In fact, the title says it all. But, I'll go more into details:
I am sending a JSON string from my JS script to the server and vice versa. The JSON contains things as some content the user wrote into a textfield, but I know that some user will manage to break the JSON array this way sooner or later, so I decided to encode it with encodeURIComponent().
But I see, that when I try to encode curly brackets, that they aren't encoded at all. Is this going to be a problem?
More precisely, I'm afraid that if someone writes: } , {, the JSON will break. This shouldn't happen, since all of it is inside doublequotes like this: "} , {", and if a user write doublequotes or singlequotes they are going to be encoded, and from what I know, JSON should handle all of that just fine, but I am not entirely sure.
So, should I encode those brackets?
(Another thing is that the data is inserted into MySQL inside prepared statements, so that shouldn't be a problem, or I am wrong with that?)
A quick quote from the JSON specifications:
A string is a sequence of zero or more Unicode characters, wrapped in double quotes, using backslash escapes.
As you can see in the image that follows the paragraph quoted above, any Unicode character except for ", \ and control characters is represented as-is; no escape is required.
why will brake? Your JSON string will be inside ""
So will be something like
{"postcontent": "Shouldnt { } be escaped"}
Related
I'm making a dialogue system in gdscript and am struggling with escape characters, specifically '\n'.
I'm using CastleDB as, although not perfect, it has allowed me to have almost everything stored in data and will allow the person doing the writing for the game to do everything outside the engine, without me having to copy and paste stuff in.
I've hit a stumbling block with escape characters. A single text entry in CastleDB doesn't support spaces, and '\n' within the string prints to '\n', not a space, in the dialog box.
I've tried using the format string function with 'some text here {space} some more text', with the space referencing a string consisting of just \n. This still prints \n. If I feed some constant string with \n in the middle directly into the function which displays the dialog text, it adds a space so I'm not really sure what is going on here.
I don't have a computer science background (I've done some C up until pointers, at which point I decided to return later).
Is there something going on in the background with my string in gdscript? It prints out just like you would expect a string to, apart from ignoring my escape characters.
Could it be something to do with the fact that it comes in as a JSON? As far as I'm aware, even if a string is chopped up and reassembled, it should still just behave like a string...?!
Anyway, I haven't included any code because I don't know what code you'd need to see. I'm hoping it's something simple that because I'm teaching myself as I go I just wasn't aware of, but can post code if it helps.
Thanks,
James
Escape sequences are a way of getting around issues with syntax. When you type a string in most programming languages, it starts with " and ends with another ". And it needs to stay on one line. Simple, right?
What if you want to put an actual " in your string? Or a new line? We need some way of telling the compiler, "hey, we want to insert a newline here, even though we can't use an actual newline character". So we use a \ to let the compiler know that the next character is part of an escape sequence.
This causes another problem: What if we literally want to put a backslash in a string? That's where the double backslash comes from: \\ is the escape sequence for \, since \ by itself has a special meaning.
But CastleDB (apparently, I'm not familiar with it) doesn't recognize escape sequences, so when you type \n it thinks you literally want \ followed by n. When it converts this to JSON, it inserts the \\ because JSON does recognize escape sequences.
GDScript also recognizes escape sequences, so print("Hello\nworld!") prints
Hello
world!
You could try input_string.replace("\\n", "\n") to replace the \n escape sequences.
I've solved this by looking at the way CastleDB data is stored on the project's github page.
For some reason "\n" was stored as "\\n" behind the scenes. Now that I know why it was printing weirdly I can change it, even though it feels like a messy solution!
To add even more weirdness to this whole backslash business, stack overflow displays a double backslash as a single backslash so I have to write \ \ \n minus the spaces to get \\n...
I'm sure there must be a reason, but it eludes me.
I am trying to escape delimiter character that appears inside data. Is there a way to do it by passing option parameters? I can do it from udf, but I am hoping it is possible using options.
val df = Seq((8, "test,me\nand your", "other")).toDF("number", "test", "t")
df.coalesce(1).write.mode("overwrite").format("csv").option("quote", "\u0000").option("delimiter", ",").option("escape", "\\").save("testcsv1")
But the escape is not working. The output file is written as
8,test,me
and your,other
I want the output file to be written as.
8,test\,me\\nand your,other
I'm not certain, but I think if you had your sequence as
Seq((8, "test\\,me\\\\nand your", "other"))
and did not specify a custom escape character, it would behave as you are expecting and give you 8,test\,me\\nand your,other as the output. This is because \\ acts simply as the character '\' rather than an escape, so they are printed where you want and the n immediately after is not interpreted as part of a newline character.
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).
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
Is it possible to have multi-line strings in JSON?
