SizeConstraint
Note
AWS WAF Classic support will end on September 30, 2025.
This is AWS WAF Classic documentation. For more information, see AWS WAF Classic in the developer guide.
For the latest version of AWS WAF , use the AWS WAFV2 API and see the AWS WAF Developer Guide. With the latest version, AWS WAF has a single set of endpoints for regional and global use.
Specifies a constraint on the size of a part of the web request. AWS WAF uses the Size
, ComparisonOperator
, and FieldToMatch
to build
an expression in the form of "Size
ComparisonOperator
size in bytes of FieldToMatch
". If that expression is true, the
SizeConstraint
is considered to match.
Contents
- ComparisonOperator
-
The type of comparison you want AWS WAF to perform. AWS WAF uses this in combination with the provided
Size
andFieldToMatch
to build an expression in the form of "Size
ComparisonOperator
size in bytes ofFieldToMatch
". If that expression is true, theSizeConstraint
is considered to match.EQ: Used to test if the
Size
is equal to the size of theFieldToMatch
NE: Used to test if the
Size
is not equal to the size of theFieldToMatch
LE: Used to test if the
Size
is less than or equal to the size of theFieldToMatch
LT: Used to test if the
Size
is strictly less than the size of theFieldToMatch
GE: Used to test if the
Size
is greater than or equal to the size of theFieldToMatch
GT: Used to test if the
Size
is strictly greater than the size of theFieldToMatch
Type: String
Valid Values:
EQ | NE | LE | LT | GE | GT
Required: Yes
- FieldToMatch
-
Specifies where in a web request to look for the size constraint.
Type: FieldToMatch object
Required: Yes
- Size
-
The size in bytes that you want AWS WAF to compare against the size of the specified
FieldToMatch
. AWS WAF uses this in combination withComparisonOperator
andFieldToMatch
to build an expression in the form of "Size
ComparisonOperator
size in bytes ofFieldToMatch
". If that expression is true, theSizeConstraint
is considered to match.Valid values for size are 0 - 21474836480 bytes (0 - 20 GB).
If you specify
URI
for the value ofType
, the / in the URI path that you specify counts as one character. For example, the URI/logo.jpg
is nine characters long.Type: Long
Valid Range: Minimum value of 0. Maximum value of 21474836480.
Required: Yes
- TextTransformation
-
Text transformations eliminate some of the unusual formatting that attackers use in web requests in an effort to bypass AWS WAF. If you specify a transformation, AWS WAF performs the transformation on
FieldToMatch
before inspecting it for a match.You can only specify a single type of TextTransformation.
Note that if you choose
BODY
for the value ofType
, you must chooseNONE
forTextTransformation
because Amazon CloudFront forwards only the first 8192 bytes for inspection.NONE
Specify
NONE
if you don't want to perform any text transformations.CMD_LINE
When you're concerned that attackers are injecting an operating system command line command and using unusual formatting to disguise some or all of the command, use this option to perform the following transformations:
-
Delete the following characters: \ " ' ^
-
Delete spaces before the following characters: / (
-
Replace the following characters with a space: , ;
-
Replace multiple spaces with one space
-
Convert uppercase letters (A-Z) to lowercase (a-z)
COMPRESS_WHITE_SPACE
Use this option to replace the following characters with a space character (decimal 32):
-
\f, formfeed, decimal 12
-
\t, tab, decimal 9
-
\n, newline, decimal 10
-
\r, carriage return, decimal 13
-
\v, vertical tab, decimal 11
-
non-breaking space, decimal 160
COMPRESS_WHITE_SPACE
also replaces multiple spaces with one space.HTML_ENTITY_DECODE
Use this option to replace HTML-encoded characters with unencoded characters.
HTML_ENTITY_DECODE
performs the following operations:-
Replaces
(ampersand)quot;
with"
-
Replaces
(ampersand)nbsp;
with a non-breaking space, decimal 160 -
Replaces
(ampersand)lt;
with a "less than" symbol -
Replaces
(ampersand)gt;
with>
-
Replaces characters that are represented in hexadecimal format,
(ampersand)#xhhhh;
, with the corresponding characters -
Replaces characters that are represented in decimal format,
(ampersand)#nnnn;
, with the corresponding characters
LOWERCASE
Use this option to convert uppercase letters (A-Z) to lowercase (a-z).
URL_DECODE
Use this option to decode a URL-encoded value.
Type: String
Valid Values:
NONE | COMPRESS_WHITE_SPACE | HTML_ENTITY_DECODE | LOWERCASE | CMD_LINE | URL_DECODE
Required: Yes
-
See Also
For more information about using this API in one of the language-specific AWS SDKs, see the following: