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Add schema constraints to time server strings #4282

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97 changes: 66 additions & 31 deletions src/time/src/mcp_server_time/server.py
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Original file line number Diff line number Diff line change
@@ -1,14 +1,22 @@
from datetime import datetime, timedelta
from enum import Enum
import json
from typing import Sequence
from typing import Any, Sequence

from zoneinfo import ZoneInfo
from tzlocal import get_localzone_name # ← returns "Europe/Paris", etc.

from mcp.server import Server
from mcp.server.stdio import stdio_server
from mcp.types import Tool, ToolAnnotations, TextContent, ImageContent, EmbeddedResource, ErrorData, INVALID_PARAMS
from mcp.types import (
Tool,
ToolAnnotations,
TextContent,
ImageContent,
EmbeddedResource,
ErrorData,
INVALID_PARAMS,
)
from mcp.shared.exceptions import McpError

from pydantic import BaseModel
Expand Down Expand Up @@ -38,6 +46,57 @@ class TimeConversionInput(BaseModel):
target_tz_list: list[str]


TIMEZONE_NAME_PATTERN = r"^[A-Za-z0-9_+\-./]+$"
TIMEZONE_NAME_MAX_LENGTH = 128
TIME_24H_PATTERN = r"^([01]?[0-9]|2[0-3]):[0-5][0-9]$"


def timezone_schema(description: str) -> dict[str, Any]:
return {
"type": "string",
"description": description,
"maxLength": TIMEZONE_NAME_MAX_LENGTH,
"pattern": TIMEZONE_NAME_PATTERN,
}


def time_24h_schema() -> dict[str, Any]:
return {
"type": "string",
"description": "Time to convert in 24-hour format (HH:MM)",
"maxLength": 5,
"pattern": TIME_24H_PATTERN,
}


def get_current_time_input_schema(local_tz: str) -> dict[str, Any]:
return {
"type": "object",
"properties": {
"timezone": timezone_schema(
f"IANA timezone name (e.g., 'America/New_York', 'Europe/London'). Use '{local_tz}' as local timezone if no timezone provided by the user."
)
},
"required": ["timezone"],
}


def convert_time_input_schema(local_tz: str) -> dict[str, Any]:
return {
"type": "object",
"properties": {
"source_timezone": timezone_schema(
f"Source IANA timezone name (e.g., 'America/New_York', 'Europe/London'). Use '{local_tz}' as local timezone if no source timezone provided by the user."
),
"time": time_24h_schema(),
"target_timezone": timezone_schema(
f"Target IANA timezone name (e.g., 'Asia/Tokyo', 'America/San_Francisco'). Use '{local_tz}' as local timezone if no target timezone provided by the user."
),
},
"required": ["source_timezone", "time", "target_timezone"],
}


def get_local_tz(local_tz_override: str | None = None) -> ZoneInfo:
if local_tz_override:
return ZoneInfo(local_tz_override)
Expand All @@ -54,7 +113,9 @@ def get_zoneinfo(timezone_name: str) -> ZoneInfo:
try:
return ZoneInfo(timezone_name)
except Exception as e:
raise McpError(ErrorData(code=INVALID_PARAMS, message=f"Invalid timezone: {str(e)}"))
raise McpError(
ErrorData(code=INVALID_PARAMS, message=f"Invalid timezone: {str(e)}")
)


class TimeServer:
Expand Down Expand Up @@ -132,16 +193,7 @@ async def list_tools() -> list[Tool]:
Tool(
name=TimeTools.GET_CURRENT_TIME.value,
description="Get current time in a specific timezone",
inputSchema={
"type": "object",
"properties": {
"timezone": {
"type": "string",
"description": f"IANA timezone name (e.g., 'America/New_York', 'Europe/London'). Use '{local_tz}' as local timezone if no timezone provided by the user.",
}
},
"required": ["timezone"],
},
inputSchema=get_current_time_input_schema(local_tz),
annotations=ToolAnnotations(
readOnlyHint=True,
destructiveHint=False,
Expand All @@ -152,24 +204,7 @@ async def list_tools() -> list[Tool]:
Tool(
name=TimeTools.CONVERT_TIME.value,
description="Convert time between timezones",
inputSchema={
"type": "object",
"properties": {
"source_timezone": {
"type": "string",
"description": f"Source IANA timezone name (e.g., 'America/New_York', 'Europe/London'). Use '{local_tz}' as local timezone if no source timezone provided by the user.",
},
"time": {
"type": "string",
"description": "Time to convert in 24-hour format (HH:MM)",
},
"target_timezone": {
"type": "string",
"description": f"Target IANA timezone name (e.g., 'Asia/Tokyo', 'America/San_Francisco'). Use '{local_tz}' as local timezone if no target timezone provided by the user.",
},
},
"required": ["source_timezone", "time", "target_timezone"],
},
inputSchema=convert_time_input_schema(local_tz),
annotations=ToolAnnotations(
readOnlyHint=True,
destructiveHint=False,
Expand Down
63 changes: 55 additions & 8 deletions src/time/test/time_server_test.py
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Open in desktop
Original file line number Diff line number Diff line change
@@ -1,11 +1,20 @@

import re
from freezegun import freeze_time
from mcp.shared.exceptions import McpError
import pytest
from unittest.mock import patch
from zoneinfo import ZoneInfo

from mcp_server_time.server import TimeServer, get_local_tz
from mcp_server_time.server import (
TIMEZONE_NAME_MAX_LENGTH,
TIMEZONE_NAME_PATTERN,
TIME_24H_PATTERN,
TimeServer,
convert_time_input_schema,
get_current_time_input_schema,
get_local_tz,
time_24h_schema,
)


