Support DATASETTE_URL and DATASETTE_TOKEN environment variables

Allow configuring a base Datasette instance URL and API token via
environment variables, so users can run commands like
`dclient query data "select ..."` without specifying a full URL each time.

DATASETTE_URL is combined with the argument as a path segment.
DATASETTE_TOKEN is used as a lowest-priority fallback for auth.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

tests/test_env.py

@@ -0,0 +1,178 @@
+from click.testing import CliRunner
+from dclient.cli import cli
+import json
+import pathlib
+
+
+QUERY_RESPONSE = {
+    "ok": True,
+    "database": "data",
+    "query_name": None,
+    "rows": [{"id": 1}],
+    "truncated": False,
+    "columns": ["id"],
+    "query": {"sql": "select 1", "params": {}},
+    "error": None,
+    "private": False,
+    "allow_execute_sql": True,
+}
+
+
+# -- DATASETTE_TOKEN tests --
+
+
+def test_datasette_token_used_as_fallback(httpx_mock, mocker, tmpdir):
+    """DATASETTE_TOKEN is used when no --token flag and no auth.json match."""
+    mocker.patch("dclient.cli.get_config_dir", return_value=pathlib.Path(tmpdir))
+    httpx_mock.add_response(json=QUERY_RESPONSE, status_code=200)
+    runner = CliRunner(env={"DATASETTE_TOKEN": "env-token-123"})
+    result = runner.invoke(cli, ["query", "https://example.com", "select 1"])
+    assert result.exit_code == 0
+    request = httpx_mock.get_request()
+    assert request.headers["authorization"] == "Bearer env-token-123"
+
+
+def test_token_flag_overrides_datasette_token(httpx_mock, mocker, tmpdir):
+    """--token flag takes priority over DATASETTE_TOKEN."""
+    mocker.patch("dclient.cli.get_config_dir", return_value=pathlib.Path(tmpdir))
+    httpx_mock.add_response(json=QUERY_RESPONSE, status_code=200)
+    runner = CliRunner(env={"DATASETTE_TOKEN": "env-token"})
+    result = runner.invoke(
+        cli, ["query", "https://example.com", "select 1", "--token", "flag-token"]
+    )
+    assert result.exit_code == 0
+    request = httpx_mock.get_request()
+    assert request.headers["authorization"] == "Bearer flag-token"
+
+
+def test_auth_json_overrides_datasette_token(httpx_mock, mocker, tmpdir):
+    """Stored auth.json token takes priority over DATASETTE_TOKEN."""
+    mocker.patch("dclient.cli.get_config_dir", return_value=pathlib.Path(tmpdir))
+    auth_file = pathlib.Path(tmpdir) / "auth.json"
+    auth_file.write_text(json.dumps({"https://example.com": "stored-token"}))
+    httpx_mock.add_response(json=QUERY_RESPONSE, status_code=200)
+    runner = CliRunner(env={"DATASETTE_TOKEN": "env-token"})
+    result = runner.invoke(cli, ["query", "https://example.com", "select 1"])
+    assert result.exit_code == 0
+    request = httpx_mock.get_request()
+    assert request.headers["authorization"] == "Bearer stored-token"
+
+
+# -- DATASETTE_URL tests --
+
+
+def test_datasette_url_combines_with_database_name(httpx_mock, mocker, tmpdir):
+    """DATASETTE_URL + database name arg → combined URL."""
+    mocker.patch("dclient.cli.get_config_dir", return_value=pathlib.Path(tmpdir))
+    httpx_mock.add_response(json=QUERY_RESPONSE, status_code=200)
+    runner = CliRunner(env={"DATASETTE_URL": "https://my-instance.datasette.cloud"})
+    result = runner.invoke(cli, ["query", "data", "select 1"])
+    assert result.exit_code == 0
+    request = httpx_mock.get_request()
+    assert request.url.host == "my-instance.datasette.cloud"
+    assert request.url.path == "/data.json"
+
+
+def test_datasette_url_with_trailing_slash(httpx_mock, mocker, tmpdir):
+    """DATASETTE_URL with trailing slash still works correctly."""
+    mocker.patch("dclient.cli.get_config_dir", return_value=pathlib.Path(tmpdir))
+    httpx_mock.add_response(json=QUERY_RESPONSE, status_code=200)
+    runner = CliRunner(env={"DATASETTE_URL": "https://my-instance.datasette.cloud/"})
+    result = runner.invoke(cli, ["query", "data", "select 1"])
+    assert result.exit_code == 0
+    request = httpx_mock.get_request()
