82 lines
2 KiB
Go
82 lines
2 KiB
Go
package pptx
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import (
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"archive/zip"
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"bytes"
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"encoding/xml"
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"fmt"
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"io"
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"strings"
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)
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func Validate(pptxContent []byte, nSlides int) error {
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reader := bytes.NewReader(pptxContent)
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zipReader, err := zip.NewReader(reader, reader.Size())
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if err != nil {
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fmt.Printf("error reading pptx content: %v", err)
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}
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expectedCount := getExpectedPptxFileCount(nSlides)
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if len(zipReader.File) != expectedCount {
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return fmt.Errorf("expected %d files, got %d", expectedCount, len(zipReader.File))
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}
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for i := 0; i < nSlides; i++ {
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if err := checkFile(zipReader, fmt.Sprintf("ppt/slides/slide%d.xml", i+1)); err != nil {
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return err
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}
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if err := checkFile(zipReader, fmt.Sprintf("ppt/slides/_rels/slide%d.xml.rels", i+1)); err != nil {
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return err
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}
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if err := checkFile(zipReader, fmt.Sprintf("ppt/media/slide%dImage.png", i+1)); err != nil {
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return err
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}
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}
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for _, file := range zipReader.File {
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if !strings.Contains(file.Name, ".xml") {
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continue
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}
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// checks if the XML content is valid
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f, err := file.Open()
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if err != nil {
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return fmt.Errorf("error opening %s: %v", file.Name, err)
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}
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decoder := xml.NewDecoder(f)
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for {
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if err := decoder.Decode(new(interface{})); err != nil {
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if err == io.EOF {
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break
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}
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return fmt.Errorf("error parsing xml content in %s: %v", file.Name, err)
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}
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}
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defer f.Close()
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}
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return nil
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}
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func checkFile(reader *zip.Reader, fname string) error {
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f, err := reader.Open(fname)
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if err != nil {
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return fmt.Errorf("error opening file %s: %v", fname, err)
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}
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defer f.Close()
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if _, err = f.Stat(); err != nil {
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return fmt.Errorf("error getting file info %s: %v", fname, err)
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}
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return nil
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}
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func getExpectedPptxFileCount(nSlides int) int {
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reader := bytes.NewReader(PPTX_TEMPLATE)
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zipReader, err := zip.NewReader(reader, reader.Size())
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if err != nil {
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return -1
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}
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baseFiles := len(zipReader.File)
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presentationFiles := 5 // presentation, rels, app, core, content types
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slideFiles := 3 * nSlides // slides, rels, images
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return baseFiles + presentationFiles + slideFiles
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}
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