query with filter in JsonPath - json
I have a structure like this:
{
title: [
{lang: “en”, value: “snickers”},
{lang: “ru”, value: “сниккерс”}
]
}
I need to take a result such this:
“snickers”
I finished with query:
$.title[?(#.lang="en")].value
but it doesn't work
JsonPath always returns an array of results, so you will not be able to get a single value such as "snickers" on its own. You will be able to get ["snickers"] though. To get it working you need to use a double equal sign instead of single:
$.title[?(#.lang=="en")].value
Also note that another reason you may be having issues is that your double quotes in the json are not the standard double quote characters. Depending on how you consume the json you may also need to wrap the property names in double quotes. The json standard is quite strict, and if you are parsing your json from text it has to follow these rules. Here is version of the json corrected in this way:
{
"title": [
{"lang": "en", "value": "snickers"},
{"lang": "ru", "value": "сниккерс"}
]
}
I have tested the above query with the corrected json using http://www.jsonquerytool.com.
Related
NiFi expression language dealing with special characters in JSON keys
So I have some json in which the keys might be something like this:
{
"name" : "John",
"num:itparams:enterprise:2.0:content" : {
"housing" : "5"
},
"num rooms": "12"
}
I get this json from an http request, and I need to use the evaluateJsonPath processor to create attributes from them.
name is easy, i just use $.name
But how would I access the other two? I imagine you would put them in quotes somehow to escape the special characters but just doing $."num:itparams:enterprise:2.0:content" doesnt work.
You can use the bracket for the key-value which has the special characters such as $.['num:itparams:enterprise:2.0:content'].housing then it will give you the evaluated result 5.
How to deserialize json string with an extra ""
I have input Json string that I am trying to deserialize
{
"ID":1,
"Details":{
"Product":""Boston,saline"",
"cost":150.0
}
}
or
{
"ID":1,
"Details":{
"Product":"Boston "Sample"",
"cost":150.0
}
}
When I try to use $JsonConvert.DeserializeObject<JObject>(input) it gives me error saying "After parsing a value an unexpected character was encountered" and this is expected. Is there a way we can deserialize this kind of strings?
Thanks!
Could you use .replace from native String method to replace all double double quotes with a single double quote.
You can’t.
Say a user is able to create a product named ", "x": "y. This will be represented as (incorrectly serialized to)
"Details": {
"Product": "", "x": "y",
"cost": 150.0
}
That is valid JSON, so there’s no syntactic way to detect that anything is wrong.
Even worse, what if an attacker creates a product named ", "cost": 1.0, "x": "y. This will be represented as (with some formatting applied)
"Details": {
"Product": "",
"cost": 1.0,
"x": "y",
"cost": 150.0
}
What will your deserializer do with that? Will it accept it? (Some will.) Will it use the first "cost" or the second "cost"—that is, will it allow an attacker to lower the cost? And would it be possible for an attacker to create a duplicate "cost" after the real one? And even if everything is currently okay when deserializing that string, will it continue to work after upgrading to a new version of the library?
As of 2017, Json.net accepts such JSON and uses the second duplicate value (see Json.net no longer throws in case of duplicate). But this behavior changed between versions 6 and 8. Will it change again?
The only real fix is to fix whatever is generating this JSON.
The stuff in your examples is not JSON; that is why you are having problems parsing it with a JSON parser. Consider fixing either how the data is stored or how it is read. Option 1: Fix how it is stored. It looks like the string value "blammy" is actually stored in your DB as something like: \"blammy\". This is zero percent correct. The value that gets stored in your DB column should be blammy (notice, no quotes). Fix that problem. Option 2: Fix how is is read Something is reading the column value from your DB. Change that thing to remove outer double quotes from string data. Then, the (incorrectly) stored value \"blammy\" would be read (and fixed) to be blammy. This will only work with example 1 in your question. You will need to do something else if you are getting example 2.
How can I find the row & column in a JSON String identified by a JsonPath?
Suppose I have a JSON string like this example:
[
{
"name": "John"
},
{
"name": "Jane"
}
]
Using JSONPath I want to select the second name like this:
[1].name
However, I am not interested in the name's value but rather in the row & column of the entire second name key-value pair as they appear in the String. In this example, the expected result when written as a JSON would be:
{
"row": 5,
"column": 4
}
Alternatively, the index within the String would be fine as well. Note that I don't require the result to be a JSON. Note also that this should work with any formatting of the JSON.
