File path validation in javascript

javascript, regex, validation

Solution

At first the obvious errors:

`+` is a repeat indicator that has the meaning at least one. so the `(\.xml+)` will match everything starting with `.xm` followed by one or more `l` (it would also match `.xmlllll`). the `?` means optional, so `(\.xml+)?` has the meaning it could have an `.xml` but it is not required.

the same is for `([a-zA-Z]:)?` this means the driver letter is optional.

Now the not so obvious errors

`[a-zA-Z0-9\\s_@-^!#$%&+={}\[\]]` here you define a list of allowed chars. you have `\\s` and i assume you want to allow spaces, but this allows `\` and `s` so you need to change it to `\s`. then you have this part `@-^` i assume you want to allow `@`, `-` and `^` but the `-` has a special meaning inside of `[` `]` with it you define a range so you allow all chars that are in the range of `@` to `^` if you want to allow `-` you need to escape it there so you have to write `@\-^` you also need to take care about `^`, if it is right after the `[` it would have also a special meaning.

your Regex should contain the following parts:

- `^[a-z]:` start with (`^`) driver letter

- `((\\|\/)[a-z0-9\s_@\-^!#$%&+={}\[\]]+)+` followed by one or more path parts that start with either `\` or `/` and having a path name containing one or more of your defined letters (`a-z0-9\s_@\-^!#$%&+={}\[\]`)

- `\.xml$` ends with (`$`) the `.xml`

therefore your final regex should look like this `/^[a-z]:((\\|\/)[a-z0-9\s_@\-^!#$%&+={}\[\]]+)+\.xml$/i.test(str)` (under the assumption you do a case insensitve regex using the `i` flag)

EDIT:

var path1 = "D:/test.xml";               // D:/test.xml
var path2 = "D:\\folder\\test.xml";      // D:\folder\test.xml
var path3 = "D:/folder/test.xml";        // D:/folder/test.xml
var path4 = "D:\\folder/test.xml";       // D:\folder/test.xml
var path5 = "D:\\test.xml";              // D:\test.xml

console.log( /^[a-z]:((\\|\/)[a-z0-9\s_@\-^!#$%&+={}\[\]]+)+\.xml$/i.test(path1) );
console.log( /^[a-z]:((\\|\/)[a-z0-9\s_@\-^!#$%&+={}\[\]]+)+\.xml$/i.test(path2) );
console.log( /^[a-z]:((\\|\/)[a-z0-9\s_@\-^!#$%&+={}\[\]]+)+\.xml$/i.test(path3) );
console.log( /^[a-z]:((\\|\/)[a-z0-9\s_@\-^!#$%&+={}\[\]]+)+\.xml$/i.test(path4) );
console.log( /^[a-z]:((\\|\/)[a-z0-9\s_@\-^!#$%&+={}\[\]]+)+\.xml$/i.test(path5) );

UPDATE:

you need to take care about the `/` and the `\` if you need to escape them depends on if you use it with `new RegExp(' ... the regex ... ',"i")` and `new RegExp(" ... the regex ... ","i")` or with `/ ... the regex ... /i`

for further informations about regular expressions you should take a look at e.g. www.regular-expressions.info

Problem

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