I'm trying to parse a String to JSON in NodeJS/Javascript, this is my string (which I cannot change, coming from an external database):
'{\\"value1\\":\\"XYZ\\",\\"value2\\":\\"ZYX\\"}'
I'm calling:
JSON.parse(row.raw_data)
But are getting:
SyntaxError: Unexpected token \ in JSON at position
I actually thought double escape was the correct way of escaping in string/JSON.
Your JSON is invalid. You've said you can't change it, which is unfortunate.
It looks like it's been double-stringified but then the outermost quotes have been left off. If so, you can fix it by adding " at each end and then double-parsing it, like this:
var str = '{\\"value1\\":\\"XYZ\\",\\"value2\\":\\"ZYX\\"}';
str = '"' + str + '"';
var obj = JSON.parse(JSON.parse(str));
console.log(obj);
Ideally, though, you'll want to go through the database and correct the invalid data.
I actually thought double escape was the correct way of escaping in string/JSON.
In JSON, strings are wrapped in double quotes ("), not double escapes. You only escape double quotes within strings (with a single \).
If you've been creating JSON strings manually (in code), don't. :-) Instead, create the structure you want to save, and then stringify it. Building JSON strings manually is error-prone, but a proper JSON stringifier will be reliable.
Related
I get the syntax error when I try to pass the following string:
JSON.parse("[{\"Date\": \"4/4/2016 4:15:19 PM\", \"Message\":\"<h3>New
Message</h3> Generated at 4/4/2016 4:15:19 PM.<br/><br/>Heavy Responsive
URL: <a href=\"https://performingarts.withgoogle.com/en_us\" ></a><br/><br/>
<img src=\"https://s-media-cache-ak0.pinimg.com/236x/06/bd/ac/06bdacc904c12abdce3381ba1404fd7e.jpg\" /> \"} ]");
I know that the error come from the link when I use double quote.
If I use single quote then no issue, but the data is getting from server side, I got no control over what going to pass in so I can only control on my side.
From what I read from the internet so far, I tried the following:
Use JSON.stringify first, then only use JSON.parse. I can parse
with no issue but problem occur when I try to loop the data. Instead
of looping it as JSON, the loop take the data as string and loop
every single text.
Escape every double quote which I'm currently doing, but it's not
working as shown above. But if I replace every double quote to
literal, I'm afraid some of the message that suppose to be double
quote will turn into literal as well, which will result in weird
looking message.
Please advice what other alternative I have to solve this.
You have JSON embedded in a JavaScript string literal.
" and \ are special characters in JSON and are also special characters in a JavaScript string literal.
href=\"https: escapes the " in the JavaScript string literal. It then becomes a " in the JSON. That causes an error.
When you want the " as data in the JSON you must:
Escape the " for JavaScript (as you are doing already)
Escape the " for JSON by adding a \.
Escape the \ for JavaScript
href=\\\"https:
hi im having trouble correctly adding to my json
here is the code.
When i console.log the string im trying to add is
{"type":"#","name":"wh2xogvi","list":[{"0":"background-color"},{"1":"border"},{"2":"width"}, {"3":"height"},{"4":"margin"}],"listvalues":[{"0":"#aaa"},{"1":"2px solid #000"},{"2":"1040px"},{"3":"50px"},{"4":"0 auto"}]}
it is valid json
var jsonltoload = JSON.stringify(eval("(" + jsonloadtostring + ")"));
console.log(jsonltoload); // this is the console log i was talking about higher up
fullJSON.styles.objectcss.push(jsonltoload);
But when i actually look at the json it is wrong ends up something like this
"{\"type\":\"#\",\"name\":\"unkd42t9\",\"list\":[{\"0\":\"background-color\"},{\"1\":\"border\"},{\"2\":\"width\"},{\"3\":\"height\"},{\"4\":\"clear\"}],\"listvalues\":[{\"0\":\"#ddd\"},{\"1\":\"2px solid #000\"},{\"2\":\"100%\"},{\"3\":\"50px\"},{\"4\":\"both\"}]}",
the fullJSON comes from JSON.parse(json); which comes from a file
You seem to confuse JSON, a textual, language-independent data representation, with JavaScript objects, a language-specific data type.
JSON.stringify returns a string (containing JSON), so jsonltoload is a string. I guess you simply want to parse the JSON and add the resulting object:
var obj = JSON.parse(jsonloadtostring);
fullJSON.styles.objectcss.push(obj);
I think the JSON string is trying to escape the double quotes character you have added to string, resulting in the string. try to enclose the whole string with single quotes rather than double quotes
I have java object which is converted as JSON string using
String paramMap = new ObjectMapper().writeValueAsString(custPolicy.getParamMap());
model.addAttribute("testTypeMap", paramMap );
In the .jsp page, on load I'm trying to parse the testTypeMap and get object back;
var paramMap = JSON.parse('${testTypeMap}');
showTestType('File content', 'LINUX', paramMap);
The object has double quotes (") in one of the fields, and it is escaped with backslash () when it is converted as JSON sting in java, that is why we see "\"" (from view source)
var paramMap = JSON.parse('{"Filepath":"/home/status.txt","Search expression":"\""}');
But the above line says, "Uncaught SyntaxError: Unexpected string".
I have seen few posts and they say it need two parses, one for javascript and one for JSON. I tried to replace \" with \\" ; but in javascript \" is always ", so I could not replace it;
Any pointer for what I miss here?
The problem is that you're not encoding the string in ${testTypeMap} as a JavaScript literal. I'm unsure how to do it specifically in your framework, but it's akin to HTML encoding a string, but for JavaScript instead.
However!
In your specific example you can avoid using JSON.parse because JSON is already in a format consumable by JavaScript.
var paramMap = ${testTypeMap};
showTestType('File content', 'LINUX', paramMap);
With the resulting source sent to browser looking like:
var paramMap = {"Filepath":"/home/status.txt","Search expression":"\""};
Actually I was not knowing how to replace \" with \\" in javascript, as \" is always represented as " (just one quote without backslash).
So I did this replace in server side after converting to a JSON string using Jackson's ObjectMapper as below:
String paramMap = new ObjectMapper().writeValueAsString(custPolicy.getParamMap());
// need to replace any \" with \\" in javascript side
paramMap = paramMap.replace("\\\"", "\\\\\"");
model.addAttribute("testTypeMap", paramMap );
Now in client-side it shows as below:
var paramMap = JSON.parse('{"Filepath":"/home/cavirin/status.txt","Search expression":"\\""}');
and this works fine as javascript parse is already taken care in server side.
I have JSON data passed by PHP and I need to parse it in Javascript.
item = JSON.parse('<?=json_encode($item_localized);?>');
Some trouble. I have string in $item_localized which contains single quote. Jsonlint says it valid json. Because I use '<?=json_encode($item_localized);?>' - I receive message Uncaught SyntaxError: Unexpected identifier. I cannot use double quotes. I tried replace single quotes with \' but it's not working.
json_encode will generate a JSON text.
JSON.parse needs to receive a string containing a JSON text.
You do need to quote the string, but you can't simply place ' around it because that won't escape any characters in the string that have special meaning in a string literal (like other ' characters).
If you put a string into json_encode then you will get out a JSON text consisting of a string representation of another JSON text. Since JSON is a JS subjet, that string will be JS safe:
item = JSON.parse(<?php echo json_encode(json_encode($item_localized)); ?>);
This is, however, silly. Since JSON is a subset of JavaScript, you can just use it directly as a JavaScript literal.
item = <?php echo json_encode($item_localized); ?>;
What about item = <?=json_encode($item_localized);?>;?
I’m making requests to my server using jQuery.post() and my server is returning JSON objects (like { "var": "value", ... }). However, if any of the values contains a single quote (properly escaped like \'), jQuery fails to parse an otherwise valid JSON string. Here’s an example of what I mean (done in Chrome’s console):
data = "{ \"status\": \"success\", \"newHtml\": \"Hello \\\'x\" }";
eval("x = " + data); // { newHtml: "Hello 'x", status: "success" }
$.parseJSON(data); // Invalid JSON: { "status": "success", "newHtml": "Hello \'x" }
Is this normal? Is there no way to properly pass a single quote via JSON?
According to the state machine diagram on the JSON website, only escaped double-quote characters are allowed, not single-quotes. Single quote characters do not need to be escaped:
Update - More information for those that are interested:
Douglas Crockford does not specifically say why the JSON specification does not allow escaped single quotes within strings. However, during his discussion of JSON in Appendix E of JavaScript: The Good Parts, he writes:
JSON's design goals were to be minimal, portable, textual, and a subset of JavaScript. The less we need to agree on in order to interoperate, the more easily we can interoperate.
So perhaps he decided to only allow strings to be defined using double-quotes since this is one less rule that all JSON implementations must agree on. As a result, it is impossible for a single quote character within a string to accidentally terminate the string, because by definition a string can only be terminated by a double-quote character. Hence there is no need to allow escaping of a single quote character in the formal specification.
Digging a little bit deeper, Crockford's org.json implementation of JSON for Java is more permissible and does allow single quote characters:
The texts produced by the toString methods strictly conform to the JSON syntax rules. The constructors are more forgiving in the texts they will accept:
...
Strings may be quoted with ' (single quote).
