I am facing trouble in sending data from an azure web api having a legitimate backslash(\). Data field is user id which is of following pattern:
Domain\UserId
I want to store it in the database as it is. But Dot liquid doesn't process it.
I tried using escape, escape_once and replace
{{ body.requestor | escape_once }}
{{ body.requestor | escape }}
{{ body.requestor | replace "\", "\\"}}
but none of them worked. I cant ask caller of my web api to pass the user id with two backslashes - \\. I have to make a change in my web api to accept the user id's as they are.
Any inputs/pointers are appreciated.
Am I too late to the party? But here is the answer. First - Replace is case-sensitive. Then you need to use colon ":" fro parameters. And third, I have no explanation but I suspect that it takes item to find with escape and item to replace with, without escape. Here is the program
string templateString =
#"Nothing: '{{ k3 }}'
Replace with dash: '{{ k3|Replace:""\\"", ""-"" }}'
Replace with double slash: '{{ k3|Replace:""\\"", ""\\"" }}'";
Template.NamingConvention = new CSharpNamingConvention();
var t = Template.Parse(templateString);
string output = t.Render(Hash.FromDictionary(new Dictionary<string, object>() {{ "k3", "Domain\\user" } }));
Console.WriteLine(output);
Output:
Nothing: 'Domain\user'
Replace with dash: 'Domain-user'
Replace with double slash: 'Domain\\user'
This may be a bug in dot Liquid implementation of escape standard filter, or arguably a point where the Shopify specification is too vague hence implementations will differ. dot Liquid is using .NET RegEx replace causing "\" for pattern matching to be interpreted as the beginning of the pattern and an escape per https://learn.microsoft.com/en-us/dotnet/standard/base-types/character-escapes-in-regular-expressions
So you need {{ body.requestor | replace "\\", "\\"}}
(!)
The pattern to search for interprets the escape (so it's a single \ been matched) while the replacement string is not interpreting the escape (so it's the actual double \\ string).
This question appear when I'm looking for the same question, only for the ruby gem liquid implementation. David Burg's answer give me hint, and this is what works:
{{ "yes \ no" | replace "\", "\\\" }}
will replace the single backlash with double backlash
You nearly got it, the correct solution is:
{{ body.requestor | replace "\", "\\\\"}}
One backslash for the first argument and four for the 2nd.
The first argument is literal.
The 2nd argument gets parsed and because we want two backslashes we need to escape each one of them with another backslash. Making a total of four backslashes.
Related
When I create a string containing backslashes, they get duplicated:
>>> my_string = "why\does\it\happen?"
>>> my_string
'why\\does\\it\\happen?'
Why?
What you are seeing is the representation of my_string created by its __repr__() method. If you print it, you can see that you've actually got single backslashes, just as you intended:
>>> print(my_string)
why\does\it\happen?
The string below has three characters in it, not four:
>>> 'a\\b'
'a\\b'
>>> len('a\\b')
3
You can get the standard representation of a string (or any other object) with the repr() built-in function:
>>> print(repr(my_string))
'why\\does\\it\\happen?'
Python represents backslashes in strings as \\ because the backslash is an escape character - for instance, \n represents a newline, and \t represents a tab.
This can sometimes get you into trouble:
>>> print("this\text\is\not\what\it\seems")
this ext\is
ot\what\it\seems
Because of this, there needs to be a way to tell Python you really want the two characters \n rather than a newline, and you do that by escaping the backslash itself, with another one:
>>> print("this\\text\is\what\you\\need")
this\text\is\what\you\need
When Python returns the representation of a string, it plays safe, escaping all backslashes (even if they wouldn't otherwise be part of an escape sequence), and that's what you're seeing. However, the string itself contains only single backslashes.
More information about Python's string literals can be found at: String and Bytes literals in the Python documentation.
As Zero Piraeus's answer explains, using single backslashes like this (outside of raw string literals) is a bad idea.
But there's an additional problem: in the future, it will be an error to use an undefined escape sequence like \d, instead of meaning a literal backslash followed by a d. So, instead of just getting lucky that your string happened to use \d instead of \t so it did what you probably wanted, it will definitely not do what you want.
As of 3.6, it already raises a DeprecationWarning, although most people don't see those. It will become a SyntaxError in some future version.
In many other languages, including C, using a backslash that doesn't start an escape sequence means the backslash is ignored.
In a few languages, including Python, a backslash that doesn't start an escape sequence is a literal backslash.
In some languages, to avoid confusion about whether the language is C-like or Python-like, and to avoid the problem with \Foo working but \foo not working, a backslash that doesn't start an escape sequence is illegal.
