def json_flatten(a, prefix=''):
"""Flatten a JSON structure into a dict with str paths as keys.
For example,
`json_flatten(json.loads('{"a": {"b": "v"}}'))` will return
`{'.a.b': u'v'}`;
`json_flatten(json.loads('{"a": [1, 2, 3]}'))` returns
`{'.a[0]': 1, '.a[2]': 3, '.a[1]': 2}`, etc.
"""
def add_flat(dict_, key, elem):
"""If `elem` is itself a dict, merge it with `dict_`.
Otherwise, store it in `dict_` under `key`.
"""
if isinstance(elem, dict):
dict_.update(elem)
else:
dict_[key] = elem
res = {}
if isinstance(a, list):
for n, elem in enumerate(a):
add_flat(res, prefix, json_flatten(elem, \
prefix + "[{0}]".format(n)))
elif isinstance(a, dict):
for key in a.keys():
new_prefix = prefix
# Use a different syntax for keys with spaces.
if ' ' in key:
new_prefix += "['{0}']".format(key)
else:
new_prefix += ".{0}".format(key)
add_flat(res, prefix, json_flatten(a[key], new_prefix))
# If a is not processable by json_flatten (e.g., it's a str) then store
# it in res. However, at the top level we don't want to store such an a
# as {'': a}. We also don't store None in res; we return it instead.
elif a is not None and prefix != '':
res[prefix] = a
else:
res = a
return res
def json_flatten(a, prefix=''):
"""Flatten a JSON structure into a dict with str paths as keys.
For example,
`json_flatten(json.loads('{"a": {"b": "v"}}'))` will return
`{'.a.b': u'v'}`;
`json_flatten(json.loads('{"a": [1, 2, 3]}'))` returns
`{'.a[0]': 1, '.a[2]': 3, '.a[1]': 2}`, etc.
"""
def add_flat(dict_, key, elem):
"""If `elem` is itself a dict, merge it with `dict_`.
Otherwise, store it in `dict_` under `key`.
"""
if isinstance(elem, dict):
dict_.update(elem)
else:
dict_[key] = elem
res = {}
if isinstance(a, list):
for n, elem in enumerate(a):
add_flat(res, prefix, json_flatten(elem, \
prefix + "[{0}]".format(n)))
elif isinstance(a, dict):
for key in a.keys():
new_prefix = prefix
# Use a different syntax for keys with spaces.
if ' ' in key:
new_prefix += "['{0}']".format(key)
else:
new_prefix += ".{0}".format(key)
add_flat(res, prefix, json_flatten(a[key], new_prefix))
# If a is not processable by json_flatten (e.g., it's a str) then store
# it in res. However, at the top level we don't want to store such an a
# as {'': a}. We also don't store None in res; we return it instead.
elif a is not None and prefix != '':
res[prefix] = a
else:
res = a
return res
def poll_loop(interval, req, date=True, initial_values=True):
"""Perform requests for JSON data. Print out changes when they occur."""
prev_output = None
output = None
try:
output = req.perform()
if initial_values:
json_print(output)
output = json_flatten(output)
except (subprocess.CalledProcessError,
urllib.error.HTTPError,
ValueError) as e:
print(traceback.format_exc(), file=sys.stderr)
while True:
try:
time.sleep(interval)
try:
prev_output, output = output, json_flatten(req.perform())
diff = json_flat_diff(prev_output, output)
if diff is not None:
msg = json_diff_str(diff)
msg.sort()
# If msg is multi-line print each difference on a new line
# with indentation.
prefix = ''
if date:
prefix += datetime.datetime.now().isoformat()
if len(msg) > 1:
print(prefix, \
"\n ", "\n ".join(msg))
else:
print(prefix, msg[0])
except (subprocess.CalledProcessError,
urllib.HTTPError,
ValueError) as e:
print(traceback.format_exc(), file=sys.stderr)
except KeyboardInterrupt:
sys.exit(0)
def poll_loop(interval, req, date=True, initial_values=True):
"""Perform requests for JSON data. Print out changes when they occur."""
prev_output = None
output = None
try:
output = req.perform()
if initial_values:
json_print(output)
output = json_flatten(output)
except (subprocess.CalledProcessError, urllib.error.HTTPError,
ValueError) as e:
print(traceback.format_exc(), file=sys.stderr)
while True:
try:
time.sleep(interval)
try:
prev_output, output = output, json_flatten(req.perform())
diff = json_flat_diff(prev_output, output)
if diff is not None:
msg = json_diff_str(diff)
msg.sort()
# If msg is multi-line print each difference on a new line
# with indentation.
prefix = ''
if date:
prefix += datetime.datetime.now().isoformat()
if len(msg) > 1:
print(prefix, \
"\n ", "\n ".join(msg))
else:
print(prefix, msg[0])
except (subprocess.CalledProcessError, urllib.HTTPError,
ValueError) as e:
print(traceback.format_exc(), file=sys.stderr)
except KeyboardInterrupt:
sys.exit(0)
