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html/template: update to new template API

Browse source 
Not quite done yet but enough is here to review.

Embedding is eliminated so clients can't accidentally reach
methods of text/template.Template that would break the
invariants.

TODO later: Add and Clone are unimplemented.
TODO later: address issue 2349

R=golang-dev, r, rsc
CC=golang-dev
https://golang.org/cl/5434077
This commit is contained in:
Rob Pike 2011-11-30 17:42:18 -05:00 committed by Russ Cox
parent 0e62c75b9d
commit 07ee3cc741
5 changed files with 213 additions and 234 deletions
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1
src/pkg/Makefile
View file

@ -102,6 +102,7 @@ DIRS=\
hash/crc64\
hash/fnv\
html\
html/template\
image\
image/bmp\
image/color\

34
src/pkg/html/template/clone_test.go
View file

@ -7,8 +7,6 @@ package template
import (
"bytes"
"testing"
"text/template"
"text/template/parse"
)
func TestClone(t *testing.T) {
@ -48,15 +46,20 @@ func TestClone(t *testing.T) {
}
for _, test := range tests {
s := template.Must(template.New("s").Parse(test.input))
d := template.New("d")
d.Tree = &parse.Tree{Name: d.Name(), Root: cloneList(s.Root)}
s, err := New("s").Parse(test.input)
if err != nil {
t.Errorf("input=%q: unexpected parse error %v", test.input, err)
}
if want, got := s.Root.String(), d.Root.String(); want != got {
d, _ := New("d").Parse(test.input)
// Hack: just replace the root of the tree.
d.text.Root = cloneList(s.text.Root)
if want, got := s.text.Root.String(), d.text.Root.String(); want != got {
t.Errorf("want %q, got %q", want, got)
}
err := escape(d)
err = escapeTemplates(d, "d")
if err != nil {
t.Errorf("%q: failed to escape: %s", test.input, err)
continue
@ -73,18 +76,17 @@ func TestClone(t *testing.T) {
data := []string{"foo", "<bar>", "baz"}
// Make sure escaping d did not affect s.
var b bytes.Buffer
s.Execute(&b, data)
if got := b.String(); got != test.want {
t.Errorf("%q: want %q, got %q", test.input, test.want, got)
continue
}
b.Reset()
d.Execute(&b, data)
if got := b.String(); got != test.wantClone {
t.Errorf("%q: want %q, got %q", test.input, test.wantClone, got)
t.Errorf("input=%q: want %q, got %q", test.input, test.wantClone, got)
}
// Make sure escaping d did not affect s.
b.Reset()
s.text.Execute(&b, data)
if got := b.String(); got != test.want {
t.Errorf("input=%q: want %q, got %q", test.input, test.want, got)
}
}
}

