RAW Image EXIF Viewer (WebAssembly + Go)

This is a privacy-focused web application that allows users to select a RAW image from their local file system and view its EXIF metadata directly in the browser. It uses Go + WebAssembly (WASM) to parse the image, with all processing happening locally — no data is uploaded anywhere.

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Key Features

• Select RAW images directly from your device
• Privacy-first: All image processing happens completely offline in your browser
• Powered by Go + WebAssembly

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Supported RAW Formats

Currently, the following RAW file formats are supported:

• .cr2 (Canon)
• .nef (Nikon)
• .arw (Sony)
• .dng (Adobe)
• .rw2 (Panasonic)
• .raf (Fujifilm)

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How It Works (Technical Overview)

WebAssembly + Go

• The core EXIF decoding logic is written in Go, using goexif to parse EXIF metadata.
• The Go code is compiled to WebAssembly (main.wasm) using:

  GOOS=js GOARCH=wasm go build -o main.wasm main.go

JS ↔ Go Interop

• In the browser, wasm_exec.js (provided by Go) bridges JavaScript and WebAssembly.
• A process(arrayBuffer) function is exposed to JS via js.FuncOf() in Go.
• JavaScript reads the selected image using FileReader.readAsArrayBuffer(), and the byte array is passed into Go using:

  js.CopyBytesToGo(imgBytes, p[0])

Data Flow

1. User selects a file → JS reads it as ArrayBuffer
2. JS passes the bytes to WASM-Go via process()
3. Go decodes EXIF using goexif.Decode and returns JSON
4. JS parses JSON and renders a styled table