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Batuhan Berk Başoğlu 2020-11-12 11:05:57 -05:00
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from .system import SystemCompleter
__all__ = ["SystemCompleter"]

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from prompt_toolkit.completion.filesystem import ExecutableCompleter, PathCompleter
from prompt_toolkit.contrib.regular_languages.compiler import compile
from prompt_toolkit.contrib.regular_languages.completion import GrammarCompleter
__all__ = [
"SystemCompleter",
]
class SystemCompleter(GrammarCompleter):
"""
Completer for system commands.
"""
def __init__(self) -> None:
# Compile grammar.
g = compile(
r"""
# First we have an executable.
(?P<executable>[^\s]+)
# Ignore literals in between.
(
\s+
("[^"]*" | '[^']*' | [^'"]+ )
)*
\s+
# Filename as parameters.
(
(?P<filename>[^\s]+) |
"(?P<double_quoted_filename>[^\s]+)" |
'(?P<single_quoted_filename>[^\s]+)'
)
""",
escape_funcs={
"double_quoted_filename": (lambda string: string.replace('"', '\\"')),
"single_quoted_filename": (lambda string: string.replace("'", "\\'")),
},
unescape_funcs={
"double_quoted_filename": (
lambda string: string.replace('\\"', '"')
), # XXX: not entirely correct.
"single_quoted_filename": (lambda string: string.replace("\\'", "'")),
},
)
# Create GrammarCompleter
super().__init__(
g,
{
"executable": ExecutableCompleter(),
"filename": PathCompleter(only_directories=False, expanduser=True),
"double_quoted_filename": PathCompleter(
only_directories=False, expanduser=True
),
"single_quoted_filename": PathCompleter(
only_directories=False, expanduser=True
),
},
)

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r"""
Tool for expressing the grammar of an input as a regular language.
==================================================================
The grammar for the input of many simple command line interfaces can be
expressed by a regular language. Examples are PDB (the Python debugger); a
simple (bash-like) shell with "pwd", "cd", "cat" and "ls" commands; arguments
that you can pass to an executable; etc. It is possible to use regular
expressions for validation and parsing of such a grammar. (More about regular
languages: http://en.wikipedia.org/wiki/Regular_language)
Example
-------
Let's take the pwd/cd/cat/ls example. We want to have a shell that accepts
these three commands. "cd" is followed by a quoted directory name and "cat" is
followed by a quoted file name. (We allow quotes inside the filename when
they're escaped with a backslash.) We could define the grammar using the
following regular expression::
grammar = \s* (
pwd |
ls |
(cd \s+ " ([^"]|\.)+ ") |
(cat \s+ " ([^"]|\.)+ ")
) \s*
What can we do with this grammar?
---------------------------------
- Syntax highlighting: We could use this for instance to give file names
different colour.
- Parse the result: .. We can extract the file names and commands by using a
regular expression with named groups.
- Input validation: .. Don't accept anything that does not match this grammar.
When combined with a parser, we can also recursively do
filename validation (and accept only existing files.)
- Autocompletion: .... Each part of the grammar can have its own autocompleter.
"cat" has to be completed using file names, while "cd"
has to be completed using directory names.
How does it work?
-----------------
As a user of this library, you have to define the grammar of the input as a
regular expression. The parts of this grammar where autocompletion, validation
or any other processing is required need to be marked using a regex named
group. Like ``(?P<varname>...)`` for instance.
When the input is processed for validation (for instance), the regex will
execute, the named group is captured, and the validator associated with this
named group will test the captured string.
There is one tricky bit:
Often we operate on incomplete input (this is by definition the case for
autocompletion) and we have to decide for the cursor position in which
possible state the grammar it could be and in which way variables could be
matched up to that point.
To solve this problem, the compiler takes the original regular expression and
translates it into a set of other regular expressions which each match certain
prefixes of the original regular expression. We generate one prefix regular
expression for every named variable (with this variable being the end of that
expression).
TODO: some examples of:
- How to create a highlighter from this grammar.
- How to create a validator from this grammar.
- How to create an autocompleter from this grammar.
- How to create a parser from this grammar.
"""
from .compiler import compile
__all__ = ["compile"]

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r"""
Compiler for a regular grammar.
Example usage::
# Create and compile grammar.
p = compile('add \s+ (?P<var1>[^\s]+) \s+ (?P<var2>[^\s]+)')
# Match input string.
m = p.match('add 23 432')
# Get variables.
m.variables().get('var1') # Returns "23"
m.variables().get('var2') # Returns "432"
Partial matches are possible::
# Create and compile grammar.
p = compile('''
# Operators with two arguments.
((?P<operator1>[^\s]+) \s+ (?P<var1>[^\s]+) \s+ (?P<var2>[^\s]+)) |
# Operators with only one arguments.
((?P<operator2>[^\s]+) \s+ (?P<var1>[^\s]+))
''')
# Match partial input string.
m = p.match_prefix('add 23')
# Get variables. (Notice that both operator1 and operator2 contain the
# value "add".) This is because our input is incomplete, and we don't know
# yet in which rule of the regex we we'll end up. It could also be that
# `operator1` and `operator2` have a different autocompleter and we want to
# call all possible autocompleters that would result in valid input.)
m.variables().get('var1') # Returns "23"
m.variables().get('operator1') # Returns "add"
m.variables().get('operator2') # Returns "add"
"""
import re
from typing import Callable, Dict, Iterable, Iterator, List
from typing import Match as RegexMatch
from typing import Optional, Pattern, Tuple, cast
from .regex_parser import (
AnyNode,
Lookahead,
Node,
NodeSequence,
Regex,
Repeat,
Variable,
parse_regex,
tokenize_regex,
)
__all__ = [
"compile",
]
# Name of the named group in the regex, matching trailing input.
# (Trailing input is when the input contains characters after the end of the
# expression has been matched.)
_INVALID_TRAILING_INPUT = "invalid_trailing"
EscapeFuncDict = Dict[str, Callable[[str], str]]
class _CompiledGrammar:
"""
Compiles a grammar. This will take the parse tree of a regular expression
and compile the grammar.
:param root_node: :class~`.regex_parser.Node` instance.
:param escape_funcs: `dict` mapping variable names to escape callables.
:param unescape_funcs: `dict` mapping variable names to unescape callables.
