defaultservlet.java

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     */
    protected boolean checkSendfile(HttpServletRequest request,
                                  HttpServletResponse response,
                                  CacheEntry entry,
                                  long length, Range range) {
        if ((sendfileSize > 0)
            && (entry.resource != null)
            && ((length > sendfileSize) || (entry.resource.getContent() == null))
            && (entry.attributes.getCanonicalPath() != null)
            && (Boolean.TRUE == request.getAttribute("org.apache.tomcat.sendfile.support"))
            && (request.getClass().getName().equals("org.apache.catalina.connector.RequestFacade"))
            && (response.getClass().getName().equals("org.apache.catalina.connector.ResponseFacade"))) {
            request.setAttribute("org.apache.tomcat.sendfile.filename", entry.attributes.getCanonicalPath());
            if (range == null) {
                request.setAttribute("org.apache.tomcat.sendfile.start", new Long(0L));
                request.setAttribute("org.apache.tomcat.sendfile.end", new Long(length));
            } else {
                request.setAttribute("org.apache.tomcat.sendfile.start", new Long(range.start));
                request.setAttribute("org.apache.tomcat.sendfile.end", new Long(range.end + 1));
            }
            request.setAttribute("org.apache.tomcat.sendfile.token", this);
            return true;
        } else {
            return false;
        }
    }
    
    
    /**
     * Check if the if-match condition is satisfied.
     *
     * @param request The servlet request we are processing
     * @param response The servlet response we are creating
     * @param resourceInfo File object
     * @return boolean true if the resource meets the specified condition,
     * and false if the condition is not satisfied, in which case request
     * processing is stopped
     */
    protected boolean checkIfMatch(HttpServletRequest request,
                                 HttpServletResponse response,
                                 ResourceAttributes resourceAttributes)
        throws IOException {

        String eTag = getETag(resourceAttributes);
        String headerValue = request.getHeader("If-Match");
        if (headerValue != null) {
            if (headerValue.indexOf('*') == -1) {

                StringTokenizer commaTokenizer = new StringTokenizer
                    (headerValue, ",");
                boolean conditionSatisfied = false;

                while (!conditionSatisfied && commaTokenizer.hasMoreTokens()) {
                    String currentToken = commaTokenizer.nextToken();
                    if (currentToken.trim().equals(eTag))
                        conditionSatisfied = true;
                }

                // If none of the given ETags match, 412 Precodition failed is
                // sent back
                if (!conditionSatisfied) {
                    response.sendError
                        (HttpServletResponse.SC_PRECONDITION_FAILED);
                    return false;
                }

            }
        }
        return true;

    }


    /**
     * Check if the if-modified-since condition is satisfied.
     *
     * @param request The servlet request we are processing
     * @param response The servlet response we are creating
     * @param resourceInfo File object
     * @return boolean true if the resource meets the specified condition,
     * and false if the condition is not satisfied, in which case request
     * processing is stopped
     */
    protected boolean checkIfModifiedSince(HttpServletRequest request,
                                         HttpServletResponse response,
                                         ResourceAttributes resourceAttributes)
        throws IOException {
        try {
            long headerValue = request.getDateHeader("If-Modified-Since");
            long lastModified = resourceAttributes.getLastModified();
            if (headerValue != -1) {

                // If an If-None-Match header has been specified, if modified since
                // is ignored.
                if ((request.getHeader("If-None-Match") == null)
                    && (lastModified <= headerValue + 1000)) {
                    // The entity has not been modified since the date
                    // specified by the client. This is not an error case.
                    response.setStatus(HttpServletResponse.SC_NOT_MODIFIED);
                    return false;
                }
            }
        } catch(IllegalArgumentException illegalArgument) {
            return true;
        }
        return true;

    }


    /**
     * Check if the if-none-match condition is satisfied.
     *
     * @param request The servlet request we are processing
     * @param response The servlet response we are creating
     * @param resourceInfo File object
     * @return boolean true if the resource meets the specified condition,
     * and false if the condition is not satisfied, in which case request
     * processing is stopped
     */
    protected boolean checkIfNoneMatch(HttpServletRequest request,
                                     HttpServletResponse response,
                                     ResourceAttributes resourceAttributes)
        throws IOException {

        String eTag = getETag(resourceAttributes);
        String headerValue = request.getHeader("If-None-Match");
        if (headerValue != null) {

            boolean conditionSatisfied = false;

            if (!headerValue.equals("*")) {

                StringTokenizer commaTokenizer =
                    new StringTokenizer(headerValue, ",");

                while (!conditionSatisfied && commaTokenizer.hasMoreTokens()) {
                    String currentToken = commaTokenizer.nextToken();
                    if (currentToken.trim().equals(eTag))
                        conditionSatisfied = true;
                }

            } else {
                conditionSatisfied = true;
            }

            if (conditionSatisfied) {

                // For GET and HEAD, we should respond with
                // 304 Not Modified.
                // For every other method, 412 Precondition Failed is sent
                // back.
                if ( ("GET".equals(request.getMethod()))
                     || ("HEAD".equals(request.getMethod())) ) {
                    response.setStatus(HttpServletResponse.SC_NOT_MODIFIED);
                    return false;
                } else {
                    response.sendError
                        (HttpServletResponse.SC_PRECONDITION_FAILED);
                    return false;
                }
            }
        }
        return true;

