ASCIInator/server/routes/convert.js

import { randomUUID } from 'node:crypto'
import { writeFile, unlink } from 'node:fs/promises'
import path from 'node:path'
import { preprocess } from '../lib/imagemagick.js'
import {
  runChafa,
  runJp2a,
  runAsciiImageConverter,
  runImgToTxt,
} from '../lib/converters.js'

const RUNNERS = {
  chafa: runChafa,
  jp2a: runJp2a,
  'ascii-image-converter': runAsciiImageConverter,
  img2txt: runImgToTxt,
}

export async function convertRoute(fastify) {
  fastify.post('/convert', async (request, reply) => {
    let tempInput = null
    let tempProcessed = null

    try {
      const parts = request.parts()
      let tool = null
      let flags = {}

      for await (const part of parts) {
        if (part.type === 'file' && part.fieldname === 'image') {
          const SAFE_EXTS = new Set(['.jpg', '.jpeg', '.png', '.gif', '.bmp', '.webp', '.tiff', '.tif', '.avif'])
          const rawExt = path.extname(part.filename || '').toLowerCase()
          const ext = SAFE_EXTS.has(rawExt) ? rawExt : '.jpg'
          tempInput = `/tmp/asciinator-${randomUUID()}${ext}`
          const buf = await part.toBuffer()
          await writeFile(tempInput, buf)
        } else if (part.type === 'field') {
          if (part.fieldname === 'tool') tool = part.value
          if (part.fieldname === 'flags') {
            try { flags = JSON.parse(part.value) } catch { flags = {} }
          }
        }
      }

      if (!tempInput) return reply.code(400).type('text/plain').send('No image provided')
      if (!tool) return reply.code(400).type('text/plain').send('No tool specified')

      const runner = RUNNERS[tool]
      if (!runner) return reply.code(400).type('text/plain').send(`Unknown tool: ${tool}`)

      const format = tool === 'jp2a' ? 'jpg' : 'png'
      tempProcessed = await preprocess(tempInput, format)
      const result = await runner(tempProcessed, flags)

      return reply.type('text/plain').send(result.stdout)
    } catch (err) {
      if (err.exitCode !== undefined) {
        return reply.code(422).type('text/plain').send(err.stderr || err.message)
      }
      return reply.code(400).type('text/plain').send(err.message)
    } finally {
      if (tempInput) await unlink(tempInput).catch(() => {})
      if (tempProcessed) await unlink(tempProcessed).catch(() => {})
    }
  })
}