This is confirmed by the JSONTokener source code. The nextString method accepts escaped single quote characters and treats them just like double-quote characters:
public String nextString(char quote) throws JSONException {
char c;
StringBuffer sb = new StringBuffer();
for (;;) {
c = next();
switch (c) {
...
case '\\':
c = this.next();
switch (c) {
...
case '"':
case '\'':
case '\\':
case '/':
sb.append(c);
break;
...
At the top of the method is an informative comment:
The formal JSON format does not allow strings in single quotes, but an implementation is allowed to accept them.
So some implementations will accept single quotes - but you should not rely on this. Many popular implementations are quite restrictive in this regard and will reject JSON that contains single quoted strings and/or escaped single quotes.
Finally to tie this back to the original question, jQuery.parseJSON first attempts to use the browser's native JSON parser or a loaded library such as json2.js where applicable (which on a side note is the library the jQuery logic is based on if JSON is not defined). Thus jQuery can only be as permissive as that underlying implementation:
parseJSON: function( data ) {
...
// Attempt to parse using the native JSON parser first
if ( window.JSON && window.JSON.parse ) {
return window.JSON.parse( data );
}
...
jQuery.error( "Invalid JSON: " + data );
},
As far as I know these implementations only adhere to the official JSON specification and do not accept single quotes, hence neither does jQuery.
If you need a single quote inside of a string, since \' is undefined by the spec, use \u0027 see http://www.utf8-chartable.de/ for all of them
edit: please excuse my misuse of the word backticks in the comments. I meant backslash. My point here is that in the event you have nested strings inside other strings, I think it can be more useful and readable to use unicode instead of lots of backslashes to escape a single quote. If you are not nested however it truly is easier to just put a plain old quote in there.
I understand where the problem lies and when I look at the specs its clear that unescaped single quotes should be parsed correctly.
I am using jquery`s jQuery.parseJSON function to parse the JSON string but still getting the parse error when there is a single quote in the data that is prepared with json_encode.
Could it be a mistake in my implementation that looks like this (PHP - server side):
$data = array();
$elem = array();
$elem['name'] = 'Erik';
$elem['position'] = 'PHP Programmer';
$data[] = json_encode($elem);
$elem = array();
$elem['name'] = 'Carl';
$elem['position'] = 'C Programmer';
$data[] = json_encode($elem);
$jsonString = "[" . implode(", ", $data) . "]";
The final step is that I store the JSON encoded string into an JS variable:
<script type="text/javascript">
employees = jQuery.parseJSON('<?=$marker; ?>');
</script>
If I use "" instead of '' it still throws an error.
SOLUTION:
The only thing that worked for me was to use bitmask JSON_HEX_APOS to convert the single quotes like this:
json_encode($tmp, JSON_HEX_APOS);
Is there another way of tackle this issue? Is my code wrong or poorly written?
Thanks
When You are sending a single quote in a query
empid = " T'via"
empid =escape(empid)
When You get the value including a single quote
var xxx = request.QueryString("empid")
xxx= unscape(xxx)
If you want to search/ insert the value which includes a single quote in a query
xxx=Replace(empid,"'","''")
Striking a similar issue using CakePHP to output a JavaScript script-block using PHP's native json_encode. $contractorCompanies contains values that have single quotation marks and as explained above and expected json_encode($contractorCompanies) doesn't escape them because its valid JSON.
<?php $this->Html->scriptBlock("var contractorCompanies = jQuery.parseJSON( '".(json_encode($contractorCompanies)."' );"); ?>
By adding addslashes() around the JSON encoded string you then escape the quotation marks allowing Cake / PHP to echo the correct javascript to the browser. JS errors disappear.
<?php $this->Html->scriptBlock("var contractorCompanies = jQuery.parseJSON( '".addslashes(json_encode($contractorCompanies))."' );"); ?>
I was trying to save a JSON object from a XHR request into a HTML5 data-* attribute. I tried many of above solutions with no success.
What I finally end up doing was replacing the single quote ' with it code ' using a regex after the stringify() method call the following way:
var productToString = JSON.stringify(productObject);
var quoteReplaced = productToString.replace(/'/g, "'");
var anchor = '<a data-product=\'' + quoteReplaced + '\' href=\'#\'>' + productObject.name + '</a>';
// Here you can use the "anchor" variable to update your DOM element.
Interesting. How are you generating your JSON on the server end? Are you using a library function (such as json_encode in PHP), or are you building the JSON string by hand?
The only thing that grabs my attention is the escape apostrophe (\'). Seeing as you're using double quotes, as you indeed should, there is no need to escape single quotes. I can't check if that is indeed the cause for your jQuery error, as I haven't updated to version 1.4.1 myself yet.