how to save a filter in Dojo

Question

I have an EnhancedGrid that users regularly use complex filters on. Is there a way to allow users to save or bookmark a filter so they can easily re-apply it in future? I know I can programmatically set a filter, but I can't predict what filters my users will want.

Thank you!

edit: made some progress myself... using grid.getFilter() to return a JSON representation of the filter, then json.stringify(jsonRepresentation) to convert it into a string. Now I'm considering my options for how to store, load and convert that string. Would loading a string into a json object then applying it as my filter open me up to XSS vulnerabilities? If I want to have filters specified as arguments in the url, can I compress the string to reduce the character count?

Answer 1

Right off the bat, here are the two three approaches I see:

Store the filter in a URL (Okay)

Simply get the window.location and parse out the query string using dojo/io-query::queryToObject():

require(['dojo/io-query'], function (ioQuery) {
    var uri = window.location.href;
    var query = uri.substring(uri.indexOf("?") + 1, uri.length);
    query = ioQuery.queryToObject(query);
});

(Documentation for dojo/io-query)

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Store the filter in a cookie (Better)

The dojo/cookie module makes this very, very easy:

require(['dojo/cookie', 'dojo/json'], function (cookie, json) {
    var filter = { ... };
    cookie("myFilter", json.stringify(filter)); //store the cookie
    // json.parse(cookie("myFilter")); 
    // ^-- returns the cookie as a JS object
});

(Documentation for dojo/cookie)

Obviously, the user must have cookies enabled for this to work, but it's much cleaner than storing a bunch of variables in a URL for them to bookmark.

---

Use HTML5 Local Storage as suggested by Dimitri M: (Even better)

Check to see if the user's agent supports Local Storage, and if so, use that global variable to hold on to the filter:

require(['dojo/json'], function(json) {
    function supportsLocalStorage() {
        return ('localStorage' in window) && window['localStorage'] !== null;
    }

    var filter = { ... };

    if(supportsLocalStorage()) {
        localStorage.setItem("myFilter", json.stringify(filter));
    }

    // json.parse(localStorage.getItem("myFilter")) 
    // ^-- returns the filter as a JS object
});

An advantage in using web storage is that you can store much more data than cookies can.

You could conceivably use cookies as a fallback for browsers that don't support Local Storage, (i.e. when supportsLocalStorage() returns false) at the cost of adding a touch more overhead to your design, so ultimately it's your call, depending on what browsers you want to support.

Browser Compatibility for Web Storage