47
src/pkg/html/template/escape.go
View file

@ -12,24 +12,15 @@ import (
"text/template/parse"
)
// escape rewrites each action in the template to guarantee that the output is
// properly escaped.
func escape(t *template.Template) error {
var s template.Set
s.Add(t)
return escapeSet(&s, t.Name())
// TODO: if s contains cloned dependencies due to self-recursion
// cross-context, error out.
}
// 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) error {
e := newEscaper(s)
// escapeTemplates rewrites the named templates, which must be
// associated with t, 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 escapeTemplates(tmpl *Template, names ...string) error {
e := newEscaper(tmpl)
for _, name := range names {
c, _ := e.escapeTree(context{}, name, 0)
var err error
@ -41,12 +32,13 @@ func escapeSet(s *template.Set, names ...string) error {
if err != nil {
// Prevent execution of unsafe templates.
for _, name := range names {
if t := s.Template(name); t != nil {
t.Tree = nil
if t := tmpl.Lookup(name); t != nil {
t.text.Tree = nil
}
}
return err
}
tmpl.escaped = true
}
e.commit()
return nil
@ -83,8 +75,7 @@ var equivEscapers = map[string]string{
// escaper collects type inferences about templates and changes needed to make
// templates injection safe.
type escaper struct {
// set is the template set being escaped.
set *template.Set
tmpl *Template
// output[templateName] is the output context for a templateName that
// has been mangled to include its input context.
output map[string]context
@ -102,9 +93,9 @@ type escaper struct {
}
// newEscaper creates a blank escaper for the given set.
func newEscaper(s *template.Set) *escaper {
func newEscaper(t *Template) *escaper {
return &escaper{
s,
t,
map[string]context{},
map[string]*template.Template{},
map[string]bool{},
@ -442,7 +433,7 @@ func (e *escaper) escapeList(c context, n *parse.ListNode) context {
// It returns the best guess at an output context, and the result of the filter
// which is the same as whether e was updated.
func (e *escaper) escapeListConditionally(c context, n *parse.ListNode, filter func(*escaper, context) bool) (context, bool) {
e1 := newEscaper(e.set)
e1 := newEscaper(e.tmpl)
// Make type inferences available to f.
for k, v := range e.output {
e1.output[k] = v
@ -501,7 +492,7 @@ func (e *escaper) escapeTree(c context, name string, line int) (context, string)
}, dname
}
if dname != name {
// Use any template derived during an earlier call to escapeSet
// Use any template derived during an earlier call to escapeTemplate
// with different top level templates, or clone if necessary.
dt := e.template(dname)
if dt == nil {
@ -729,7 +720,7 @@ func (e *escaper) commit() {
e.template(name).Funcs(funcMap)
}
for _, t := range e.derived {
e.set.Add(t)
e.tmpl.text.Add(t)
}
for n, s := range e.actionNodeEdits {
ensurePipelineContains(n.Pipe, s)
@ -744,7 +735,7 @@ func (e *escaper) commit() {
// template returns the named template given a mangled template name.
func (e *escaper) template(name string) *template.Template {
t := e.set.Template(name)
t := e.tmpl.text.Lookup(name)
if t == nil {
t = e.derived[name]
}

38
src/pkg/html/template/escape_test.go
View file

@ -806,13 +806,15 @@ func TestEscapeSet(t *testing.T) {
for name, body := range test.inputs {
source += fmt.Sprintf("{{define %q}}%s{{end}} ", name, body)
}
s := &Set{}
s.Funcs(fns)
s.Parse(source)
tmpl, err := New("root").Funcs(fns).Parse(source)
if err != nil {
t.Errorf("error parsing %q: %v", source, err)
continue
}
var b bytes.Buffer
if err := s.Execute(&b, "main", data); err != nil {
t.Errorf("%q executing %v", err.Error(), s.Template("main"))
if err := tmpl.ExecuteTemplate(&b, "main", data); err != nil {
t.Errorf("%q executing %v", err.Error(), tmpl.Lookup("main"))
continue
}
if got := b.String(); test.want != got {
@ -929,13 +931,13 @@ func TestErrors(t *testing.T) {
"z:1: no such template foo",
},
{
`{{define "z"}}<div{{template "y"}}>{{end}}` +
`<div{{template "y"}}>` +
// Illegal starting in stateTag but not in stateText.
`{{define "y"}} foo<b{{end}}`,
`"<" in attribute name: " foo<b"`,
},
{
`{{define "z"}}<script>reverseList = [{{template "t"}}]</script>{{end}}` +
`<script>reverseList = [{{template "t"}}]</script>` +
// Missing " after recursive call.
`{{define "t"}}{{if .Tail}}{{template "t" .Tail}}{{end}}{{.Head}}",{{end}}`,
`: cannot compute output context for template t$htmltemplate_stateJS_elementScript`,
@ -967,21 +969,13 @@ func TestErrors(t *testing.T) {
}
for _, test := range tests {
var err error
buf := new(bytes.Buffer)
if strings.HasPrefix(test.input, "{{define") {
var s *Set
s, err = (&Set{}).Parse(test.input)
if err == nil {
err = s.Execute(buf, "z", nil)
}
} else {
var t *Template
t, err = New("z").Parse(test.input)
if err == nil {
err = t.Execute(buf, nil)
}
tmpl, err := New("z").Parse(test.input)
if err != nil {
t.Errorf("input=%q: unexpected parse error %s\n", test.input, err)
continue
}
err = tmpl.Execute(buf, nil)
var got string
if err != nil {
got = err.Error()
@ -1569,11 +1563,11 @@ func TestEscapeErrorsNotIgnorable(t *testing.T) {
func TestEscapeSetErrorsNotIgnorable(t *testing.T) {
var b bytes.Buffer
s, err := (&Set{}).Parse(`{{define "t"}}<a{{end}}`)
tmpl, err := New("root").Parse(`{{define "t"}}<a{{end}}`)
if err != nil {
t.Errorf("failed to parse set: %q", err)
}
err = s.Execute(&b, "t", nil)
err = tmpl.ExecuteTemplate(&b, "t", nil)
if err == nil {
t.Errorf("Expected error")
} else if b.Len() != 0 {

