{"id":796,"date":"2014-03-09T00:12:52","date_gmt":"2014-03-09T00:12:52","guid":{"rendered":"http:\/\/tech.avant.net\/q\/?p=796"},"modified":"2019-06-01T02:02:09","modified_gmt":"2019-06-01T02:02:09","slug":"node-js-redirect-with-query-string","status":"publish","type":"post","link":"https:\/\/tech.avant.net\/q\/node-js-redirect-with-query-string\/","title":{"rendered":"node.js redirect with query string"},"content":{"rendered":"

Previously, I discussed javascript appending to query string<\/a>, where we serialized an associative array to a query string. I would now like to leverage this technique within node.js<\/a> as a redirect service.<\/p>\n

Specifically, I am using express<\/a> to make a web app in node.js and the app includes a redirect service, e.g.,<\/p>\n

var app = express();\nvar redirectVars = {'foo':'spam and eggs', 'tracker':42 };\n\n\/\/ redirect and append redirectVars\napp.get('\/redirect', function(request, result, next) {\n  if(request.query.url) {\n    var urle = request.query.url;\n    var url = decodeURIComponent(urle);\n    var firstSeperator = (url.indexOf('?')==-1 ? '?' : '&');\n\n    var queryStringParts = new Array();\n    for(var key in redirectVars) {\n      queryStringParts.push(key + '=' + encodeURIComponent(redirectVars[key]));\n    }\n    var queryString = queryStringParts.join('&');\n\n    result.redirect(url + firstSeperator + queryString);\n  }\n  result.send(\"400\", \"Bad request\");\n});<\/pre>\n
Usage of this service is as simple as,<\/p>\n
\/redirect?url=new-location\n<\/pre>\n
Any external app could use this service, which will append server controlled query string variables to the redirected URL. This is useful for a redirect service that needs to dynamically construct query string variables, such as cross-domain authentication and authorization.<\/p>\n
Importantly, in order to preserve an existing query string in the new-location, simply encode the entire URL string before sending it into the service, e.g.,<\/p>\n
var new_location = encodeURIComponent(\"http:\/\/foo.com\/?q=test\");\nwindow.location = \"http:\/\/www.yourapp.com\/redirect?url=\" + new_location;\n<\/pre>\n
Using the above node.js example, this would have the effect of redirecting the user to<\/p>\n
http:\/\/foo.com\/?q=test&foo=spam%20and%20eggs&tracker=42<\/pre>\n
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