"""
def __init__(
self,
root_node: Node,
escape_funcs: Optional[EscapeFuncDict] = None,
unescape_funcs: Optional[EscapeFuncDict] = None,
) -> None:
self.root_node = root_node
self.escape_funcs = escape_funcs or {}
self.unescape_funcs = unescape_funcs or {}
#: Dictionary that will map the regex names to Node instances.
self._group_names_to_nodes: Dict[
str, str
] = {} # Maps regex group names to varnames.
counter = [0]
def create_group_func(node: Variable) -> str:
name = "n%s" % counter[0]
self._group_names_to_nodes[name] = node.varname
counter[0] += 1
return name
# Compile regex strings.
self._re_pattern = "^%s$" % self._transform(root_node, create_group_func)
self._re_prefix_patterns = list(
self._transform_prefix(root_node, create_group_func)
)
# Compile the regex itself.
flags = re.DOTALL # Note that we don't need re.MULTILINE! (^ and $
# still represent the start and end of input text.)
self._re = re.compile(self._re_pattern, flags)
self._re_prefix = [re.compile(t, flags) for t in self._re_prefix_patterns]
# We compile one more set of regexes, similar to `_re_prefix`, but accept any trailing
# input. This will ensure that we can still highlight the input correctly, even when the
# input contains some additional characters at the end that don't match the grammar.)
self._re_prefix_with_trailing_input = [
re.compile(
r"(?:%s)(?P<%s>.*?)$" % (t.rstrip("$"), _INVALID_TRAILING_INPUT), flags
)
for t in self._re_prefix_patterns
]
def escape(self, varname: str, value: str) -> str:
"""
Escape `value` to fit in the place of this variable into the grammar.
"""
f = self.escape_funcs.get(varname)
return f(value) if f else value
def unescape(self, varname: str, value: str) -> str:
"""
Unescape `value`.
"""
f = self.unescape_funcs.get(varname)
return f(value) if f else value
@classmethod
def _transform(
cls, root_node: Node, create_group_func: Callable[[Variable], str]
) -> str:
"""
Turn a :class:`Node` object into a regular expression.
:param root_node: The :class:`Node` instance for which we generate the grammar.
:param create_group_func: A callable which takes a `Node` and returns the next
free name for this node.
"""
def transform(node: Node) -> str:
# Turn `AnyNode` into an OR.
if isinstance(node, AnyNode):
return "(?:%s)" % "|".join(transform(c) for c in node.children)
# Concatenate a `NodeSequence`
elif isinstance(node, NodeSequence):
return "".join(transform(c) for c in node.children)
# For Regex and Lookahead nodes, just insert them literally.
elif isinstance(node, Regex):
return node.regex
elif isinstance(node, Lookahead):
before = "(?!" if node.negative else "(="
return before + transform(node.childnode) + ")"
# A `Variable` wraps the children into a named group.
elif isinstance(node, Variable):
return "(?P<%s>%s)" % (
create_group_func(node),
transform(node.childnode),
)
# `Repeat`.
elif isinstance(node, Repeat):
if node.max_repeat is None:
if node.min_repeat == 0:
repeat_sign = "*"
elif node.min_repeat == 1:
repeat_sign = "+"
else:
repeat_sign = "{%i,%s}" % (
node.min_repeat,
("" if node.max_repeat is None else str(node.max_repeat)),
)
return "(?:%s)%s%s" % (
transform(node.childnode),
repeat_sign,
("" if node.greedy else "?"),
)
else:
raise TypeError("Got %r" % (node,))
return transform(root_node)
@classmethod
def _transform_prefix(
cls, root_node: Node, create_group_func: Callable[[Variable], str]
) -> Iterable[str]:
"""
Yield all the regular expressions matching a prefix of the grammar
defined by the `Node` instance.
For each `Variable`, one regex pattern will be generated, with this
named group at the end. This is required because a regex engine will
terminate once a match is found. For autocompletion however, we need
the matches for all possible paths, so that we can provide completions
for each `Variable`.
- So, in the case of an `Any` (`A|B|C)', we generate a pattern for each
clause. This is one for `A`, one for `B` and one for `C`. Unless some
groups don't contain a `Variable`, then these can be merged together.
- In the case of a `NodeSequence` (`ABC`), we generate a pattern for
each prefix that ends with a variable, and one pattern for the whole
sequence. So, that's one for `A`, one for `AB` and one for `ABC`.
:param root_node: The :class:`Node` instance for which we generate the grammar.
:param create_group_func: A callable which takes a `Node` and returns the next
free name for this node.
"""
def contains_variable(node: Node) -> bool:
if isinstance(node, Regex):
return False
elif isinstance(node, Variable):
return True
elif isinstance(node, (Lookahead, Repeat)):
return contains_variable(node.childnode)
elif isinstance(node, (NodeSequence, AnyNode)):
return any(contains_variable(child) for child in node.children)
return False
def transform(node: Node) -> Iterable[str]:
# Generate separate pattern for all terms that contain variables
# within this OR. Terms that don't contain a variable can be merged
# together in one pattern.
if isinstance(node, AnyNode):
# If we have a definition like:
# (?P<name> .*) | (?P<city> .*)
# Then we want to be able to generate completions for both the
# name as well as the city. We do this by yielding two
# different regular expressions, because the engine won't
# follow multiple paths, if multiple are possible.
children_with_variable = []
children_without_variable = []
for c in node.children:
if contains_variable(c):
children_with_variable.append(c)
else:
children_without_variable.append(c)
for c in children_with_variable:
yield from transform(c)
# Merge options without variable together.
if children_without_variable:
yield "|".join(
r for c in children_without_variable for r in transform(c)
)
# For a sequence, generate a pattern for each prefix that ends with
# a variable + one pattern of the complete sequence.
# (This is because, for autocompletion, we match the text before
# the cursor, and completions are given for the variable that we
# match right before the cursor.)
elif isinstance(node, NodeSequence):
# For all components in the sequence, compute prefix patterns,
# as well as full patterns.
complete = [cls._transform(c, create_group_func) for c in node.children]
prefixes = [list(transform(c)) for c in node.children]
variable_nodes = [contains_variable(c) for c in node.children]
# If any child is contains a variable, we should yield a
# pattern up to that point, so that we are sure this will be
# matched.
for i in range(len(node.children)):
if variable_nodes[i]:
for c_str in prefixes[i]:
yield "".join(complete[:i]) + c_str
# If there are non-variable nodes, merge all the prefixes into
# one pattern. If the input is: "[part1] [part2] [part3]", then
# this gets compiled into:
# (complete1 + (complete2 + (complete3 | partial3) | partial2) | partial1 )
# For nodes that contain a variable, we skip the "|partial"
# part here, because thees are matched with the previous
# patterns.
if not all(variable_nodes):
result = []
# Start with complete patterns.
for i in range(len(node.children)):
result.append("(?:")
result.append(complete[i])
# Add prefix patterns.
for i in range(len(node.children) - 1, -1, -1):
if variable_nodes[i]:
# No need to yield a prefix for this one, we did
# the variable prefixes earlier.
result.append(")")
else:
result.append("|(?:")
# If this yields multiple, we should yield all combinations.
assert len(prefixes[i]) == 1
result.append(prefixes[i][0])
result.append("))")
yield "".join(result)
elif isinstance(node, Regex):
yield "(?:%s)?" % node.regex
elif isinstance(node, Lookahead):
if node.negative:
yield "(?!%s)" % cls._transform(node.childnode, create_group_func)
else:
# Not sure what the correct semantics are in this case.
# (Probably it's not worth implementing this.)
raise Exception("Positive lookahead not yet supported.")