    }


    /**
     * Check if the if-unmodified-since condition is satisfied.
     *
     * @param request The servlet request we are processing
     * @param response The servlet response we are creating
     * @param resourceInfo File object
     * @return boolean true if the resource meets the specified condition,
     * and false if the condition is not satisfied, in which case request
     * processing is stopped
     */
    protected boolean checkIfUnmodifiedSince(HttpServletRequest request,
                                           HttpServletResponse response,
                                           ResourceAttributes resourceAttributes)
        throws IOException {
        try {
            long lastModified = resourceAttributes.getLastModified();
            long headerValue = request.getDateHeader("If-Unmodified-Since");
            if (headerValue != -1) {
                if ( lastModified > (headerValue + 1000)) {
                    // The entity has not been modified since the date
                    // specified by the client. This is not an error case.
                    response.sendError(HttpServletResponse.SC_PRECONDITION_FAILED);
                    return false;
                }
            }
        } catch(IllegalArgumentException illegalArgument) {
            return true;
        }
        return true;

    }


    /**
     * Copy the contents of the specified input stream to the specified
     * output stream, and ensure that both streams are closed before returning
     * (even in the face of an exception).
     *
     * @param resourceInfo The resource information
     * @param ostream The output stream to write to
     *
     * @exception IOException if an input/output error occurs
     */
    protected void copy(CacheEntry cacheEntry, InputStream is,
                      ServletOutputStream ostream)
        throws IOException {

        IOException exception = null;
        InputStream resourceInputStream = null;

        // Optimization: If the binary content has already been loaded, send
        // it directly
        if (cacheEntry.resource != null) {
            byte buffer[] = cacheEntry.resource.getContent();
            if (buffer != null) {
                ostream.write(buffer, 0, buffer.length);
                return;
            }
            resourceInputStream = cacheEntry.resource.streamContent();
        } else {
            resourceInputStream = is;
        }

        InputStream istream = new BufferedInputStream
            (resourceInputStream, input);

        // Copy the input stream to the output stream
        exception = copyRange(istream, ostream);

        // Clean up the input stream
        try {
            istream.close();
        } catch (Throwable t) {
            ;
        }

        // Rethrow any exception that has occurred
        if (exception != null)
            throw exception;

    }


    /**
     * Copy the contents of the specified input stream to the specified
     * output stream, and ensure that both streams are closed before returning
     * (even in the face of an exception).
     *
     * @param resourceInfo The resource info
     * @param writer The writer to write to
     *
     * @exception IOException if an input/output error occurs
     */
    protected void copy(CacheEntry cacheEntry, InputStream is, PrintWriter writer)
        throws IOException {

        IOException exception = null;

        InputStream resourceInputStream = null;
        if (cacheEntry.resource != null) {
            resourceInputStream = cacheEntry.resource.streamContent();
        } else {
            resourceInputStream = is;
        }

        Reader reader;
        if (fileEncoding == null) {
            reader = new InputStreamReader(resourceInputStream);
        } else {
            reader = new InputStreamReader(resourceInputStream,
                                           fileEncoding);
        }

        // Copy the input stream to the output stream
        exception = copyRange(reader, writer);

        // Clean up the reader
        try {
            reader.close();
        } catch (Throwable t) {
            ;
        }

        // Rethrow any exception that has occurred
        if (exception != null)
            throw exception;

    }


    /**
     * Copy the contents of the specified input stream to the specified
     * output stream, and ensure that both streams are closed before returning
     * (even in the face of an exception).
     *
     * @param resourceInfo The ResourceInfo object
     * @param ostream The output stream to write to
     * @param range Range the client wanted to retrieve
     * @exception IOException if an input/output error occurs
     */
    protected void copy(CacheEntry cacheEntry, ServletOutputStream ostream,
                      Range range)
        throws IOException {

        IOException exception = null;

        InputStream resourceInputStream = cacheEntry.resource.streamContent();
        InputStream istream =
            new BufferedInputStream(resourceInputStream, input);
        exception = copyRange(istream, ostream, range.start, range.end);

        // Clean up the input stream
        try {
            istream.close();
        } catch (Throwable t) {
            ;
        }

        // Rethrow any exception that has occurred
        if (exception != null)
            throw exception;

    }


    /**
     * Copy the contents of the specified input stream to the specified
     * output stream, and ensure that both streams are closed before returning
     * (even in the face of an exception).
     *
     * @param resourceInfo The ResourceInfo object
     * @param writer The writer to write to
     * @param range Range the client wanted to retrieve
     * @exception IOException if an input/output error occurs
     */
    protected void copy(CacheEntry cacheEntry, PrintWriter writer,
                      Range range)
        throws IOException {

        IOException exception = null;

        InputStream resourceInputStream = cacheEntry.resource.streamContent();

        Reader reader;
        if (fileEncoding == null) {
            reader = new InputStreamReader(resourceInputStream);
        } else {
            reader = new InputStreamReader(resourceInputStream,
                                           fileEncoding);
        }

        exception = copyRange(reader, writer, range.start, range.end);

        // Clean up the input stream
        try {
            reader.close();
        } catch (Throwable t) {
            ;
        }

        // Rethrow any exception that has occurred
        if (exception != null)
            throw exception;

    }


    /**
     * Copy the contents of the specified input stream to the specified
     * output stream, and ensure that both streams are closed before returning
     * (even in