It's mostly for visual comfort so I suppose I can just turn word wrap on in my editor, but I'm just kinda curious.
I'm writing some data files in JSON format and would like to have some really long string values split over multiple lines. Using python's JSON module I get a whole lot of errors, whether I use \ or \n as an escape.
JSON does not allow real line-breaks. You need to replace all the line breaks with \n.
eg:
"first line
second line"
can be saved with:
"first line\nsecond line"
Note:
for Python, this should be written as:
"first line\\nsecond line"
where \\ is for escaping the backslash, otherwise python will treat \n as
the control character "new line"
Unfortunately many of the answers here address the question of how to put a newline character in the string data. The question is how to make the code look nicer by splitting the string value across multiple lines of code. (And even the answers that recognize this provide "solutions" that assume one is free to change the data representation, which in many cases one is not.)
And the worse news is, there is no good answer.
In many programming languages, even if they don't explicitly support splitting strings across lines, you can still use string concatenation to get the desired effect; and as long as the compiler isn't awful this is fine.
But json is not a programming language; it's just a data representation. You can't tell it to concatenate strings. Nor does its (fairly small) grammar include any facility for representing a string on multiple lines.
Short of devising a pre-processor of some kind (and I, for one, don't feel like effectively making up my own language to solve this issue), there isn't a general solution to this problem. IF you can change the data format, then you can substitute an array of strings. Otherwise, this is one of the numerous ways that json isn't designed for human-readability.
I have had to do this for a small Node.js project and found this work-around to store multiline strings as array of lines to make it more human-readable (at a cost of extra code to convert them to string later):
{
"modify_head": [
"<script type='text/javascript'>",
"<!--",
" function drawSomeText(id) {",
" var pjs = Processing.getInstanceById(id);",
" var text = document.getElementById('inputtext').value;",
" pjs.drawText(text);}",
"-->",
"</script>"
],
"modify_body": [
"<input type='text' id='inputtext'></input>",
"<button onclick=drawSomeText('ExampleCanvas')></button>"
],
}
Once parsed, I just use myData.modify_head.join('\n') or myData.modify_head.join(), depending upon whether I want a line break after each string or not.
This looks quite neat to me, apart from that I have to use double quotes everywhere. Though otherwise, I could, perhaps, use YAML, but that has other pitfalls and is not supported natively.
Check out the specification! The JSON grammar's char production can take the following values:
any-Unicode-character-except-"-or-\-or-control-character
\"
\\
\/
\b
\f
\n
\r
\t
\u four-hex-digits
Newlines are "control characters" so, no, you may not have a literal newline within your string. However you may encode it using whatever combination of \n and \r you require.
JSON doesn't allow breaking lines for readability.
Your best bet is to use an IDE that will line-wrap for you.
This is a really old question, but I came across this on a search and I think I know the source of your problem.
JSON does not allow "real" newlines in its data; it can only have escaped newlines. See the answer from #YOU. According to the question, it looks like you attempted to escape line breaks in Python two ways: by using the line continuation character ("\") or by using "\n" as an escape.
But keep in mind: if you are using a string in python, special escaped characters ("\t", "\n") are translated into REAL control characters! The "\n" will be replaced with the ASCII control character representing a newline character, which is precisely the character that is illegal in JSON. (As for the line continuation character, it simply takes the newline out.)
So what you need to do is to prevent Python from escaping characters. You can do this by using a raw string (put r in front of the string, as in r"abc\ndef", or by including an extra slash in front of the newline ("abc\\ndef").
Both of the above will, instead of replacing "\n" with the real newline ASCII control character, will leave "\n" as two literal characters, which then JSON can interpret as a newline escape.
Write property value as a array of strings. Like example given over here https://gun.io/blog/multi-line-strings-in-json/. This will help.
We can always use array of strings for multiline strings like following.
{
"singleLine": "Some singleline String",
"multiline": ["Line one", "line Two", "Line Three"]
}
And we can easily iterate array to display content in multi line fashion.
While not standard, I found that some of the JSON libraries have options to support multiline Strings. I am saying this with the caveat, that this will hurt your interoperability.
However in the specific scenario I ran into, I needed to make a config file that was only ever used by one system readable and manageable by humans. And opted for this solution in the end.
Here is how this works out on Java with Jackson:
JsonMapper mapper = JsonMapper.builder()
.enable(JsonReadFeature.ALLOW_UNESCAPED_CONTROL_CHARS)
.build()
This is a very old question, but I had the same question when I wanted to improve readability of our Vega JSON Specification code which uses complex conditoinal expressions. The code is like this.
As this answer says, JSON is not designed for human. I understand that is a historical decision and it makes sense for data exchange purposes. However, JSON is still used as source code for such cases. So I asked our engineers to use Hjson for source code and process it to JSON.