elif isinstance(node, Variable):
# (Note that we should not append a '?' here. the 'transform'
# method will already recursively do that.)
for c_str in transform(node.childnode):
yield "(?P<%s>%s)" % (create_group_func(node), c_str)
elif isinstance(node, Repeat):
# If we have a repetition of 8 times. That would mean that the
# current input could have for instance 7 times a complete
# match, followed by a partial match.
prefix = cls._transform(node.childnode, create_group_func)
if node.max_repeat == 1:
yield from transform(node.childnode)
else:
for c_str in transform(node.childnode):
if node.max_repeat:
repeat_sign = "{,%i}" % (node.max_repeat - 1)
else:
repeat_sign = "*"
yield "(?:%s)%s%s%s" % (
prefix,
repeat_sign,
("" if node.greedy else "?"),
c_str,
)
else:
raise TypeError("Got %r" % node)
for r in transform(root_node):
yield "^(?:%s)$" % r
def match(self, string: str) -> Optional["Match"]:
"""
Match the string with the grammar.
Returns a :class:`Match` instance or `None` when the input doesn't match the grammar.
:param string: The input string.
"""
m = self._re.match(string)
if m:
return Match(
string, [(self._re, m)], self._group_names_to_nodes, self.unescape_funcs
)
return None
def match_prefix(self, string: str) -> Optional["Match"]:
"""
Do a partial match of the string with the grammar. The returned
:class:`Match` instance can contain multiple representations of the
match. This will never return `None`. If it doesn't match at all, the "trailing input"
part will capture all of the input.
:param string: The input string.
"""
# First try to match using `_re_prefix`. If nothing is found, use the patterns that
# also accept trailing characters.
for patterns in [self._re_prefix, self._re_prefix_with_trailing_input]:
matches = [(r, r.match(string)) for r in patterns]
matches2 = [(r, m) for r, m in matches if m]
if matches2 != []:
return Match(
string, matches2, self._group_names_to_nodes, self.unescape_funcs
)
return None
class Match:
"""
:param string: The input string.
:param re_matches: List of (compiled_re_pattern, re_match) tuples.
:param group_names_to_nodes: Dictionary mapping all the re group names to the matching Node instances.
"""
def __init__(
self,
string: str,
re_matches: List[Tuple[Pattern[str], RegexMatch[str]]],
group_names_to_nodes: Dict[str, str],
unescape_funcs: Dict[str, Callable[[str], str]],
):
self.string = string
self._re_matches = re_matches
self._group_names_to_nodes = group_names_to_nodes
self._unescape_funcs = unescape_funcs
def _nodes_to_regs(self) -> List[Tuple[str, Tuple[int, int]]]:
"""
Return a list of (varname, reg) tuples.
"""
def get_tuples() -> Iterable[Tuple[str, Tuple[int, int]]]:
for r, re_match in self._re_matches:
for group_name, group_index in r.groupindex.items():
if group_name != _INVALID_TRAILING_INPUT:
regs = cast(Tuple[Tuple[int, int], ...], re_match.regs)
reg = regs[group_index]
node = self._group_names_to_nodes[group_name]
yield (node, reg)
return list(get_tuples())
def _nodes_to_values(self) -> List[Tuple[str, str, Tuple[int, int]]]:
"""
Returns list of (Node, string_value) tuples.
"""
def is_none(sl: Tuple[int, int]) -> bool:
return sl[0] == -1 and sl[1] == -1
def get(sl: Tuple[int, int]) -> str:
return self.string[sl[0] : sl[1]]
return [
(varname, get(slice), slice)
for varname, slice in self._nodes_to_regs()
if not is_none(slice)
]
def _unescape(self, varname: str, value: str) -> str:
unwrapper = self._unescape_funcs.get(varname)
return unwrapper(value) if unwrapper else value
def variables(self) -> "Variables":
"""
Returns :class:`Variables` instance.
"""
return Variables(
[(k, self._unescape(k, v), sl) for k, v, sl in self._nodes_to_values()]
)
def trailing_input(self) -> Optional["MatchVariable"]:
"""
Get the `MatchVariable` instance, representing trailing input, if there is any.
"Trailing input" is input at the end that does not match the grammar anymore, but
when this is removed from the end of the input, the input would be a valid string.
"""
slices: List[Tuple[int, int]] = []
# Find all regex group for the name _INVALID_TRAILING_INPUT.
for r, re_match in self._re_matches:
for group_name, group_index in r.groupindex.items():
if group_name == _INVALID_TRAILING_INPUT:
slices.append(re_match.regs[group_index])
# Take the smallest part. (Smaller trailing text means that a larger input has
# been matched, so that is better.)
if slices:
slice = (max(i[0] for i in slices), max(i[1] for i in slices))
value = self.string[slice[0] : slice[1]]
return MatchVariable("<trailing_input>", value, slice)
return None
def end_nodes(self) -> Iterable["MatchVariable"]:
"""
Yields `MatchVariable` instances for all the nodes having their end
position at the end of the input string.
"""
for varname, reg in self._nodes_to_regs():
# If this part goes until the end of the input string.
if reg[1] == len(self.string):
value = self._unescape(varname, self.string[reg[0] : reg[1]])
yield MatchVariable(varname, value, (reg[0], reg[1]))
class Variables:
def __init__(self, tuples: List[Tuple[str, str, Tuple[int, int]]]) -> None:
#: List of (varname, value, slice) tuples.
self._tuples = tuples
def __repr__(self) -> str:
return "%s(%s)" % (
self.__class__.__name__,
", ".join("%s=%r" % (k, v) for k, v, _ in self._tuples),
)
def get(self, key: str, default: Optional[str] = None) -> Optional[str]:
items = self.getall(key)
return items[0] if items else default
def getall(self, key: str) -> List[str]:
return [v for k, v, _ in self._tuples if k == key]
def __getitem__(self, key: str) -> Optional[str]:
return self.get(key)
def __iter__(self) -> Iterator["MatchVariable"]:
"""
Yield `MatchVariable` instances.
