I am just trying to parse a Json document with a field Date like this:
´ death':Date('2007-03-17T04:00:00Z') using
com.mongodb.util.JSON.parse(document)
There is an exception when the value Date is encountered. Any help?
The key here is whatever has exported the data has done it wrong. Possibly someone has run something from the MongoDB shell and redirecting console output to a file. That is basically "doing it wrong".
There is a concept called MongoDB Extended JSON and has in fact been picked up in a few other areas, notably the EJSON project.What this tries to do is make sure that any exported JSON maintains "type" information to the BSON type identifier ( or other Object Type, in the purpose of EJSON ) so that a similar "extended JSON" parser can "re-construct" the object to it's intended form.
For a "date" object, the intented JSON representation is this:
{ "death": { "$date": "2007-03-17T04:00:00Z" } }
Since com.mongodb.util.JSON.parse is enabled with knowledge of the Extended JSON spec, then any such JSON contruct will result in a correct date object being constructed from the parsed data.
So what you have right now is just a "string". In fact, if it is not "quoted" like this:
´ { "death" : "Date('2007-03-17T04:00:00Z')" }
Then it is not in fact even valid JSON and would even need to be manipulated to a correct form before even a basic JSON parser would not error. At any rate, the result is just a "string" still, so you would need to make a regex match for the numerical data, then pass that to a date object construct.
Clearly the "best" thing to do here is to fix the "export" source of the data so that it is doing this date parsing to JSON in the correct extended way. Then the parser you are using will do the right thing.
Related
The data is stored as an array of objects wrapped in a string that looks like this
["{\"x\"=>15, \"y\"=>7}", "{\"x\"=>14, \"y\"=>7}", "{\"x\"=>13, \"y\"=>7}", "{\"x\"=>13, \"y\"=>6}", "{\"x\"=>13, \"y\"=>5}", "{\"x\"=>13, \"y\"=>4}", "{\"x\"=>13, \"y\"=>3}", "{\"x\"=>12, \"y\"=>3}", "{\"x\"=>11, \"y\"=>3}"]
The reason it is stored that way is because when I was storing the data from a json, I had to convert what was wrapped in Action Parameters to a hash.
I took a look at How to convert a ruby hash object to JSON? and Parse JSON in JavaScript?, and my answer is not addressed.
First, the problem is that it would seem JSON does not parse anything wrapped in double quotations, nor with rocket hash notation, and so I am not able to convert to convert "{"x"=>15, "y"=>7}" to {"x"=>15, "y"=>7}.
Perhaps, I have to serialize the object, see where I get my data from here: How can I access the data for the snake object sent through JSON in my params?
Any ideas on what the right approach would be?
Following radiantshaw's lead, using either
eval("{\"x\"=>15, \"y\"=>7}")
or
JSON.parse("{\"x\"=>15, \"y\"=>7}".gsub('=>', ':'))
I got the following: {"x"=>15, "y"=>7}, which is a Ruby object. However in order to convert this to a Javascript object, I also needed to convert it to json.
So by taking it one step further, I am able to parse it into json like so:
Put require 'json' in the .rb file, and then do {"x"=>15, "y"=>7}.to_json which will result in
"{\"x\":15,\"y\":7}".
The reason you're not able to convert to JSON because hash rocket is not a proper JSON syntax. Hash rocket is purely Ruby syntax.
What that means is that you somehow managed to take a Hash and convert it to a String. So the converted string is actually Ruby code and not JSON.
You could do...
eval("{\"x\"=>15, \"y\"=>7}")
... and it will return a Ruby Hash.
Or if you don't want to use eval due to security reasons, you can do...
JSON.parse("{\"x\"=>15, \"y\"=>7}".gsub('=>', ':'))
I have a Java JSON Object, its format is [{a=b}], I am trying to pass this object into javascript as a JSON object but its missing " on both the key and value as well as having "=" instead of ":"
Is there a simple way of converting this JAVA JSON object to be consumable by different services?
Parsing is proving to be very complicated as the actual JSON is nested and the lack of quotations and the lacking of indications for nestedness.
