tests/get-with-headers.py

errors: make exit codes class variables instead

Kyle pointed out to me that we can simply make the exit codes class
variables. Python provides some magic for making them accessible as
instance variables.

This also makes it easier to let subclasses of existing errors
override the exit codes by letting them simply define their own values
as class variables. That means that there's no need to pass them into
the superclass's constructor arguments, so the superclass doesn't need
to expose the them as arguments. (Making a subclass set a different
exit code for a subclass of `StorageError` was actually the goal with
my recent series.)

Differential Revision: https://phab.mercurial-scm.org/D10758

#!/usr/bin/env python3

"""This does HTTP GET requests given a host:port and path and returns
a subset of the headers plus the body of the result."""

from __future__ import absolute_import

import argparse
import json
import os
import sys

from mercurial import (
    pycompat,
    util,
)

httplib = util.httplib

try:
    import msvcrt

    msvcrt.setmode(sys.stdout.fileno(), os.O_BINARY)
    msvcrt.setmode(sys.stderr.fileno(), os.O_BINARY)
except ImportError:
    pass

stdout = getattr(sys.stdout, 'buffer', sys.stdout)

parser = argparse.ArgumentParser()
parser.add_argument('--twice', action='store_true')
parser.add_argument('--headeronly', action='store_true')
parser.add_argument('--json', action='store_true')
parser.add_argument('--hgproto')
parser.add_argument(
    '--requestheader',
    nargs='*',
    default=[],
    help='Send an additional HTTP request header. Argument '
    'value is <header>=<value>',
)
parser.add_argument('--bodyfile', help='Write HTTP response body to a file')
parser.add_argument('host')
parser.add_argument('path')
parser.add_argument('show', nargs='*')

args = parser.parse_args()

twice = args.twice
headeronly = args.headeronly
formatjson = args.json
hgproto = args.hgproto
requestheaders = args.requestheader

tag = None


def request(host, path, show):
    assert not path.startswith('/'), path
    global tag
    headers = {}
    if tag:
        headers['If-None-Match'] = tag
    if hgproto:
        headers['X-HgProto-1'] = hgproto

    for header in requestheaders:
        key, value = header.split('=', 1)
        headers[key] = value

    conn = httplib.HTTPConnection(host)
    conn.request("GET", '/' + path, None, headers)
    response = conn.getresponse()
    stdout.write(
        b'%d %s\n' % (response.status, response.reason.encode('ascii'))
    )
    if show[:1] == ['-']:
        show = sorted(
            h for h, v in response.getheaders() if h.lower() not in show
        )
    for h in [h.lower() for h in show]:
        if response.getheader(h, None) is not None:
            stdout.write(
                b"%s: %s\n"
                % (h.encode('ascii'), response.getheader(h).encode('ascii'))
            )
    if not headeronly:
        stdout.write(b'\n')
        data = response.read()

        if args.bodyfile:
            bodyfh = open(args.bodyfile, 'wb')
        else:
            bodyfh = stdout

        # Pretty print JSON. This also has the beneficial side-effect
        # of verifying emitted JSON is well-formed.
        if formatjson:
            # json.dumps() will print trailing newlines. Eliminate them
            # to make tests easier to write.
            data = pycompat.json_loads(data)
            lines = json.dumps(data, sort_keys=True, indent=2).splitlines()
            for line in lines:
                bodyfh.write(pycompat.sysbytes(line.rstrip()))
                bodyfh.write(b'\n')
        else:
            bodyfh.write(data)

        if args.bodyfile:
            bodyfh.close()

    if twice and response.getheader('ETag', None):
        tag = response.getheader('ETag')

    return response.status


status = request(args.host, args.path, args.show)
if twice:
    status = request(args.host, args.path, args.show)

if 200 <= status <= 305:
    sys.exit(0)
sys.exit(1)