I have an application mainly written in PHP. The translations are done using gettext().
There is a small JavaScript part which also contains strings to be translated. I wrote this simple but working method using XMLHttpRequest:
function gettext(string_to_translate) {
var filename = get_php_script_folder() + 'gettext.php?string_to_translate=' + string_to_translate;
var xmlhttp = new XMLHttpRequest();
xmlhttp.open("GET", filename, false);
xmlhttp.send();
if (xmlhttp.status === 200) {
var translated_string = xmlhttp.responseText;
return translated_string;
} else {
console.log("Error while translating " + string_to_translate + " Status " + xmlhttp.status);
return string_to_translate; //Just give the original string.
}
}
The php file is also quite simple:
require_once '../../default.php'; //configures gettext, session management, etc.
//TODO: support for ngettext might be added.
$string_to_translate = filter_input(INPUT_GET, 'string_to_translate', FILTER_SANITIZE_STRING);
$translated_string = gettext($string_to_translate);
echo $translated_string;
In the JavaScript I just call:
var input_box_form_default_reason = gettext("Vacation");
document.getElementById('input_box_form_reason').value = input_box_form_default_reason;
If I call this function synchronously [xmlhttp.open("GET", filename, false);] Firefox/Chrome warns me that:
[Deprecation] Synchronous XMLHttpRequest on the main thread is deprecated because of its detrimental effects to the end user's experience. For more help, check https://xhr.spec.whatwg.org/.
So while this method works, it may cease to do so at any time.
But if I run the code async [xmlhttp.open("GET", filename, true);], then the next line will be executed before the result is there. The value will be undefined.
Is it feasable to make async XMLHttpRequest work in this context? Should I stick to synchronously fetching the values until some clever API is written? Should I write my JS files with PHP? (I hope not.)
PS:
I do not use any framework like jQuery. That is a "religious" thing. I want to fully understand and maintain the whole codebase myself.
I read the following questions, which did not answer mine:
Yes, you need a callback!
function gettext(string_to_translate, obj, callback)
... //your original xmlhttprequest
xmlhttp.callback = callback;, add a callback to the xmlhttp
//set the readystate event that listens to changes in the ajax call
xmlhttp.onreadystatechange = function()
{
//target found and request complete
if (this.status === 200 && this.readyState == 4) {
//send result to the callback function
this.callback(obj, this.responseText);
} else {
console.log("Error while translating " + string_to_translate + " Status " + xmlhttp.status);
this.callback(obj, string_to_translate);
}
}
//callback function specific for this case.
function setValue(obj, value)
{
obj.value = value;
}
To call this:
gettext("Vacation", document.getElementById('input_box_form_reason'), setValue);
An extended ajax function with callback
function ajax(url, method, json, callBack)
{
//it supports get and post
//returns parsed JSON, when json is set to true. | json accessible via this.JSON in the callBack
//a callback can be attached where the this refers to the xmlHTTP
//supply an url like you would in a get request: http://www.example.com/page.php?query=1
//start the request with xmlDoc.fire.
var xmlDoc = new XMLHttpRequest
xmlDoc.JSON = json ? true : false;
xmlDoc.error = true;
xmlDoc.errorMessage = "";
xmlDoc.errorObj = {"error" : xmlDoc.error, "object" : "XMLHttpRequest", "message" : xmlDoc.errorMessage, "url" : url, "sync" : true, "method" : (method ? "POST" : "GET")};
xmlDoc.url = url
xmlDoc.method = method ? "post" : "get";
xmlDoc.preserveWhiteSpace = true;
if (method == "post")
{
xmlDoc.pUrl = url;
xmlDoc.pArg = "";
if (url.match(/\?/)) //we need to filter out the arguments since the are send seperately.
{
var splitted = url.split(/\?/);
xmlDoc.pUrl = splitted[0];
xmlDoc.pArg = "";
for (var i = 1; i < splitted.length; i++)
{
xmlDoc.pArg += splitted[i]; //prevent additional questionmarks from being splitted.
}
}
xmlDoc.open.apply(xmlDoc, ["post", xmlDoc.pUrl , true]); //set up the connection
xmlDoc.setRequestHeader("Content-type", "application/x-www-form-urlencoded ; charset=UTF-8");
}
else
{
//get request, no special action need, just pass the url
this.xmlDoc.open("get", url, true); //true for async
}
xmlDoc.onreadystatechange = readyStateXML.bind(xmlDoc, callBack);
xmlDoc.setRequestHeader("Pragma", "no-cache");
xmlDoc.setRequestHeader("Cache-Control", "no-cache, must-revalidate");
xmlDoc.fire = fireXmlRequest; //set up fire function.
return xmlDoc;
}
function fireXmlRequest()
{
if (this.method == "post")
{
this.send(this.pArg); //post
}
else
{
this.send(null); //get
}
}
function readyStateXML(callBack)
{
if (this.readyState == 4)
{
//request completed, now check the returned data
//We always assume that a request fails.
if (this.errorMessage == "XML Not loaded." || this.errorMessage == "")
{
this.error = false; //set error to false, request succeeded.
this.errorObj.error = false;
if (!this.responseXML && !this.JSON)
{
this.error = true;
this.errorMessage = "invalid XML.";
this.errorObj.error = this.error;
this.errorObj.message = this.errorMessage;
}
if (this.error == false)
{
this.xmlData = this.responseXML;
if (this.JSON)
{
try
{
this.JSON = JSON.parse(this.responseText);
}
catch(err)
{
//JSON couldn't be parsed
this.error = true;
this.errorMessage = err.message + "<br />" + this.responseText;
this.errorObj.error = this.error;
this.errorObj.message = this.errorMessage;
}
}
}
//404 or 400, not found error
if (this.status == "400" || this.status == "404" || this.status == 400 || this.status == 404)
{
this.error = true;
this.errorMessage = "404: The requested page isn't found.";
this.errorObj.error = this.error;
this.errorObj.message = this.errorMessage;
}
else if(this.status == "500")
{
this.error = true;
this.errorMessage = "500: Internal server error.";
this.errorObj.error = this.error;
this.errorObj.message = this.errorMessage;
}
if (typeof(callBack) != "undefined")
{
callBack.call(this); //pass the xmlDoc object to the callBack
}
}
else
{
alert("Error \n" + this.errorMessage);
if (typeof(callBack) != "undefined")
{
callBack.call(this);
}
}
}
else
{
this.error = true;
this.errorMessage = "XML Not loaded.";
this.errorObj.error = this.error;
this.errorObj.message = this.errorMessage;
}
}
//to use
ajx = ajax("index.php?query=1", "post", true, false, function(){/*callback*/});
console.log(ajx);
ajx.fire();