I'm using GKeyFile to store configuration. I need to store a dictionary of URLs to boolean values. URLs are strings, so .
GKeyFile seemed like a good fit, but some of my URLs have equals signs in them, e.g. http://example.com?x=y
This doesn't work, because the first equal sign is interpreted as the key/value separator.
[Links]
http://example.com?x=y=true
Escaping the equal sign doesn't seem to help either.
[Links]
http://example.com?x\=y=true
Is there any way to do what I want in a GKeyFile file?
According to the spec:
Only the characters A-Za-z0-9- may be used in key names.
A simple way to work around this (at the cost of human-readability) is to encode your URIs when writing them, e.g., using g_base64_encode, and doing the reverse when reading them.
Related
I am facing one issue in one of my Rails project.
My users database contain names with special character and i want them to be shown in search result while searching it with simple characters.
Example: Lets suppose i have a user whose name is "Noël Nocciolo" (please notice soft sign on e) and i want that to be searched if i pass "Noel Nocciolo" as a parameter.
Can anyone tell me how to handle with these cases because no one knows how to provide input of "e with two dots".
And i am using postgres as my databse.
Regards,
Karan
You can create separate field "indexed_name" for search and fill it only with ASCII characters.
Then you have to preprocess query string with .gsub('ë', 'e') (or any other non ASCII characters to its ASCII analog) and search with this processed query
and i believe there is more elegant way to convert any string to ascii analog i just gave you direction )
.parameterize or ActiveSupport::Inflector.transliterate will probably be acceptable for your use case.
"àáâãäå".parameterize
=> "aaaaaa"
However, it won't handle ligatures such as ffi, so for that you'll need:
"àáâãÀffi".mb_chars.normalize(:kd).gsub(/[^\x00-\x7F]/,'').to_s
=> "aaaaAffi"
I have 2D array in which the second column has domain names of some emails, let us call the array myData[][]. I decided to use ArrayLib in order to search the second column for a specific domain.
ArrayLib.indexOf(myData, 1, domain)
Here is where I found an issue. In myData array, one of the domains look like this "ewmining.com" (pay attention to the w).
While searching for "e.mining.com" (notice the first dot), the indexOf() function actully gave me the row containing "ewmining.com".
This is what is in the array "ewmining.com"
This is what is in the serach string "e.mining.com"
It seams that ArrayLib treats the dot to mean any character. Is this supposed to be the correct behavior? Is there a way to stop this behavior and search for exact match.
I really need help on this issue.
Thanks in advance for your help.
The dot usually represents "any character" in regular expressions. I am not familiar with ArrayLib, but maybe you should look for a way to turn off regular expressions when searching. Otherwise you might have to escape the dot, for example search for e[.]mining[.]com
I am trying to write a function to encode URIs in order to make them compliant with rfc 3986.
I.e. checking that every character other than alphanum; /?:#&=+$-_.!~*'()|\^[]``# gets replaced by %[hex octet]
I want to be sure that if the function gets called with an already encoded URI, the code won't ruin it.
So far all I am doing is looking for a '%' sign followed by 2 octect characters. Any other reserved character I find I replace.
Is there any other check I should be doing?
Don't mind security issues; they are being handled somewhere else.
I think that properly-encoded URIs should always pass through cleanly the second time.
The reason being that you have to correctly parse a URI no matter what, because it's entirely legal to have characters such as / # . : ? & = in a URI, provided they appear in the right places.
So you only encode a character if it is not legal in that part of the URI. With that assertion, you then create an encoded string that IS legal at every position, so when you parse it, there is nothing left to encode.
Bear in mind that if someone throws a URI at you to be encoded and it happens to be ambiguous (ie it contains special characters that alter the URI syntax), they cannot expect a correct result.
To answer your question more directly, I would say yes: in light of all the above, you only need to have special treatment for the % escape sequences.
Um, how do you know that an already encoded URI should not be encoded once again? Maybe the URI contains, I don't know, example how to encode URIs, and if will not get encoded a second time, then the decoding will break it?
That said, you can check whether only allowed characters plus % are present, and whether every % is followed by a hex number. If yes, there is a good chance (but no guarantee) that the encoding has already been done.
I'm looking for a RAIL way to create a very secure UID that will act as a authentication token.
I had been using UUID but was told they are not secure. I'd like to learn, what is the method of choice these days in ruby/rails 3?
This question is in no way Rails specific.
UUID is not secure for the simple fact that it is a unique identifier and it contains 'constant' parts of a given machine (e.g. it might use the MAC address for a machine), which makes it easier to guess.
If you want 100k+ strings without someone guessing one, you need to be able to distribute your keys across a large key-space. Let me explain:
If you only need 1 key (let's), you might pick 'A'. In a key-space of A-Z you have 1:26 chance of guessing it. Now, if you'd extend your key-space to A-Za-z you have a 1:52 chance of guessing.
Need more security still? Use a longer key: 'AA' 1:2704 chance.
Now, if you'd want to have 2000 keys and use a key length of 2 (e.g. 'AA'), there's a 2000:2704 => 1:1.352 chance someone might guess it. Pretty bad.
