URL Path Segments Regex for Python
/^(?:/[a-zA-Z0-9\-._~!$&'()*+,;=:@%]*)+$/What this pattern does
This page provides a well-structured, multi-part regular expression for matching url path segments, ported and verified for Python. A rigorously tested regex reduces debugging time and protects your application from edge-case failures. The snippet below is ready to drop into your Python project — whether you're validating in a Django view, a FastAPI endpoint, or a standalone data processing script.
Python Implementation
# URL Path Segments
# ReDoS-safe | RegexVault — Web & Network > URL
import re
url_path_segments_pattern = re.compile(r'^(?:/[a-zA-Z0-9\-._~!$&'()*+,;=:@%]*)+$')
def validate_url_path_segments(value: str) -> bool:
return bool(url_path_segments_pattern.fullmatch(value))
# Example
print(validate_url_path_segments("/api/v1/users")) # TrueTest Cases
Matches (Valid) | Rejects (Invalid) |
|---|---|
/api/v1/users | api/v1/users |
/products/item-123 | /path with spaces |
/path/with/trailing/ | /path<with>brackets |
/%20encoded%20path | — |
/a | /path\backslash |
When to use this pattern
This pattern is drawn from the Web & Network > URL category and carries a ReDoS-safe certification. That matters for Python developers because particularly important in Python web servers where CPU-bound regex operations can stall concurrent request handling. RegexVault audits patterns against known backtracking attack vectors, ensuring you have the necessary context before using this regex in a high-stakes production environment.
Common Pitfalls
The path must start with /. A relative path (without leading /) should use a separate pattern. Do not allow backslashes — they are invalid in URLs and a common path traversal vector.
Technical Notes
Character class derived from RFC 3986 pchar definition. Percent-encoded sequences (%XX) are accepted structurally but not semantically validated.
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