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Adding a new operation

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n1474335 edited this page Jun 21, 2024 · 14 revisions

How to add an operation

The easiest way to create a new operation is to use the provided quickstart script. This can be run using the command npm run newop. This script will walk you through the configuration process and create your operation file in the src/core/operations directory.

Once this file has been created, add your operation to the src/core/config/Categories.json file. This determines which menu it will appear in. You can add it to multiple menus if you feel it is appropriate.

Finally, run npm start if you haven't already. If it's already running, it should automatically build a development version when you save the files. You should now be able to view your operation on the site by browsing to localhost:8080.

You can write whatever code you like as long as it does not interfere with other operations or functionality. Take a look at src/core/operations/ParseTCP.mjs for a good example.

You may find it useful to use some helper functions which have been written in src/core/Utils.mjs (e.g. Utils.strToByteArray("Hello") returns [72,101,108,108,111]).

Data types

Input and Output

Nine data types are supported for the input and output of operations:

  1. string - e.g. "hello"
  2. byteArray - e.g. [104,101,108,108,111]
  3. number - e.g. 562 or 3.14159265
  4. html - e.g. "<p>hello</p>"
  5. ArrayBuffer - e.g. new Uint8Array([104,101,108,108,111]).buffer
  6. BigNumber - e.g. 12345678901234567890
  7. JSON - e.g. [{"a":1,"b":2}]
  8. File - e.g. new File()
  9. List<File> - e.g. [new File(), new File()]

Each operation can define any of these data types as their input or output. The data will be automatically converted to the specified type before running the operation.

Ingredients

Operation arguments (ingredients) can be set to any of the following types:

  1. string or shortString
    • e.g. "hello"
    • A shortString will simply display a smaller input box.
  2. binaryString or binaryShortString
    • e.g. "hello\nworld"
    • Escaped characters entered by the user will be automatically converted to the bytes they represent. A simple string type will return "hello\\nworld" in the above case.
  3. text
    • User is given a textbox for free-flow text.
  4. byteArray
    • e.g. user inputs "68 65 6c 6c 6f", operation receives [104,101,108,108,111].
  5. number
    • e.g. 562
    • This can handle both integer and float values.
  6. boolean
    • User is presented with a checkbox, operation receives true or false.
  7. option
    • Given an array of strings, the user is presented with a dropdown selection box with each of those strings as an option. The selected string is sent to the operation.
    • You can use the defaultIndex property to define which index should be selected by default, if required.
  8. populateOption
    • Given an array of {name: "", value: ""} objects, the user is presented with a dropdown selection box with the names as options. The corresponding value will be assigned to whichever argument index the target parameter is set to.
    • See the Regular expression operation for an example of how this works.
  9. editableOption or editableOptionShort
    • Given an array of {name: "", value: ""} objects, the user is presented with an editable dropdown menu. The items in the dropdown are labelled with name and set the argument to value when selected.
    • You can use the defaultIndex property to define which index should be selected by default, if required.
    • See the DNS Over HTTPS operation for an example of how this works.
  10. toggleString
    • User is presented with a string input box with a toggleable dropdown attached.
    • Populate the dropdown using the toggleValues property.
    • Operation receives an object with two properties: option containing the user's dropdown selection, and string containing the input box contents.
    • Particularly useful for arguments that can be specified in various different formats.
    • See the XOR operation for an example of how this works.

Presenting complex data

The output of your operation will be passed on to the next operation in the recipe, or to the Output field if it is the final operation. If your operation has a complex output, it should be presented to the user in a friendly format, perhaps using HTML markup, however this format should not be sent to follow-on operations, as it would make onward processing unnecessarily complex.

In these situations, the present function should be used. This function is called if your operation is the final operation in the recipe. It is passed the output of your run function which you can then manipulate into a suitable format for displaying to the user. This allows you to return a sensible format from your run which can be easily processed by the rest of the recipe if it is not the final operation.

The data type for your present function should be specified in the operation constructor using this.presentType.

Good examples of this are the Unzip, Parse UDP, and JSON Beautify operations.

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