So, the key here is to pick a very long key size. With Digest::SHA1 you get 40-character keys (using Hex, with 16 different values per character). That's 1.46150164e48 unique values. Your 100k values should be random enough.
Edit:
With 40-digit HEX SHA1 values you have a 1:461501640000000000000000000000000000000000000000000 chance of guessing one. That takes ages.
Question
I would like to be able to use a single regex (if possible) to require that a string fits [A-Za-z0-9_] but doesn't allow:
Strings containing just numbers or/and symbols.
Strings starting or ending with symbols
Multiple symbols next to eachother
Valid
test_0123
t0e1s2t3
0123_test
te0_s1t23
t_t
Invalid
t__t
____
01230123
_0123
_test
_test123
test_
test123_
Reasons for the Rules
The purpose of this is to filter usernames for a website I'm working on. I've arrived at the rules for specific reasons.
Usernames with only numbers and/or symbols could cause problems with routing and database lookups. The route for /users/#{id} allows id to be either the user's id or user's name. So names and ids shouldn't be able to collide.
_test looks wierd and I don't believe it's valid subdomain i.e. _test.example.com
I don't like the look of t__t as a subdomain. i.e. t__t.example.com
This matches exactly what you want:
/\A(?!_)(?:[a-z0-9]_?)*[a-z](?:_?[a-z0-9])*(?<!_)\z/i
At least one alphabetic character (the [a-z] in the middle).
Does not begin or end with an underscore (the (?!_) and (?<!_) at the beginning and end).
May have any number of numbers, letters, or underscores before and after the alphabetic character, but every underscore must be separated by at least one number or letter (the rest).
Edit: In fact, you probably don't even need the lookahead/lookbehinds due to how the rest of the regex works - the first ?: parenthetical won't allow an underscore until after an alphanumeric, and the second ?: parenthetical won't allow an underscore unless it's before an alphanumeric:
/\A(?:[a-z0-9]_?)*[a-z](?:_?[a-z0-9])*\z/i
Should work fine.
I'm sure that you could put all this into one regular expression, but it won't be simple and I'm not sure why insist on it being one regex. Why not use multiple passes during validation? If the validation checks are done when users create a new account, there really isn't any reason to try to cram it into one regex. (That is, you will only be dealing with one item at a time, not hundreds or thousands or more. A few passes over a normal sized username should take very little time, I would think.)
First reject if the name doesn't contain at least one number; then reject if the name doesn't contain at least one letter; then check that the start and end are correct; etc. Each of those passes could be a simple to read and easy to maintain regular expression.
What about:
/^(?=[^_])([A-Za-z0-9]+_?)*[A-Za-z](_?[A-Za-z0-9]+)*$/
It doesn't use a back reference.
Edit:
Succeeds for all your test cases. Is ruby compatible.
This doesn't block "__", but it does get the rest:
([A-Za-z]|[0-9][0-9_]*)([A-Za-z0-9]|_[A-Za-z0-9])*
And here's the longer form that gets all your rules:
([A-Za-z]|([0-9]+(_[0-9]+)*([A-Za-z|_[A-Za-z])))([A-Za-z0-9]|_[A-Za-z0-9])*
dang, that's ugly. I'll agree with Telemachus, that you probably shouldn't do this with one regex, even though it's technically possible. regex is often a pain for maintenance.
The question asks for a single regexp, and implies that it should be a regexp that matches, which is fine, and answered by others. For interest, though, I note that these rules are rather easier to state directly as a regexp that should not match. I.e.:
x !~ /[^A-Za-z0-9_]|^_|_$|__|^\d+$/
no other characters than letters, numbers and _
can't start with a _
can't end with a _
can't have two _s in a row
can't be all digits
You can't use it this way in a Rails validates_format_of, but you could put it in a validate method for the class, and I think you'd have much better chance of still being able to make sense of what you meant, a month or a year from now.
Here you go:
^(([a-zA-Z]([^a-zA-Z0-9]?[a-zA-Z0-9])*)|([0-9]([^a-zA-Z0-9]?[a-zA-Z0-9])*[a-zA-Z]+([^a-zA-Z0-9]?[a-zA-Z0-9])*))$
If you want to restrict the symbols you want to accept, simply change all [^a-zA-Z0-9] with [] containing all allowed symbols
(?=.*[a-zA-Z].*)^[A-Za-z0-9](_?[A-Za-z0-9]+)*$
This one works.
Look ahead to make sure there's at least one letter in the string, then start consuming input. Every time there is an underscore, there must be a number or a letter before the next underscore.
/^(?![\d_]+$)[A-Za-z0-9]+(?:_[A-Za-z0-9]+)*$/
Your question is essentially the same as this one, with the added requirement that at least one of the characters has to be a letter. The negative lookahead - (?![\d_]+$) - takes care of that part, and is much easier (both to read and write) than incorporating it into the basic regex as some others have tried to do.
[A-Za-z][A-Za-z0-9_]*[A-Za-z]
That would work for your first two rules (since it requires a letter at the beginning and end for the second rule, it automatically requires letters).
I'm not sure the third rule is possible using regexes.