327
src/pkg/html/template/template.go
View file

@ -7,233 +7,224 @@ package template
import (
"fmt"
"io"
"io/ioutil"
"path/filepath"
"text/template"
)
// Set is a specialized template.Set that produces a safe HTML document
// fragment.
type Set struct {
escaped map[string]bool
template.Set
}
// Template is a specialized template.Template that produces a safe HTML
// document fragment.
type Template struct {
escaped bool
*template.Template
// We could embed the text/template field, but it's safer not to because
// we need to keep our version of the name space and the underlying
// template's in sync.
text *template.Template
// Templates are grouped by sharing the set, a pointer.
set *map[string]*Template
}
// Execute applies the named template to the specified data object, writing
// the output to wr.
func (s *Set) Execute(wr io.Writer, name string, data interface{}) error {
if !s.escaped[name] {
if err := escapeSet(&s.Set, name); err != nil {
// ExecuteTemplate applies the template associated with t that has the given name
// to the specified data object and writes the output to wr.
func (t *Template) ExecuteTemplate(wr io.Writer, name string, data interface{}) error {
tmpl := t.Lookup(name)
if tmpl == nil {
return fmt.Errorf("template: no template %q associated with template %q", name, t.Name())
}
if !tmpl.escaped {
if err := escapeTemplates(tmpl, name); err != nil { // TODO: make a method of set?
return err
}
if s.escaped == nil {
s.escaped = make(map[string]bool)
}
s.escaped[name] = true
}
return s.Set.Execute(wr, name, data)
return tmpl.text.ExecuteTemplate(wr, name, data)
}
// Parse parses a string into a set of named templates. Parse may be called
// multiple times for a given set, adding the templates defined in the string
// to the set. If a template is redefined, the element in the set is
// overwritten with the new definition.
func (set *Set) Parse(src string) (*Set, error) {
set.escaped = nil
s, err := set.Set.Parse(src)
func (t *Template) Parse(src string) (*Template, error) {
t.escaped = false
ret, err := t.text.Parse(src)
if err != nil {
return nil, err
}
if s != &(set.Set) {
panic("allocated new set")
// In general, all the named templates might have changed underfoot.
// Regardless, some new ones may have been defined.
// The template.Template set has been updated; update ours.
for _, v := range ret.Templates() {
name := v.Name()
tmpl := t.Lookup(name)
if tmpl == nil {
tmpl = t.New(name)
}
tmpl.escaped = false
tmpl.text = v
}
return set, nil
}
// Parse parses the template definition string to construct an internal
// representation of the template for execution.
func (tmpl *Template) Parse(src string) (*Template, error) {
tmpl.escaped = false
t, err := tmpl.Template.Parse(src)
if err != nil {
return nil, err
}
tmpl.Template = t
return tmpl, nil
return t, nil
}
// Execute applies a parsed template to the specified data object,
// writing the output to wr.
func (t *Template) Execute(wr io.Writer, data interface{}) error {
if !t.escaped {
if err := escape(t.Template); err != nil {
if err := escapeTemplates(t, t.Name()); err != nil {
return err
}
t.escaped = true
}
return t.Template.Execute(wr, data)
return t.text.Execute(wr, data)
}
// Add is unimplemented.
func (t *Template) Add(*Template) error {
return fmt.Errorf("html/template: Add unimplemented")
}
// Clone is unimplemented.
func (t *Template) Clone(name string) error {
return fmt.Errorf("html/template: Add unimplemented")
}
// New allocates a new HTML template with the given name.
func New(name string) *Template {
return &Template{false, template.New(name)}
set := make(map[string]*Template)
tmpl := &Template{
false,
template.New(name),
&set,
}
(*tmpl.set)[name] = tmpl
return tmpl
}
// New allocates a new HTML template associated with the given one
// and with the same delimiters. The association, which is transitive,
// allows one template to invoke another with a {{template}} action.
func (t *Template) New(name string) *Template {
tmpl := &Template{
false,
t.text.New(name),
t.set,
}
(*tmpl.set)[name] = tmpl
return tmpl
}
// Name returns the name of the template.
func (t *Template) Name() string {
return t.text.Name()
}
// Funcs adds the elements of the argument map to the template's function map.
// It panics if a value in the map is not a function with appropriate return
// type. However, it is legal to overwrite elements of the map. The return
// value is the template, so calls can be chained.
