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Added documentation for the new expression language functions for escapes 

Signed-off-by: Matt Burgess <mattyb149@apache.org>
This commit is contained in:
Devin Fisher 2016-07-28 17:23:41 -06:00 committed by Matt Burgess
parent 219e0e96fb
commit c385651209
1 changed files with 294 additions and 111 deletions
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nifi-docs/src/main/asciidoc/expression-language-guide.adoc
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@ -534,45 +534,6 @@ Each of the following functions manipulates a String in some way.
[.function]
=== urlEncode
*Description*: [.description]#Returns a URL-friendly version of the Subject. This is useful, for instance, when using an
attribute value to indicate the URL of a website.#
*Subject Type*: [.subject]#String#
*Arguments*: No arguments
*Return Type*: [.returnType]#String#
*Examples*: We can URL-Encode an attribute named "url" by using the Expression `${url:urlEncode()}`. If
the value of the "url" attribute is "https://nifi.apache.org/some value with spaces", this
Expression will then return "https://nifi.apache.org/some%20value%20with%20spaces".
[.function]
=== urlDecode
*Description*: [.description]#Converts a URL-friendly version of the Subject into a human-readable form.#
*Subject Type*: [.subject]#String#
*Arguments*: No arguments
*Return Type*: [.returnType]#String#
*Examples*: If we have a URL-Encoded attribute named "url" with the value
"https://nifi.apache.org/some%20value%20with%20spaces", then the Expression
`${url:urlDecode()}` will return "https://nifi.apache.org/some value with spaces".
[.function] [.function]
=== substring === substring
@ -993,6 +954,229 @@ Expressions will provide the following results:
[[escape]]
== Escape Functions
Each of the following functions will escape a string according the rules of the given data format.
[.function]
=== escapeJson
*Description*: [.description]#This function prepares the Subject to be inserted into JSON document by escaping the characters
in the String using Json String rules. The function correctly escapes quotes and control-chars (tab, backslash,
cr, ff, etc.)#
*Subject Type*: [.subject]#String#
*Arguments*: No arguments
*Return Type*: [.returnType]#String#
*Examples*: If the "message" attribute is 'He didn't say, "Stop!"', then the Expression `${message:escapeJson()}`
will return 'He didn't say, \"Stop!\"'
[.function]
=== escapeXml
*Description*: [.description]#This function prepares the Subject to be inserted into XML document by escaping the characters
in a String using XML entities. The function correctly escapes quotes, apostrophe, ampersand, <, > and
control-chars.#
*Subject Type*: [.subject]#String#
*Arguments*: No arguments
*Return Type*: [.returnType]#String#
*Examples*: If the "message" attribute is '"bread" & "butter"', then the Expression `${message:escapeXml()}`
will return '&quot;bread&quot; &amp; &quot;butter&quot;'
[.function]
=== escapeCsv
*Description*: [.description]#This function prepares the Subject to be inserted into CSV document by escaping the characters
in a String using the rules in RFC 4180. The function correctly escapes quotes and surround the string in quotes if needed.#
*Subject Type*: [.subject]#String#
*Arguments*: No arguments
*Return Type*: [.returnType]#String#
*Examples*: If the "message" attribute is 'But finally, she left', then the Expression `${message:escapeCsv()}`
will return '"But finally, she left"'
[.function]
=== escapeHtml3
*Description*: [.description]#This function prepares the Subject to be inserted into HTML document by escaping the characters
in a String using the HTML entities. Supports only the HTML 3.0 entities.#
*Subject Type*: [.subject]#String#
*Arguments*: No arguments
*Return Type*: [.returnType]#String#
*Examples*: If the "message" attribute is '"bread" & "butter"', then the Expression `${message:escapeHtml3()}`
will return '&quot;bread&quot; &amp; &quot;butter&quot;'
[.function]
=== escapeHtml4
*Description*: [.description]#This function prepares the Subject to be inserted into HTML document by escaping the characters
in a String using the HTML entities. Supports all known HTML 4.0 entities.#
*Subject Type*: [.subject]#String#
*Arguments*: No arguments
*Return Type*: [.returnType]#String#
*Examples*: If the "message" attribute is '"bread" & "butter"', then the Expression `${message:escapeHtml4()}`
will return '&quot;bread&quot; &amp; &quot;butter&quot;'
[.function]
=== unescapeJson
*Description*: [.description]#This function unescapes any Json literals found in the String.#
*Subject Type*: [.subject]#String#
*Arguments*: No arguments
*Return Type*: [.returnType]#String#
*Examples*: If the "message" attribute is 'He didn't say, \"Stop!\"', then the Expression `${message:unescapeJson()}`
will return 'He didn't say, "Stop!"'
