Systems & architecture

#file-upload

2 posts tagged #file-upload on DiCodeWeb, from fundamentals to production, newest first.

2 postsUpdated Oct 29, 2026

Oct 29, 2026

SSRF and File Upload Security: URL Fetching and Uploads That Don't Hand Over Your Network

Link previews, webhooks, image import and file uploads look like boring features, yet they keep showing up in incident reports. Why SSRF blocklists fail, a safe fetch in Node with undici and pinned IPs, IMDSv2, and an upload pipeline: presigned S3, magic bytes, sharp, a separate domain and async scanning.

Systems & architecture18 min

Apr 23, 2026

Multimodal Input for LLM Features: Images, PDFs and Audio from the Browser

The frontend side of sending files to an LLM: file input, drag-and-drop and paste, sniffing types by magic bytes, downscaling images and stripping EXIF in the browser, HEIC from iPhones, PDFs, recording audio with MediaRecorder, presigned uploads with progress and cancellation, object URL cleanup, accessibility and what the server must still check.

Frontend & UI8 min

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SSRF and File Upload Security: URL Fetching and Uploads That Don't Hand Over Your Network

Multimodal Input for LLM Features: Images, PDFs and Audio from the Browser

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