func (t *Template) Funcs(funcMap template.FuncMap) *Template {
t.text.Funcs(funcMap)
return t
}
// Delims sets the action delimiters to the specified strings, to be used in
// subsequent calls to Parse, ParseFiles, or ParseGlob. Nested template
// definitions will inherit the settings. An empty delimiter stands for the
// corresponding default: {{ or }}.
// The return value is the template, so calls can be chained.
func (t *Template) Delims(left, right string) *Template {
t.text.Delims(left, right)
return t
}
// Lookup returns the template with the given name that is associated with t,
// or nil if there is no such template.
func (t *Template) Lookup(name string) *Template {
return (*t.set)[name]
}
// Must panics if err is non-nil in the same way as template.Must.
func Must(t *Template, err error) *Template {
t.Template = template.Must(t.Template, err)
t.text = template.Must(t.text, err)
return t
}
// ParseFile creates a new Template and parses the template definition from
// the named file. The template name is the base name of the file.
func ParseFile(filename string) (*Template, error) {
t, err := template.ParseFile(filename)
if err != nil {
return nil, err
}
return &Template{false, t}, nil
// ParseFiles creates a new Template and parses the template definitions from
// the named files. The returned template's name will have the (base) name and
// (parsed) contents of the first file. There must be at least one file.
// If an error occurs, parsing stops and the returned *Template is nil.
func ParseFiles(filenames ...string) (*Template, error) {
return parseFiles(nil, filenames...)
}
// ParseFile reads the template definition from a file and parses it to
// construct an internal representation of the template for execution.
// The returned template will be nil if an error occurs.
func (tmpl *Template) ParseFile(filename string) (*Template, error) {
t, err := tmpl.Template.ParseFile(filename)
if err != nil {
return nil, err
}
tmpl.Template = t
return tmpl, nil
// ParseFiles parses the named files and associates the resulting templates with
// t. If an error occurs, parsing stops and the returned template is nil;
// otherwise it is t. There must be at least one file.
func (t *Template) ParseFiles(filenames ...string) (*Template, error) {
return parseFiles(t, filenames...)
}
// SetMust panics if the error is non-nil just like template.SetMust.
func SetMust(s *Set, err error) *Set {
if err != nil {
template.SetMust(&(s.Set), err)
// parseFiles is the helper for the method and function. If the argument
// template is nil, it is created from the first file.
func parseFiles(t *Template, filenames ...string) (*Template, error) {
if len(filenames) == 0 {
// Not really a problem, but be consistent.
return nil, fmt.Errorf("template: no files named in call to ParseFiles")
}
return s
for _, filename := range filenames {
b, err := ioutil.ReadFile(filename)
if err != nil {
return nil, err
}
s := string(b)
name := filepath.Base(filename)
// First template becomes return value if not already defined,
// and we use that one for subsequent New calls to associate
// all the templates together. Also, if this file has the same name
// as t, this file becomes the contents of t, so
// t, err := New(name).Funcs(xxx).ParseFiles(name)
// works. Otherwise we create a new template associated with t.
var tmpl *Template
if t == nil {
t = New(name)
}
if name == t.Name() {
tmpl = t
} else {
tmpl = t.New(name)
}
_, err = tmpl.Parse(s)
if err != nil {
return nil, err
}
}
return t, nil
}
// ParseFiles parses the named files into a set of named templates.
// Each file must be parseable by itself.
// If an error occurs, parsing stops and the returned set is nil.
func (set *Set) ParseFiles(filenames ...string) (*Set, error) {
s, err := set.Set.ParseFiles(filenames...)
if err != nil {
return nil, err
}
if s != &(set.Set) {
panic("allocated new set")
}
return set, nil
// ParseGlob creates a new Template and parses the template definitions from the
// files identified by the pattern, which must match at least one file. The
// returned template will have the (base) name and (parsed) contents of the
// first file matched by the pattern. ParseGlob is equivalent to calling
// ParseFiles with the list of files matched by the pattern.
func ParseGlob(pattern string) (*Template, error) {
return parseGlob(nil, pattern)
}
// ParseSetFiles creates a new Set and parses the set definition from the
// named files. Each file must be individually parseable.
