---
page: htroot/RegexTest.html
help: help/RegexTest.md
title: Regex Test
package: blacklist-security-access
access: public
kind: ui-page
backend_java: source/net/yacy/htroot/RegexTest.java
---

# Regex Test

## Purpose

Regex Test helps validate regular expressions used in crawls, blacklists, and filters.

Use it before applying a pattern to crawling or deletion, where a broad match can have large effects.

## What You Can Do Here

- Regex Test helps validate regular expressions used in crawls, blacklists, and filters.
- Test a concrete URL, request, user, or pattern before applying broad policy.
- Keep rules narrow enough that they block the intended problem without hiding useful content.

## Page Architecture

Security and blacklist pages turn names, patterns, credentials, or request properties into allow/block decisions. The architecture is rule-oriented: define the rule, test the rule, then apply it to crawling, search, or access.

| Control | Meaning | Values or examples |
| --- | --- | --- |
| `text` | Text used as input for a test, preview, or stored content field. | Text value; use the page label and surrounding context to choose the exact content. |
| `regex` | Regular expression to test or apply. Escape special characters deliberately. | Regular expression syntax. |
| `submit` | Submit action for the form. Its meaning depends on the surrounding fields. | Submit button value generated by the page; direct clients normally send the named action parameter. |

## Correct Use

Test with a concrete example. A blacklist, regular expression, rate limit, cookie rule, or access rule is only understandable when checked against a real URL or request. Prefer narrow patterns and document the reason for broad rules.

## Access And Safety

The page is normally public or read-only, unless the peer is configured to require authentication for all pages.

## Automation And API

Page backend: `source/net/yacy/htroot/RegexTest.java`.

| Endpoint | Method | Access | Backend |
| --- | --- | --- | --- |
| `/RegexTest.html` | `GET` | public or page-dependent | `source/net/yacy/htroot/RegexTest.java` |

### Parameter Guide

The table explains values that an agent or script must set deliberately. Parameters not relevant to a task should be omitted or left at the page default.

| Parameter | Meaning and valid values | Care |
| --- | --- | --- |
| `text` | Text used as input for a test, preview, or stored content field. | Set only when this option is part of the intended request; otherwise omit it and let YaCy use the page default. |
| `regex` | Regular expression to test or apply. Escape special characters deliberately. | Set only when this option is part of the intended request; otherwise omit it and let YaCy use the page default. |
| `submit` | Submit action for the form. Its meaning depends on the surrounding fields. | Changes stored data, configuration, or a running job. Use the authenticated action flow where required and verify the result. |

Example request shape:

```http
GET /RegexTest.html?text=...&regex=...&submit=...
```

## What To Expect

Expect a rule list, match test, access record, cookie view, or confirmation. The real proof is behavioral: the same URL, request, or user should now be accepted, blocked, limited, or displayed as intended.

## Related Pages

- `https://docs.oracle.com/javase/8/docs/api/java/util/regex/Pattern.html`