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