specification, and in the order they should appear in the header).

     * @return A string of comma separated encoding tokens, or

     *    <strong>null</strong> if not defined.

     */

    public String getContentEncoding() {

  String def = (String) attributes[ATTR_CONTENT_ENCODING].getDefault();

  String s =  (String) getString (ATTR_CONTENT_ENCODING, def) ;

  return (String) getString (ATTR_CONTENT_ENCODING, def) ;

    }

    /**

     * Get this resource charset.

     * @return A String, or <strong>null</strong> if not

     *    defined.

     */

    public String getCharset() {

  return (String) getValue(ATTR_CHARSET, null);

    }

    /**

     * Get this resource content type.

     * @return An instance of MIMEType, or <strong>null</strong> if not

     *    defined.

     */

    public MimeType getContentType() {

  return (MimeType) getValue(ATTR_CONTENT_TYPE, null);

    }

    /**

     * Compute the ETag string

     * @return a string or null if not applicable

     */

    public String computeETag() {

  String etag_s = null;

  if (fresource != null) {

      long lstamp = fresource.getFileStamp();

      if ( lstamp >= 0L ) {

    StringBuffer sb = new StringBuffer(32);

    sb.append(Integer.toString(getOid(), 32));

    sb.append(':');

    sb.append(Long.toString(lstamp, 32));

    etag_s = sb.toString();

      }

  }

  return etag_s;

    }

    /**

     * Get this resource Etag

     * @return an instance of HttpEntityTag, or <strong>null</strong> if not

     *    defined.

     */

    public HttpEntityTag getETag() {

  if (etag == null) {

      String etag_s = computeETag();

      // no luck, exit

      if (etag_s == null) {

    return null;

      }

      etag = HttpFactory.makeETag(false, etag_s);

  }

  return etag;

    }

    /**

     * Get this resource content length.

     * @return The resource content length, or <strong>-1</strong> if not

     *    defined.

     */

    public int getContentLength() {

  return getInt(ATTR_CONTENT_LENGTH, -1) ;

    }

    /**

     * Get this resource's icon.

     */

    public String getIcon() {

  return getString(ATTR_ICON, null) ;

    }

    /**

     * Get this resource's max age.

     * The max age of a resource indicates how much drift is allowed between

     * the physicall version of the resource, and any in-memory cached version

     * of it.

     * <p>The max age attribute is a long number giving the number of

     * milliseconds of allowed drift.

     */

    public long getMaxAge() {

  return getLong(ATTR_MAXAGE, (long) -1) ;

    }

    //

    // Relative to FileResource ...

    //

    /**

     * Does this resource support byte ranges.

     */

    protected boolean acceptRanges = false;

    /**

     * Get the PUT'able flag (are we allow to PUT to the resource ?)

     */

    public boolean getPutableFlag() {

  return getBoolean(ATTR_PUTABLE, false) ;

    }

    /**

     * Do we send the MD5 digest?

     */

    public boolean getMD5Flag() {

  return getBoolean(ATTR_MD5, false) ;

    }

    /**

     * delete allowed for the associated resource ?

     */

    public boolean getAllowDeleteFlag() {

  return getBoolean(ATTR_ALLOW_DEL, false);

    }

    /**

     * get the Allowed methods for this resource

     * @return an HttpTokenList

     */

    protected HttpTokenList getAllow() {

  if (allowed != null) {

      return allowed;

  }

  int size = 4; // the default HEAD GET OPTIONS TRACE

  if (getPutableFlag()) {

      size++;

  }

  if (getAllowDeleteFlag()) {

      size++;

  }

  String allow_str[] = new String[size];

  int i = 0;

  if (getAllowDeleteFlag()) {

      allow_str[i++] = "DELETE";

  }

  allow_str[i++] = "HEAD";

  allow_str[i++] = "GET";

  allow_str[i++] = "OPTIONS";

  if (getPutableFlag()) {

      allow_str[i++] = "PUT";

  }

  allow_str[i] = "TRACE";

  allowed = HttpFactory.makeStringList(allow_str);

  return allowed;

    }

    /**

     * handles a Range Request

     * @param request, the request

     * @param r, the HttpRange

     * @return a Reply if range is valid, or null if there is a change in the

     * resource, or if the HttpRange is not valid ( 4-2, for example).

     * @exception ProtocolException If processsing the request failed.

     */

    public Reply handleRangeRequest(Request request, HttpRange r)

  throws ProtocolException

    {

  // Should we check against a IfRange header ?