I have the following two lines of code:
json_str = _cases.to_json
path += " #{USER} #{PASS} #{json_str}"
When I use the debugger, I noticed that json_str appears to be formatted as JSON:
"[["FMCE","Wiltone","Wiltone","04/10/2018","Marriage + - DOM"]]"
However, when I interpolate it into another string, the quotes are removed:
"node superuser 123456 [["FMCE","Wiltone","Wiltone","04/10/2018","Marriage + - DOM"]]"
Why does string interpolation remove the quotes from JSON string and how can I resolve this?
I did find one solution to the problem, which was manually escaping the string:
json_str = _cases.to_json.gsub('"','\"')
path += " #{USER} #{PASS} \"#{json_str}\""
So basically I escape the double quotes generated in the to_json call. Then I manually add two escaped quotes around the interpolated variable. This will produce a desired result:
node superuser 123456 "[[\"FMCE\",\"Wiltone\",\"Wiltone\",\"04/10/2018\",\"Marriage + - DOM\"]]"
Notice how the outer quotes around the collection are not escaped, but the strings inside the collection are escaped. That will enable JavaScript to parse it with JSON.parse.
It is important to note that in this part:
json_str = _cases.to_json.gsub('"','\"')
it is adding a LITERAL backslash. Not an escape sequence.
But in this part:
path += " #{USER} #{PASS} \"#{json_str}\""
The \" wrapping the interpolated variable is an escape sequence and NOT a literal backslash.
Why do you think the first and last quote marks are part of the string? They do not belong to the JSON format. Your program’s behavior looks correct to me.
(Or more precisely, your program seems to be doing exactly what you told it to. Whether your instructions are any good is a question I can’t answer without more context.)
It's hard to tell with the small sample, but it looks like you might be getting quotes from your debugger output. assuming the output of .to_json is a string (usually is), then "#{json_str}" should be exactly equal to json_str. If it isn't, that's a bug in ruby somehow (doubtful).
If you need the quotes, you need to either add them manually or escape the string using whatever escape function is appropriate for your use case. You could use .to_json as your escape function even ("#{json_str.to_json}", for example).
I am trying to extract an email address from user input text in Watson Conversation. First thing first, I need to trigger a particular node using an if condition like this:
input.text.contains('\^(([^<>()[].,;:s#\"]+(.[^<>()[].,;:s#\"]+)*)|(\".+\"))#(([[0-9]{1,3}.[0-9]{1,3}.[0-9]{1,3}.[0-9]{1,3}])|(([a-zA-Z-0-9]+.)+[a-zA-Z]{2,}))$\')
But it doesn't work, I tried a lot of regexes that I found on the internet but none of them work. Does anyone know how to write a proper regex?
I suggest using a much simpler, approximate, regex to match emails that you need to use with String.matches(string regexp) method that accepts a regex:
input.text.matches('^\\S+#\\S+\\.\\S+$')
Do not forget to double escape backslashes so as to define literal backslashes in the pattern.
Pattern details:
^ - start of string
\\S+ - one or more non-whitespace chars
# - a # symbol
\\S+ - one or more non-whitespace chars
\\. - a literal dot
\\S+ - one or more non-whitespace chars
$ - end of string.
I'm trying to put a tilde character in a variable that I'm going to use in a template in Ansible and for the life of me I cannot achieve what I want, as the tilde is being expanded in all sorts of weird ways.
What I want to achieve is to have some_var defined in my vars file so that I can use it in a template like so:
random_setting: "{{ some_var }}" and get this as a result: random_setting: ~, i.e. pure tilde, no quotes added.
Instead I keep getting this: random_setting: '~' (which is not acceptable for my use case) or this: random_setting: '' (which is just as bad).
My question is: how do I escape the tilde character, so that I can use it without it being either surrounded by quotes or expanded in some obscure way? I've already tried a few tricks including encoding the ~ character with base64 and using the | b64decode filter in Ansible, but nothing seems to work.
I think you might be confusing the real value with the output of Ansible.
If you run this:
---
- hosts: localhost
connection: local
vars:
var1: "~"
tasks:
- template: src=tilde-template.j2 dest=result.txt
with tilde-template.j2:
{{ var1 }}
And check the contents of result.txt it will contain just the tilde.
Here is my string
{
'user': {
'name': 'abc',
'fx': {
'message': {
'color': 'red'
},
'user': {
'color': 'blue'
}
}
},
'timestamp': '2013-10-04T08: 10: 41+0100',
'message': 'I'mABC..',
'nanotime': '19993363098581330'
}
Here the message contains single quotation mark, which is same as the quotation used in JSON. What I do is fill up a string from user inputs such as message. So, I need to escape those kind of special scenarios which breaks the code. But other than string replace, is there any way to make them escape but still allow HTML to process them back to the correct message?
