httpframe.java

很棒的web服务器源代码

		    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.getURLPath());
	} 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 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) ;