url.go | Explore in Territory

// urlFilter returns its input unless it contains an unsafe scheme in which
// case it defangs the entire URL.
//
// Schemes that cause unintended side effects that are irreversible without user
// interaction are considered unsafe. For example, clicking on a "javascript:"
// link can immediately trigger JavaScript code execution.
//
// This filter conservatively assumes that all schemes other than the following
// are unsafe:
//   - http:   Navigates to a new website, and may open a new window or tab.
//     These side effects can be reversed by navigating back to the
//     previous website, or closing the window or tab. No irreversible
//     changes will take place without further user interaction with
//     the new website.
//   - https:  Same as http.
//   - mailto: Opens an email program and starts a new draft. This side effect
//     is not irreversible until the user explicitly clicks send; it
//     can be undone by closing the email program.
//
// To allow URLs containing other schemes to bypass this filter, developers must
// explicitly indicate that such a URL is expected and safe by encapsulating it
// in a template.URL value.
func urlFilter(args ...any) string { … }

// isSafeURL is true if s is a relative URL or if URL has a protocol in
// (http, https, mailto).
func isSafeURL(s string) bool { … }

// urlEscaper produces an output that can be embedded in a URL query.
// The output can be embedded in an HTML attribute without further escaping.
func urlEscaper(args ...any) string { … }

// urlNormalizer normalizes URL content so it can be embedded in a quote-delimited
// string or parenthesis delimited url(...).
// The normalizer does not encode all HTML specials. Specifically, it does not
// encode '&' so correct embedding in an HTML attribute requires escaping of
// '&' to '&amp;'.
func urlNormalizer(args ...any) string { … }

// urlProcessor normalizes (when norm is true) or escapes its input to produce
// a valid hierarchical or opaque URL part.
func urlProcessor(norm bool, args ...any) string { … }

// processURLOnto appends a normalized URL corresponding to its input to b
// and reports whether the appended content differs from s.
func processURLOnto(s string, norm bool, b *strings.Builder) bool { … }

// Filters and normalizes srcset values which are comma separated
// URLs followed by metadata.
func srcsetFilterAndEscaper(args ...any) string { … }

const htmlSpaceAndASCIIAlnumBytes …

// isHTMLSpace is true iff c is a whitespace character per
// https://infra.spec.whatwg.org/#ascii-whitespace
func isHTMLSpace(c byte) bool { … }

func isHTMLSpaceOrASCIIAlnum(c byte) bool { … }

func filterSrcsetElement(s string, left int, right int, b *strings.Builder) { … }
go/src/html/template/url.go