@pytest.mark.parametrize(
Expand Down Expand Up @@ -91,6 +100,44 @@ def test_get_current_time_with_invalid_timezone():
time_server.get_current_time("Invalid/Timezone")


def test_tool_input_schemas_include_string_constraints():
current_time_schema = get_current_time_input_schema("UTC")
convert_time_schema = convert_time_input_schema("UTC")
timezone = current_time_schema["properties"]["timezone"]
source_timezone = convert_time_schema["properties"]["source_timezone"]
target_timezone = convert_time_schema["properties"]["target_timezone"]
time = convert_time_schema["properties"]["time"]

assert timezone["maxLength"] == TIMEZONE_NAME_MAX_LENGTH
assert timezone["pattern"] == TIMEZONE_NAME_PATTERN
assert source_timezone["maxLength"] == TIMEZONE_NAME_MAX_LENGTH
assert source_timezone["pattern"] == TIMEZONE_NAME_PATTERN
assert target_timezone["maxLength"] == TIMEZONE_NAME_MAX_LENGTH
assert target_timezone["pattern"] == TIMEZONE_NAME_PATTERN
assert time["maxLength"] == 5
assert time["pattern"] == TIME_24H_PATTERN


@pytest.mark.parametrize("timezone", ["America/New_York", "Etc/GMT+5", "UTC"])
def test_timezone_schema_pattern_accepts_common_iana_names(timezone):
assert re.fullmatch(TIMEZONE_NAME_PATTERN, timezone)


@pytest.mark.parametrize("timezone", ["America/New York", "Bad\tZone"])
def test_timezone_schema_pattern_rejects_whitespace(timezone):
assert not re.fullmatch(TIMEZONE_NAME_PATTERN, timezone)


@pytest.mark.parametrize("time", ["00:00", "7:30", "23:59"])
def test_time_schema_pattern_accepts_runtime_compatible_times(time):
assert re.fullmatch(time_24h_schema()["pattern"], time)


@pytest.mark.parametrize("time", ["24:00", "12:60", "12:345"])
def test_time_schema_pattern_rejects_invalid_times(time):
assert not re.fullmatch(time_24h_schema()["pattern"], time)


@pytest.mark.parametrize(
"source_tz,time_str,target_tz,expected_error",
[
Expand Down Expand Up @@ -475,7 +522,7 @@ def test_get_local_tz_with_invalid_override():
get_local_tz("Invalid/Timezone")


@patch('mcp_server_time.server.get_localzone_name')
@patch("mcp_server_time.server.get_localzone_name")
def test_get_local_tz_with_valid_iana_name(mock_get_localzone):
"""Test that valid IANA timezone names from tzlocal work correctly."""
mock_get_localzone.return_value = "Europe/London"
Expand All @@ -484,18 +531,18 @@ def test_get_local_tz_with_valid_iana_name(mock_get_localzone):
assert isinstance(result, ZoneInfo)


@patch('mcp_server_time.server.get_localzone_name')
@patch("mcp_server_time.server.get_localzone_name")
def test_get_local_tz_when_none_returned(mock_get_localzone):
"""Test default to UTC when tzlocal returns None."""
mock_get_localzone.return_value = None
result = get_local_tz()
assert str(result) == "UTC"


@patch('mcp_server_time.server.get_localzone_name')
@patch("mcp_server_time.server.get_localzone_name")
def test_get_local_tz_handles_windows_timezones(mock_get_localzone):
"""Test that tzlocal properly handles Windows timezone names.

Note: tzlocal should convert Windows names like 'Pacific Standard Time'
to proper IANA names like 'America/Los_Angeles'.
"""
Expand All @@ -510,7 +557,7 @@ def test_get_local_tz_handles_windows_timezones(mock_get_localzone):
"timezone_name",
[
"America/New_York",
"Europe/Paris",
"Europe/Paris",
"Asia/Tokyo",
"Australia/Sydney",
"Africa/Cairo",
Expand All @@ -519,7 +566,7 @@ def test_get_local_tz_handles_windows_timezones(mock_get_localzone):
"UTC",
],
)
@patch('mcp_server_time.server.get_localzone_name')
@patch("mcp_server_time.server.get_localzone_name")
def test_get_local_tz_various_timezones(mock_get_localzone, timezone_name):
"""Test various timezone names that tzlocal might return."""
mock_get_localzone.return_value = timezone_name
Expand Down
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