Maillot de REPOS soutien de reprise/de diffusion multimédia en continu

Depuis que j'ai été confronté à la même problema, j'ai essayé plusieurs solution générale[1] avec un ContainerResponseFilter qui se déclenchent quand un Range en-tête est présent dans la demande et de travailler de façon transparente avec tous les supports de type, des entités et des ressources méthodes.

C'est le ContainerResponseFilter qui utilisera encapsuler le flux de sortie dans un RangedOutputStream (voir ci-dessous):

public class RangeResponseFilter implements ContainerResponseFilter {

    private static final String RANGE = "Range";

    private static final String ACCEPT_RANGES = "Accept-Ranges";

    @Override
    public void filter(ContainerRequestContext requestContext, ContainerResponseContext responseContext)
            throws IOException {
        if (requestContext.getHeaders().containsKey(RANGE)) {
            String rangeHeader = requestContext.getHeaderString(RANGE);
            String contentType = responseContext.getMediaType().toString();
            OutputStream originOutputStream = responseContext.getEntityStream();
            RangedOutputStream rangedOutputStream = new RangedOutputStream(originOutputStream, rangeHeader, contentType, responseContext.getHeaders());
            responseContext.setStatus(Status.PARTIAL_CONTENT.getStatusCode());
            responseContext.getHeaders().putSingle(ACCEPT_RANGES, rangedOutputStream.getAcceptRanges());
            responseContext.setEntityStream(rangedOutputStream);
        }
    }

}

Et voici le RangedOutputStream:

public class RangedOutputStream extends OutputStream {

    public class Range extends OutputStream {

        private ByteArrayOutputStream outputStream;

        private Integer from;

        private Integer to;

        public Range(Integer from, Integer to) {
            this.outputStream = new ByteArrayOutputStream();
            this.from = from;
            this.to = to;
        }

        public boolean contains(Integer i) {
            if (this.to == null) {
                return (this.from <= i);
            }
            return (this.from <= i && i <= this.to);
        }

        public byte[] getBytes() {
            return this.outputStream.toByteArray();
        }

        public Integer getFrom() {
            return this.from;
        }

        public Integer getTo(Integer ifNull) {
            return this.to == null ? ifNull : this.to;
        }

        @Override
        public void write(int b) throws IOException {
            this.outputStream.write(b);
        }

    }

    private final static char[] MULTIPART_CHARS = "-_1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
            .toCharArray();

    private static final String BOUNDARY_LINE_FORMAT = "--%s";

    private static final String CONTENT_TYPE_LINE_FORMAT = "Content-Type: %s";

    private static final String CONTENT_RANGE_FORMAT = "%s %d-%d/%d";

    private static final String CONTENT_RANGE_LINE_FORMAT = "Content-Range: " + CONTENT_RANGE_FORMAT;

    private static final String EMPTY_LINE = "\r\n";

    private OutputStream outputStream;

    private String boundary;

    private String accept;

    private String contentType;

    private boolean multipart;

    private boolean flushed = false;

    private int pos = 0;

    List<Range> ranges;

    MultivaluedMap<String, Object> headers;

    public RangedOutputStream(OutputStream outputStream, String ranges, String contentType, MultivaluedMap<String, Object> headers) {
        this.outputStream = outputStream;
        this.ranges = new ArrayList<>();
        String[] acceptRanges = ranges.split("=");
        this.accept = acceptRanges[0];
        for (String range : acceptRanges[1].split(",")) {
            String[] bounds = range.split("-");
            this.ranges.add(new Range(Integer.valueOf(bounds[0]), bounds.length == 2 ? Integer.valueOf(bounds[1]) : null ));
        }
        this.headers = headers;
        this.contentType = contentType;
        this.multipart = this.ranges.size() > 1;
        this.boundary = this.generateBoundary();
    }

    private String generateBoundary() {
        StringBuilder buffer = new StringBuilder();
        Random rand = new Random();
        int count = rand.nextInt(11) + 30;
        for (int i = 0; i < count; i++) {
            buffer.append(MULTIPART_CHARS[rand.nextInt(MULTIPART_CHARS.length)]);
        }
        return buffer.toString();
    }

    public boolean isMultipart() {
        return this.multipart;
    }

    public String getBoundary() {
        return this.boundary;
    }

    public String getAcceptRanges() {
        return this.accept;
    }

    public String getContentRange(int index) {
        Range range = this.ranges.get(index);
        return String.format(CONTENT_RANGE_LINE_FORMAT, this.accept, range.getFrom(), range.getTo(this.pos), this.pos);
    }

    @Override
    public void write(int b) throws IOException {
        for (Range range : this.ranges) {
            if (range.contains(this.pos)) {
                range.write(b);
            }
        }
        this.pos++;
    }

    @Override
    public void flush() throws IOException {
        if (this.flushed) {
            return;
        }
        if (this.multipart) {
            this.headers.putSingle(HttpHeaders.CONTENT_TYPE, String.format("multipart/byteranges; boundary=%s", this.boundary));
            for (Range range : this.ranges) {
                this.outputStream.write(String.format(BOUNDARY_LINE_FORMAT + EMPTY_LINE, this.boundary).getBytes());
                this.outputStream.write(String.format(CONTENT_TYPE_LINE_FORMAT + EMPTY_LINE, this.contentType).getBytes());
                this.outputStream.write(
                        String.format(CONTENT_RANGE_LINE_FORMAT + EMPTY_LINE, this.accept, range.getFrom(), range.getTo(this.pos), this.pos)
                                .getBytes());
                this.outputStream.write(EMPTY_LINE.getBytes());
                this.outputStream.write(range.getBytes());
                this.outputStream.write(EMPTY_LINE.getBytes());
            }
            this.outputStream.write(String.format(BOUNDARY_LINE_FORMAT, this.boundary + "--").getBytes());
        } else {
            Range range = this.ranges.get(0);
            this.headers.putSingle("Content-Range", String.format(CONTENT_RANGE_FORMAT, this.accept, range.getFrom(), range.getTo(this.pos), this.pos));
            this.outputStream.write(range.getBytes());
        }
        this.flushed = true;
    }

}

[1] https://github.com/heruan/jersey-range-filter

OriginalL'auteur Giovanni Lovato