Add a LanguageClient autogenerated from lsprotocol type definitions

CHANGELOG.md

@@ -7,11 +7,16 @@ and this project adheres to [Semantic Versioning][semver].
 
 ## [Unreleased]
 ### Added
+
+- Add `LanguageClient` with LSP methods autogenerated from type annotations in `lsprotocol` ([#328])
+- Add base JSON-RPC `Client` with support for running servers in a subprocess and communicating over stdio. ([#328])
+
 ### Changed
 ### Fixed
 
 - `pygls` no longer overrides the event loop for the current thread when given an explicit loop to use. ([#334])
 
+[#328]: https://github.com/openlawlibrary/pygls/issues/328
 [#334]: https://github.com/openlawlibrary/pygls/issues/334
 
 

examples/servers/code_actions.py

@@ -0,0 +1,82 @@
+############################################################################
+# Copyright(c) Open Law Library. All rights reserved.                      #
+# See ThirdPartyNotices.txt in the project root for additional notices.    #
+#                                                                          #
+# Licensed under the Apache License, Version 2.0 (the "License")           #
+# you may not use this file except in compliance with the License.         #
+# You may obtain a copy of the License at                                  #
+#                                                                          #
+#     http: // www.apache.org/licenses/LICENSE-2.0                         #
+#                                                                          #
+# Unless required by applicable law or agreed to in writing, software      #
+# distributed under the License is distributed on an "AS IS" BASIS,        #
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. #
+# See the License for the specific language governing permissions and      #
+# limitations under the License.                                           #
+############################################################################
+import re
+from pygls.server import LanguageServer
+from lsprotocol.types import (
+    TEXT_DOCUMENT_CODE_ACTION,
+    CodeAction,
+    CodeActionKind,
+    CodeActionOptions,
+    CodeActionParams,
+    Position,
+    Range,
+    TextEdit,
+    WorkspaceEdit,
+)
+
+
+ADDITION = re.compile(r"^\s*(\d+)\s*\+\s*(\d+)\s*=")
+server = LanguageServer("code-action-server", "v0.1")
+
+
+@server.feature(
+    TEXT_DOCUMENT_CODE_ACTION,
+    CodeActionOptions(
+        code_action_kinds=[CodeActionKind.QuickFix]
+    )
+)
+def code_actions(params: CodeActionParams):
+    items = []
+    document_uri = params.text_document.uri
+    document = server.workspace.get_document(document_uri)
+
+    start_line = params.range.start.line
+    end_line = params.range.end.line
+
+    lines = document.lines[start_line:end_line+1]
+    for idx, line in enumerate(lines):
+
+        match = ADDITION.match(line)
+        if match is not None:
+
+            range_ = Range(
+                start=Position(line=start_line + idx, character=0),
+                end=Position(line=start_line + idx, character=len(line)-1)
+            )
+
+            left = int(match.group(1))
+            right = int(match.group(2))
+            answer = left + right
+
+            text_edit = TextEdit(
+                range=range_, new_text=f"{line.strip()} {answer}!"
+            )
+
+            action = CodeAction(
+                title=f"Evaluate '{match.group(0)}'",
+                kind=CodeActionKind.QuickFix,
+                edit=WorkspaceEdit(
+                    changes={document_uri: [text_edit]}
+                )
+            )
+            items.append(action)
+
+    return items
+
+
+if __name__ == "__main__":
+    server.start_io()

examples/workspace/sums.txt

@@ -0,0 +1,7 @@
+1 + 1 =
+
+
+2 + 3 =
+
+
+6 + 6 =

pygls/client.py

@@ -0,0 +1,115 @@
+############################################################################
+# Copyright(c) Open Law Library. All rights reserved.                      #
+# See ThirdPartyNotices.txt in the project root for additional notices.    #
+#                                                                          #
+# Licensed under the Apache License, Version 2.0 (the "License")           #
+# you may not use this file except in compliance with the License.         #
+# You may obtain a copy of the License at                                  #
+#                                                                          #
+#     http: // www.apache.org/licenses/LICENSE-2.0                         #
+#                                                                          #
+# Unless required by applicable law or agreed to in writing, software      #
+# distributed under the License is distributed on an "AS IS" BASIS,        #
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. #
+# See the License for the specific language governing permissions and      #
+# limitations under the License.                                           #
+############################################################################
+import asyncio
+import logging
+import re
+from threading import Event
+from typing import Callable
+from typing import List
+from typing import Optional
+from typing import Type
+
+from cattrs import Converter
+
+from pygls.protocol import JsonRPCProtocol, default_converter
+
+
+logger = logging.getLogger(__name__)
+
+
+async def aio_readline(stop_event, reader, message_handler):
+
+    CONTENT_LENGTH_PATTERN = re.compile(rb'^Content-Length: (\d+)\r\n$')
+
+    # Initialize message buffer
+    message = []
+    content_length = 0
+
+    while not stop_event.is_set():
+        # Read a header line
+        header = await reader.readline()
+        if not header:
+            break
+        message.append(header)
+
+        # Extract content length if possible
+        if not content_length:
+            match = CONTENT_LENGTH_PATTERN.fullmatch(header)
+            if match:
+                content_length = int(match.group(1))
+                logger.debug('Content length: %s', content_length)
+
+        # Check if all headers have been read (as indicated by an empty line \r\n)
+        if content_length and not header.strip():
+
+            # Read body
+            body = await reader.read(content_length)
+            if not body:
+                break
+            message.append(body)
+
+            # Pass message to protocol
+            message_handler(b''.join(message))
+
+            # Reset the buffer
+            message = []
+            content_length = 0
+
+
+class Client:
+    """Base JSON-RPC client."""
+
+    def __init__(
+        self,
+        protocol_cls: Type[JsonRPCProtocol] = JsonRPCProtocol,
+        converter_factory: Callable[[], Converter] = default_converter,
+    ):
+
+        self.protocol = protocol_cls(self, converter_factory())
+
+        self._server: Optional[asyncio.subprocess.Process] = None
+        self._stop_event = Event()
+        self._async_tasks: List[asyncio.Task] = []
+
+    async def start_io(self, cmd: str, *args, **kwargs):
+        """Start the given server and communicate with it over stdio."""
+
+        server = await asyncio.create_subprocess_exec(
+            cmd,
+            *args,
+            stdout=asyncio.subprocess.PIPE,
+            stdin=asyncio.subprocess.PIPE,
+            stderr=asyncio.subprocess.PIPE,
+            **kwargs,
+        )
+
+        self.protocol.connection_made(server.stdin)  # type: ignore
+        connection = asyncio.create_task(
+            aio_readline(
+                self._stop_event,
+                server.stdout,
+                self.protocol.data_received
+            )
+        )
+        self._server = server
+        self._async_tasks.append(connection)
+
+    async def stop(self):
+        self._stop_event.set()
+
+        if len(self._async_tasks) > 0:
+            await asyncio.gather(*self._async_tasks)