func ParseSetFiles(filenames ...string) (*Set, error) {
set := new(Set)
s, err := set.Set.ParseFiles(filenames...)
if err != nil {
return nil, err
}
if s != &(set.Set) {
panic("allocated new set")
}
return set, nil
// ParseGlob parses the template definitions in the files identified by the
// pattern and associates the resulting templates with t. The pattern is
// processed by filepath.Glob and must match at least one file. ParseGlob is
// equivalent to calling t.ParseFiles with the list of files matched by the
// pattern.
func (t *Template) ParseGlob(pattern string) (*Template, error) {
return parseGlob(t, pattern)
}
// ParseGlob parses the set definition from the files identified by the
// pattern. The pattern is processed by filepath.Glob and must match at
// least one file.
// If an error occurs, parsing stops and the returned set is nil.
func (s *Set) ParseGlob(pattern string) (*Set, error) {
// parseGlob is the implementation of the function and method ParseGlob.
func parseGlob(t *Template, pattern string) (*Template, error) {
filenames, err := filepath.Glob(pattern)
if err != nil {
return nil, err
}
if len(filenames) == 0 {
return nil, fmt.Errorf("pattern matches no files: %#q", pattern)
return nil, fmt.Errorf("template: pattern matches no files: %#q", pattern)
}
return s.ParseFiles(filenames...)
}
// ParseSetGlob creates a new Set and parses the set definition from the
// files identified by the pattern. The pattern is processed by filepath.Glob
// and must match at least one file.
func ParseSetGlob(pattern string) (*Set, error) {
set, err := new(Set).ParseGlob(pattern)
if err != nil {
return nil, err
}
return set, nil
}
// Functions and methods to parse stand-alone template files into a set.
// ParseTemplateFiles parses the named template files and adds them to the set
// in the same way as template.ParseTemplateFiles but ensures that templates
// with upper-case names are contextually-autoescaped.
func (set *Set) ParseTemplateFiles(filenames ...string) (*Set, error) {
s, err := set.Set.ParseTemplateFiles(filenames...)
if err != nil {
return nil, err
}
if s != &(set.Set) {
panic("new set allocated")
}
return set, nil
}
// ParseTemplateGlob parses the template files matched by the
// patern and adds them to the set. Each template will be named
// the base name of its file.
// Unlike with ParseGlob, each file should be a stand-alone template
// definition suitable for Template.Parse (not Set.Parse); that is, the
// file does not contain {{define}} clauses. ParseTemplateGlob is
// therefore equivalent to calling the ParseFile function to create
// individual templates, which are then added to the set.
// Each file must be parseable by itself.
// If an error occurs, parsing stops and the returned set is nil.
func (s *Set) ParseTemplateGlob(pattern string) (*Set, error) {
filenames, err := filepath.Glob(pattern)
if err != nil {
return nil, err
}
return s.ParseTemplateFiles(filenames...)
}
// ParseTemplateFiles creates a set by parsing the named files,
// each of which defines a single template. Each template will be
// named the base name of its file.
// Unlike with ParseFiles, each file should be a stand-alone template
// definition suitable for Template.Parse (not Set.Parse); that is, the
// file does not contain {{define}} clauses. ParseTemplateFiles is
// therefore equivalent to calling the ParseFile function to create
// individual templates, which are then added to the set.
// Each file must be parseable by itself. Parsing stops if an error is
// encountered.
func ParseTemplateFiles(filenames ...string) (*Set, error) {
return new(Set).ParseTemplateFiles(filenames...)
}
// ParseTemplateGlob creates a set by parsing the files matched
// by the pattern, each of which defines a single template. The pattern
// is processed by filepath.Glob and must match at least one file. Each
// template will be named the base name of its file.
// Unlike with ParseGlob, each file should be a stand-alone template
// definition suitable for Template.Parse (not Set.Parse); that is, the
// file does not contain {{define}} clauses. ParseTemplateGlob is
// therefore equivalent to calling the ParseFile function to create
// individual templates, which are then added to the set.
// Each file must be parseable by itself. Parsing stops if an error is
// encountered.
func ParseTemplateGlob(pattern string) (*Set, error) {
return new(Set).ParseTemplateGlob(pattern)
return parseFiles(t, filenames...)
}