+    assert request.url.path == "/data.json"
+
+
+def test_full_url_ignores_datasette_url(httpx_mock, mocker, tmpdir):
+    """A full URL argument is used as-is, ignoring DATASETTE_URL."""
+    mocker.patch("dclient.cli.get_config_dir", return_value=pathlib.Path(tmpdir))
+    httpx_mock.add_response(json=QUERY_RESPONSE, status_code=200)
+    runner = CliRunner(env={"DATASETTE_URL": "https://should-be-ignored.com"})
+    result = runner.invoke(cli, ["query", "https://other.example.com/db", "select 1"])
+    assert result.exit_code == 0
+    request = httpx_mock.get_request()
+    assert request.url.host == "other.example.com"
+    assert request.url.path == "/db.json"
+
+
+def test_alias_takes_priority_over_datasette_url(httpx_mock, mocker, tmpdir):
+    """Alias match takes priority over DATASETTE_URL."""
+    mocker.patch("dclient.cli.get_config_dir", return_value=pathlib.Path(tmpdir))
+    aliases_file = pathlib.Path(tmpdir) / "aliases.json"
+    aliases_file.write_text(json.dumps({"myalias": "https://aliased.example.com/db"}))
+    httpx_mock.add_response(json=QUERY_RESPONSE, status_code=200)
+    runner = CliRunner(env={"DATASETTE_URL": "https://should-be-ignored.com"})
+    result = runner.invoke(cli, ["query", "myalias", "select 1"])
+    assert result.exit_code == 0
+    request = httpx_mock.get_request()
+    assert request.url.host == "aliased.example.com"
+    assert request.url.path == "/db.json"
+
+
+# -- DATASETTE_URL with other commands --
+
+
+def test_datasette_url_with_insert(httpx_mock, mocker, tmpdir):
+    """DATASETTE_URL works with the insert command."""
+    mocker.patch("dclient.cli.get_config_dir", return_value=pathlib.Path(tmpdir))
+    httpx_mock.add_response(json={"ok": True}, status_code=200)
+    csv_path = pathlib.Path(tmpdir) / "data.csv"
+    csv_path.write_text("id,name\n1,hello\n")
+    runner = CliRunner(
+        env={
+            "DATASETTE_URL": "https://my-instance.datasette.cloud",
+            "DATASETTE_TOKEN": "env-token",
+        }
+    )
+    result = runner.invoke(
+        cli,
+        ["insert", "data", "my_table", str(csv_path), "--csv", "--create"],
+        catch_exceptions=False,
+    )
+    assert result.exit_code == 0
+    request = httpx_mock.get_request()
+    assert request.url.host == "my-instance.datasette.cloud"
+    assert "/-/create" in str(request.url.path)
+    assert request.headers["authorization"] == "Bearer env-token"
+
+
+def test_datasette_url_with_actor(httpx_mock, mocker, tmpdir):
+    """DATASETTE_URL works with the actor command."""
+    mocker.patch("dclient.cli.get_config_dir", return_value=pathlib.Path(tmpdir))
+    httpx_mock.add_response(
+        json={"actor": {"id": "root"}},
+        status_code=200,
+    )
+    runner = CliRunner(
+        env={
+            "DATASETTE_URL": "https://my-instance.datasette.cloud",
+            "DATASETTE_TOKEN": "env-token",
+        }
+    )
+    result = runner.invoke(cli, ["actor", "data"])
+    assert result.exit_code == 0
+    request = httpx_mock.get_request()
+    assert request.url.host == "my-instance.datasette.cloud"
+    assert request.headers["authorization"] == "Bearer env-token"
+
+
+# -- Both together --
+
+
+def test_datasette_url_and_token_together(httpx_mock, mocker, tmpdir):
+    """DATASETTE_URL and DATASETTE_TOKEN work together for a complete config."""
+    mocker.patch("dclient.cli.get_config_dir", return_value=pathlib.Path(tmpdir))
+    httpx_mock.add_response(json=QUERY_RESPONSE, status_code=200)
+    runner = CliRunner(
+        env={
+            "DATASETTE_URL": "https://my-instance.datasette.cloud",
+            "DATASETTE_TOKEN": "env-token-456",
+        }
+    )
+    result = runner.invoke(cli, ["query", "mydb", "select 1"])
+    assert result.exit_code == 0
+    request = httpx_mock.get_request()
+    assert request.url.host == "my-instance.datasette.cloud"
+    assert request.url.path == "/mydb.json"
+    assert request.headers["authorization"] == "Bearer env-token-456"