  HttpEntityTag t = request.getIfRange();

  if ( t != null ) {

      if (t.isWeak() || ! t.getTag().equals(etag.getTag()))

    return null;

  }

  // Check the range:

  int cl = getContentLength();

  int fb = r.getFirstPosition();

  int lb = r.getLastPosition();

  int sz;

  if (fb > cl-1) { // first byte already out of range

      HttpContentRange cr = HttpFactory.makeContentRange("bytes", 0,

                     cl - 1, cl);

      Reply rr;

      rr = createDefaultReply(request,

            HTTP.REQUESTED_RANGE_NOT_SATISFIABLE);

      rr.setContentLength(-1);

      rr.setHeaderValue(rr.H_CONTENT_RANGE, cr);

      if (getMD5Flag())

    rr.setContentMD5(null);

      return rr;

  }

  if ((fb < 0) && (lb >= 0)) { // ex: bytes=-20 final 20 bytes

      if (lb >= cl)   // cut the end

    lb = cl;

      sz = lb;

      fb = cl - lb;

      lb = cl - 1;

  } else if (lb < 0) {  // ex: bytes=10- the last size - 10

      lb = cl-1;

      sz = lb-fb+1;

  } else {              // ex: bytes=10-20

      if (lb >= cl)  // cut the end

    lb = cl-1;

      sz = lb-fb+1;

  }

  if ((fb < 0) || (lb < 0) || (fb <= lb)) {

      HttpContentRange cr = null;

      fb = (fb < 0) ? 0 : fb;

      lb = ((lb > cl) || (lb < 0)) ? cl : lb;

      cr = HttpFactory.makeContentRange("bytes", fb, lb, cl);

      // Emit reply:

      Reply rr = createDefaultReply(request, HTTP.PARTIAL_CONTENT);

      // FIXME check for MD5 of only the subpart

      try { // create the MD5 for the subpart

    if (getMD5Flag()) {

        String s = null;

        try {

      ByteRangeOutputStream br;

      br = new ByteRangeOutputStream(fresource.getFile(),

                   fb, lb+1);

      Md5 md5 = new Md5 (br);

      byte b[] = md5.getDigest();

      Base64Encoder b64;

      ByteArrayOutputStream bs = new ByteArrayOutputStream();

      b64 = new Base64Encoder(new ByteArrayInputStream(b),

            bs);

      b64.process();

      s = bs.toString();

        } catch (Exception md_ex) {

      // default to null, no action here then

        }

        if (s == null)

      rr.setContentMD5(null);

        else

      rr.setContentMD5(s);

    }

          rr.setContentLength(sz);

    rr.setHeaderValue(rr.H_CONTENT_RANGE, cr);

    rr.setStream(new ByteRangeOutputStream(fresource.getFile(),

                   fb,

                   lb+1));

    return rr;

      } catch (IOException ex) {

      }

  }

  return null;

    }

    //

    // Relative to DirectoryResource ...

    //

    /**

     * Get this class browsable flag.

     */

    public boolean getBrowsableFlag() {

  return getBoolean (ATTR_BROWSABLE, false) ;

    }

    /**

     * Get this frame style sheet link

     */

    public String getStyleSheetURL() {

  return getString (ATTR_STYLE_LINK, null);

    }

    /**

     * Our current (cached) directory listing.

     */

    protected HtmlGenerator listing = null ;

    /**

     * The time at which we generated the directory index.

     */

    protected long listing_stamp = -1 ;

    private String getUnextendedName(String name) {

  int strlen = name.length() ;

  for (int i = 0 ; i < strlen ; i++) {

      // FIXME: Should use the system props to get the right sep

      if ( name.charAt(i) == '.' ) {

    if ( i == 0 )

        return null ;

    return name.substring(0, i) ;

      }

  }

  return null ;

    }

    /**

     * Get the optional icon directory.

     */

    public String getIconDirectory() {

  return getString(ATTR_ICONDIR, "/icons") ;

    }

    /**

     * Should we relocate invalid requests to this directory.

     * @return A boolean <strong>true</strong> if we should relocate.

     */

    public boolean getRelocateFlag() {

  return getBoolean(ATTR_RELOCATE, true) ;

    }

    /**

     * Get the optional main index name for this directory listing.

     * @return The name of the resource responsible to list that container.

     */

    public String getIndex() {

  return (String) getValue(ATTR_INDEX, null) ;

    }

    /**

     * Get the optional index name array for this directory listing.

     * @return The index name array (including the main index)

     * @see #getIndex

     */

    public String[] getIndexes() {