How to escape a JSON string to have it in a URL?

Question

encodeURIComponent(JSON.stringify(object_to_be_serialised))

You could use the encodeURIComponent to safely URL encode parts of a query string:

var array = JSON.stringify([ 'foo', 'bar' ]);
var url = 'http://example.com/?data=' + encodeURIComponent(array);

or if you are sending this as an AJAX request:

var array = JSON.stringify([ 'foo', 'bar' ]);
$.ajax({
    url: 'http://example.com/',
    type: 'GET',
    data: { data: array },
    success: function(result) {
        // process the results
    }
});

I was looking to do the same thing. problem for me was my url was getting way too long. I found a solution today using Bruno Jouhier's jsUrl.js library.

I haven't tested it very thoroughly yet. However, here is an example showing character lengths of the string output after encoding the same large object using 3 different methods:

• 2651 characters using jQuery.param
• 1691 characters using JSON.stringify + encodeURIComponent
• 821 characters using JSURL.stringify

clearly JSURL has the most optimized format for urlEncoding a js object.

the thread at https://groups.google.com/forum/?fromgroups=#!topic/nodejs/ivdZuGCF86Q shows benchmarks for encoding and parsing.

Note: After testing, it looks like jsurl.js library uses ECMAScript 5 functions such as Object.keys, Array.map, and Array.filter. Therefore, it will only work on modern browsers (no ie 8 and under). However, are polyfills for these functions that would make it compatible with more browsers.

• for array: https://stackoverflow.com/a/2790686/467286
• for object.keys: https://stackoverflow.com/a/3937321/467286

Using encodeURIComponent():

var url = 'index.php?data='+encodeURIComponent(JSON.stringify({"json":[{"j":"son"}]})),

I'll offer an oddball alternative. Sometimes it's easier to use different encoding, especially if you're dealing with a variety of systems that don't all handle the details of URL encoding the same way. This isn't the most mainstream approach but can come in handy in certain situations.

Rather than URL-encoding the data, you can base64-encode it. The benefit of this is the encoded data is very generic, consisting only of alpha characters and sometimes trailing ='s. Example:

JSON array-of-strings:

["option", "Fred's dog", "Bill & Trudy", "param=3"]

That data, URL-encoded as the data param:

"data=%5B%27option%27%2C+%22Fred%27s+dog%22%2C+%27Bill+%26+Trudy%27%2C+%27param%3D3%27%5D"

Same, base64-encoded:

"data=WyJvcHRpb24iLCAiRnJlZCdzIGRvZyIsICJCaWxsICYgVHJ1ZHkiLCAicGFyYW09MyJd"

The base64 approach can be a bit shorter, but more importantly it's simpler. I often have problems moving URL-encoded data between cURL, web browsers and other clients, usually due to quotes, embedded % signs and so on. Base64 is very neutral because it doesn't use special characters.