Random HTTP Basic Auth Parser Corpus Generator

Description

Construct synthetic ASCII Basic credential bytes and malformed controls, preserving delegated split and error outcomes without real credentials.

A protocol fixture is local test data representing headers, messages, identifiers, or request decisions. Serialization and parsing can be checked without contacting a server, while authentication, delivery, and actual client behavior require separate tests.

Construct synthetic ASCII Basic credential bytes and malformed controls, preserving delegated split and error outcomes without real credentials.

When to use this tool

Use this generator to create reproducible http basic auth parser corpus cases from the supplied model or bank. Inspect the returned evidence before using cases in a test or exercise.

How to use the tool and how it works

Supply usernames, passwords, modes, count in the field shapes below. Set seed when you need an explicit replay.
Run the tool and correct any input error. For generated controls, distinguish a successful fixture containing an invalid case from failure to generate the fixture.
Read cases. Use the conventions below and keep answer-bearing fields separate when presenting an exercise.

Draw printable-ASCII usernames and passwords and encode their colon-separated bytes into a Basic header. Controls omit the separator or supply malformed Base64; delegate parsing and return byte arrays or issues.^[1]

Delegated operations used for this result: basic auth parser. Their calculation or parsing conventions apply to the corresponding result fields.^[2]

Input field	Meaning and units	Accepted input
usernames	Usernames	Required. Array of Text; maximum UTF-16 length 65536.; minimum items 1; maximum items 16.
passwords	Passwords	Required. Array of Text; maximum UTF-16 length 65536.; minimum items 1; maximum items 16.
modes	Modes	Required. Array of Text; one of "valid", "missing-colon", "bad-base64".; minimum items 1; maximum items 3.
count	Requested count; the mechanics explain whether one draw expands into several returned records.	Required. Safe integer; minimum 1; maximum 32.
seed	Optional numeric seed; takes precedence over context randomness. Without either, use the fixed tool.io default seed.	Optional. Safe integer.

Output field	Interpretation	Returned shape
cases	Cases	Required. Array of Object; no unknown keys.; minimum items 1; maximum items 32.
cases[].header	Header	Required. Text; maximum UTF-16 length 65536.
cases[].mode	Mode	Required. Text; maximum UTF-16 length 65536.
cases[].accepted	Accepted	Required. Boolean.
cases[].usernameBytes	Username Bytes	Required. Array of Safe integer; minimum 0; maximum 255.; minimum items 0; maximum items 2048.
cases[].passwordBytes	Password Bytes	Required. Array of Safe integer; minimum 0; maximum 255.; minimum items 0; maximum items 2048.
cases[].errorCode	Error Code	Required. Text; maximum UTF-16 length 65536.
randomness	Replay metadata: source is seed or context; seed is the normalized 32-bit seed or null for a context source.	Required. Object; no unknown keys.
randomness.seed	Optional numeric replay seed; normalization and precedence are explained below.	Required. Safe integer. or Null.
randomness.source	Source	Required. Text; one of "context", "seed".

An explicit safe-integer seed takes precedence over injected context randomness and is normalized to an unsigned 32-bit integer. With no seed and no context source, replay uses the fixed tool.io default seed. A context source must return finite values from zero inclusive to one exclusive; its advancing state must be retained separately. randomness records the source and normalized seed, or null for context. These generators are not cryptographic random sources.

json

{
  "input": {
    "usernames": [
      "a"
    ],
    "passwords": [
      "b:c"
    ],
    "modes": [
      "valid"
    ],
    "count": 1,
    "seed": 42
  },
  "output": {
    "cases": [
      {
        "header": "Basic YTpiOmM=",
        "mode": "valid",
        "accepted": true,
        "usernameBytes": [
          97
        ],
        "passwordBytes": [
          98,
          58,
          99
        ],
        "errorCode": ""
      }
    ],
    "randomness": {
      "seed": 42,
      "source": "seed"
    }
  }
}

Limitations and assumptions

Usernames cannot contain colons while passwords can. Base64 is reversible encoding rather than encryption. This does not authenticate credentials or decide non-ASCII charset interoperability.
A replay requires the same complete input and implementation. Randomized construction does not guarantee uniform coverage of every feasible output; finite samples can repeat unless a distinct-selection rule is explicitly stated.
The field tables state structural bounds; cross-field constraints and bounded search or output budgets also apply. Unknown keys are rejected where the object contract disallows them. Input errors are distinct from null fields and deliberate invalid controls in a successful output.

Alternative or Complementary methods

For a supplied example, inspect the returned construction or delegated check directly. To evaluate a consumer, also test cases chosen for its own boundaries; a generated finite corpus does not establish exhaustive coverage.

References

Tool behavior and example: Random HTTP Basic Auth Parser Corpus Generator — tool.io
Calculation or validation: http/basic-auth-parser — tool.io

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