Jakub Zych
f22d08902e
- add a content textarea (size huge) after description, with en and pl phrases - add content to Category.Fillable - export classes.CheckHTML and run it from FormBeforeCreate and FormBeforeUpdate: unsafe category content answers 422 on content, blank content is stored as NULL
59 lines
1.8 KiB
Go
59 lines
1.8 KiB
Go
package classes
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import (
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"bytes"
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"fmt"
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"regexp"
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"strings"
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"github.com/yuin/goldmark"
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"github.com/yuin/goldmark/extension"
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"github.com/yuin/goldmark/parser"
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)
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var (
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markdownEngine = goldmark.New(
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goldmark.WithExtensions(extension.Footnote, extension.Table),
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goldmark.WithParserOptions(parser.WithAttribute()),
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)
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markdownUnsafeTag = regexp.MustCompile(`(?i)<(?:script|iframe|object|embed)\b`)
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markdownEventHandler = regexp.MustCompile(`(?i)\son[a-z]+\s*=`)
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markdownDangerousURL = regexp.MustCompile(`(?i)(?:javascript|vbscript|data):`)
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)
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// FormatHTML converts journal post markdown to stored HTML using goldmark
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// footnote, table, and attribute extensions, then the same rejectUnsafe gate
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// as cabana.RenderMarkdown. It does not call cabana.RenderMarkdown.
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func FormatHTML(src string) (string, error) {
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var buf bytes.Buffer
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if err := markdownEngine.Convert([]byte(strings.TrimSpace(src)), &buf); err != nil {
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return "", fmt.Errorf("journal: markdown: %w", err)
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}
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html := buf.String()
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if err := rejectUnsafe(html); err != nil {
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return "", err
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}
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return html, nil
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}
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// CheckHTML applies the FormatHTML safety gate to HTML that is stored as is,
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// such as category content. It refuses raw script, iframe, object and embed
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// tags, event handler attributes and javascript, vbscript or data URL schemes.
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func CheckHTML(html string) error {
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return rejectUnsafe(html)
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}
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func rejectUnsafe(html string) error {
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if markdownUnsafeTag.MatchString(html) {
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return fmt.Errorf("journal: rendered HTML contains raw unsafe tags")
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}
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if markdownEventHandler.MatchString(html) {
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return fmt.Errorf("journal: rendered HTML contains event handlers")
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}
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if markdownDangerousURL.MatchString(html) {
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return fmt.Errorf("journal: rendered HTML contains a dangerous URL scheme")
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}
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return nil
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}
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