Hi,
Frederik Sdun wrote:
Hi,
I try to package some maps for navit. Because I don't want to waste hard
disk space on the SHR server I want to use postinst and postrm and
download the maps from cloudmade.com [0].
The problems:
* maps are really big and you might get problems if you don't use a
memory card
* navit needs a fixed directory for maps in the config file(see PATCH #3)
* How should the versioning be done (cloudmade updates weekly)
My ideas:
* The sze of the maps must be known before downloading
* figure out which partition has enough space left, else bail out
* create a link to /usr/share/navit/maps
* remove everything on postrm
My new problems:
* My test package for andorra is empty
* Some fights against navit compilation
Why bother packaging the maps? They change weekly and unless the repo is
updated fast enough the users will be left behind. My thinking for this
was to create a script that downloads the data for the user and updates
it for him.
Attached is the script I wrote, I'm not even sure at what state it is. I
think it works.
My plan for the script was to run it from if-up.d so that it will update
whenever the user connects to the network, but that's pretty excessive.
Baruch
#!/usr/bin/python
import pickle, sys, os, time, urllib2, re, zipfile, stat
#MAP_LOCATION = '/media/card/Maps/navit'
MAP_LOCATION = '.'
CONFIG_FILE = 'navit-osmmap.pickle'
mapname_re_str = r'cloudmade_map_([A-Za-z]+)/([A-Za-z]+).navit.bin$'
mapname_re = re.compile(mapname_re_str)
map_updated = False
if 1:
def debug(msg):
print 'debug:', msg
def info(msg):
print 'INFO:', msg
def missing(msg):
print 'MISSING FEATURE:', msg
class DefaultErrorHandler(urllib2.HTTPDefaultErrorHandler):
def http_error_default(self, req, fp, code, msg, headers):
result = urllib2.HTTPError(req.get_full_url(), code, msg, headers, fp)
result.status = code
return result
def get_map_name_from_gsm():
missing('Fetching info from GSM is not yet implemented, using a default')
return ('asia', 'israel')
def safe_file_save(filename, writer):
tmp_fname = filename + '.tmp'
debug('Open file %s' % tmp_fname)
f = open(tmp_fname, 'w')
debug('Writing content of tmp file')
writer(f)
debug('fsync content to disk')
os.fsync(f.fileno())
debug('close file')
f.close()
debug('Rename %s to %s' % (tmp_fname, filename))
os.rename(tmp_fname, filename)
debug('Done safe file save')
def load_config():
conf = None
try:
f = open(CONFIG_FILE, 'r')
conf = pickle.load(f)
f.close()
except OSError, e:
info('Config file "%s" failed to load due to %s' % (CONFIG_FILE, e))
except IOError, e:
info('Config file "%s" not read due to %s' % (CONFIG_FILE, e))
if not conf:
conf = dict(last_check = 0, url=dict())
return conf
def save_config():
safe_file_save(CONFIG_FILE, lambda f: pickle.dump(conf, f))
def regular_file_iter(root):
for root, dirs, files in os.walk(root):
for file in files:
fname = os.path.join(root, file)
st = os.stat(fname)
if stat.S_ISREG(st[stat.ST_MODE]):
yield fname
def map_to_filename(p):
return os.path.join(MAP_LOCATION, 'cloudmade_map_%s.%s.navit.bin' % p)
def download_country(p, map_fname = None):
if not map_fname:
map_fname = map_to_filename(p)
# Get URL from filename
url = 'http://download.cloudmade.com/%s/%s/%s.navit.bin.zip' % (p[0], p[1], p[1])
global conf
lastModified = conf['url'].get(url, None)
# Download from url to a temporary file (only download if changed)
info('Starting request for %s last modified %s' % (url, lastModified))
request = urllib2.Request(url)
if lastModified:
request.add_header('If-Modified-Since', lastModified)
opener = urllib2.build_opener(DefaultErrorHandler())
stream = opener.open(request)
try:
a = stream.status
except AttributeError:
stream.status = 200
info('Reuqest status is %d' % stream.status)
if stream.status == 200:
conf['url'][url] = stream.headers.get('Last-Modified')
if stream.status != 200:
info('File not retrievent http response=%d' % stream.status)
tmp_fname = 'tmp.navit.bin'
info('Saving zipfile to %s' % tmp_fname)
f = open(tmp_fname, 'w')
f.write(stream.read())
f.close()
stream.close()
# extract file from zip to temporary location
def save_as_zipfile(f):
debug('Writing zip content')
zf = zipfile.ZipFile(tmp_fname)
names = zf.namelist()
assert(len(names) == 1)
print names
f.write(zf.read(names[0]))
zf.close()
info('Save the file inside the zipfile')
safe_file_save(map_fname, save_as_zipfile)
# Mark maps as updated
global map_updated
map_updated = True
conf = load_config()
force_download = False
gsm_map = get_map_name_from_gsm()
if gsm_map and not os.path.exists(map_to_filename(gsm_map)):
force_download = True
# If not forced and last update was less than 24 hours ago, do not try to download anything
now = time.time()
debug('now=%d last_check=%d diff=%d' % (now, conf['last_check'], now-conf['last_check']))
if not force_download and now - conf['last_check'] > 24*60*60:
info('Not forced download and last check is less than 24 hours ago')
sys.exit(0)
downloaded = []
# List all cloudmade maps
for map_fname in regular_file_iter(MAP_LOCATION):
match = mapname_re.match(map_fname)
# Is it a cloudmade map?
if match is None:
debug('%s is not a cloudmade map' % map_fname)
continue
p = (match[1], match[2])
if p in downloaded:
os.unlink(map_fname)
else:
downloaded.append(p)
download_country(p, map_fname)
if gsm_map not in downloaded:
download_country(gsm_map, None)
downloaded.append(gsm_map)
# If any map was updated, notify navit somehow
if map_updated:
missing('Dont know how to update navit that a map was changed')
# Update configuration
conf['last_check'] = now
save_config()
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