Python's SimpleHTTPServer extended to handle HTTP/1.1 Range requests (and pytest fixture)

RangeHTTPServer.py

"""From https://gist.github.com/shivakar/82ac5c9cb17c95500db1906600e5e1ea"""

import os
from SimpleHTTPServer import SimpleHTTPRequestHandler
import sys
import BaseHTTPServer


class RangeHTTPRequestHandler(SimpleHTTPRequestHandler):
    """RangeHTTPRequestHandler is a SimpleHTTPRequestHandler
    with HTTP 'Range' support"""

    def send_head(self):
        """Common code for GET and HEAD commands.
        Return value is either a file object or None
        """

        path = self.translate_path(self.path)
        ctype = self.guess_type(path)

        # Handling file location
        # If directory, let SimpleHTTPRequestHandler handle the request
        if os.path.isdir(path):
            return SimpleHTTPRequestHandler.send_head(self)

        # Handle file not found
        if not os.path.exists(path):
            return self.send_error(404, self.responses.get(404)[0])

        # Handle file request
        f = open(path, 'rb')
        fs = os.fstat(f.fileno())
        size = fs[6]

        # Parse range header
        # Range headers look like 'bytes=500-1000'
        start, end = 0, size - 1
        print('headers', self.headers.__dict__)
        if 'Range' in self.headers:
            start, end = self.headers.get('Range').strip().strip('bytes=').split('-')
        if start == "":
            # If no start, then the request is for last N bytes
            ## e.g. bytes=-500
            try:
                end = int(end)
            except ValueError as e:
                self.send_error(400, 'invalid range')
            start = size - end
        else:
            try:
                start = int(start)
            except ValueError as e:
                self.send_error(400, 'invalid range')
            if start >= size:
                # If requested start is greater than filesize
                self.send_error(416, self.responses.get(416)[0])
            if end == "":
                # If only start is provided then serve till end
                end = size - 1
            else:
                try:
                    end = int(end)
                except ValueError as e:
                    self.send_error(400, 'invalid range')

        # Correct the values of start and end
        start = max(start, 0)
        end = min(end, size - 1)
        self.range = (start, end)
        # Setup headers and response
        l = end - start + 1
        if 'Range' in self.headers:
            self.send_response(206)
        else:
            self.send_response(200)
        self.send_header('Content-type', ctype)
        self.send_header('Accept-Ranges', 'bytes')
        self.send_header('Content-Range',
                         'bytes %s-%s/%s' % (start, end, size))
        self.send_header('Content-Length', str(l))
        self.send_header('Last-Modified', self.date_time_string(fs.st_mtime))
        self.end_headers()

        return f

    def copyfile(self, infile, outfile):
        """Copies data between two file objects
        If the current request is a 'Range' request then only the requested
        bytes are copied.
        Otherwise, the entire file is copied using SimpleHTTPServer.copyfile
        """
        if 'Range' not in self.headers:
            SimpleHTTPRequestHandler.copyfile(self, infile, outfile)
            return

        start, end = self.range
        infile.seek(start)
        bufsize = 64 * 1024  # 64KB
        remainder = (end - start) % bufsize
        times = int((end - start) / bufsize)
        steps = [bufsize] * times + [remainder]
        for astep in steps:
            buf = infile.read(bufsize)
            print('sending', infile, len(buf))
            outfile.write(buf)
        return

import pytest
@pytest.fixture(scope='session')
def range_http_test_server(request, xprocess):
    xprocess.ensure("server8", lambda cwd:
            ("started MJC", [sys.executable, os.path.abspath("test/fixtures/RangeHTTPServer.py"), 8056]))

    def finalizer():
        print('killing server8')
        xprocess.getinfo('server8').kill()
    request.addfinalizer(finalizer)
    return xprocess.getinfo('server8')

if __name__ == '__main__':
    # arguments
    try:
        cwd = os.path.abspath(sys.argv[2])
    except IndexError:
        # root of repo as current working dir
        cwd = os.path.dirname(os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
    try:
        port = int(sys.argv[1])
    except IndexError:
        port = 8056
    print('serving from cwd', cwd, 'port', port)

    os.chdir(cwd)
    server_address = ('', port)

    HandlerClass = RangeHTTPRequestHandler
    ServerClass = BaseHTTPServer.HTTPServer
    HandlerClass.protocol_version = "HTTP/1.1"
    httpd = ServerClass(server_address, HandlerClass)
    sa = httpd.socket.getsockname()
    sys.stderr.write("started MJC\n cwd=%s port=%s\n%s\n" % (cwd, port))
    sys.stderr.flush()
    print "Serving HTTP on", sa[0], "port", sa[1], "... in background"
    httpd.serve_forever()