patrick
9a24ea29e1
Git-Repository für bestehenden archivdms-Code initialisiert, Branch-/Commit-Konvention (feature/<ticket>-<slug>-Branches, Ticket-Prefix in Commit-Nachricht) etabliert.
65 lines
2.2 KiB
Go
65 lines
2.2 KiB
Go
// Package barcode wraps the system zbarimg binary (Debian package
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// zbar-tools) as a best-effort barcode decoding sidecar, consistent with
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// archivdms's general philosophy of shelling out to small CLI tools via
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// os/exec instead of adding CGO/native Go dependencies (see
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// internal/ocr/ocr.go package comment for the same rationale applied to
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// tesseract/poppler-utils).
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//
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// Barcode decoding failures (binary missing, non-zero exit because no
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// barcode was found, timeout) are never fatal to an upload: DecodeBarcodes
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// returns an empty slice and a nil error in the "nothing found / binary
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// missing" cases, matching how OCR failures are tolerated by callers.
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package barcode
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import (
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"bytes"
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"context"
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"fmt"
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"os/exec"
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"strings"
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"time"
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)
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const defaultTimeout = 20 * time.Second
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// DecodeBarcodes runs `zbarimg --raw -q <imagePath>` and returns the
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// decoded raw values, one per line of output. If zbarimg is not installed,
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// this returns an empty slice and a nil error (tolerant, no hard-fail) —
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// callers that want to warn about a missing binary should check
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// exec.LookPath("zbarimg") themselves if they need to distinguish
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// "not installed" from "installed, nothing found".
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func DecodeBarcodes(ctx context.Context, imagePath string) ([]string, error) {
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if _, err := exec.LookPath("zbarimg"); err != nil {
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// Binary not present: tolerated, same as a missing tesseract binary.
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return nil, nil
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}
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cctx, cancel := context.WithTimeout(ctx, defaultTimeout)
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defer cancel()
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cmd := exec.CommandContext(cctx, "zbarimg", "--raw", "-q", imagePath)
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var out, stderr bytes.Buffer
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cmd.Stdout = &out
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cmd.Stderr = &stderr
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err := cmd.Run()
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if err != nil {
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// zbarimg exits non-zero (typically exit code 4) when no barcode is
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// found in the image at all — that is a normal, expected outcome for
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// the vast majority of scanned documents, not an error condition.
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if exitErr, ok := err.(*exec.ExitError); ok {
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_ = exitErr
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return nil, nil
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}
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return nil, fmt.Errorf("barcode: zbarimg failed: %w (%s)", err, strings.TrimSpace(stderr.String()))
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}
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var values []string
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for _, line := range strings.Split(out.String(), "\n") {
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line = strings.TrimSpace(line)
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if line != "" {
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values = append(values, line)
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}
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}
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return values, nil
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}
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