"""
for varname, value, slice in self._tuples:
yield MatchVariable(varname, value, slice)
class MatchVariable:
"""
Represents a match of a variable in the grammar.
:param varname: (string) Name of the variable.
:param value: (string) Value of this variable.
:param slice: (start, stop) tuple, indicating the position of this variable
in the input string.
"""
def __init__(self, varname: str, value: str, slice: Tuple[int, int]) -> None:
self.varname = varname
self.value = value
self.slice = slice
self.start = self.slice[0]
self.stop = self.slice[1]
def __repr__(self) -> str:
return "%s(%r, %r)" % (self.__class__.__name__, self.varname, self.value)
def compile(
expression: str,
escape_funcs: Optional[EscapeFuncDict] = None,
unescape_funcs: Optional[EscapeFuncDict] = None,
) -> _CompiledGrammar:
"""
Compile grammar (given as regex string), returning a `CompiledGrammar`
instance.
"""
return _compile_from_parse_tree(
parse_regex(tokenize_regex(expression)),
escape_funcs=escape_funcs,
unescape_funcs=unescape_funcs,
)
def _compile_from_parse_tree(
root_node: Node,
escape_funcs: Optional[EscapeFuncDict] = None,
unescape_funcs: Optional[EscapeFuncDict] = None,
) -> _CompiledGrammar:
"""
Compile grammar (given as parse tree), returning a `CompiledGrammar`
instance.
"""
return _CompiledGrammar(
root_node, escape_funcs=escape_funcs, unescape_funcs=unescape_funcs
)

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"""
Completer for a regular grammar.
"""
from typing import Dict, Iterable, List
from prompt_toolkit.completion import CompleteEvent, Completer, Completion
from prompt_toolkit.document import Document
from .compiler import Match, _CompiledGrammar
__all__ = [
"GrammarCompleter",
]
class GrammarCompleter(Completer):
"""
Completer which can be used for autocompletion according to variables in
the grammar. Each variable can have a different autocompleter.
:param compiled_grammar: `GrammarCompleter` instance.
:param completers: `dict` mapping variable names of the grammar to the
`Completer` instances to be used for each variable.
"""
def __init__(
self, compiled_grammar: _CompiledGrammar, completers: Dict[str, Completer]
) -> None:
self.compiled_grammar = compiled_grammar
self.completers = completers
def get_completions(
self, document: Document, complete_event: CompleteEvent
) -> Iterable[Completion]:
m = self.compiled_grammar.match_prefix(document.text_before_cursor)
if m:
completions = self._remove_duplicates(
self._get_completions_for_match(m, complete_event)
)
for c in completions:
yield c
def _get_completions_for_match(
self, match: Match, complete_event: CompleteEvent
) -> Iterable[Completion]:
"""
Yield all the possible completions for this input string.
(The completer assumes that the cursor position was at the end of the
input string.)
"""
for match_variable in match.end_nodes():
varname = match_variable.varname
start = match_variable.start
completer = self.completers.get(varname)
if completer:
text = match_variable.value
# Unwrap text.
unwrapped_text = self.compiled_grammar.unescape(varname, text)
# Create a document, for the completions API (text/cursor_position)
document = Document(unwrapped_text, len(unwrapped_text))
# Call completer
for completion in completer.get_completions(document, complete_event):
new_text = (
unwrapped_text[: len(text) + completion.start_position]
+ completion.text
)
# Wrap again.
yield Completion(
text=self.compiled_grammar.escape(varname, new_text),
start_position=start - len(match.string),
display=completion.display,
display_meta=completion.display_meta,
)
def _remove_duplicates(self, items: Iterable[Completion]) -> List[Completion]:
"""
Remove duplicates, while keeping the order.
(Sometimes we have duplicates, because the there several matches of the
same grammar, each yielding similar completions.)
"""
result: List[Completion] = []
for i in items:
if i not in result:
result.append(i)
return result

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"""
`GrammarLexer` is compatible with other lexers and can be used to highlight
the input using a regular grammar with annotations.
"""
from typing import Callable, Dict, Optional
from prompt_toolkit.document import Document
from prompt_toolkit.formatted_text.base import StyleAndTextTuples
from prompt_toolkit.formatted_text.utils import split_lines
from prompt_toolkit.lexers import Lexer
from .compiler import _CompiledGrammar
__all__ = [
"GrammarLexer",
]
class GrammarLexer(Lexer):
"""
Lexer which can be used for highlighting of fragments according to variables in the grammar.
(It does not actual lexing of the string, but it exposes an API, compatible
with the Pygments lexer class.)
:param compiled_grammar: Grammar as returned by the `compile()` function.
:param lexers: Dictionary mapping variable names of the regular grammar to
the lexers that should be used for this part. (This can
call other lexers recursively.) If you wish a part of the
grammar to just get one fragment, use a
`prompt_toolkit.lexers.SimpleLexer`.
"""
def __init__(
self,
compiled_grammar: _CompiledGrammar,
default_style: str = "",
lexers: Optional[Dict[str, Lexer]] = None,
) -> None:
self.compiled_grammar = compiled_grammar
self.default_style = default_style
self.lexers = lexers or {}
def _get_text_fragments(self, text: str) -> StyleAndTextTuples:
m = self.compiled_grammar.match_prefix(text)
if m:
characters: StyleAndTextTuples = [(self.default_style, c) for c in text]
for v in m.variables():
# If we have a `Lexer` instance for this part of the input.
# Tokenize recursively and apply tokens.
lexer = self.lexers.get(v.varname)
if lexer:
document = Document(text[v.start : v.stop])
lexer_tokens_for_line = lexer.lex_document(document)
text_fragments: StyleAndTextTuples = []
for i in range(len(document.lines)):
text_fragments.extend(lexer_tokens_for_line(i))
text_fragments.append(("", "\n"))
if text_fragments:
text_fragments.pop()
i = v.start
for t, s, *_ in text_fragments:
for c in s:
if characters[i][0] == self.default_style:
characters[i] = (t, characters[i][1])
i += 1
# Highlight trailing input.
trailing_input = m.trailing_input()
if trailing_input:
for i in range(trailing_input.start, trailing_input.stop):
characters[i] = ("class:trailing-input", characters[i][1])
return characters
else:
return [("", text)]
def lex_document(self, document: Document) -> Callable[[int], StyleAndTextTuples]:
lines = list(split_lines(self._get_text_fragments(document.text)))
def get_line(lineno: int) -> StyleAndTextTuples:
try:
return lines[lineno]
except IndexError:
return []
return get_line

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"""
Parser for parsing a regular expression.