I have thought about constructing a regular expression but this might be fragile if the key's name "name" also appears as text in values.
I am using Jayway JSONPath in my Java backend but a solution with a different JSONPath library, or one in JavaScript using an Node.js compatible library would also be fine.
Invalid JSON but validates on JSONLint
I have the following JSON which validates on JSONLint.com but when I pass it to JSON.parse() I get the error
SyntaxError: JSON.parse: unexpected character
...0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,...
This is apparently the last "correct": line
var theJSON = JSON.parse({
"data": [
{
"wrong": "0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0",
"correct": "0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0"
},
{
"wrong": "0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0",
"correct": "0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0"
},
{
"wrong": "0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0",
"correct": "0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0"
},
{
"wrong": "0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0",
"correct": "0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0"
}
]
});
You, like many, have confused JavaScript's literal syntax with JSON. This happens a lot as JSON uses a subset of JavaScript's literal syntax so it looks a lot alike. JSON, however, is always a string. It is a serialized data scheme for porting data structures between langs/platforms.
Also confusing is that a string of JSON which has been output by any platform can be copied and pasted right into JavaScript and used. Again, this is because of the shared syntax. Having pasted such output right into JavaScript, however, one is no longer using JSON--they are now writing JavaScript in literal syntax. That is, unless, you pasted it between quotes and properly escaped the resulting string. But there's no sense in doing so as then it needs to be parsed in order to end up with what you already had.
JSON.parse() is a method for unserializing data which had been serialized into JSON. It expects a string because, well, JSON is a string. You're passing an object (in literal syntax). It does not need parsing...it is already the thing you want.
Wrapping your object literal in single quotes would make the code work, but it would be pointless to do so as the parse would simply result in what you already have.
Your code would be better written if you replaced the variable named theJSON with one named theObject and made it look as such:
var theObject = {
data: [
{
wrong: "0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0",
correct: "0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0"
},
{
wrong: "0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0",
correct: "0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0"
},
{
wrong: "0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0",
correct: "0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0"
},
{
wrong: "0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0",
correct: "0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0"
}
]
};
Whatever code wanted to use the parse result should be fine once you've done it.
How do you represent a JSON array of strings?
This is all you need for valid JSON, right? ["somestring1", "somestring2"]
I'll elaborate a bit more on ChrisR awesome answer and bring images from his awesome reference.
A valid JSON always starts with either curly braces { or square brackets [, nothing else.
{ will start an object:
{ "key": value, "another key": value }
Hint: although javascript accepts single quotes ', JSON only takes double ones ".
[ will start an array:
[value, value]
Hint: spaces among elements are always ignored by any JSON parser.
And value is an object, array, string, number, bool or null:
So yeah, ["a", "b"] is a perfectly valid JSON, like you could try on the link Manish pointed.
Here are a few extra valid JSON examples, one per block:
{}
[0]
{"__comment": "json doesn't accept comments and you should not be commenting even in this way", "avoid!": "also, never add more than one key per line, like this"}
[{ "why":null} ]
{
"not true": [0, false],
"true": true,
"not null": [0, 1, false, true, {
"obj": null
}, "a string"]
}
Your JSON object in this case is a list. JSON is almost always an object with attributes; a set of one or more key:value pairs, so you most likely see a dictionary:
{ "MyStringArray" : ["somestring1", "somestring2"] }
then you can ask for the value of "MyStringArray" and you would get back a list of two strings, "somestring1" and "somestring2".
Basically yes, JSON is just a javascript literal representation of your value so what you said is correct. You can find a pretty clear and good explanation of JSON notation on http://json.org/
String strJson="{\"Employee\":
[{\"id\":\"101\",\"name\":\"Pushkar\",\"salary\":\"5000\"},
{\"id\":\"102\",\"name\":\"Rahul\",\"salary\":\"4000\"},
{\"id\":\"103\",\"name\":\"tanveer\",\"salary\":\"56678\"}]}";
This is an example of a JSON string with Employee as object, then multiple strings and values in an array as a reference to #cregox...
A bit complicated but can explain a lot in a single JSON string.