Can OfficeCLI Generate Documents from Custom Templates? A Complete Guide

OfficeCLI supports custom template generation through its merge command, which replaces {{placeholder}} tags in Word, Excel, and PowerPoint files with JSON data values.

The iOfficeAI/OfficeCLI repository provides a command-line interface for automating Microsoft Office document workflows. Its template generation capability allows you to create dynamic documents from custom templates without manual editing. This feature is implemented by the TemplateMerger class and exposed through the merge command, enabling AI agents and automation scripts to produce populated Office files at scale.

How Template Merging Works in OfficeCLI

The TemplateMerger Class Implementation

The core document generation logic resides in src/officecli/Core/TemplateMerger.cs. This class parses the OOXML structure of Office files and scans for text nodes matching the {{key}} placeholder pattern. It performs context-aware replacements throughout the document, including paragraph text, table cells, shape text, chart titles, headers, and footers, while preserving the original styling and layout.

Supported File Formats and Placeholder Syntax

OfficeCLI generates documents from custom templates across three major Office formats:

• Word documents (.docx)
• Excel workbooks (.xlsx)
• PowerPoint presentations (.pptx)

Placeholders use the standard {{variableName}} syntax. When the merge command processes a template, it substitutes these placeholders with corresponding values from the provided JSON data payload.

Generating Documents from Custom Templates: Practical Examples

Single Document Generation with Inline JSON

To generate one document from a custom template, provide the JSON data directly via the --data flag:

officecli merge invoice-template.docx out-001.docx \
  --data '{"client":"Acme Corp","total":"$5,200","date":"2024-07-25"}'

This command creates out-001.docx by replacing every instance of {{client}}, {{total}}, and {{date}} in the template with the specified values.

Batch Processing from JSON Files

For generating multiple documents, create a JSON array file and execute:

officecli merge invoice-template.docx out-$(seq -f "%03g" 1 10).docx \
  --data data.json

When data.json contains an array of objects, OfficeCLI iterates through each entry and produces a separate output file for every data set, using the same custom template for all iterations.

PowerPoint Template Processing

The merge command handles PowerPoint files identically to Word documents:

officecli merge q4-template.pptx q4-acme.pptx \
  --data '{"company":"Acme","quarter":"Q4","revenue":"$12M"}'

All {{company}}, {{quarter}}, and {{revenue}} placeholders on slides, shapes, and chart titles are populated with the JSON values.

Excel Workbook Generation

Excel templates work with the same syntax:

officecli merge budget-template.xlsx budget-2024.xlsx \
  --data '{"dept":"Engineering","budget":"$1.5M"}'

Placeholders in cells, table headers, and chart titles are substituted while maintaining the workbook's formulas and formatting.

CLI Integration and Command Structure

The merge command implementation in src/officecli/CommandBuilder.Merge.cs provides the interface between the CLI and the TemplateMerger engine. According to the repository's SKILL.md file, this command is optimized for AI agent integration, allowing automated document generation pipelines that can process custom templates with minimal token costs and zero manual intervention.

Summary

• OfficeCLI generates documents from custom templates via the merge command backed by the TemplateMerger class in src/officecli/Core/TemplateMerger.cs.
• The tool supports Word (.docx), Excel (.xlsx), and PowerPoint (.pptx) files using {{key}} placeholder syntax.
• Data injection accepts JSON strings or JSON files via the --data parameter.
• Batch generation processes JSON arrays to create multiple documents from a single template.
• Template merging preserves all original formatting, styles, and document structure during placeholder replacement.

Frequently Asked Questions

Can OfficeCLI use any .docx file as a template?

Yes, any valid .docx, .xlsx, or .pptx file can serve as a custom template provided it contains {{placeholder}} tags where data should be injected. The TemplateMerger class parses the OOXML structure regardless of the document's original complexity or design.

What JSON format does the merge command expect?

The --data flag accepts either a JSON object for single-document generation or a JSON array for batch processing. Each key must correspond to a placeholder name in the template minus the curly braces. For example, a placeholder {{clientName}} maps to a JSON key named clientName.

Does template merging preserve formatting and styles?

Yes, the implementation in TemplateMerger.cs performs context-aware replacement that maintains all original styling, fonts, colors, and layout properties. Only the text content of the placeholders is modified, ensuring the generated document retains the visual design of the custom template.

Can I generate multiple documents from a single template?

Yes, by passing a JSON array to the --data parameter, you can generate multiple output files from one template file in a single command execution. This is efficient for producing bulk reports, invoices, or personalized presentations using the same custom template design.

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