[.function]
=== unescapeXml
*Description*: [.description]#This function unescapes a string containing XML entity escapes to a string containing the
actual Unicode characters corresponding to the escapes. Supports only the five basic XML entities (gt, lt,
quot, amp, apos).#
*Subject Type*: [.subject]#String#
*Arguments*: No arguments
*Return Type*: [.returnType]#String#
*Examples*: If the "message" attribute is '&quot;bread&quot; &amp; &quot;butter&quot;', then the Expression `${message:unescapeXml()}`
will return '"bread" & "butter"'
[.function]
=== unescapeCsv
*Description*: [.description]#This function unescapes a String from a CSV document according to the rules of RFC 4180.#
*Subject Type*: [.subject]#String#
*Arguments*: No arguments
*Return Type*: [.returnType]#String#
*Examples*: If the "message" attribute is '"But finally, she left"', then the Expression `${message:unescapeCsv()}`
will return 'But finally, she left'
[.function]
=== unescapeHtml3
*Description*: [.description]#This function unescapes a string containing HTML 3 entity to a string containing the
actual Unicode characters corresponding to the escapes. Supports only HTML 3.0 entities.#
*Subject Type*: [.subject]#String#
*Arguments*: No arguments
*Return Type*: [.returnType]#String#
*Examples*: If the "message" attribute is '&quot;bread&quot; &amp; &quot;butter&quot;', then the Expression `${message:unescapeHtml3()}`
will return '"bread" & "butter"'
[.function]
=== unescapeHtml4
*Description*: [.description]#This function unescapes a string containing HTML 4 entity to a string containing the
actual Unicode characters corresponding to the escapes. Supports all known HTML 4.0 entities.#
*Subject Type*: [.subject]#String#
*Arguments*: No arguments
*Return Type*: [.returnType]#String#
*Examples*: If the "message" attribute is '&quot;bread&quot; &amp; &quot;butter&quot;', then the Expression `${message:unescapeHtml4()}`
will return '"bread" & "butter"'
[.function]
=== urlEncode
*Description*: [.description]#Returns a URL-friendly version of the Subject. This is useful, for instance, when using an
attribute value to indicate the URL of a website.#
*Subject Type*: [.subject]#String#
*Arguments*: No arguments
*Return Type*: [.returnType]#String#
*Examples*: We can URL-Encode an attribute named "url" by using the Expression `${url:urlEncode()}`. If
the value of the "url" attribute is "https://nifi.apache.org/some value with spaces", this
Expression will then return "https://nifi.apache.org/some%20value%20with%20spaces".
[.function]
=== urlDecode
*Description*: [.description]#Converts a URL-friendly version of the Subject into a human-readable form.#
*Subject Type*: [.subject]#String#
*Arguments*: No arguments
*Return Type*: [.returnType]#String#
*Examples*: If we have a URL-Encoded attribute named "url" with the value
"https://nifi.apache.org/some%20value%20with%20spaces", then the Expression
`${url:urlDecode()}` will return "https://nifi.apache.org/some value with spaces".
[[searching]] [[searching]]
@ -1921,4 +2105,3 @@ provides several functions for evaluating the same conditions against groups of
| `${allAttributes("abc", "non-existent-attr", "xyz"):count()}` | `2` | `${allAttributes("abc", "non-existent-attr", "xyz"):count()}` | `2`
| `${allMatchingAttributes(".*"):length():gt(10):count()}` | `2` | `${allMatchingAttributes(".*"):length():gt(10):count()}` | `2`
|=========================================================================== |===========================================================================