I'm getting
/json/common.rb:156:in `parse': 783: unexpected token at '' (JSON::ParserError) while trying to parse a json file in ruby. The problem was because there were some single quotes in one of the strings:
parsed = JSON.parse("{
\"key1\":\"value1\",
\"key2\":\"value2\",
\"key3\":12345,
\"key4\":\"''value4''\",
}")
Is there a way to escape the single quotes in the strings without affect words like don't? The json is read from a file using JSON.parse(file.get_input_stream.read) that's why there are \.
The single quotes aren't your problem, your problem is that you have a stray trailing comma:
parsed = JSON.parse("{
\"key1\":\"value1\",
\"key2\":\"value2\",
\"key3\":12345,
\"key4\":\"''value4''\",
}") #--------------------^ This should not be there.
JSON doesn't allow that comma so you don't actually have a JSON file.
You should figure out where the file came from and fix that tool to produce real JSON rather than the "looks mostly like JSON" that is currently being written to the file.
Related
I have a CSV file that contains a JSON string, which itself has a double-quote in one of its values. This means that the double quote must be escaped twice, first with another double-quote, and then with a backslash. However, I was not able to get this to work until I had escaped the backslash as well! Otherwise, I got a JSON parse error.
In other words, this raw value: " should became this in JSON: \" but then this did not work in the CSV file (JSON Parse Error): \"" but THIS did: \\""
Or, for a clearer example:
Value with double quote: You "know" it!
JSON: [{ "value" : "You \"know\" it!" }]
CSV (JSON Parse Error): "John Smith","[{ ""value"" : ""You \""know\"" it!"" }]"
CSV (DID work): "John Smith","[{ ""value"" : ""You \\""know\\"" it!"" }]"
This seems a bit unexpected. It's as if I have to escape a backslash in JSON. Why would I need to do this?
If it makes any difference, I'm using Java to parse all this, with OpenCSV for parsing the CSV data and Gson for parsing the JSON data.
Hmm, it's old question, but still, I needed to do something similar. My solution was to save csv in db, and then export it to json format.
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 have a string in R which escapes quotation marks:
my_text = {\"stim\":[\"platery\",\"denial\",\"generic\"]}
When using cat() I get:
{"stim":["platery","denial","generic"]}
Now my whole string is a JSON string that needs to be parsed and is evaluated invalid by JSONLint. If I copy&paste the cat() version, this is valid a JSON, so I think I just miss some pre-processing here.
I saw this SO post here, and this one, and this really good one, so I tried to replace the single quotation marks with double quotation marks for the JSON parser:
gsub("\\\\", "\\\\\\\\", my_text, fixed=TRUE)
but it did't change my string as I wanted. How can I change the string to become valid JSON?
As Wiktor said your gsub didn't work because you are attempting to replace backslashes, but there aren't any backslashes in your string. R is just using the backslashes as a way to store the double quotes. The third SO post you link does a good job explaining R's string literals which addresses this. A backslash in R is stored as a double backslash.
My first piece of advice would be to use the R package jsonlite to construct your JSON from an R object as opposed to a string if possible (heres the vignette).
Example:
myJSON <- jsonlite::toJSON(list(stim=c("platery","denial","generic")))
# {"stim":["platery","denial","generic"]}
Second, (as the third SO post again does a good job of explaining) copying/pasting the print method of the string may not be the best way to validate the JSON. I'm not sure of the use case, but R storing the double quotes with escape characters is probably not a bad thing.
If you want to get a prettier print method you can use numerous tricks in R (noquote(), cat(), print(quote=F)) but this won't change that R stores the double quotes with backslashes:
Additionally, in some cases constructing the JSON isn't necessary. I have an API built using the plumbr package that returns a list as JSON without any modifications (recJSON <- list(message=messages,recommendations=list(name=names, link=URLs)))
Building a Json respose with erlang. First I construct the data in terms and then use jsx to convert it to JSON:
Response = jsx:term_to_json(MealsListResponse),
The response actually is valid JSON according to the validators I have used:
The problem is when parsing the response in the front end. Is there a way to strip the backslashes from the Erlang side, so that the will not appear on the payload response?
The backslashes are not actually part of the string. They're just used when the string is printed as a term - that is, in the same way you'd write it in an Erlang source file. This works in the same way as character escapes in strings in C and similar languages: inside double quotes, double quotes that should be part of the string need to be escaped with backslashes, but the backslashes don't actually make it into the string.
To print the string without character escapes, you can use the ~s directive of io:format:
io:format("~s~n", [Response]).
If you're sending the response over a TCP socket, all you need to do is converting the string to binary with an appropriate Unicode conversion. Most of the time you'll want UTF-8, which you can get with:
gen_tcp:send(MySocket, unicode:characters_to_binary(Response)).
I'm having trouble properly escaping a string I'm trying to use to represent JSON in Erlang. I'm not sure why this particular sequence is giving the parser trouble. I have this string in a Basho Bench configuration file.
'{
"stats":"completed",
"times":[
{
"time":"2014-10-29T23:40:46.558Z"
}
]
}'
I am getting this error:
23:37:18.521 [error] Failed to parse config file server/http.config.erl: {29,erl_scan,{illegal,atom}}
It seems like maybe the issue is the numbers in the string but I don't get how I would escape them. Any thoughts?
You provided insufficient info but anyway, server/http.config.erl is not JSON. It is erlang term, so this error is from Erlang parser. The whole text you provided is parsed as atom because of ' which is delimiter for atoms.
The string is not a string. Single quotes denote an atom. It must be wrapped in double quotes to be interpreted as a string.