Take a string representing a regular expression and return the root node of its
parse tree.
usage::
root_node = parse_regex('(hello|world)')
Remarks:
- The regex parser processes multiline, it ignores all whitespace and supports
multiple named groups with the same name and #-style comments.
Limitations:
- Lookahead is not supported.
"""
import re
from typing import List, Optional
__all__ = [
"Repeat",
"Variable",
"Regex",
"Lookahead",
"tokenize_regex",
"parse_regex",
]
class Node:
"""
Base class for all the grammar nodes.
(You don't initialize this one.)
"""
def __add__(self, other_node: "Node") -> "NodeSequence":
return NodeSequence([self, other_node])
def __or__(self, other_node: "Node") -> "AnyNode":
return AnyNode([self, other_node])
class AnyNode(Node):
"""
Union operation (OR operation) between several grammars. You don't
initialize this yourself, but it's a result of a "Grammar1 | Grammar2"
operation.
"""
def __init__(self, children: List[Node]) -> None:
self.children = children
def __or__(self, other_node: Node) -> "AnyNode":
return AnyNode(self.children + [other_node])
def __repr__(self) -> str:
return "%s(%r)" % (self.__class__.__name__, self.children)
class NodeSequence(Node):
"""
Concatenation operation of several grammars. You don't initialize this
yourself, but it's a result of a "Grammar1 + Grammar2" operation.
"""
def __init__(self, children: List[Node]) -> None:
self.children = children
def __add__(self, other_node: Node) -> "NodeSequence":
return NodeSequence(self.children + [other_node])
def __repr__(self) -> str:
return "%s(%r)" % (self.__class__.__name__, self.children)
class Regex(Node):
"""
Regular expression.
"""
def __init__(self, regex: str) -> None:
re.compile(regex) # Validate
self.regex = regex
def __repr__(self) -> str:
return "%s(/%s/)" % (self.__class__.__name__, self.regex)
class Lookahead(Node):
"""
Lookahead expression.
"""
def __init__(self, childnode: Node, negative: bool = False) -> None:
self.childnode = childnode
self.negative = negative
def __repr__(self) -> str:
return "%s(%r)" % (self.__class__.__name__, self.childnode)
class Variable(Node):
"""
Mark a variable in the regular grammar. This will be translated into a
named group. Each variable can have his own completer, validator, etc..
:param childnode: The grammar which is wrapped inside this variable.
:param varname: String.
"""
def __init__(self, childnode: Node, varname: str = "") -> None:
self.childnode = childnode
self.varname = varname
def __repr__(self) -> str:
return "%s(childnode=%r, varname=%r)" % (
self.__class__.__name__,
self.childnode,
self.varname,
)
class Repeat(Node):
def __init__(
self,
childnode: Node,
min_repeat: int = 0,
max_repeat: Optional[int] = None,
greedy: bool = True,
) -> None:
self.childnode = childnode
self.min_repeat = min_repeat
self.max_repeat = max_repeat
self.greedy = greedy
def __repr__(self) -> str:
return "%s(childnode=%r)" % (self.__class__.__name__, self.childnode)
def tokenize_regex(input: str) -> List[str]:
"""
Takes a string, representing a regular expression as input, and tokenizes
it.
:param input: string, representing a regular expression.
:returns: List of tokens.
"""
# Regular expression for tokenizing other regular expressions.
p = re.compile(
r"""^(
\(\?P\<[a-zA-Z0-9_-]+\> | # Start of named group.
\(\?#[^)]*\) | # Comment
\(\?= | # Start of lookahead assertion
\(\?! | # Start of negative lookahead assertion
\(\?<= | # If preceded by.
\(\?< | # If not preceded by.
\(?: | # Start of group. (non capturing.)
\( | # Start of group.
\(?[iLmsux] | # Flags.
\(?P=[a-zA-Z]+\) | # Back reference to named group
\) | # End of group.
\{[^{}]*\} | # Repetition
\*\? | \+\? | \?\?\ | # Non greedy repetition.
\* | \+ | \? | # Repetition
\#.*\n | # Comment
\\. |
# Character group.
\[
( [^\]\\] | \\.)*
\] |
[^(){}] |
.
)""",
re.VERBOSE,
)
tokens = []
while input:
m = p.match(input)
if m:
token, input = input[: m.end()], input[m.end() :]
if not token.isspace():
tokens.append(token)
else:
raise Exception("Could not tokenize input regex.")
return tokens
def parse_regex(regex_tokens: List[str]) -> Node:
"""
Takes a list of tokens from the tokenizer, and returns a parse tree.
"""
# We add a closing brace because that represents the final pop of the stack.
tokens: List[str] = [")"] + regex_tokens[::-1]
def wrap(lst: List[Node]) -> Node:
""" Turn list into sequence when it contains several items. """
if len(lst) == 1:
return lst[0]
else:
return NodeSequence(lst)
def _parse() -> Node:
or_list: List[List[Node]] = []
result: List[Node] = []
def wrapped_result() -> Node:
if or_list == []:
return wrap(result)
else:
or_list.append(result)
return AnyNode([wrap(i) for i in or_list])
while tokens:
t = tokens.pop()
if t.startswith("(?P<"):
variable = Variable(_parse(), varname=t[4:-1])
result.append(variable)
elif t in ("*", "*?"):
greedy = t == "*"
result[-1] = Repeat(result[-1], greedy=greedy)
elif t in ("+", "+?"):
greedy = t == "+"
result[-1] = Repeat(result[-1], min_repeat=1, greedy=greedy)
elif t in ("?", "??"):
if result == []:
raise Exception("Nothing to repeat." + repr(tokens))
else:
greedy = t == "?"
result[-1] = Repeat(
result[-1], min_repeat=0, max_repeat=1, greedy=greedy
)
elif t == "|":
or_list.append(result)
result = []
elif t in ("(", "(?:"):
result.append(_parse())
elif t == "(?!":
result.append(Lookahead(_parse(), negative=True))
elif t == "(?=":
result.append(Lookahead(_parse(), negative=False))
elif t == ")":
return wrapped_result()
elif t.startswith("#"):
pass
elif t.startswith("{"):
# TODO: implement!
raise Exception("{}-style repetition not yet supported".format(t))
elif t.startswith("(?"):
raise Exception("%r not supported" % t)
elif t.isspace():
pass
else:
result.append(Regex(t))
raise Exception("Expecting ')' token")
result = _parse()
if len(tokens) != 0:
raise Exception("Unmatched parentheses.")
else:
return result

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"""
Validator for a regular language.
