def next(self):
try:
p_start, param_format, p_end = self._get_next_param_format()
param_name, default_value = self._get_param_name_default_value(
param_format)
except ValueError:
# If we get back a ValueError then time to stop the iteration.
raise StopIteration()
# compute forward progress of the alias format pointer
v_start = p_start - self._alias_fmt_ptr + self._param_strm_ptr
value = None
# make sure v_start is within param_stream
if v_start < len(self._param_stream):
_, value, v_end = self._get_next_value(v_start)
# move the alias_fmt_ptr to one beyond the end of each
self._alias_fmt_ptr = p_end
self._param_strm_ptr = v_end
if not value and not default_value:
raise content.ParseException(
'No value supplied and no default value found.')
return param_name, value if value else default_value
def next(self):
try:
p_start, param_format, p_end = self._get_next_param_format()
param_name, default_value = self._get_param_name_default_value(param_format)
except ValueError:
# If we get back a ValueError then time to stop the iteration.
raise StopIteration()
# compute forward progress of the alias format pointer
v_start = p_start - self._alias_fmt_ptr + self._param_strm_ptr
value = None
# make sure v_start is within param_stream
if v_start < len(self._param_stream):
_, value, v_end = self._get_next_value(v_start)
# move the alias_fmt_ptr to one beyond the end of each
self._alias_fmt_ptr = p_end
self._param_strm_ptr = v_end
elif v_start < len(self._format):
# Advance in the format string
# Note: We still want to advance in the format string even though
# there is nothing left in the param stream since we support default
# values and param_stream can be empty
self._alias_fmt_ptr = p_end
if not value and not default_value:
raise content.ParseException('No value supplied and no default value found.')
return param_name, value if value else default_value
def _get_next_param_format(self):
mrkr_strt_ps = self._format.index(self.FORMAT_MARKER_START, self._alias_fmt_ptr)
try:
mrkr_end_ps = self._format.index(self.FORMAT_MARKER_END, mrkr_strt_ps)
except ValueError:
# A start marker was found but end is not therefore this is a Parser exception.
raise content.ParseException('Expected end marker.')
param_format = self._format[mrkr_strt_ps + len(self.FORMAT_MARKER_START): mrkr_end_ps]
return mrkr_strt_ps, param_format.strip(), mrkr_end_ps + len(self.FORMAT_MARKER_END)
def parse(start, stream):
end = stream.find(DefaultParser.end, start)
# if not found pick until end of stream. In this way the default parser is different
# from other parser as they would always requires an end marker
if end == -1:
end = len(stream)
try:
return start, stream[start:end], end
except IndexError:
raise content.ParseException('What sort of messed up stream did you provide!')
def parse(start, stream):
end = 0
char_idx = start + 1
while not end:
char = stream[char_idx]
if char == StringValueParser.end and stream[char_idx - 1] != StringValueParser.escape:
end = char_idx
else:
char_idx += 1
if char_idx == len(stream):
raise content.ParseException('What sort of messed up stream did you provide!')
# skip the start and end chars
return start, stream[start + 1:end], end + 1
def parse(start, stream):
end = 0
char_idx = start
message_depth = 0
while not end:
char = stream[char_idx]
if char == JsonValueParser.start:
message_depth += 1
elif char == JsonValueParser.end:
message_depth -= 1
if not message_depth:
end = char_idx
else:
char_idx += 1
if char_idx == len(stream):
raise content.ParseException('What sort of messed up stream did you provide!')
# preserve the start and end chars
return start, stream[start:end + 1], end + 1
def get_extracted_param_value(self):
result = {}
# As there's a lot of questions about using regular expressions,
# I'll try to be thorough when documenting this code.
# We're parsing the arbitrary key-value pairs at the end of the stream
# to support passing of parameters not specified in the format string,
# and cutting them from the stream as they're no longer needed.
# Possible values are quoted strings, a word, or anything inside "{}".
pairs_match = r'(?:^|\s+)(\S+)=("(.*?)"|\'(.*?)\'|({.*?})|(\S+))'
extra = re.match(r'.*?((' + pairs_match + r'\s*)*)$',
self._param_stream, re.DOTALL)
if extra:
kv_pairs = re.findall(pairs_match,
extra.group(1), re.DOTALL)
self._param_stream = self._param_stream.replace(extra.group(1), '')
self._param_stream = " %s " % self._param_stream
# Now we'll match parameters with default values in form of
# {{ value = parameter }} (and all possible permutations of spaces),
# compiling them into a list.
# "test {{ url = http://google.com }} {{ extra = Test }}" will become
# [ ["url", "http://google.com"], ["extra", "Test"] ]
params = re.findall(r'{{\s*(.+?)\s*(?:=\s*[\'"]?({.+?}|.+?)[\'"]?)?\s*}}',
self._format, re.DOTALL)
# Now we're transforming our format string into a regular expression,
# substituting {{ ... }} with regex named groups, so that param_stream
# matched against this expression yields a dict of params with values.
param_match = r'["\']?(?P<\2>(?:(?<=\').+?(?=\')|(?<=").+?(?=")|{.+?}|.+?))["\']?'
