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 | Type | Escape string |
|---|---|---|
backspace | Represented As | "\b" |
| Escaped | "\\\\b" | |
| form feed | Represented As | "\f" |
| Escaped | "\\\\f" | |
| tab | Represented As | "\t" |
| Escaped | "\\\\t" | |
| carraige return | Represented As | "\r" |
| Escaped | "\\\\r" | |
| newline | Represented As | "\n" |
| Escaped | "\\\\n" | |
| backslash | Represented As |
|
| Escaped | "\\\\\\\\" | |
| double quote | Represented As | '"' |
| Escaped | '\\\\"' |
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 , '"','\\\\"')
)
Validating JSON Files
JSON code can include characters that cannot be written to a database that is using the UTF-8 character set. For example, 4-bit Emojis are not supported by UTF-8.
The following regular expression lists the characters expected in a JSON file and removes invalid characters from it.
replaceAll(JSON Code,"[^\\p{Space}0-9A-Za-z!:\\\"%&\\[*()\\],-/_\\\\{}\\.]","")
The backslash character escapes special characters such as [] , . and \
The UTF-8mb4 character set supports a wider range of characters, such as Emojis. Migrating your database to use this character set would allow JSON to be used without needing to validate it using a regular expression.
See also: Regular Expressions