soxoj/maigret · error · FileNotFoundError

Invalid data file URL '{url}'.

Error message

Invalid data file URL '{url}'.

What it means

Maigret's MaigretDatabase.load_from_http() only accepts URLs with an http:// or https:// scheme. When the supplied string does not start with one of those prefixes, the method immediately raises FileNotFoundError('Invalid data file URL ...') before any network activity. This is a guard against feeding filesystem paths, FTP links, or malformed strings into the HTTP loader. It usually surfaces indirectly through load_from_path, which routes arguments starting with 'http' to this method.

Source

Thrown at maigret/sites.py:557

        except Exception as error:
            raise ValueError(
                f"Problem parsing json contents from str"
                f"'{db_str[:50]}'...:  {str(error)}."
            )

        return self.load_from_json(data)

    def load_from_path(self, path: str) -> "MaigretDatabase":
        if '://' in path:
            return self.load_from_http(path)
        else:
            return self.load_from_file(path)

    def load_from_http(self, url: str) -> "MaigretDatabase":
        is_url_valid = url.startswith("http://") or url.startswith("https://")

        if not is_url_valid:
            raise FileNotFoundError(f"Invalid data file URL '{url}'.")

        import requests

        try:
            response = requests.get(url=url)
        except Exception as error:
            raise FileNotFoundError(
                f"Problem while attempting to access "
                f"data file URL '{url}':  "
                f"{str(error)}"
            )

        if response.status_code == 200:
            try:
                data = response.json()
            except Exception as error:
                raise ValueError(
                    f"Problem parsing json contents at " f"'{url}':  {str(error)}."

View on GitHub (pinned to 41674631a9)

Solutions

  1. Check the URL string: it must literally start with http:// or https://; fix the scheme/typo.
  2. If you meant to load a local file, call load_from_file(path) or pass a plain path that load_from_path routes correctly.
  3. Build URLs from a validated base (e.g. urllib.parse) or a config constant that includes the scheme.
  4. If loading arbitrary user-supplied sources, branch on urlparse(url).scheme in {'http','https'} before calling.

Example fix

// before
db.load_from_path('raw.githubusercontent.com/soxoj/maigret/main/resources/data.json')

// after
from urllib.parse import urlparse
url = 'https://raw.githubusercontent.com/soxoj/maigret/main/resources/data.json'
assert urlparse(url).scheme in ('http', 'https')
db.load_from_path(url)
Defensive patterns

Strategy: validation

Validate before calling

from urllib.parse import urlparse

def is_http_url(s: str) -> bool:
    return urlparse(s).scheme in ('http', 'https') and bool(urlparse(s).netloc)

if not is_http_url(source):
    raise SystemExit(f'Expected http(s) URL, got: {source}')
db = MaigretDatabase().load_from_path(source)

Type guard

from urllib.parse import urlparse

def is_http_url(s: str) -> bool:
    u = urlparse(s)
    return u.scheme in ('http', 'https') and bool(u.netloc)

Prevention

When it happens

Trigger: Calling db.load_from_path('ftp://example.com/data.json') or load_from_http('data.json'), or passing a URL with a typo like 'htp://...' or a scheme-less host like 'raw.githubusercontent.com/...'. Any string not prefixed by http:// or https:// triggers it.

Common situations: Passing a local file path to load_from_path on a system where the routing check ('http' prefix) half-matches (e.g. a path like './http_data.json'), building the data URL from a config variable that lost its scheme, or copy-pasting an FTP/raw link without the scheme.

Related errors

AI-assisted analysis of soxoj/maigret@41674631a9 (2026-08-27). Data as JSON: /api/errors/29b55e2d06727cb3. Report an issue: GitHub.