"""
from typing import Dict
from prompt_toolkit.document import Document
from prompt_toolkit.validation import ValidationError, Validator
from .compiler import _CompiledGrammar
__all__ = [
"GrammarValidator",
]
class GrammarValidator(Validator):
"""
Validator which can be used for validation according to variables in
the grammar. Each variable can have its own validator.
:param compiled_grammar: `GrammarCompleter` instance.
:param validators: `dict` mapping variable names of the grammar to the
`Validator` instances to be used for each variable.
"""
def __init__(
self, compiled_grammar: _CompiledGrammar, validators: Dict[str, Validator]
) -> None:
self.compiled_grammar = compiled_grammar
self.validators = validators
def validate(self, document: Document) -> None:
# Parse input document.
# We use `match`, not `match_prefix`, because for validation, we want
# the actual, unambiguous interpretation of the input.
m = self.compiled_grammar.match(document.text)
if m:
for v in m.variables():
validator = self.validators.get(v.varname)
if validator:
# Unescape text.
unwrapped_text = self.compiled_grammar.unescape(v.varname, v.value)
# Create a document, for the completions API (text/cursor_position)
inner_document = Document(unwrapped_text, len(unwrapped_text))
try:
validator.validate(inner_document)
except ValidationError as e:
raise ValidationError(
cursor_position=v.start + e.cursor_position,
message=e.message,
) from e
else:
raise ValidationError(
cursor_position=len(document.text), message="Invalid command"
)

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from .server import PromptToolkitSSHServer, PromptToolkitSSHSession
__all__ = [
"PromptToolkitSSHSession",
"PromptToolkitSSHServer",
]

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"""
Utility for running a prompt_toolkit application in an asyncssh server.
"""
import asyncio
import traceback
from typing import Awaitable, Callable, Optional, TextIO, cast
import asyncssh
from prompt_toolkit.application.current import AppSession, create_app_session
from prompt_toolkit.data_structures import Size
from prompt_toolkit.input import create_pipe_input
from prompt_toolkit.output.vt100 import Vt100_Output
__all__ = ["PromptToolkitSSHSession", "PromptToolkitSSHServer"]
class PromptToolkitSSHSession(asyncssh.SSHServerSession):
def __init__(
self, interact: Callable[["PromptToolkitSSHSession"], Awaitable[None]]
) -> None:
self.interact = interact
self.interact_task: Optional[asyncio.Task[None]] = None
self._chan = None
self.app_session: Optional[AppSession] = None
# PipInput object, for sending input in the CLI.
# (This is something that we can use in the prompt_toolkit event loop,
# but still write date in manually.)
self._input = create_pipe_input()
self._output = None
# Output object. Don't render to the real stdout, but write everything
# in the SSH channel.
class Stdout:
def write(s, data):
try:
if self._chan is not None:
self._chan.write(data.replace("\n", "\r\n"))
except BrokenPipeError:
pass # Channel not open for sending.
def isatty(s) -> bool:
return True
def flush(s):
pass
@property
def encoding(s):
return self._chan._orig_chan.get_encoding()[0]
self.stdout = cast(TextIO, Stdout())
def _get_size(self) -> Size:
"""
Callable that returns the current `Size`, required by Vt100_Output.
"""
if self._chan is None:
return Size(rows=20, columns=79)
else:
width, height, pixwidth, pixheight = self._chan.get_terminal_size()
return Size(rows=height, columns=width)
def connection_made(self, chan):
self._chan = chan
def shell_requested(self) -> bool:
return True
def session_started(self) -> None:
self.interact_task = asyncio.get_event_loop().create_task(self._interact())
async def _interact(self) -> None:
if self._chan is None:
# Should not happen.
raise Exception("`_interact` called before `connection_made`.")
if hasattr(self._chan, "set_line_mode") and self._chan._editor is not None:
# Disable the line editing provided by asyncssh. Prompt_toolkit
# provides the line editing.
self._chan.set_line_mode(False)
term = self._chan.get_terminal_type()
self._output = Vt100_Output(
self.stdout, self._get_size, term=term, write_binary=False
)
with create_app_session(input=self._input, output=self._output) as session:
self.app_session = session
try:
await self.interact(self)
except BaseException:
traceback.print_exc()
finally:
# Close the connection.
self._chan.close()
def terminal_size_changed(self, width, height, pixwidth, pixheight):
# Send resize event to the current application.
if self.app_session and self.app_session.app:
self.app_session.app._on_resize()
def data_received(self, data, datatype):
self._input.send_text(data)
class PromptToolkitSSHServer(asyncssh.SSHServer):
"""
Run a prompt_toolkit application over an asyncssh server.
This takes one argument, an `interact` function, which is called for each
connection. This should be an asynchronous function that runs the
prompt_toolkit applications. This function runs in an `AppSession`, which
means that we can have multiple UI interactions concurrently.
Example usage:
.. code:: python
async def interact(ssh_session: PromptToolkitSSHSession) -> None:
await yes_no_dialog("my title", "my text").run_async()
prompt_session = PromptSession()
text = await prompt_session.prompt_async("Type something: ")
print_formatted_text('You said: ', text)
server = PromptToolkitSSHServer(interact=interact)
loop = get_event_loop()
loop.run_until_complete(
asyncssh.create_server(
lambda: MySSHServer(interact),
"",
port,
server_host_keys=["/etc/ssh/..."],
)
)
loop.run_forever()
"""
def __init__(
self, interact: Callable[[PromptToolkitSSHSession], Awaitable[None]]
) -> None:
self.interact = interact
def begin_auth(self, username):
# No authentication.
return False
def session_requested(self) -> PromptToolkitSSHSession:
return PromptToolkitSSHSession(self.interact)

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from .server import TelnetServer
__all__ = [
"TelnetServer",
]

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"""
Python logger for the telnet server.
"""
import logging
logger = logging.getLogger(__package__)
__all__ = [
"logger",
]

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"""
Parser for the Telnet protocol. (Not a complete implementation of the telnet
specification, but sufficient for a command line interface.)
Inspired by `Twisted.conch.telnet`.
