Как это уже было сказано, это зависит от платформы.
В целом, я предпочитаю использовать только сам интерпретатор Python, который упаковывается для моей ОС, и установите все остальное в виртуальная среда , но это - совершенно другая история... Если Вы имеете установленный setuptools, установка большинства пакетов Python так же проста как:
easy_install pycurl
If the files are on the same domain, then you can use AJAX to test for their existence as Alex Sexton said; however, you should not use the GET
method, just HEAD
and then check the HTTP status for the expect value (200, or just less than 400).
Here's a simple method provided from a related question:
function urlExists(url, callback) {
var xhr = new XMLHttpRequest();
xhr.onreadystatechange = function() {
if (xhr.readyState === 4) {
callback(xhr.status < 400);
}
};
xhr.open('HEAD', url);
xhr.send();
}
urlExists(someUrl, function(exists) {
console.log('"%s" exists?', someUrl, exists);
});
If the files are not on an external website, you could try making an ajax request for each file. If it comes back as a failure, then you know it doesn't exist, otherwise, if it completes and/or takes longer than a given threshold to return, you can guess that it exists. It's not always perfect, but generally 'filenotfound' requests are quick.
var threshold = 500,
successFunc = function(){ console.log('It exists!'); };
var myXHR = $.ajax({
url: $('#checkme').attr('href'),
type: 'text',
method: 'get',
error: function() {
console.log('file does not exist');
},
success: successFunc
});
setTimeout(function(){
myXHR.abort();
successFunc();
}, threshold);
You can $.ajax
to it. If file does not exist you will get 404 error and then you can do whatever you need (UI-wise) in the error callback. It's up to you how to trigger the request (timer?) Of course if you also have ability to do some server-side coding you can do a single AJAX request - scan the directory and then return results as say JSON.