Joren
25410749db
Clone the twdehands SDK into mrktplaats and retarget naming and defaults for app.marktplaats.nl while keeping the same request/response bodies and endpoint behavior.
80 lines
2.3 KiB
Go
80 lines
2.3 KiB
Go
package mrktplaats
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import (
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"bytes"
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"image"
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"image/jpeg"
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_ "image/jpeg" // register JPEG decoder for image.Decode
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"io"
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)
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// maxImageUploadBytes is the threshold above which we attempt to compress an
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// image before sending it to the API. The marktplaats endpoints reject payloads
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// that are too large (HTTP 413 / LIMIT_UNEXPECTED_FILE).
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const maxImageUploadBytes = 900 * 1024 // 900 KB
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// autoCompressImage reads all bytes from r and, if the result exceeds
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// maxImageUploadBytes, decodes it as an image and re-encodes it as a JPEG at
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// progressively smaller dimensions until it fits. If the data cannot be decoded
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// as a recognised image format it is returned unchanged (the server will then
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// return whatever error it normally would). The original data is also returned
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// unchanged if it is already within the size limit.
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func autoCompressImage(r io.Reader) ([]byte, error) {
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data, err := io.ReadAll(r)
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if err != nil {
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return nil, err
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}
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if len(data) <= maxImageUploadBytes {
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return data, nil
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}
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src, _, err := image.Decode(bytes.NewReader(data))
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if err != nil {
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// Not a format we can handle — return as-is.
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return data, nil
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}
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for maxDim := 1200; maxDim >= 300; maxDim = maxDim * 3 / 4 {
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scaled := scaleImageNN(src, maxDim)
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var buf bytes.Buffer
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if err := jpeg.Encode(&buf, scaled, &jpeg.Options{Quality: 80}); err != nil {
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return data, nil // encoding failed, return original
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}
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if buf.Len() <= maxImageUploadBytes {
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return buf.Bytes(), nil
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}
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}
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return data, nil // could not get small enough, let the server handle it
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}
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// scaleImageNN scales src down so that neither dimension exceeds maxDim,
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// preserving the aspect ratio using nearest-neighbour sampling.
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// Returns src unchanged if it already fits within maxDim×maxDim.
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func scaleImageNN(src image.Image, maxDim int) image.Image {
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bounds := src.Bounds()
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w, h := bounds.Dx(), bounds.Dy()
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dstW, dstH := w, h
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if dstW > maxDim {
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dstH = dstH * maxDim / dstW
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dstW = maxDim
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}
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if dstH > maxDim {
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dstW = dstW * maxDim / dstH
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dstH = maxDim
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}
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if dstW == w && dstH == h {
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return src
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}
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dst := image.NewRGBA(image.Rect(0, 0, dstW, dstH))
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for y := 0; y < dstH; y++ {
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srcY := bounds.Min.Y + y*h/dstH
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for x := 0; x < dstW; x++ {
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srcX := bounds.Min.X + x*w/dstW
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dst.Set(x, y, src.At(srcX, srcY))
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}
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}
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return dst
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}
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