reg = re.sub(r'(\s*){{\s*([^=}]+?)\s*}}(?![\'"]?\s+}})',
r'\1' + param_match,
self._format)
reg = re.sub(r'(\s*){{\s*(\S+)\s*=\s*(?:{.+?}|.+?)\s*}}',
r'(?:\1' + param_match + r')?',
reg)
reg = re.sub(r'(\s*){{\s*(.+?)\s*}}',
r'\1' + param_match,
reg)
reg = '^\s*' + reg + r'\s*$'
# Now we're matching param_stream against our format string regex,
# getting a dict of values. We'll also get default values from
# "params" list if something is not present.
# Priority, from lowest to highest:
# 1. Default parameters
# 2. Matched parameters
# 3. Extra parameters
matched_stream = re.match(reg, self._param_stream, re.DOTALL)
if matched_stream:
values = matched_stream.groupdict()
for param in params:
matched_value = values[param[0]] if matched_stream else None
result[param[0]] = matched_value or param[1]
if extra:
for pair in kv_pairs:
result[pair[0]] = ''.join(pair[2:])
if self._format and not (self._param_stream.strip() or any(result.values())):
raise content.ParseException('No value supplied and no default value found.')
return result
def get_extracted_param_value(self):
result = {}
# As there's a lot of questions about using regular expressions,
# I'll try to be thorough when documenting this code.
# I'll split the whole convoluted regex into snippets to make it
# a bit more readable (hopefully).
snippets = dict()
# Formats for keys and values: key is a non-spaced string,
# value is anything in quotes or curly braces, or a single word.
snippets['key'] = r'\s*(\S+?)\s*'
snippets['value'] = r'""|\'\'|"(.+?)"|\'(.+?)\'|({.+?})|(\S+)'
# Extended value: also matches unquoted text (caution).
snippets['ext_value'] = r'""|\'\'|"(.+?)"|\'(.+?)\'|({.+?})|(.+?)'
# Key-value pair:
snippets['pairs'] = r'(?:^|\s+){key}=({value})'.format(**snippets)
# End of string: multiple space-separated key-value pairs:
snippets['ending'] = r'.*?(({pairs}\s*)*)$'.format(**snippets)
# Default value in optional parameters:
snippets['default'] = r'\s*=\s*(?:{ext_value})\s*'.format(**snippets)
# Optional parameter (has a default value):
snippets[
'optional'] = '{{' + snippets['key'] + snippets['default'] + '}}'
# Required parameter (no default value):
snippets['required'] = '{{' + snippets['key'] + '}}'
# 1. Matching the arbitrary key-value pairs at the end of the command
# to support extra parameters (not specified in the format string),
# and cutting them from the command string afterwards.
ending_pairs = re.match(snippets['ending'], self._param_stream,
re.DOTALL)
if ending_pairs:
kv_pairs = re.findall(snippets['pairs'], ending_pairs.group(1),
re.DOTALL)
self._param_stream = self._param_stream.replace(
ending_pairs.group(1), '')
self._param_stream = " %s " % self._param_stream
# 2. Matching optional parameters (with default values).
optional = re.findall(snippets['optional'], self._format, re.DOTALL)
# Transforming our format string into a regular expression,
# substituting {{ ... }} with regex named groups, so that param_stream
# matched against this expression yields a dict of params with values.
param_match = r'\1["\']?(?P<\2>(?:(?<=\').+?(?=\')|(?<=").+?(?=")|{.+?}|.+?))["\']?'
reg = re.sub(r'(\s*)' + snippets['optional'],
r'(?:' + param_match + r')?', self._format)
reg = re.sub(r'(\s*)' + snippets['required'], param_match, reg)
reg = '^\s*' + reg + r'\s*$'
# 3. Matching the command against our regex to get the param values
matched_stream = re.match(reg, self._param_stream, re.DOTALL)
# Compiling results from the steps 1-3.
if matched_stream:
result = matched_stream.groupdict()
for param in optional:
matched_value = result[param[0]] if matched_stream else None
matched_result = matched_value or ''.join(param[1:])
if matched_result is not None:
result[param[0]] = matched_result
if ending_pairs:
for pair in kv_pairs:
result[pair[0]] = ''.join(pair[2:])
if self._format and not (self._param_stream.strip()
or any(result.values())):
raise content.ParseException(
'No value supplied and no default value found.')
return result
