Office Open Xml Download [portable] Guide

When reading any ZIP part, normalize the entry name and reject any containing .. or absolute paths. 5. Reference Implementation: A Secure Streaming Downloader We present a pseudo-code implementation for a REST endpoint that generates a simple .docx report from JSON data, using streaming and security best practices. 5.1 System Architecture [JSON Input] -> [Streaming XML Writer] -> [In-memory ZIP stream] -> [HTTP Response] ^ | | (direct write) v [Content Types & Relationships] [File Download] 5.2 Core Implementation (C#/.NET Core Example) [HttpGet("report.docx")] public IActionResult GenerateDocx(string title, string content)

// 3. Main document part - STREAMING XML (no DOM) var docEntry = archive.CreateEntry("word/document.xml"); using (var docStream = docEntry.Open()) using (var xmlWriter = XmlWriter.Create(docStream, new XmlWriterSettings Indent = true )) xmlWriter.WriteStartDocument(); xmlWriter.WriteStartElement("w:document", "http://schemas.openxmlformats.org/wordprocessingml/2006/main"); xmlWriter.WriteStartElement("w:body"); // Title paragraph xmlWriter.WriteStartElement("w:p"); xmlWriter.WriteStartElement("w:r"); xmlWriter.WriteStartElement("w:t"); xmlWriter.WriteString(title); xmlWriter.WriteEndElement(); // t xmlWriter.WriteEndElement(); // r xmlWriter.WriteEndElement(); // p // Content paragraph (sanitized) var safeContent = System.Security.SecurityElement.Escape(content); xmlWriter.WriteStartElement("w:p"); xmlWriter.WriteStartElement("w:r"); xmlWriter.WriteStartElement("w:t"); xmlWriter.WriteString(safeContent); xmlWriter.WriteEndElement(); xmlWriter.WriteEndElement(); xmlWriter.WriteEndElement(); xmlWriter.WriteEndElement(); // body xmlWriter.WriteEndElement(); // document xmlWriter.WriteEndDocument(); office open xml download

stream.Position = 0; return File(stream, "application/vnd.openxmlformats-officedocument.wordprocessingml.document", "report.docx"); When reading any ZIP part, normalize the entry

Critical note: Microsoft Office defaults to , whereas some open-source parsers prefer Strict . For maximum compatibility in download scenarios, target Transitional. 3. The "Download" Problem: Generation and Delivery 3.1 Two Primary Strategies | Strategy | Description | Pros | Cons | | :--- | :--- | :--- | :--- | | Template-based | Load a pre-created .docx template, replace placeholders (e.g., name ). | Preserves complex formatting. | Requires template management; large memory if using DOM. | | Programmatic build | Build XML trees (e.g., using DocumentBuilder libraries). | Full control; scalable. | Steeper learning curve for complex layouts. | 3.2 Performance Bottleneck: DOM vs. Streaming Most naive implementations load the entire document.xml into an XML DOM (Document Object Model). For a 50-page report, this may be ~10 MB; for a 500,000-row Excel sheet, this can exceed 2 GB of RAM. this may be ~10 MB

| Method | Peak Memory (MB) | Time (s) | Max Concurrent Requests | | :--- | :--- | :--- | :--- | | (deprecated) | 1,200 | 62 | 2 (serialized) | | Open XML SDK + DOM | 890 | 28 | 8 | | Open XML SDK + Streaming (our method) | 230 | 22 | 35 |