dynamic attributes, descriptors and first concurrency examples

Author: ramalho

concurrency/charfinder.py

@@ -0,0 +1,201 @@
+#!/usr/bin/env python3
+
+"""
+Unicode character finder utility:
+find characters based on words in their official names.
+
+This can be used from the command line, just pass words as arguments.
+
+Here is the ``main`` function which makes it happen::
+
+    >>> main('rook')  # doctest: +NORMALIZE_WHITESPACE
+    U+2656  ♖  WHITE CHESS ROOK
+    U+265C  ♜  BLACK CHESS ROOK
+    (2 matches for 'rook')
+    >>> main('rook', 'black')  # doctest: +NORMALIZE_WHITESPACE
+    U+265C  ♜  BLACK CHESS ROOK
+    (1 match for 'rook black')
+    >>> main('white bishop')  # doctest: +NORMALIZE_WHITESPACE
+    U+2657  ♗   WHITE CHESS BISHOP
+    (1 match for 'white bishop')
+    >>> main("jabberwocky's vest")
+    (No match for "jabberwocky's vest")
+
+
+For exploring words that occur in the character names, there is the
+``word_report`` function::
+
+    >>> index = UnicodeNameIndex(sample_chars)
+    >>> index.word_report()
+        3 SIGN
+        2 A
+        2 EURO
+        2 LATIN
+        2 LETTER
+        1 CAPITAL
+        1 CURRENCY
+        1 DOLLAR
+        1 SMALL
+    >>> index = UnicodeNameIndex()
+    >>> index.word_report(7)
+    13196 SYLLABLE
+    11735 HANGUL
+     7616 LETTER
+     2232 WITH
+     2180 SIGN
+     2122 SMALL
+     1709 CAPITAL
+
+Note: character names starting with the string ``'CJK UNIFIED IDEOGRAPH'``
+are not indexed. Those names are not useful for searching, since the only
+unique part of the name is the codepoint in hexadecimal.
+
+"""
+
+import sys
+import re
+import unicodedata
+import pickle
+import warnings
+
+RE_WORD = re.compile('\w+')
+
+INDEX_NAME = 'charfinder_index.pickle'
+MINIMUM_SAVE_LEN = 10000
+CJK_PREFIX = 'CJK UNIFIED IDEOGRAPH'
+
+sample_chars = [
+    '$',  # DOLLAR SIGN
+    'A',  # LATIN CAPITAL LETTER A
+    'a',  # LATIN SMALL LETTER A
+    '\u20a0',  # EURO-CURRENCY SIGN
+    '\u20ac',  # EURO SIGN
+]
+
+
+def tokenize(text):
+    """return iterable of uppercased words"""
+    for match in RE_WORD.finditer(text):
+        yield match.group().upper()
+
+
+class UnicodeNameIndex:
+
+    def __init__(self, chars=None):
+        self.load(chars)
+
+    def load(self, chars=None):
+        self.index = None
+        if chars is None:
+            try:
+                with open(INDEX_NAME, 'rb') as fp:
+                    self.index = pickle.load(fp)
+            except OSError:
+                pass
+        if self.index is None:
+            self.build_index(chars)
+        if len(self.index) > MINIMUM_SAVE_LEN:
+            try:
+                self.save()
+            except OSError as exc:
+                warnings.warn('Could not save {!r}: {}'
+                              .format(INDEX_NAME, exc))
+
+    def save(self):
+        with open(INDEX_NAME, 'wb') as fp:
+            pickle.dump(self.index, fp)
+
+    def build_index(self, chars=None):
+        if chars is None:
+            chars = (chr(i) for i in range(32, sys.maxunicode))
+        index = {}
+        for char in chars:
+            try:
+                name = unicodedata.name(char)
+            except ValueError:
+                continue
+            if name.startswith(CJK_PREFIX):
+                name = CJK_PREFIX
+            code = ord(char)
+
+            for word in tokenize(name):
+                index.setdefault(word, set()).add(code)
+
+        self.index = index
+
+    def __len__(self):
+        return len(self.index)
+
+    def word_rank(self, top=None):
+        res = [(len(self.index[key]), key) for key in self.index]
+        res.sort(key=lambda item: (-item[0], item[1]))
+        if top is not None:
+            res = res[:top]
+        return res
+
+    def word_report(self, top=None):
+        """
+        Generate report with most frequent words
+
+            >>> index = UnicodeNameIndex()
+            >>> index.word_report(7)
+            13196 SYLLABLE
+            11735 HANGUL
+             7616 LETTER
+             2232 WITH
+             2180 SIGN
+             2122 SMALL
+             1709 CAPITAL
+        """
+        for postings, key in self.word_rank(top):
+            print('{:5} {}'.format(postings, key))
+
+    def find_codes(self, query):
+        result_sets = []
+        for word in tokenize(query):
+            if word in self.index:
+                result_sets.append(self.index[word])
+            else:  # shorcut: no such word
+                result_sets = []
+                break
+        if result_sets:
+            result = result_sets[0]
+            result.intersection_update(*result_sets[1:])
+        else:
+            result = set()
+        if len(result) > 0:
+            for code in sorted(result):
+                yield code
+
+    def describe(self, code):
+        code_str = 'U+{:04X}'.format(code)
+        char = chr(code)
+        name = unicodedata.name(char)
+        return '{:7}\t{}\t{}'.format(code_str, char, name)
+
+    def find_descriptions(self, query):
+        for code in self.find_codes(query):
+            yield self.describe(code)
+
+
+def main(*args):
+    index = UnicodeNameIndex()
+    query = ' '.join(args)
+    counter = 0
+    for line in index.find_descriptions(query):
+        print(line)
+        counter += 1
+    if counter == 0:
+        msg = 'No match'
+    elif counter == 1:
+        msg = '1 match'
+    else:
+        msg = '{} matches'.format(counter)
+    print('({} for {!r})'.format(msg, query))
+
+
+if __name__ == '__main__':
+    if len(sys.argv) > 1:
+        main(*sys.argv[1:])
+    else:
+        print('Usage: {} word1 [word2]...'.format(sys.argv[0]))

