rls.py

#!/usr/bin/env python3
import json
import subprocess
import os
import re

class LangServer:
    def __init__(self):
        self.server = subprocess.Popen(
            ["/Users/tbelaire/.cargo/bin/cargo", "run", "-q"],
            env={ "RUST_BACKTRACE": "1",
                 "SYS_ROOT": "/Users/tbelaire/.multirust/toolchains/nightly-x86_64-apple-darwin",
                 "TMPDIR": "/Users/tbelaire/tmp"},
            bufsize=0,
            stdin=subprocess.PIPE,
            stdout=subprocess.PIPE,
            stderr=subprocess.DEVNULL,
            universal_newlines=True)

        self.header_regex = re.compile("(?P<header>(\w|-)+): (?P<value>\d+)")
        self.stdin = self.server.stdin
        self.stdout = self.server.stdout
        self.poll = self.server.poll


    def read_headers(self):
        """Reads in the headers for a response"""
        result = {}
        while True:
            line = self.server.stdout.readline()
            if line == "\n":
                break
            m = self.header_regex.match(line)
            result[m.group("header")] = m.group("value")
        return result

    def read_response(self):
        headers = self.read_headers()
        size = int(headers["Content-Length"])
        content = self.server.stdout.read(size)
        return json.loads(content)



rls = LangServer()

def format_request(request):
    content = json.dumps(request, indent=2)
    content_length = len(content)

    result = "Content-Length: {}\r\n\r\n{}".format(content_length, content)
    return result

init_request = {
    "jsonrpc": "2.0",
    "id": 1,
    "method": "initialize",
    "params": {
        "processId": os.getpid(),
        "rootPath": "/Users/tbelaire/github/rustls/sample_project",
        "capabilities":{
        }
    }
}



# _ = rls.stdout.read()
request = format_request(init_request)
print("Request:")
print(request)


rls.stdin.write(request)
rls.stdin.flush()
if rls.poll() != None:
    print("Exited!")

print("Response:")
response = rls.read_response()
print(json.dumps(response, indent=2))
print("Response:")
response = rls.read_response()
print(json.dumps(response, indent=2))


print("Done")