"""
import struct
from typing import Callable, Generator
from .log import logger
__all__ = [
"TelnetProtocolParser",
]
def int2byte(number: int) -> bytes:
return bytes((number,))
# Telnet constants.
NOP = int2byte(0)
SGA = int2byte(3)
IAC = int2byte(255)
DO = int2byte(253)
DONT = int2byte(254)
LINEMODE = int2byte(34)
SB = int2byte(250)
WILL = int2byte(251)
WONT = int2byte(252)
MODE = int2byte(1)
SE = int2byte(240)
ECHO = int2byte(1)
NAWS = int2byte(31)
LINEMODE = int2byte(34)
SUPPRESS_GO_AHEAD = int2byte(3)
TTYPE = int2byte(24)
SEND = int2byte(1)
IS = int2byte(0)
DM = int2byte(242)
BRK = int2byte(243)
IP = int2byte(244)
AO = int2byte(245)
AYT = int2byte(246)
EC = int2byte(247)
EL = int2byte(248)
GA = int2byte(249)
class TelnetProtocolParser:
"""
Parser for the Telnet protocol.
Usage::
def data_received(data):
print(data)
def size_received(rows, columns):
print(rows, columns)
p = TelnetProtocolParser(data_received, size_received)
p.feed(binary_data)
"""
def __init__(
self,
data_received_callback: Callable[[bytes], None],
size_received_callback: Callable[[int, int], None],
ttype_received_callback: Callable[[str], None],
) -> None:
self.data_received_callback = data_received_callback
self.size_received_callback = size_received_callback
self.ttype_received_callback = ttype_received_callback
self._parser = self._parse_coroutine()
self._parser.send(None) # type: ignore
def received_data(self, data: bytes) -> None:
self.data_received_callback(data)
def do_received(self, data: bytes) -> None:
""" Received telnet DO command. """
logger.info("DO %r", data)
def dont_received(self, data: bytes) -> None:
""" Received telnet DONT command. """
logger.info("DONT %r", data)
def will_received(self, data: bytes) -> None:
""" Received telnet WILL command. """
logger.info("WILL %r", data)
def wont_received(self, data: bytes) -> None:
""" Received telnet WONT command. """
logger.info("WONT %r", data)
def command_received(self, command: bytes, data: bytes) -> None:
if command == DO:
self.do_received(data)
elif command == DONT:
self.dont_received(data)
elif command == WILL:
self.will_received(data)
elif command == WONT:
self.wont_received(data)
else:
logger.info("command received %r %r", command, data)
def naws(self, data: bytes) -> None:
"""
Received NAWS. (Window dimensions.)
"""
if len(data) == 4:
# NOTE: the first parameter of struct.unpack should be
# a 'str' object. Both on Py2/py3. This crashes on OSX
# otherwise.
columns, rows = struct.unpack(str("!HH"), data)
self.size_received_callback(rows, columns)
else:
logger.warning("Wrong number of NAWS bytes")
def ttype(self, data: bytes) -> None:
"""
Received terminal type.
"""
subcmd, data = data[0:1], data[1:]
if subcmd == IS:
ttype = data.decode("ascii")
self.ttype_received_callback(ttype)
else:
logger.warning("Received a non-IS terminal type Subnegotiation")
def negotiate(self, data: bytes) -> None:
"""
Got negotiate data.
"""
command, payload = data[0:1], data[1:]
if command == NAWS:
self.naws(payload)
elif command == TTYPE:
self.ttype(payload)
else:
logger.info("Negotiate (%r got bytes)", len(data))
def _parse_coroutine(self) -> Generator[None, bytes, None]:
"""
Parser state machine.
Every 'yield' expression returns the next byte.
"""
while True:
d = yield
if d == int2byte(0):
pass # NOP
# Go to state escaped.
elif d == IAC:
d2 = yield
if d2 == IAC:
self.received_data(d2)
# Handle simple commands.
elif d2 in (NOP, DM, BRK, IP, AO, AYT, EC, EL, GA):
self.command_received(d2, b"")
# Handle IAC-[DO/DONT/WILL/WONT] commands.
elif d2 in (DO, DONT, WILL, WONT):
d3 = yield
self.command_received(d2, d3)
# Subnegotiation
elif d2 == SB:
# Consume everything until next IAC-SE
data = []
while True:
d3 = yield
if d3 == IAC:
d4 = yield
if d4 == SE:
break
else:
data.append(d4)
else:
data.append(d3)
self.negotiate(b"".join(data))
else:
self.received_data(d)
def feed(self, data: bytes) -> None:
"""
Feed data to the parser.
"""
for b in data:
self._parser.send(int2byte(b))

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"""
Telnet server.
"""
import asyncio
import contextvars # Requires Python3.7!
import socket
from asyncio import get_event_loop
from typing import Awaitable, Callable, List, Optional, Set, TextIO, Tuple, cast
from prompt_toolkit.application.current import create_app_session, get_app
from prompt_toolkit.application.run_in_terminal import run_in_terminal
from prompt_toolkit.data_structures import Size
from prompt_toolkit.formatted_text import AnyFormattedText, to_formatted_text
from prompt_toolkit.input import create_pipe_input
from prompt_toolkit.output.vt100 import Vt100_Output
from prompt_toolkit.renderer import print_formatted_text as print_formatted_text
from prompt_toolkit.styles import BaseStyle, DummyStyle
from .log import logger
from .protocol import (
DO,
ECHO,
IAC,
LINEMODE,
MODE,
NAWS,
SB,
SE,
SEND,
SUPPRESS_GO_AHEAD,
TTYPE,
WILL,
TelnetProtocolParser,
)
__all__ = [
"TelnetServer",
]
def int2byte(number: int) -> bytes:
return bytes((number,))
def _initialize_telnet(connection: socket.socket) -> None:
logger.info("Initializing telnet connection")
# Iac Do Linemode
connection.send(IAC + DO + LINEMODE)
# Suppress Go Ahead. (This seems important for Putty to do correct echoing.)
# This will allow bi-directional operation.
connection.send(IAC + WILL + SUPPRESS_GO_AHEAD)
# Iac sb
connection.send(IAC + SB + LINEMODE + MODE + int2byte(0) + IAC + SE)
# IAC Will Echo
connection.send(IAC + WILL + ECHO)
# Negotiate window size
connection.send(IAC + DO + NAWS)
# Negotiate terminal type
# Assume the client will accept the negociation with `IAC + WILL + TTYPE`
connection.send(IAC + DO + TTYPE)
# We can then select the first terminal type supported by the client,
# which is generally the best type the client supports
# The client should reply with a `IAC + SB + TTYPE + IS + ttype + IAC + SE`
connection.send(IAC + SB + TTYPE + SEND + IAC + SE)
class _ConnectionStdout:
"""
Wrapper around socket which provides `write` and `flush` methods for the
Vt100_Output output.