concurrency/http_charserver.py

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+import asyncio
+from aiohttp import web
+
+from charfinder import UnicodeNameIndex
+
+TEMPLATE = '''
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>title</title>
+  </head>
+  <body>
+    <form action="/">
+      <input type="search" name="query" value="{query}">
+      <input type="submit" value="find">
+    </form>
+    <p>{message}</p>
+    <hr>
+  <pre>
+{result}
+  </pre>
+  </body>
+</html>
+'''
+
+CONTENT_TYPE = 'text/html; charset=UTF-8'
+
+index = None  # a UnicodeNameIndex instance
+
+
+@asyncio.coroutine
+def handle(request):
+    query = request.GET.get('query', '')
+    print('Query: {!r}'.format(query))
+    if query:
+        lines = list(index.find_descriptions(query))
+        res = '\n'.join(lines)
+        plural = 'es' if len(lines) > 1 else ''
+        msg = '{} match{} for {!r}'.format(len(lines), plural, query)
+    else:
+        lines = []
+        res = ''
+        msg = 'Type words describing characters, e.g. chess.'
+
+    text = TEMPLATE.format(query=query, result=res, message=msg)
+    return web.Response(content_type=CONTENT_TYPE, text=text)
+
+
+@asyncio.coroutine
+def init(loop):
+    app = web.Application(loop=loop)
+    app.router.add_route('GET', '/', handle)
+
+    server = yield from loop.create_server(app.make_handler(),
+                                           '127.0.0.1', 8080)
+    host = server.sockets[0].getsockname()
+    print('Serving on {}. Hit CTRL-C to stop.'.format(host))
+
+
+def main():
+    loop = asyncio.get_event_loop()
+    loop.run_until_complete(init(loop))
+    loop.run_forever()
+
+
+if __name__ == '__main__':
+    index = UnicodeNameIndex()
+    main()

concurrency/tcp_charserver.py

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+#!/usr/bin/env python3
+
+import asyncio
+
+from charfinder import UnicodeNameIndex
+
+CRLF = b'\r\n'
+PROMPT = b'?> '
+
+index = None  # a UnicodeNameIndex instance
+
+
+def writeln(writer, arg):
+    if isinstance(arg, str):
+        lines = [arg]
+    else:
+        lines = arg
+    writer.writelines(line.encode() + CRLF for line in lines)
+
+
+@asyncio.coroutine
+def handle_queries(reader, writer):
+    while True:
+        writer.write(PROMPT)
+        yield from writer.drain()
+        data = yield from reader.readline()
+        try:
+            query = data.decode().strip()
+        except UnicodeDecodeError:
+            query = '\x00'
+        if ord(query[:1]) < 32:
+            break
+        client = writer.get_extra_info('peername')
+        print('Received from {}: {}'.format(client, query))
+        lines = list(index.find_descriptions(query))
+        if lines:
+            writeln(writer, lines)
+            plural = 'es' if len(lines) > 1 else ''
+            msg = '({} match{} for {!r})'.format(len(lines), plural, query)
+            writeln(writer, msg)
+            print('Sent: {} lines + total'.format(len(lines)))
+        else:
+            writeln(writer, '(No match for {!r})'.format(query))
+            print('Sent: 1 line, no match')
+        yield from writer.drain()
+
+    print('Close the client socket')
+    writer.close()
+
+
+def main():
+    loop = asyncio.get_event_loop()
+    coro = asyncio.start_server(handle_queries, '127.0.0.1', 8888, loop=loop)
+    server = loop.run_until_complete(coro)
+
+    host = server.sockets[0].getsockname()
+    print('Serving on {}. Hit CTRL-C to stop.'.format(host))
+    try:
+        loop.run_forever()
+    except KeyboardInterrupt:  # CTRL+C pressed
+        pass
+
+    server.close()
+    loop.run_until_complete(server.wait_closed())
+    loop.close()
+
+
+if __name__ == '__main__':
+    index = UnicodeNameIndex()
+    main()