// EscapeSet rewrites the template set to guarantee that the output of any of
// the named templates is properly escaped.
// Names should include the names of all templates that might be Executed but
// need not include helper templates.
// If no error is returned, then the named templates have been modified.
// Otherwise the named templates have been rendered unusable.
func EscapeSet(s *template.Set, names ...string) (*template.Set, os.Error) {
if len(names) == 0 {
// TODO: Maybe add a method to Set to enumerate template names
// and use those instead.
return nil, &Error{ErrNoNames, "", 0, "must specify names of top level templates"}
}
e := newEscaper(s)
for _, name := range names {
c, _ := e.escapeTree(context{}, name, 0)
var err os.Error
if c.err != nil {
err, c.err.Name = c.err, name
} else if c.state != stateText {
err = &Error{ErrEndContext, name, 0, fmt.Sprintf("ends in a non-text context: %v", c)}
}
if err != nil {
// Prevent execution of unsafe templates.
for _, name := range names {
if t := s.Template(name); t != nil {
t.Tree = nil
}
}
return nil, err
}
}
e.commit()
return s, nil
}
func TestEscapeSet(t *testing.T) {
type dataItem struct {
Children []*dataItem
X string
}
data := dataItem{
Children: []*dataItem{
&dataItem{X: "foo"},
&dataItem{X: "<bar>"},
&dataItem{
Children: []*dataItem{
&dataItem{X: "baz"},
},
},
},
}
tests := []struct {
inputs map[string]string
want string
}{
// The trivial set.
{
map[string]string{
"main": ``,
},
``,
},
// A template called in the start context.
{
map[string]string{
"main": `Hello, {{template "helper"}}!`,
// Not a valid top level HTML template.
// "<b" is not a full tag.
"helper": `{{"<World>"}}`,
},
`Hello, <World>!`,
},
// A template called in a context other than the start.
{
map[string]string{
"main": `<a onclick='a = {{template "helper"}};'>`,
// Not a valid top level HTML template.
// "<b" is not a full tag.
"helper": `{{"<a>"}}<b`,
},
`<a onclick='a = "\u003ca\u003e"<b;'>`,
},
// A recursive template that ends in its start context.
{
map[string]string{
"main": `{{range .Children}}{{template "main" .}}{{else}}{{.X}} {{end}}`,
},
`foo <bar> baz `,
},
// A recursive helper template that ends in its start context.
{
map[string]string{
"main": `{{template "helper" .}}`,
"helper": `{{if .Children}}<ul>{{range .Children}}<li>{{template "main" .}}</li>{{end}}</ul>{{else}}{{.X}}{{end}}`,
},
`<ul><li>foo</li><li><bar></li><li><ul><li>baz</li></ul></li></ul>`,
},
// Co-recursive templates that end in its start context.
{
map[string]string{
"main": `<blockquote>{{range .Children}}{{template "helper" .}}{{end}}</blockquote>`,
"helper": `{{if .Children}}{{template "main" .}}{{else}}{{.X}}<br>{{end}}`,
},
`<blockquote>foo<br><bar><br><blockquote>baz<br></blockquote></blockquote>`,
},
// A template that is called in two different contexts.
{
map[string]string{
"main": `<button onclick="title='{{template "helper"}}'; ...">{{template "helper"}}</button>`,
"helper": `{{11}} of {{"<100>"}}`,
},
`<button onclick="title='11 of \x3c100\x3e'; ...">11 of <100></button>`,
},
// A non-recursive template that ends in a different context.
// helper starts in jsCtxRegexp and ends in jsCtxDivOp.
{
map[string]string{
"main": `<script>var x={{template "helper"}}/{{"42"}};</script>`,
"helper": "{{126}}",
},
`<script>var x= 126 /"42";</script>`,
},
// A recursive template that ends in a similar context.
{
map[string]string{
"main": `<script>var x=[{{template "countdown" 4}}];</script>`,
"countdown": `{{.}}{{if .}},{{template "countdown" . | pred}}{{end}}`,
},
`<script>var x=[ 4 , 3 , 2 , 1 , 0 ];</script>`,
},
// A recursive template that ends in a different context.
/*
{
map[string]string{
"main": `<a href="/foo{{template "helper" .}}">`,
"helper": `{{if .Children}}{{range .Children}}{{template "helper" .}}{{end}}{{else}}?x={{.X}}{{end}}`,
},
`<a href="/foo?x=foo?x=%3cbar%3e?x=baz">`,
},
*/
}
// pred is a template function that returns the predecessor of a
// natural number for testing recursive templates.
fns := template.FuncMap{"pred": func(a ...interface{}) (interface{}, error) {
if len(a) == 1 {
if i, _ := a[0].(int); i > 0 {
return i - 1, nil
}
}
return nil, fmt.Errorf("undefined pred(%v)", a)
}}
for _, test := range tests {
var s template.Set
for name, src := range test.inputs {
t := template.New(name)
t.Funcs(fns)
s.Add(template.Must(t.Parse(src)))
}
s.Funcs(fns)
if _, err := EscapeSet(&s, "main"); err != nil {
t.Errorf("%s for input:\n%v", err, test.inputs)
continue
}
var b bytes.Buffer
if err := s.Execute(&b, "main", data); err != nil {
t.Errorf("%q executing %v", err.Error(), s.Template("main"))
continue
}
if got := b.String(); test.want != got {
t.Errorf("want\n\t%q\ngot\n\t%q", test.want, got)
}
}
}