"""
def __init__(self, connection: socket.socket, encoding: str) -> None:
self._encoding = encoding
self._connection = connection
self._errors = "strict"
self._buffer: List[bytes] = []
def write(self, data: str) -> None:
data = data.replace("\n", "\r\n")
self._buffer.append(data.encode(self._encoding, errors=self._errors))
self.flush()
def isatty(self) -> bool:
return True
def flush(self) -> None:
try:
self._connection.send(b"".join(self._buffer))
except socket.error as e:
logger.warning("Couldn't send data over socket: %s" % e)
self._buffer = []
@property
def encoding(self) -> str:
return self._encoding
@property
def errors(self) -> str:
return self._errors
class TelnetConnection:
"""
Class that represents one Telnet connection.
"""
def __init__(
self,
conn: socket.socket,
addr: Tuple[str, int],
interact: Callable[["TelnetConnection"], Awaitable[None]],
server: "TelnetServer",
encoding: str,
style: Optional[BaseStyle],
) -> None:
self.conn = conn
self.addr = addr
self.interact = interact
self.server = server
self.encoding = encoding
self.style = style
self._closed = False
self._ready = asyncio.Event()
self.vt100_output = None
# Create "Output" object.
self.size = Size(rows=40, columns=79)
# Initialize.
_initialize_telnet(conn)
# Create input.
self.vt100_input = create_pipe_input()
# Create output.
def get_size() -> Size:
return self.size
self.stdout = cast(TextIO, _ConnectionStdout(conn, encoding=encoding))
def data_received(data: bytes) -> None:
""" TelnetProtocolParser 'data_received' callback """
self.vt100_input.send_bytes(data)
def size_received(rows: int, columns: int) -> None:
""" TelnetProtocolParser 'size_received' callback """
self.size = Size(rows=rows, columns=columns)
if self.vt100_output is not None:
get_app()._on_resize()
def ttype_received(ttype: str) -> None:
""" TelnetProtocolParser 'ttype_received' callback """
self.vt100_output = Vt100_Output(
self.stdout, get_size, term=ttype, write_binary=False
)
self._ready.set()
self.parser = TelnetProtocolParser(data_received, size_received, ttype_received)
self.context: Optional[contextvars.Context] = None
async def run_application(self) -> None:
"""
Run application.
"""
def handle_incoming_data() -> None:
data = self.conn.recv(1024)
if data:
self.feed(data)
else:
# Connection closed by client.
logger.info("Connection closed by client. %r %r" % self.addr)
self.close()
# Add reader.
loop = get_event_loop()
loop.add_reader(self.conn, handle_incoming_data)
try:
# Wait for v100_output to be properly instantiated
await self._ready.wait()
with create_app_session(input=self.vt100_input, output=self.vt100_output):
self.context = contextvars.copy_context()
await self.interact(self)
except Exception as e:
print("Got %s" % type(e).__name__, e)
import traceback
traceback.print_exc()
raise
finally:
self.close()
def feed(self, data: bytes) -> None:
"""
Handler for incoming data. (Called by TelnetServer.)
"""
self.parser.feed(data)
def close(self) -> None:
"""
Closed by client.
"""
if not self._closed:
self._closed = True
self.vt100_input.close()
get_event_loop().remove_reader(self.conn)
self.conn.close()
def send(self, formatted_text: AnyFormattedText) -> None:
"""
Send text to the client.
"""
if self.vt100_output is None:
return
formatted_text = to_formatted_text(formatted_text)
print_formatted_text(
self.vt100_output, formatted_text, self.style or DummyStyle()
)
def send_above_prompt(self, formatted_text: AnyFormattedText) -> None:
"""
Send text to the client.
This is asynchronous, returns a `Future`.
"""
formatted_text = to_formatted_text(formatted_text)
return self._run_in_terminal(lambda: self.send(formatted_text))
def _run_in_terminal(self, func: Callable[[], None]) -> None:
# Make sure that when an application was active for this connection,
# that we print the text above the application.
if self.context:
self.context.run(run_in_terminal, func)
else:
raise RuntimeError("Called _run_in_terminal outside `run_application`.")
def erase_screen(self) -> None:
"""
Erase the screen and move the cursor to the top.
"""
if self.vt100_output is None:
return
self.vt100_output.erase_screen()
self.vt100_output.cursor_goto(0, 0)
self.vt100_output.flush()
async def _dummy_interact(connection: TelnetConnection) -> None:
pass
class TelnetServer:
"""
Telnet server implementation.
"""
def __init__(
self,
host: str = "127.0.0.1",
port: int = 23,
interact: Callable[[TelnetConnection], Awaitable[None]] = _dummy_interact,
encoding: str = "utf-8",
style: Optional[BaseStyle] = None,
) -> None:
self.host = host
self.port = port
self.interact = interact
self.encoding = encoding
self.style = style
self._application_tasks: List[asyncio.Task] = []
self.connections: Set[TelnetConnection] = set()
self._listen_socket: Optional[socket.socket] = None
@classmethod
def _create_socket(cls, host: str, port: int) -> socket.socket:
# Create and bind socket
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
s.bind((host, port))
s.listen(4)
return s
def start(self) -> None:
"""
Start the telnet server.
Don't forget to call `loop.run_forever()` after doing this.
"""
self._listen_socket = self._create_socket(self.host, self.port)
logger.info(
"Listening for telnet connections on %s port %r", self.host, self.port
)
get_event_loop().add_reader(self._listen_socket, self._accept)
async def stop(self) -> None:
if self._listen_socket:
get_event_loop().remove_reader(self._listen_socket)
self._listen_socket.close()
# Wait for all applications to finish.
for t in self._application_tasks:
t.cancel()
for t in self._application_tasks:
await t
def _accept(self) -> None:
"""
Accept new incoming connection.
"""
if self._listen_socket is None:
return # Should not happen. `_accept` is called after `start`.
conn, addr = self._listen_socket.accept()
logger.info("New connection %r %r", *addr)
connection = TelnetConnection(
conn, addr, self.interact, self, encoding=self.encoding, style=self.style
)
self.connections.add(connection)
# Run application for this connection.
async def run() -> None:
logger.info("Starting interaction %r %r", *addr)
try:
await connection.run_application()
except Exception as e:
print(e)
finally:
self.connections.remove(connection)
self._application_tasks.remove(task)
logger.info("Stopping interaction %r %r", *addr)
task = get_event_loop().create_task(run())
self._application_tasks.append(task)