I'm appalled by the presence of highly-upvoted misinformation on such a highly-viewed question about a basic topic.
JSON strings cannot be quoted with single quotes. The various versions of the spec (the original by Douglas Crockford, the ECMA version, and the IETF version) all state that strings must be quoted with double quotes. This is not a theoretical issue, nor a matter of opinion as the accepted answer currently suggests; any JSON parser in the real world will error out if you try to have it parse a single-quoted string.
Crockford's and ECMA's version even display the definition of a string using a pretty picture, which should make the point unambiguously clear:
The pretty picture also lists all of the legitimate escape sequences within a JSON string:
\"
\\
\/
\b
\f
\n
\r
\t
\u followed by four-hex-digits
Note that, contrary to the nonsense in some other answers here, \' is never a valid escape sequence in a JSON string. It doesn't need to be, because JSON strings are always double-quoted.
Finally, you shouldn't normally have to think about escaping characters yourself when programatically generating JSON (though of course you will when manually editing, say, a JSON-based config file). Instead, form the data structure you want to encode using whatever native map, array, string, number, boolean, and null types your language has, and then encode it to JSON with a JSON-encoding function. Such a function is probably built into whatever language you're using, like JavaScript's JSON.stringify, PHP's json_encode, or Python's json.dumps. If you're using a language that doesn't have such functionality built in, you can probably find a JSON parsing and encoding library to use. If you simply use language or library functions to convert things to and from JSON, you'll never even need to know JSON's escaping rules. This is what the misguided question asker here ought to have done.
A JSON string must be double-quoted, according to the specs, so you don't need to escape '.
If you have to use special character in your JSON string, you can escape it using \ character.
See this list of special character used in JSON :
\b Backspace (ascii code 08)
\f Form feed (ascii code 0C)
\n New line
\r Carriage return
\t Tab
\" Double quote
\\ Backslash character
However, even if it is totally contrary to the spec, the author could use \'.
This is bad because :
It IS contrary to the specs
It is no-longer JSON valid string
But it works, as you want it or not.
For new readers, always use a double quotes for your json strings.
Everyone is talking about how to escape ' in a '-quoted string literal. There's a much bigger issue here: single-quoted string literals aren't valid JSON. JSON is based on JavaScript, but it's not the same thing. If you're writing an object literal inside JavaScript code, fine; if you actually need JSON, you need to use ".
With double-quoted strings, you won't need to escape the '. (And if you did want a literal " in the string, you'd use \".)
Most of these answers either does not answer the question or is unnecessarily long in the explanation.
OK so JSON only uses double quotation marks, we get that!
I was trying to use JQuery AJAX to post JSON data to server and then later return that same information.
The best solution to the posted question I found was to use:
var d = {
name: 'whatever',
address: 'whatever',
DOB: '01/01/2001'
}
$.ajax({
type: "POST",
url: 'some/url',
dataType: 'json',
data: JSON.stringify(d),
...
}
This will escape the characters for you.
This was also suggested by Mark Amery, Great answer BTW
Hope this helps someone.
May be i am too late to the party but this will parse/escape single quote (don't want to get into a battle on parse vs escape)..
JSON.parse("\"'\"")
The answer the direct question:
To be safe, replace the required character with \u+4-digit-hex-value
Example:
If you want to escape the apostrophe ' replace with \u0027
D'Amico becomes D\u0027Amico
NICE REFERENCE:
http://es5.github.io/x7.html#x7.8.4
https://mathiasbynens.be/notes/javascript-escapes
Using template literals...
var json = `{"1440167924916":{"id":1440167924916,"type":"text","content":"It's a test!"}}`;
Use encodeURIComponent() to encode the string.
Eg.:
var product_list = encodeURIComponent(JSON.stringify(product_list));
You don't need to decode it since the web server automatically do the same.
To allow single quotes within doubule quoted string for the purpose of json, you double the single quote. {"X": "What's the question"} ==> {"X": "What''s the question"}
https://codereview.stackexchange.com/questions/69266/json-conversion-to-single-quotes
The \' sequence is invalid.
regarding AlexB's post:
\' Apostrophe or single quote
\" Double quote
escaping single quotes is only valid in single quoted json strings
escaping double quotes is only valid in double quoted json strings
example:
'Bart\'s car' -> valid
'Bart says \"Hi\"' -> invalid