1 package pptx
2
3 import (
4 "archive/zip"
5 "bytes"
6 "encoding/xml"
7 "fmt"
8 "io"
9 "strings"
10 )
11
12 func Validate(pptxContent []byte, nSlides int) error {
13 reader := bytes.NewReader(pptxContent)
14 zipReader, err := zip.NewReader(reader, reader.Size())
15 if err != nil {
16 fmt.Printf("error reading pptx content: %v", err)
17 }
18
19 expectedCount := getExpectedPptxFileCount(nSlides)
20 if len(zipReader.File) != expectedCount {
21 return fmt.Errorf("expected %d files, got %d", expectedCount, len(zipReader.File))
22 }
23
24 for i := 0; i < nSlides; i++ {
25 if err := checkFile(zipReader, fmt.Sprintf("ppt/slides/slide%d.xml", i+1)); err != nil {
26 return err
27 }
28 if err := checkFile(zipReader, fmt.Sprintf("ppt/slides/_rels/slide%d.xml.rels", i+1)); err != nil {
29 return err
30 }
31 if err := checkFile(zipReader, fmt.Sprintf("ppt/media/slide%dImage.png", i+1)); err != nil {
32 return err
33 }
34 }
35
36 for _, file := range zipReader.File {
37 if !strings.Contains(file.Name, ".xml") {
38 continue
39 }
40
41 f, err := file.Open()
42 if err != nil {
43 return fmt.Errorf("error opening %s: %v", file.Name, err)
44 }
45 decoder := xml.NewDecoder(f)
46 for {
47 if err := decoder.Decode(new(interface{})); err != nil {
48 if err == io.EOF {
49 break
50 }
51 return fmt.Errorf("error parsing xml content in %s: %v", file.Name, err)
52 }
53 }
54 defer f.Close()
55 }
56
57 return nil
58 }
59
60 func checkFile(reader *zip.Reader, fname string) error {
61 f, err := reader.Open(fname)
62 if err != nil {
63 return fmt.Errorf("error opening file %s: %v", fname, err)
64 }
65 defer f.Close()
66 if _, err = f.Stat(); err != nil {
67 return fmt.Errorf("error getting file info %s: %v", fname, err)
68 }
69 return nil
70 }
71
72 func getExpectedPptxFileCount(nSlides int) int {
73 reader := bytes.NewReader(PPTX_TEMPLATE)
74 zipReader, err := zip.NewReader(reader, reader.Size())
75 if err != nil {
76 return -1
77 }
78 baseFiles := len(zipReader.File)
79 presentationFiles := 5
80 slideFiles := 3 * nSlides
81 return baseFiles + presentationFiles + slideFiles
82 }
83
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