This page is for anyone writing expressions, macros or scripts in which you need to escape special characters.
When writing expressions, macros or scripts you may need to enter a character that has special meaning. For example, a string could include a double-quote, but in the expression PhixFlow will read this as the end of the string. To tell PhixFlow to ignore a special character, you can use the backslash character.
| Character | Escape string |
|---|---|
backspace | "\b" |
"\\\\b" | |
| form feed | "\f" |
"\\\\f" | |
| tab | "\t" |
"\\\\t" | |
| carraige return | "\r" |
"\\\\r" | |
| newline | "\n" |
"\\\\n" | |
| backslash |
|
"\\\\\\\\" | |
| double quote | '"' |
'\\\\"' |
Macro: Escaping Invalid Characters
If you are working with JSON, return messages can contain characters that are not recognised in PhixFlow. The following macro escapes these invalid characters.
do(
$value = $args[1],
$value = replaceAll( $value , "\b","\\\\b"),
$value = replaceAll( $value , "\f","\\\\f"),
$value = replaceAll( $value , "\t","\\\\t"),
$value = replaceAll( $value , "\r","\\\\r"),
$value = replaceAll( $value , "\n","\\\\n"),
$value = replaceAll( $value , "\\\\","\\\\\\\\"),
$value = replaceAll( $value , '"','\\\\"')
)
Note: JSON Code can also include characters that cannot be written to the UTF-8 database such as Emojis which are 4 bit characters. This may be solved in the future by migrating the database to UTF-8mb4 but in the meantime, invalid characters can be removed using the following regular expression to do an initial validation on any JSON:
replaceAll(JSON Code,"[^\\p{Space}0-9A-Za-z!:\\\"%&\\[*()\\],-/_\\\\{}\\.]","")
The expression contains a list of expected characters to be found in JSON files. Note how back slashes are used to escape special characters such as [] , . and \