tests/get-with-headers.py

transaction: quietly rollback if no other changes than temporary files

If no actual change have been made, we don't really need to roll them back. We
only have to cleanup some temporary files and it seems reasonable to do that
quietly.

This will help us to use the transaction in wider context¹ without impacting the
user experience.

[1] as in Python context managers that lives longer.

#!/usr/bin/env python

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


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('--method', default='GET', help='HTTP method to use')
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(method, 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(method, '/' + 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 headeronly:
        # still read the body to prevent windows to be unhappy about that
        # (this might some flakyness in test-hgweb-filelog.t on Windows)
        data = response.read()
    else:
        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')

    # further try to please the windows-flakyness deity
    conn.close()

    return response.status


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

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