Responder

A simple RESP server which accepts requests, pattern matches the command using regexp, and returns a corresponding response from a YAML file.

Install

Responder requires a recent version of Crystal (0.35.1 as of this time).

To build, follow the standard Crystal build process:

# shards install
# crystal build --release --no-debug src/responder.cr

This will produce a single responder binary that can then be moved to somewhere in your PATH, for example /usr/local/bin.

Usage

# responder
Usage: responder [arguments]
    -c FILE, --config=FILE           Configuration YAML file
    -h, --help                       Show this help

Configuration

The YAML file format is as follows:

host: "{your IP or localhost}"
port: {your port, for example 3001}
rules:
  - match: "{a regex}"
    wait: {int}
    response: "{response value}"

Rules are made up of the following values:

• match: a regular expression which should match the RESP command and arguments, in the format you would issue via redis-cli
• wait: an optional delay, in milliseconds, before returning the result
• response: the response value

Responses

Responses can be defined in YAML. For example:

rules:
  - match: "PING"
    response:
      success: true
      result: "PONG"

The response will be converted to a JSON string, which can then be parsed using a JSON or YAML parser by the client.

Regular expressions

Captures can be used in the match regular expression, and those captures can be returned in the response. For example:

rules:
  - match: "HELLO ([^\\s]+)"  # regex
    response: >-
      {"success": true, "result": "HELLO $1"}

Calling this with HELLO world will capture world and return it in the place of $1 in the response.

Contributing

1. Fork it (https://github.com/Green-Edge/responder/fork)
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new pull request

Liability

We take no responsibility for the use of our tool, or external instances provided by third parties. We strongly recommend you abide by the valid official regulations in your country. Furthermore, we refuse liability for any inappropriate or malicious use of this tool. This tool is provided to you in the spirit of free, open software.

You may view the LICENSE in which this software is provided to you here.

8. Limitation of Liability. In no event and under no legal theory, whether in tort (including negligence), contract, or otherwise, unless required by applicable law (such as deliberate and grossly negligent acts) or agreed to in writing, shall any Contributor be liable to You for damages, including any direct, indirect, special, incidental, or consequential damages of any character arising as a result of this License or out of the use or inability to use the Work (including but not limited to damages for loss of goodwill, work stoppage, computer failure or malfunction, or any and all other commercial damages or losses), even if such Contributor has been advised of the possibility of such damages.