Sample of 'JSON' data:
[{wwnType=Virtual, serialNumberType=Virtual, connections=[], modified=2016-10-29T19:00:04.457Z, macType=Virtual, category=server-profile-templates, serverHardwareTypeUri=/rest/server-hardware-types/32006464-D3C6-4B4E-8328-47A193C6116C, bios={overriddenSettings=[], manageBios=false}, firmware={firmwareBaselineUri=null, manageFirmware=false, forceInstallFirmware=false, firmwareInstallType=null}, boot={manageBoot=true, order=[CD, Floppy, USB, HardDisk, PXE]}, hideUnusedFlexNics=true, bootMode=null, state=null, affinity=Bay, localStorage={controllers=[]}, type=ServerProfileTemplateV1, status=OK, description=, eTag=1477767604457/1, serverProfileDescription=test, name=test, created=2016-10-29T19:00:04.428Z, enclosureGroupUri=/rest/enclosure-groups/e989621b-930e-40e7-9db0-a6ddbf841709, uri=/rest/server-profile-templates/db1dbdcc-4237-4452-acc3-cf9dfdc75365, sanStorage={manageSanStorage=false, volumeAttachments=[]}}]
Thanks
It's not going to be simple. However, I think you can do this without writing a full-fledged parser, as long as you're willing to write a tokenizer, or lexical analyzer, to break your input string into tokens. The basic plan could be something like:
Convert your input into a list of tokens. I don't know what the format of your input is, so you'll need to do your own analysis. A token would be something like a single character [, ], {, }, comma, =; or an identifier (a or b in your example, but I don't know what the possible valid formats are); or, maybe, a string literal in quotes, or a numeric literal, depending on what your needs are.
Go through the string and replace the tokens you need to. Based on your example, I'd say that after a {: if the first token after that is an identifier, put it in quotes; if the second token after that is =, change it to :; if the third token after that is an identifier, put it in quotes. The same could be true after a comma, but you'll need to keep track of whether the comma is a separator for a list of key-value pairs in an object, or a list of values in an array. For that, you may need to keep a stack that you push whenever you see [ or {, and pop whenever you see } or ], so that you know whether you're inside an object or an array.
After you're done replacing everything, concatenate the tokens back together. The result should be a well-formed JSON object.
This is just a rough outline, since I really don't know all your requirements. You'll probably have to adapt this answer to meet your exact needs. But I hope this helps as a general idea of how you could approach the problem.
Sorry, I don't think there's a simpler answer, except that you might want to look into parser generators (see Yacc equivalent for Java). I haven't actually looked at any in Java, so I don't know how simple they are to use. Please don't try to solve the whole thing with regexes. (Regexes will be useful for breaking your string into tokens, but trying to do more than that with regexes is likely to produce nothing but migraine.)
I think isn't json object. json object should be like this.
Example:
JSONObject obj = new JSONObject();
obj.put("a", "b");
obj.put("name", "your name");
Output: {"a": "b", "name":"your name"}
Passing into javascript
var obj = '{"a": "b", "name":"your name"}',
var json = JSON.parse(obj);
this is a very specific request, and for that i apologise, but i am at a loss for what to do..
for a javascript project i am working on i want to be able to parse javascript with python and i found this implementation`port of the original narcissus called pynarcissus:
https://github.com/jtolds/pynarcissus
the problem for me is the information is buried in the python class structure.. something with which i am only vaguely competent.. and i want the output to be in JSON
i have tried to mine the data out but each time the JSON is invalid
my question is how would you go about doing something like this? i'd appreciate any specifics because the project contains nested classes of disparate types creating what seems to be a wholly unique problem
here are my attempts:
i took the return value for parse() and created a function that descends through the class structure returning values based on their type: 'str', 'int', 'bool', 'NoneType', 'list', 'dict', 'main.Node', 'main.Tokenizer', 'main.Object'; but the returned object is missing some properties in the classes, ie 'type', while retaining others like 'type_', also tokenizer always contains the same values
i took the output of the str function that the program prints to stdout, removed the clear and copy functions and the tokenizer: [object Object], then tried to manually add in double quotes where necessary to make the output a valid JSON object.. a few problems here, first off ignoring the tokenizer object seems like i am missing out on vital information, and the other problem was that sometimes there is "value" : "{" and sometimes there is "value" : { .. }, after completing the work the JSON was invalid
assuming the issue lied in the "value" : { .. } issue i resolved to add a new function identical the the str function but instead of printing just %s values, it would print \"%s\" where necessary.. now, i could differentiate between "value": "{" and "value" : "{ .. }" but i would have to go through and manually remove the quotes around objects.. after doing so the JSON was invalid
i've tried every copy'pasta solution for python class to json from the stacks but the nested aspect of the classes along with the changing types add complexity.. some properties lack a .dict even when the type is "class 'dict'" so the one'method'fits'all lambda solutions fail
for posterity:
once i massaged the code of pynarcissus to print json i found that the process fails on nested functions.. hilariously exactly the reason i stepped away from my homebrew method
in another thread(i) #firstfire suggested esprima and pyesprima
so i looked into the esprima suggestions, and after a bit of 2to3`ing and some more work returning valid json i got it working and so far it fits my needs perfectly
check out the issue, pull request, and fork:
issues : https://github.com/int3/pyesprima/issues/1
pr : https://github.com/int3/pyesprima/pull/2
fork : https://github.com/ghissues/pyesprima
(i) http://www.linuxquestions.org/questi....php?p=5364199
the old answer::
closed the issue and added a pull request
https://github.com/jtolds/pynarcissus/issues/6
you can check out the fork if you got here by looking for a way to parse javascript to json in python 3
https://github.com/ghissues/pynarcissus
In Mongodb (2.6.1), I need to query a document by _id using pure json (without using ObjectIds). As mentioned in the mongodb extended json, I was expecting db.collection.findOne({"_id": {"$oid": "51b6eab8cd794eb62bb3e131"}}) to work but it does not. It even throw the following exception.
