# Server-Sent Events (SSE) { #server-sent-events-sse }

You can stream data to the client using **Server-Sent Events** (SSE).

This is similar to [Stream JSON Lines](stream-json-lines.md), but uses the `text/event-stream` format, which is supported natively by browsers with the [`EventSource` API](https://developer.mozilla.org/en-US/docs/Web/API/EventSource).

/// info

Added in FastAPI 0.135.0.

///

            if (line.isEmpty()) {
                continue;
            }
            if (false == line.startsWith(leadingSpaces)) {
                log.accept(lines.lastLineNumber, "snippet line should start with [" + leadingSpaces + "]");
                continue;
            }
            int width = line.length() - leadingSpaces.length();
            if (width > max) {

    String separator = System.getProperty("line.separator");
    sink.writeLines(lines);

    assertContainsExpectedLines(separator);
  }

  public void testWriteLines_specificSeparator() throws IOException {
    String separator = "\r\n";
    sink.writeLines(lines, separator);

    assertContainsExpectedLines(separator);
  }

  }

  /**
   * Streams lines from a URL, stopping when our callback returns false, or we have read all of the
   * lines.
   *
   * @param url the URL to read from
   * @param charset the charset used to decode the input stream; see {@link StandardCharsets} for
   *     helpful predefined constants
   * @param callback the LineProcessor to use to handle the lines
   * @return the output of processing the lines

    public static List<String> format(String... lines) {
        int size = DEFAULT_MAX_SIZE;
        int remainder = size - 4; // 4 chars = 2 box_char + 2 spaces
        List<String> result = new ArrayList<>();
        StringBuilder sb = new StringBuilder(size);
        // first line
        sb.setLength(0);
        repeat(sb, BOX_CHAR, size);
        result.add(sb.toString());
        // lines
        for (String line : lines) {

// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package json

import (
	"encoding/xml"
	"fmt"
	"strings"
)

const (
	document = "document"
	lines    = "lines"

	defaultRecordDelimiter = "\n"
)

// ReaderArgs - represents elements inside <InputSerialization><JSON/> in request XML.
type ReaderArgs struct {
	ContentType string `xml:"Type"`
	unmarshaled bool
}

    }

    /**
     * @return a mapping from remote names to remote URLs.
     */
    public Map<String, String> listRemotes() {
        return runCommand("git", "remote", "-v").lines()
            .filter(l -> l.contains("(fetch)"))
            .map(line -> line.split("\\s+"))
            .collect(Collectors.toMap(parts -> parts[0], parts -> parts[1]));
    }

    String runCommand(String... args) {

   * @return a mutable {@link List} containing all the lines
   * @throws IOException if an I/O error occurs
   */
  public static List<String> readLines(Readable r) throws IOException {
    List<String> result = new ArrayList<>();
    LineReader lineReader = new LineReader(r);
    String line;
    while ((line = lineReader.readLine()) != null) {
      result.add(line);
    }
    return result;
  }

  /**

        List<String> failures = new ArrayList<>();
        for (File f : getFiles()) {
            List<String> lines;
            try (Stream<String> stream = Files.lines(f.toPath(), StandardCharsets.UTF_8)) {
                lines = stream.collect(Collectors.toList());
            } catch (UncheckedIOException e) {

# Usage: setup.packages.sh <package_list.txt>
set -e

# Prevent apt install tzinfo from asking our location (assumes UTC)
export DEBIAN_FRONTEND=noninteractive

apt-get update
# Remove commented lines and blank lines
apt-get install -y --no-install-recommends $(sed -e '/^\s*#.*$/d' -e '/^\s*$/d' "$1" | sort -u)