ref: 2b8e8e6d9619af2095bff9e27b3b486cd4fc4b4c
dir: /tpl/internal/go_templates/htmltemplate/attr.go/
// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package template
import (
"strings"
)
// attrTypeMap[n] describes the value of the given attribute.
// If an attribute affects (or can mask) the encoding or interpretation of
// other content, or affects the contents, idempotency, or credentials of a
// network message, then the value in this map is contentTypeUnsafe.
// This map is derived from HTML5, specifically
// https://www.w3.org/TR/html5/Overview.html#attributes-1
// as well as "%URI"-typed attributes from
// https://www.w3.org/TR/html4/index/attributes.html
var attrTypeMap = map[string]contentType{
"accept": contentTypePlain,
"accept-charset": contentTypeUnsafe,
"action": contentTypeURL,
"alt": contentTypePlain,
"archive": contentTypeURL,
"async": contentTypeUnsafe,
"autocomplete": contentTypePlain,
"autofocus": contentTypePlain,
"autoplay": contentTypePlain,
"background": contentTypeURL,
"border": contentTypePlain,
"checked": contentTypePlain,
"cite": contentTypeURL,
"challenge": contentTypeUnsafe,
"charset": contentTypeUnsafe,
"class": contentTypePlain,
"classid": contentTypeURL,
"codebase": contentTypeURL,
"cols": contentTypePlain,
"colspan": contentTypePlain,
"content": contentTypeUnsafe,
"contenteditable": contentTypePlain,
"contextmenu": contentTypePlain,
"controls": contentTypePlain,
"coords": contentTypePlain,
"crossorigin": contentTypeUnsafe,
"data": contentTypeURL,
"datetime": contentTypePlain,
"default": contentTypePlain,
"defer": contentTypeUnsafe,
"dir": contentTypePlain,
"dirname": contentTypePlain,
"disabled": contentTypePlain,
"draggable": contentTypePlain,
"dropzone": contentTypePlain,
"enctype": contentTypeUnsafe,
"for": contentTypePlain,
"form": contentTypeUnsafe,
"formaction": contentTypeURL,
"formenctype": contentTypeUnsafe,
"formmethod": contentTypeUnsafe,
"formnovalidate": contentTypeUnsafe,
"formtarget": contentTypePlain,
"headers": contentTypePlain,
"height": contentTypePlain,
"hidden": contentTypePlain,
"high": contentTypePlain,
"href": contentTypeURL,
"hreflang": contentTypePlain,
"http-equiv": contentTypeUnsafe,
"icon": contentTypeURL,
"id": contentTypePlain,
"ismap": contentTypePlain,
"keytype": contentTypeUnsafe,
"kind": contentTypePlain,
"label": contentTypePlain,
"lang": contentTypePlain,
"language": contentTypeUnsafe,
"list": contentTypePlain,
"longdesc": contentTypeURL,
"loop": contentTypePlain,
"low": contentTypePlain,
"manifest": contentTypeURL,
"max": contentTypePlain,
"maxlength": contentTypePlain,
"media": contentTypePlain,
"mediagroup": contentTypePlain,
"method": contentTypeUnsafe,
"min": contentTypePlain,
"multiple": contentTypePlain,
"name": contentTypePlain,
"novalidate": contentTypeUnsafe,
// Skip handler names from
// https://www.w3.org/TR/html5/webappapis.html#event-handlers-on-elements,-document-objects,-and-window-objects
// since we have special handling in attrType.
"open": contentTypePlain,
"optimum": contentTypePlain,
"pattern": contentTypeUnsafe,
"placeholder": contentTypePlain,
"poster": contentTypeURL,
"profile": contentTypeURL,
"preload": contentTypePlain,
"pubdate": contentTypePlain,
"radiogroup": contentTypePlain,
"readonly": contentTypePlain,
"rel": contentTypeUnsafe,
"required": contentTypePlain,
"reversed": contentTypePlain,
"rows": contentTypePlain,
"rowspan": contentTypePlain,
"sandbox": contentTypeUnsafe,
"spellcheck": contentTypePlain,
"scope": contentTypePlain,
"scoped": contentTypePlain,
"seamless": contentTypePlain,
"selected": contentTypePlain,
"shape": contentTypePlain,
"size": contentTypePlain,
"sizes": contentTypePlain,
"span": contentTypePlain,
"src": contentTypeURL,
"srcdoc": contentTypeHTML,
"srclang": contentTypePlain,
"srcset": contentTypeSrcset,
"start": contentTypePlain,
"step": contentTypePlain,
"style": contentTypeCSS,
"tabindex": contentTypePlain,
"target": contentTypePlain,
"title": contentTypePlain,
"type": contentTypeUnsafe,
"usemap": contentTypeURL,
"value": contentTypeUnsafe,
"width": contentTypePlain,
"wrap": contentTypePlain,
"xmlns": contentTypeURL,
}
// attrType returns a conservative (upper-bound on authority) guess at the
// type of the lowercase named attribute.
func attrType(name string) contentType {
if strings.HasPrefix(name, "data-") {
// Strip data- so that custom attribute heuristics below are
// widely applied.
// Treat data-action as URL below.
name = name[5:]
} else if colon := strings.IndexRune(name, ':'); colon != -1 {
if name[:colon] == "xmlns" {
return contentTypeURL
}
// Treat svg:href and xlink:href as href below.
name = name[colon+1:]
}
if t, ok := attrTypeMap[name]; ok {
return t
}
// Treat partial event handler names as script.
if strings.HasPrefix(name, "on") {
return contentTypeJS
}
// Heuristics to prevent "javascript:..." injection in custom
// data attributes and custom attributes like g:tweetUrl.
// https://www.w3.org/TR/html5/dom.html#embedding-custom-non-visible-data-with-the-data-*-attributes
// "Custom data attributes are intended to store custom data
// private to the page or application, for which there are no
// more appropriate attributes or elements."
// Developers seem to store URL content in data URLs that start
// or end with "URI" or "URL".
if strings.Contains(name, "src") ||
strings.Contains(name, "uri") ||
strings.Contains(name, "url") {
return contentTypeURL
}
return contentTypePlain
}