Can't canonicalize query: BadValue unknown operator: $oid
Anyone knows how to do it?
The extended JSON syntax is intended as a "transfer" format so that if for example you are sending JSON ouput to a remote client there is still a way to determine the actual implemented type such as ObjectId, Date, Binary etc.
The only place AFIAK where this is implemented is within the C# driver which provides a json parser utility method which would take JSON with the extended syntax fields and then "cast" those into objects of the required type.
So in much the same way you can implement your own parser routine to do much the same thing, it is just a matter of testing the key values for something that represents the type of object specified in the key. Given a sample fragment:
{ "_id": { "$oid": "51b6eab8cd794eb62bb3e131" } }
In simplified form without recursively checking by depth:
data = JSON.parse( json );
for ( k in data ) {
if ( data[k].hasOwnProperty("$oid") )
data[k] = new ObjectId( data[k]["$oid"] );
// etc
}
So just because you may be using JavaScript it doesn't mean the "extended syntax" is valid as a query source, but you can as with other languages post-process the parsed JSON into the valid object notation required by that language and the query interface.
Similar "casting" is performed by some drivers on "string" values supplied against an _id field in order to cast to the correct object type required by the BSON wire protocol.
From JSON website:
JSON is built on two structures:
A collection of name/value pairs. In various languages, this is realized as an object, record, struct, dictionary, hash table, keyed list, or associative array.
An ordered list of values. In most languages, this is realized as an array, vector, list, or sequence.
Now I have a sample service that returns a boolean (this is in PHP, but it could be any server side language):
<?php
header('Content-Type: application/json');
echo 'true';
exit;
And when requesting this page with ajax (for example with jQuery):
$.ajax({
url: 'service.php',
dataType: 'json',
success: function (data) {
console.log(data);
console.log(typeof data);
}
});
The result would be:
-> true
-> boolean
My question is why it's allowed to return boolean as a JSON.
Doesn't it have conflict with JSON definition?
ALSO
Also I can return number or string in my service:
<?php
header('Content-Type: application/json');
echo '2013';
exit;
And the result is:
-> 2013
-> number
And for string:
<?php
header('Content-Type: application/json');
echo '"What is going on?"';
exit;
And the result is:
-> What is going on?
-> string
You are correct that a valid JSON text can only be an object or an array. I asked Douglas Crockford about this in 2009 and he confirmed it, saying "Strictly speaking, it is object|array, as in the RFC."
The JSON RFC specifies this in section 2:
A JSON text is a serialized object or array.
JSON-text = object / array
The original JSON syntax listed on json.org does not make this clear at all. It defines all of the JSON types, but it doesn't say anywhere which of these types may be used as a "JSON text" - a complete valid piece of JSON.
That's why I asked Doug about it and he referred me to the RFC. Unfortunately, he didn't follow up on my suggestion to update json.org to clarify this.
Probably because of this confusion, many JSON libraries will happily create and parse (invalid) JSON for a standalone string, number, boolean, etc. even though those aren't really valid JSON.
Some JSON parsers are more strict. For example, jsonlint.com rejects JSON texts such as 101, "abc", and true. It only accepts an object or array.
This distinction may not matter much if you're just generating JSON data for consumption in your own web app. After all, JSON.parse() is happy to parse it, and that probably holds true in all browsers.
But it is important if you ever generate JSON for other people to use. There you should follow the standard more strictly.
I would suggest following it even in your own app, partly because there's a practical benefit: By sending down an object instead of a bare string, you have a built-in place to add more information if you ever need to, in the form of additional properties in the object.
Along those lines, when I'm defining a JSON API, I never use an array at the topmost level. If what I have is an array of items of some sort, I still wrap it in an object:
{
"items": [
...
]
}
This is partly for the same reason: If I later want to add something else to the response, having the top level be an object makes that easy to do without disrupting any existing client code.
Perhaps more importantly, there's also a possible security risk with JSON arrays. (I think that risk only affects the use of eval() or the Function constructor to parse JSON, so you're safe with JSON.parse(), but I'm not 100% sure on this.)
Note, the answer from Michael Geary is outdated since rfc7158 in 2013 which does not limit JSON text to array or object anymore. The current RFC https://www.rfc-editor.org/rfc/rfc8259 says:
A JSON text is a serialized value. Note that certain previous
specifications of JSON constrained a JSON text to be an object or an
array. Implementations that generate only objects or arrays where a
JSON text is called for will be interoperable in the sense that all
implementations will accept these as conforming JSON texts.