Documentation: Generate PDF Node

Overview

The Generate PDF Node is an action node that builds a PDF document from a block-based model (header, content, and footer) defined visually. It allows generating reports with text, tables, lists, images, dividers, QR/barcodes, and page breaks, with control over page size, orientation, margins, and font.

In IoT and industrial environments it is ideal for producing automatic reports: incident records, maintenance work orders, event summaries, or shift reports, generated on the fly with flow data and delivered as a file or attachment.

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When to use this node?

Use this node when you need to:

• Generate a PDF report as part of an automation (incident, maintenance, shift).
• Compose documents with rich structure (headings, paragraphs, tables, lists, images) using flow data.
• Produce a PDF to attach to an email, save to disk, or reuse its content in other nodes.

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Node Configuration

The form is organized into five selectable sections: Page, Header, Content, Footer, and Output. It also has the Preview and JSON Editor tabs.

Section: Page

Defines the document format:

• Page Size: page size (A4, A3, A5, A6, Letter, Legal, Tabloid).
• Orientation: orientation (Portrait / Landscape).
• Custom Margins: custom margins in mm (optional).
• Default Font: default font for the document (family, size, color, bold/italic) (optional).

Sections: Header / Content / Footer

Block editors for the document's header, body, and footer. Use Add block... to add blocks of different types, which can be reordered and edited:

• Paragraph, Heading (H1–H6), Image (image by URL/base64), Table, List (ordered/unordered), Divider, Spacer, Columns, Page Break, QR Code, and Barcode.

Block text supports variable interpolation ({{variable}}) to insert flow data.

Section: Output

Defines how the PDF is delivered:

• Output Format: Base64 (output includes pdf_base64), File (saved as a file), or Both.
• File Name / Directory Path: file name and path (when the format is File or Both). The name supports interpolation (for example, report-{{id}}.pdf).

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Preview View

The Preview tab shows an approximate representation of the document (size, orientation, and blocks) to validate the design before generating it.

JSON Editor View

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JSON Structure (Input Parameters)

{
  "document": {
    "page_size": "A4",
    "orientation": "portrait",
    "margins": null,
    "default_font": null,
    "header": [],
    "footer": [],
    "blocks": [
      { "type": "heading", "text": "Incident Report", "level": 1, "align": "left" },
      { "type": "paragraph", "text": "An intrusion alarm was triggered at the North Gate on {{trigger.datetime}}. Sensor: {{trigger.object_name}}. Status: {{trigger.state.state}}.", "align": "left" }
    ]
  },
  "output_format": "base64",
  "file_name": "",
  "file_path": ""
}

JSON Fields

Field	Type	Description
document	object	Document model (page, font, margins, and header/content/footer blocks).
document.page_size	string	Page size (A4, Letter, etc.).
document.orientation	string	portrait or landscape.
document.blocks	array	Body blocks of the document (each with its type and fields).
output_format	string	base64, file, or both.
file_name	string	File name (when applicable). Supports interpolation.
file_path	string	Server directory where the file is saved (when applicable).

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Output: Where the node's data comes from

With output_format: base64, the output includes the PDF as pdf_base64, ready to be used in subsequent nodes (for example, converting it to a file with [[base64-to-file]] or attaching it to an email). With file or both, the PDF is saved as a file at the specified path.

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Usage Examples

Example 1: Intrusion incident record

Use case: When an intrusion alarm triggers, a PDF is generated with the incident title and a paragraph containing the event data, to attach to the notification email.

• Page: A4, Portrait
• Content: a Heading block (Incident Report) and a Paragraph block with flow data.
• Output Format: Base64

(see JSON structure above)

Example 2: Maintenance work order with table

Use case: Generate a maintenance work order with a table of completed tasks and save it as a file.

• Content: Table block with the tasks.
• Output Format: File · File Name: maintenance-{{trigger.object_id}}.pdf

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Validation and Errors

Condition	Common cause / fix
PDF comes out empty	Add at least one content block in the Content section.
File is not saved	With File/Both format, verify that File Name and Directory Path are valid and accessible on the server.
Variables not replaced	Check that {{variable}} expressions correspond to data available in the flow.

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Best Practices

• Structure with blocks: combine headings, paragraphs, and tables for readable reports; use the preview to validate the result.
• Dynamic data: take advantage of {{variable}} interpolation to insert the date, object, and event state.
• Choose the right output format: use base64 to attach/chain and file when you need to persist the document.
• Chain with other nodes: combine with [[base64-to-file]] or with Send Email to deliver the generated report.