n8n-nodes-doc-filler

n8n-nodes-doc-filler is a custom node package for n8n derived from n8n-nodes-doc-fill that allows you to programmatically extract PDF form field info, fill PDF forms, and add text to PDFs from your n8n workflows. It contains three nodes:

• Doc Get Form Fields – Analyze a PDF and extract information about all form fields present in the document.
• Doc Fill – Retrieve and fill PDF form fields based on provided keys and values.
• Doc Create Field – Add custom text at specified coordinates on a PDF page.

Benefits of this node package:

• fixed memory consumption issue in Doc Fill and Doc Create Field when Continue On Error is enabled and exception is thrown.
• Doc Get Form Fields extends functionality by adding the ability to extract form fields from a PDF.
• better error handling and better description of node parameters.
• added unit tests and coverage for all nodes.

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Requirements

• n8n (Tested with version 1.0.0 and later)
• Node.js >= 18.x

Contributing

Contributions are welcome! Please open an issue or submit a pull request for bug fixes, feature requests, or improvements.

License

This project is licensed under the MIT License. See LICENSE for details.

n8n is a fair-code licensed workflow automation platform.

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Doc Get Form Fields

The Doc Get Form Fields node analyzes a PDF file and extracts information about all form fields present in the document.

Parameters

• Property Name: The name of the binary property containing the PDF file to analyze (default: data).
• Max PDF Size: Maximum allowed size of the PDF file in MB (default: 10).

Output

The node outputs a JSON object with:

• totalFields: The total number of form fields detected in the PDF.
• fields: An array of objects, each containing:
  • key: The field's key.
  • type: The type of the field (e.g., textfield, checkbox, radiogroup, dropdown).

Example Output

{
  "totalFields": 2,
  "fields": [
    { "key": "firstName", "type": "textfield" },
    { "key": "acceptTerms", "type": "checkbox" }
  ]
}

Doc Fill

Doc Fill takes a PDF as input and 4 parameters: Property Name, Property Name Out, Configuration JSON, Max PDF Size.

• Property Name: The internal name representing the PDF file given as input (default: 'data').
• Property Name Out: The internal name you want to give to the output PDF file (default: 'data').
• Configuration JSON: A JSON following the structure given below to specify which fields you want to change.
• Max PDF Size: Maximum allowed size of the PDF file in MB (default: 10).

Configuration JSON structure

This is the base structure to configure one field, Configuration JSON is expecting an array of this structure.

interface DocFillConfig {
    key: string;
    value: string;
    type: 'textfield' | 'checkbox' | 'dropdown' | 'radiogroup';
}

• key: The key to find and retrieve the field in the PDF Form.
• value: The value you want to insert for the retrieved field (must be 'true' (check) or 'false' (uncheck) for checkbox field type).
• type: The type of field you want to retrieve (can be 'textfield', 'checkbox', 'dropdown' or 'radiogroup').

Example

[
  {
    "key": "keyOfMyTextField",
    "value": "John Doe",
    "type": "textfield"
  },
  {
    "key": "keyOfMyCheckbox",
    "value": "true",
    "type": "checkbox"
  }
]

Doc Create Field

Doc Create Field takes a PDF as input and 4 parameters: Property Name, Property Name Out, Configuration JSON, Max PDF Size.

• Property Name: The internal name representing the PDF file given as input (default: 'data').
• Property Name Out: The internal name you want to give to the output PDF file (default: 'data').
• Configuration JSON: A JSON following the structure given below to specify the text you want to draw and how/where you want to draw it.
• Max PDF Size: Maximum allowed size of the PDF file in MB (default: 10).

Configuration JSON structure

This is the base structure to draw one text, Configuration JSON is expecting an array of this structure.

interface DocCreateFieldConfig {
    page: number,
    value: string;
    options: {
        x: number,
        y: number,
        size: number | undefined,
        opacity: number | undefined,
        colorRed: number | undefined,
        colorGreen: number | undefined,
        colorBlue: number | undefined,
    }
}

• page: The page in the PDF on which you want to draw your text.
• value: The text you want to draw.
• options.x: Position on the x axis where you want to start drawing the text.
• options.y: Position on the y axis where you want to start drawing the text.
• options.size: Size of the text you want to draw. (optional, default is 24)
• options.opacity: Opacity of the text you want to draw, must be between 0 and 1. (optional, default is 1)
• options.colorRed: Red value of the RGB color representation. (optional, default is 0)
• options.colorGreen: Green value of the RGB color representation. (optional, default is 0)
• options.colorBlue: Blue value of the RGB color representation. (optional, default is 0)

Example

[
  {
    "page": 0,
    "value": "this is a test!",
    "options": {
      "x": 300,
      "y": 30,
      "size": 12
    }
  }
]