For example, in Git for Windows environment,
you can download the Hjson cli binary and put it in git/bin directory to use.
Then, convert (transpile) Hjson source to JSON. To use automation tools such as Make will be useful to generate JSON.
$ which hjson
/c/Program Files/git/bin/hjson
$ cat example.hjson
{
md:
'''
First line.
Second line.
This line is indented by two spaces.
'''
}
$ hjson -j example.hjson > example.json
$ cat example.json
{
"md": "First line.\nSecond line.\n This line is indented by two spaces."
}
In case of using the transformed JSON in programming languages, language-specific libraries like hjson-js will be useful.
I noticed the same idea was posted in a duplicated question but I would share a bit more information.
You can encode at client side and decode at server side. This will take care of \n and \t characters as well
e.g. I needed to send multiline xml through json
{
"xml": "PD94bWwgdmVyc2lvbj0iMS4wIiBlbmNvZGluZz0idXRmLTgiID8+CiAgPFN0cnVjdHVyZXM+CiAgICAgICA8aW5wdXRzPgogICAgICAgICAgICAgICAjIFRoaXMgcHJvZ3JhbSBhZGRzIHR3byBudW1iZXJzCgogICAgICAgICAgICAgICBudW0xID0gMS41CiAgICAgICAgICAgICAgIG51bTIgPSA2LjMKCiAgICAgICAgICAgICAgICMgQWRkIHR3byBudW1iZXJzCiAgICAgICAgICAgICAgIHN1bSA9IG51bTEgKyBudW0yCgogICAgICAgICAgICAgICAjIERpc3BsYXkgdGhlIHN1bQogICAgICAgICAgICAgICBwcmludCgnVGhlIHN1bSBvZiB7MH0gYW5kIHsxfSBpcyB7Mn0nLmZvcm1hdChudW0xLCBudW0yLCBzdW0pKQogICAgICAgPC9pbnB1dHM+CiAgPC9TdHJ1Y3R1cmVzPg=="
}
then decode it on server side
public class XMLInput
{
public string xml { get; set; }
public string DecodeBase64()
{
var valueBytes = System.Convert.FromBase64String(this.xml);
return Encoding.UTF8.GetString(valueBytes);
}
}
public async Task<string> PublishXMLAsync([FromBody] XMLInput xmlInput)
{
string data = xmlInput.DecodeBase64();
}
once decoded you'll get your original xml
<?xml version="1.0" encoding="utf-8" ?>
<Structures>
<inputs>
# This program adds two numbers
num1 = 1.5
num2 = 6.3
# Add two numbers
sum = num1 + num2
# Display the sum
print('The sum of {0} and {1} is {2}'.format(num1, num2, sum))
</inputs>
</Structures>
\n\r\n worked for me !!
\n for single line break and \n\r\n for double line break
I see many answers here that may not works in most cases but may be the easiest solution if let's say you wanna output what you wrote down inside a JSON file (for example: for language translations where you wanna have just one key with more than 1 line outputted on the client) can be just adding some special characters of your choice PS: allowed by the JSON files like \\ before the new line and use some JS to parse the text ... like:
Example:
File (text.json)
{"text": "some JSON text. \\ Next line of JSON text"}
import text from 'text.json'
{text.split('\\')
.map(line => {
return (
<div>
{line}
<br />
</div>
);
})}}
Assuming the question has to do with easily editing text files and then manually converting them to json, there are two solutions I found:
hjson (that was mentioned in this previous answer), in which case you can convert your existing json file to hjson format by executing hjson source.json > target.hjson, edit in your favorite editor, and convert back to json hjson -j target.hjson > source.json. You can download the binary here or use the online conversion here.
jsonnet, which does the same, but with a slightly different format (single and double quoted strings are simply allowed to span multiple lines). Conveniently, the homepage has editable input fields so you can simply insert your multiple line json/jsonnet files there and they will be converted online to standard json immediately. Note that jsonnet supports much more goodies for templating json files, so it may be useful to look into, depending on your needs.
The reason OP asked is the same reason I ended up here. Had a json file with long text.
In VS Code it's just ALT+Z to turn on word wrapping in a json file. Changing the actual data isn't what you want, if all you really want is to read the contents of the file as a developer.
If it's just for presentation in your editor you may use ` instead of " or '
const obj = {
myMultiLineString: `This is written in a \
multiline way. \
The backside of it is that you \
can't use indentation on every new \
line because is would be included in \
your string. \
The backslash after each line escapes the carriage return.
`
}
Examples:
console.log(`First line \
Second line`);
will put in console:
First line Second line
console.log(`First line
second line`);
will put in console:
First line
second line
Hope this answered your question.