Need to quote a search string in javascript, then unquote it on the python backend

Question

First, my code.

HTML

<form action= "/" onSubmit= "return validate(this);" method= "post">
    <!--irrelevant from this point-->

Javascript, later in the file

<script language= "JavaScript">

    function validate(form){

        if(form.text_box.value == ""){
            alert("Please enter something");
            return false;
        }

        search_string = form.text_box.value;
        var encoded = encodeURIComponent(search_string).replace(/%20/g,'+');

        form.action = "/search_results/" + encoded;
        return true;
    }
</script>

Lastly, the python/flask backend.

@maverick.route('/search_results/<search>', methods= ['GET', 'POST'])
def generateSearchResults(search = None):
    search_string = urllib.unquote_plus(search)

To explain, I am trying to quote a string before I put it in my url, because that string will contain slashes. However, when I do the search, the page doesn't load and I see this is the url bar.

http://localhost:7666/search_results/%2Fthis%2Fis%2Fmy%2Fsearch

Does anyone see any problems with my setup?

It might not be working because Flask is unquoting the URL internally before mapping the URL to the view and `/`'s are preventing it from being mapped to your view. You can encode the string twice in JS and then decode it back twice on the server end. Alternatively, how about passing the string as URL query parameters like `?q=this/is/my/search`? — vivekagr, Mar 12 '14 at 20:06
tried the query parameters thing. did not work unfortunately — Zack, Mar 12 '14 at 20:15
Also, when I tried to encode twice, I just saw the twice encoded version in the url bar. — Zack, Mar 12 '14 at 20:23
Encoding it twice worked on my end (flask served the page). Can you confirm that `/search/%252Fthis%252Fis%252Fmy%252Fsearch` URL isn't opening? Also, I was wrong about decoding twice on server end. Flask will automatically decode it once and then you'll have to decode it once more. — vivekagr, Mar 12 '14 at 20:42
For the query string to work, you need to remove the `/` from url pattern and then open `/search?q=this/is/my/search`. I'll post this as an answer in an elaborate manner shortly. — vivekagr, Mar 12 '14 at 20:45

vivekagr · Accepted Answer · 2014-03-12T20:59:21.817

/search_results/%2Fthis%2Fis%2Fmy%2Fsearch isn't opening because werkzeug router is decoding it internally before mapping it to a view and it is resulting in /search_results//this/is/my/search which is not compatible with the pattern /search_results/<search> in your endpoint, hence the 404 error.

You can encode the string twice with javascript (which would result in %252Fthis%252Fis%252Fmy%252Fsearch) and /search_results/%252Fthis%252Fis%252Fmy%252Fsearch will be mapped correctly to your view function. Note that flask will automatically decode it once so you'll need to decode the value received in search parameter once again.

The other (and cleaner) way it to pass the input string as URL query parameters like /search?q=this/is/my/search. To achieve this, modify the endpoint pattern like so:

@maverick.route('/search_results', methods= ['GET', 'POST'])
def generateSearchResults():
    search_string = request.args.get('q')

Thanks. I really like your second suggestion, my code is WAY cleaner now. The urls look sort of bad because I think flask automatically escapes the '/' character, but fortunately I won't need to manually generate urls too much. — Zack, Mar 13 '14 at 15:19

Need to quote a search string in javascript, then unquote it on the python backend

1 Answers1