$parse removes object keys that begin with $ (dollar sign)

[daryllstrauss]

If you attempt to send {'_id':{'$oid':'123'}} as an argument to a resource, the {'$oid':'123'} is removed from the http request that is sent.

This is a problem, because mongodb uses keys that start with $ as a way to serialize certain objects.

As far as I can tell there's no restriction on $ from the strings in a JSON object, so it seems the behavior of parse is wrong.

[jtymes]

Angular is stripping the $ because it is used for Angular (mostly) properties/methods and when they are converted to JSON, they're stripped because it's extraneous.

Here's an idea for a solution:
For certain components, e.g. $resource or $http, allow a special leading sequence (such as "+$") to signal that the $ not be stripped. I don't believe this would be a breaking change.

So, for this example, '+$oid' would be stripped down to '$oid'.

Thoughts?

[daryllstrauss]

Quoting might be a good solution.

My question is where the quoting/dequoting would occur.

I believe $http is the low level transport. From my point of view, the
ideal solution would be to have $http quote and dequote the identifiers.
That way it would be transparent to my python (mongodb) application. My
angular application would see +$oid as an identifier, but that wouldn't
be so bad.

$ would be a more traditional way to quote it.

[mstein]

Same issue here, writing a plugin for grails and mongodb, I was forced to parse/marshall json object manually to keep the '$xxx' keys in the object received/sent.

As a workaround for now, you can send your JSON as a string using a standard or custom json stringifier, same for the parser as the keys would be stripped from the response as well, ex:

var args = {"$oid":"xxx"};
// MongoJSON is a custom parser/stringifier, also handling a bit of mongodb '10Gen' syntax
$http.post('mongo/find', MongoJSON.stringify(args), {transformResponse:parseMongoJson}).success(function(data) {
    successCallback(data);
}).error(function(data){ errorCallback(data); });

function parseMongoJson(data, headerGetter) {
    return MongoJSON.parse(data, mongoJsonReviver);
}

Still waiting for a proper fix for this issue, actually even passing an object with "$xx" keys between scopes seems to strip those keys...

[IgorMinar]

how about writing a custom serializer and replace the default one with $httpProvider.defaults.transformRequest ?

current implementation:

    transformRequest: [function(d) {
      return isObject(d) && !isFile(d) ? toJson(d) : d;
    }],

where toJson contains the problematic stripping json serializer:

function toJson(obj, pretty) {
  return JSON.stringify(obj, toJsonReplacer, pretty ? '  ' : null);
}

[IgorMinar]

I'm not keen on not dropping the $* properties during serialization, but I wonder if allowing developers to whitelist properties that should not be stripped would be a sufficient solution to this issue.

[jtymes]

@IgorMinar 👍 I think it is a small number of users that this impacts and allows for flexibility unlike service APIs such as the one mentioned above that tend to be near impossible to change.

[tompro]

👍 I think mongodb and angular will be quite a common stack. With static typed languages on the serverside (where json serialization is handled by 3rd party libs) this is especially problematic, as one has to rebuild all serialization.

[MarkTroutfetter]

+1 Would really like a solution to this!! Thanks!

[jspeaks]

This is an issue when working with MongoDB based services that are dependent on $ prefixed object properties. The framework needs to provide an escape mechanism for this.

[lukemadera]

I had the same problem (also using MongoDB on the backend) but it seems just manually stringifying the data/params prior to calling the $http service works, i.e.

opts.data =JSON.stringify(opts.data);
opts.params =JSON.stringify(opts.params);
$http(opts).success(...).error(...);

[dcolens]

Could this be documented at: http://docs.angularjs.org/api/angular.toJson, right now there's no mention that angular.toJson strips properties starting with a '$'.

[jamescookie]

I would like to see the whitelist approach taken, this would seem the simplest solution.
Then avoiding $oid removal would be trivial.
In the meantime, we had to override the behaviour like this:

angular.module('myApp', ['myDirectives']).
    run(['$document', '$http', function ($document, $http) {
        var toJsonReplacer = function(key, value) {
            var val = value;

            if (/^\$+/.test(key) && key !== '$oid') {
                val = undefined;
            } else if (value && value.document && value.location && value.alert && value.setInterval) {
                val = '$WINDOW';
            } else if (value && $document === value) {
                val = '$DOCUMENT';
            } else if (value && value.$evalAsync && value.$watch) {
                val = '$SCOPE';
            }
            return val;
        };

        angular.toJson = function(obj, pretty) {
            return JSON.stringify(obj, toJsonReplacer, pretty ? '  ' : null);
        };

        $http.defaults.transformRequest = function(d) {
            return angular.isObject(d) && !(angular.toString.apply(d) === '[object File]') ? angular.toJson(d) : d;
        };
    }]);