io.jooby

Class XSS

java.lang.Object

io.jooby.XSS

public final class XSS
extends Object

Set of escaping routines for fixing cross-site scripting (XSS).

Method Summary

Modifier and Type	Method and Description
static String	html(String value) Perform an HTML5 level 2 (result is ASCII) escape operation on a String input.
static String	javaScript(String value) Perform a JavaScript level 2 (basic set and all non-ASCII chars) escape operation on a String input.
static String	json(String value) Perform a JSON level 2 (basic set and all non-ASCII chars) escape operation on a String input.
static String	uri(String value) Perform am URI path escape operation on a String input using UTF-8 as encoding.
static String	xml(String value) Perform an XML 1.1 level 2 (markup-significant and all non-ASCII chars) escape operation on a String input.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

uri

@Nullable
public static String uri(@Nullable
                                   String value)

Perform am URI path escape operation on a String input using UTF-8 as encoding.

The following are the only allowed chars in an URI path (will not be escaped):

• A-Z a-z 0-9
• - . _ ~
• ! $ & ' ( ) * + , ; =
• : @
• /

All other chars will be escaped by converting them to the sequence of bytes that represents them in the UTF-8 and then representing each byte in %HH syntax, being HH the hexadecimal representation of the byte.

This method is thread-safe.

Parameters:

value - the String to be escaped.

Returns:

The escaped result String. As a memory-performance improvement, will return the exact same object as the text input argument if no escaping modifications were required (and no additional String objects will be created during processing). Will return null if input is null.

html

@Nullable
public static String html(@Nullable
                                    String value)

Perform an HTML5 level 2 (result is ASCII) escape operation on a String input.

Level 2 means this method will escape:

• The five markup-significant characters: <, >, &, " and '
• All non ASCII characters.

This escape will be performed by replacing those chars by the corresponding HTML5 Named Character References (e.g. '&acute;') when such NCR exists for the replaced character, and replacing by a decimal character reference (e.g. '&#8345;') when there there is no NCR for the replaced character.

This method is thread-safe.

Parameters:

value - the String to be escaped.

Returns:

The escaped result String. As a memory-performance improvement, will return the exact same object as the text input argument if no escaping modifications were required (and no additional String objects will be created during processing). Will return null if input is null.

javaScript

@Nullable
public static String javaScript(@Nullable
                                          String value)

Perform a JavaScript level 2 (basic set and all non-ASCII chars) escape operation on a String input.

Level 2 means this method will escape:

• The JavaScript basic escape set:
  • The Single Escape Characters: \0 (U+0000), \b (U+0008), \t (U+0009), \n (U+000A), \v (U+000B), \f (U+000C), \r (U+000D), \" (U+0022), \' (U+0027), \\ (U+005C) and \/ (U+002F). Note that \/ is optional, and will only be used when the / symbol appears after <, as in </. This is to avoid accidentally closing <script> tags in HTML. Also, note that \v (U+000B) is actually included as a Single Escape Character in the JavaScript (ECMAScript) specification, but will not be used as it is not supported by Microsoft Internet Explorer versions < 9.
  • Two ranges of non-displayable, control characters (some of which are already part of the single escape characters list): U+0001 to U+001F and U+007F to U+009F.
• All non ASCII characters.

This escape will be performed by using the Single Escape Chars whenever possible. For escaped characters that do not have an associated SEC, default to using \xFF Hexadecimal Escapes if possible (characters <= U+00FF), then default to \uFFFF Hexadecimal Escapes. This type of escape produces the smallest escaped string possible.

This method is thread-safe.

Parameters:

value - the String to be escaped.

Returns:

The escaped result String. As a memory-performance improvement, will return the exact same object as the text input argument if no escaping modifications were required (and no additional String objects will be created during processing). Will return null if input is null.

json

@Nullable
public static String json(@Nullable
                                    String value)

Perform a JSON level 2 (basic set and all non-ASCII chars) escape operation on a String input.

Level 2 means this method will escape:

• The JSON basic escape set:
  • The Single Escape Characters: \b (U+0008), \t (U+0009), \n (U+000A), \f (U+000C), \r (U+000D), \" (U+0022), \\ (U+005C) and \/ (U+002F). Note that \/ is optional, and will only be used when the / symbol appears after <, as in </. This is to avoid accidentally closing <script> tags in HTML.
  • Two ranges of non-displayable, control characters (some of which are already part of the single escape characters list): U+0000 to U+001F (required by the JSON spec) and U+007F to U+009F (additional).
• All non ASCII characters.

This escape will be performed by using the Single Escape Chars whenever possible. For escaped characters that do not have an associated SEC, default to \uFFFF Hexadecimal Escapes.

This method is thread-safe.

Parameters:

value - the String to be escaped.

Returns:

The escaped result String. As a memory-performance improvement, will return the exact same object as the text input argument if no escaping modifications were required (and no additional String objects will be created during processing). Will return null if input is null.

xml

@Nullable
public static String xml(@Nullable
                                   String value)

Perform an XML 1.1 level 2 (markup-significant and all non-ASCII chars) escape operation on a String input.

Level 2 means this method will escape:

• The five markup-significant characters: <, >, &, " and '
• All non ASCII characters.

This escape will be performed by replacing those chars by the corresponding XML Character Entity References (e.g. '&lt;') when such CER exists for the replaced character, and replacing by a hexadecimal character reference (e.g. '&#x2430;') when there there is no CER for the replaced character.

This method is thread-safe.

Parameters:

value - the String to be escaped.

Returns:

The escaped result String. As a memory-performance improvement, will return the exact same object as the text input argument if no escaping modifications were required (and no additional String objects will be created during processing). Will return null if input is null.