Redirect preserve query string about amazon-cloudfront-functions HOT 11 OPEN

function objectToQueryString(obj) {
  var str = [];
  for (var param in obj)
      if (obj[param].multiValue)
          str.push(encodeURIComponent(param) + "=" + encodeURIComponent(obj[param].multiValue.map((item) => item.value).join(',')))
      else if (obj[param].value == '') 
          str.push(encodeURIComponent(param));
      else 
          str.push(encodeURIComponent(param) + "=" + encodeURIComponent(obj[param].value));   
      
  return str.join("&");
}

function objectToQueryString(obj) {
      var str = [];
    for (var param in obj)
        if (obj[param].multiValue)
            str.push(param + "=" + obj[param].multiValue.map((item) => item.value).join(','));
        else if (obj[param].value == '')
            str.push(param);
        else
            str.push(param + "=" + obj[param].value);

    return str.join("&");
}

function handler(event) {
    // Get the request object from the event
    var request = event.request;

    // Get the URI of the requested resource
    var uri = request.uri;

    // Get the query string parameters
    var queryStringParameters = request.querystring;

    // Remove all trailing slashes from the URI using a regular expression
    var newUri = uri.replace(/\/+$/, "");

    // Check if the URI had trailing slashes
    if (newUri !== uri) {
        // Check if querystring is not empty
        var hasQueryString = Object.keys(queryStringParameters).length > 0;

        // Construct the new URI without the trailing slashes and include the query parameters if querystring is not empty
        var redirectUri = newUri + (hasQueryString ? '?' + getURLSearchParamsString(queryStringParameters) : '');

        // Redirect to the new URI without the trailing slashes
        var response = {
            statusCode: 301,
            statusDescription: "Moved Permanently",
            headers: {
                location: { value: redirectUri },
            },
        };

        return response;
    }

    // If there's no trailing slash, proceed with the request as is
    return request;
}

// Helper function to format query string parameters
function getURLSearchParamsString(querystring) {
    var str = [];

    for (var param in querystring) {
        var query = querystring[param];
        var multiValue = query.multiValue;

        if (multiValue) {
            str.push(multiValue.map((item) => param + '=' + item.value).join('&'));
        } else if (query.value === '') {
            str.push(param);
        } else {
            str.push(param + '=' + query.value);
        }
    }

    return str.join('&');
}

function isEncoded(uri) {
  uri = uri || '';
  return uri !== decodeURIComponent(uri);
}

function fullyDecodeURI(uri){
  while (isEncoded(uri)) {
    uri = decodeURIComponent(uri);
  }

  return uri;
}

function encode(param) {
  return encodeURIComponent(fullyDecodeURI(param));
}

function objectToQueryString(obj) {
  var str = [];

  for (var param in obj) {
      if (obj[param].multiValue) {
          str.push(encode(param) + "=" + obj[param].multiValue.map((item) => encode(item.value)).join(','));
      } else if (obj[param].value == '') {
          str.push(encode(param));
      } else {
          str.push(encode(param) + "=" + encode(obj[param].value));
      }
  }
      
  return str.join("&");
}

function handler(event) {
  var request = event.request;
  request.headers["x-forwarded-host"] = request.headers.host;
  request.querystring = objectToQueryString(request.querystring);
  return request;
}