renumbering chapters >= 19

21-async/mojifinder/tcp_mojifinder.py

@@ -0,0 +1,76 @@
+#!/usr/bin/env python3
+
+# tag::TCP_MOJIFINDER_TOP[]
+import asyncio
+import functools
+import sys
+from asyncio.trsock import TransportSocket
+from typing import cast
+
+from charindex import InvertedIndex, format_results  # <1>
+
+CRLF = b'\r\n'
+PROMPT = b'?> '
+
+async def finder(index: InvertedIndex,          # <2>
+                 reader: asyncio.StreamReader,
+                 writer: asyncio.StreamWriter):
+    client = writer.get_extra_info('peername')  # <3>
+    while True:  # <4>
+        writer.write(PROMPT)  # can't await!  # <5>
+        await writer.drain()  # must await!  # <6>
+        data = await reader.readline()  # <7>
+        try:
+            query = data.decode().strip()  # <8>
+        except UnicodeDecodeError:  # <9>
+            query = '\x00'
+        print(f' From {client}: {query!r}')  # <10>
+        if query:
+            if ord(query[:1]) < 32:  # <11>
+                break
+            results = await search(query, index, writer)  # <12>
+            print(f'   To {client}: {results} results.')  # <13>
+
+    writer.close()  # <14>
+    await writer.wait_closed()  # <15>
+    print(f'Close {client}.')  # <16>
+# end::TCP_MOJIFINDER_TOP[]
+
+# tag::TCP_MOJIFINDER_SEARCH[]
+async def search(query: str,  # <1>
+                 index: InvertedIndex,
+                 writer: asyncio.StreamWriter) -> int:
+    chars = index.search(query)  # <2>
+    lines = (line.encode() + CRLF for line  # <3>
+                in format_results(chars))
+    writer.writelines(lines)  # <4>
+    await writer.drain()      # <5>
+    status_line = f'{"─" * 66} {len(chars)} found'  # <6>
+    writer.write(status_line.encode() + CRLF)
+    await writer.drain()
+    return len(chars)
+# end::TCP_MOJIFINDER_SEARCH[]
+
+# tag::TCP_MOJIFINDER_MAIN[]
+async def supervisor(index: InvertedIndex, host: str, port: int):
+    server = await asyncio.start_server(    # <1>
+        functools.partial(finder, index),   # <2>
+        host, port)                         # <3>
+
+    socket_list = cast(tuple[TransportSocket, ...], server.sockets)  # <4>
+    addr = socket_list[0].getsockname()
+    print(f'Serving on {addr}. Hit CTRL-C to stop.')  # <5>
+    await server.serve_forever()  # <6>
+
+def main(host: str = '127.0.0.1', port_arg: str = '2323'):
+    port = int(port_arg)
+    print('Building index.')
+    index = InvertedIndex()                         # <7>
+    try:
+        asyncio.run(supervisor(index, host, port))  # <8>
+    except KeyboardInterrupt:                       # <9>
+        print('\nServer shut down.')
+
+if __name__ == '__main__':
+    main(*sys.argv[1:])
+# end::TCP_MOJIFINDER_MAIN[]